JPH11295589A - Automatic focus control device - Google Patents

Abstract

(57) [Problem] To provide an automatic focus control device capable of performing a high-speed and high-accuracy focusing operation. An automatic focus control point device according to the present invention captures an image at an initial focus lens position and outputs image data,
The image data is subjected to image data restoration using a plurality of restoration filters corresponding to the point image radius, and an AF evaluation value is calculated for each image data group restored for each restoration filter. In an automatic focus control device that performs a so-called one-shot AF that collates each AF evaluation value and determines a focus position, each negative value integrated value of a restored image data group in an AF area is calculated as an AF evaluation value. While the minimum value of each AF evaluation value is focused, if there are a plurality of the minimum values, the one with the largest point image radius among the plurality of minimum values is the focus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an automatic focus control device, and more particularly, to an automatic focus control device applied to an image input device using an image pickup device such as a video camera and a still video camera.

[0002]

2. Description of the Related Art Conventionally, as an in-focus position determining method in an automatic focus control device, there are an AF method using infrared rays or ultrasonic waves, an external light passive method, and a passive AF method such as a hill-climbing servo. In particular, digital still video cameras (hereinafter "DS
VC), a passive AF method that does not require a special distance measuring component is often used. Passive A
In the F system, Japanese Patent Application Laid-Open No. 6-181532 discloses an "in-focus position detecting device for an electronic camera" which detects a focus position in one shot in recent years. Such a focus position detection device uses one-shot AF, that is,
The in-focus position is detected in one shot using a restoration filter.

More specifically, such an in-focus position detecting device obtains and stores a plurality of point spread functions of an optical imaging system or functions obtained by converting the point spread functions of an optical imaging system at a focal position and lens positions before and after the focal position. Characteristic value storage means, image restoration means for restoring image data for one screen or a part thereof for each of the plurality of lens positions by the characteristic values stored in the characteristic value storage means, Focus position estimating means for obtaining an evaluation value of the in-focus position for each lens position from the image data obtained and comparing each evaluation value to estimate the in-focus position. , It is possible to do more accurately.

[0004]

However, in the prior art, a one-shot AF using a restoration filter is used.
However, there are problems in high-speed and high-precision specification of the focal point, such as a pseudo peak, luminance dependence, and a large amount of calculation.

In the conventional one-shot AF, AF
As the evaluation value, the minimum value of the negative integrated value of the restored image data (which does not originally exist) is used. However, such a method can be applied only when there is no pseudo peak of the negative integrated value, and in fact, a pseudo peak often exists,
There is a problem that the focus indicator is caught at a position other than the original focus.

Further, when the focus index is calculated by the conventional one-shot AF, the focus index follows the brightness of the taken-in AF area, and indicates a position shifted from the original focus. There is.

Further, when performing the one-shot AF process, a normal Fourier transform is performed.
When the FT) process is performed on the AF area, an edge near the side of the AF area may become an edge, and an unnecessary high frequency component may be generated. In the one-shot AF, an integrated value of a high-frequency component may be used to specify a focal point, and there is a problem that if the unnecessary high-frequency component is mixed, the accuracy of the focal point specification is reduced.

In the one-shot AF, when specifying the focal point, the focal point actually has not only one point, but has a certain width in consideration of the depth of field. That is, it is determined within a range in which it is apparently in focus. In particular, the farther the subject is, the wider the focusing allowable range becomes, and it is meaningless to arrange a plurality of corresponding restoration filters in this range. Conversely, the closer the distance is, the narrower the permissible focusing range becomes. Therefore, there is a problem that more corresponding restoration filters must be arranged.

When a plurality of subject candidates are present and the photographer is selecting which subject to target, AF
When there is only one area, the AF area must be sequentially adjusted to the subject candidate, and a one-shot AF focusing operation must be performed each time, which causes a problem that a redundant operation is performed.

In general, as the number of restoration filters increases, the more accurate and versatile the lens can be, the more practically, the larger the number of restoration filters is due to the limitation of the mounted ROM (memory). There is a problem that it is difficult to prepare.

Further, the one-shot AF involves an image restoration process using a restoration filter, so that the amount of calculation becomes enormous. When all of these processes are performed by software, the flexibility of changing or improving the algorithm is excellent, but the processing speed of the CPU is improving year by year, but it is still not enough in terms of speed. There is a problem that it cannot be said.

The present invention has been made in view of the above, and has as its object to provide an automatic focus control device capable of performing a high-speed and high-precision focusing operation.

[0013]

According to a first aspect of the present invention, there is provided an automatic focus control device which picks up an image at an initial focus lens position and outputs image data. The image data is restored using a plurality of restoration filters corresponding to the image radii, the AF evaluation values are calculated for the image data groups restored for each restoration filter, and the calculated AF evaluation values are compared. In the automatic focus control device for determining the in-focus position, a negative value integrated value calculating means for calculating each negative value integrated value of the restored image data group in the AF area; Focusing on the minimum value of the AF evaluation values, and when there are a plurality of the minimum values, a focusing point specifying unit that focuses on the largest value of the point image radius among the plurality of the minimum values. And It is intended.

According to a second aspect of the present invention, there is provided an automatic focus control device which picks up an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Negative value integrated value calculation means for calculating each negative value integrated value of the restored image data group in the AF area; and high frequency component calculation for calculating each high frequency component integrated value of the restored image data group in the AF area Means for calculating each AF evaluation value of the image data group based on a ratio between the negative value integrated value and the high frequency component integrated value corresponding to the restored image data, and calculating the calculated AF evaluation values Focusing on the minimum value among the values, and when there are a plurality of the minimum values, focusing means for focusing on the largest one of the plurality of minimum values with the point image radius. It is a thing.

Further, the automatic focus control device according to claim 3 captures an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Negative value integrated value calculation means for calculating each negative value integrated value of the restored image data group in the AF area; and high frequency component calculation for calculating each high frequency component integrated value of the restored image data group in the AF area Means for calculating each AF evaluation value of the image data group based on a ratio between the negative value integrated value and the high frequency component integrated value corresponding to each image data, and calculating the minimum of the calculated AF evaluation values A temporary focus specifying unit that sets the value to a temporary focus, and from the temporary focus, the ratio between the negative integrated value and the high-frequency component integrated value is again scanned in a direction in which the point image radius increases, When the ratio of the scanned negative value integrated value to the high-frequency component integrated value is equal to or less than a specific threshold value, a point focus radius is added to a temporary focus point as a weight to specify a true focus point. Focus specifying means.

According to a fourth aspect of the present invention, there is provided an automatic focus control device, which picks up an image at an initial focus lens position, outputs image data, and applies a plurality of restoration filters corresponding to a point image radius to the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Negative value integrated value calculation means for calculating each negative value integrated value of the restored image data group in the AF area; and high frequency component calculation for calculating each high frequency component integrated value of the restored image data group in the AF area A means for calculating each AF evaluation value of the image data group based on a ratio between the negative value integrated value and the high frequency component integrated value corresponding to each image data, and among the calculated AF evaluation values, From a temporary focusing point specifying unit that sets the minimum value to a temporary focusing point, from the temporary focusing point,
The ratio between the negative value integrated value and the high frequency component integrated value is again scanned in the direction in which the point image radius increases, and the ratio between the scanned negative value integrated value and the high frequency component integrated value becomes equal to or less than a specific threshold value In this case, the difference between the point image radius and the ratio between the negative value integrated value and the high frequency component integrated value and the specific threshold value is added as a weight to the temporary focus point to specify the true focus point. And true focusing point specifying means.

An automatic focus control device according to a fifth aspect of the present invention captures an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Before performing the focusing operation, the average luminance of the image data in the AF area is calculated, and if the calculated average luminance is not within the specific luminance range, the luminance is adjusted so that the average luminance falls within the specific luminance range. After the adjustment, the focusing operation is performed.

The automatic focus control device according to claim 6 is the automatic focus control device according to claim 5, wherein the specific luminance range is 40% to 40% of the maximum luminance setting reference for A / D conversion. It was determined to be 50%.

An automatic focus control device according to a seventh aspect of the present invention captures an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Before the image restoration, a window function processing means for performing one-dimensional or two-dimensional window function processing on the image data in the AF area is provided.

The automatic focus control device according to claim 8 is the automatic focus control device according to claim 7, wherein the window function processing means includes a window function holding means for storing or generating a plurality of window functions; Window function selecting means for selecting an optimal window function from a plurality of window functions; and window function executing means for performing a window function process on the image data of the AF area based on the selected window function. It is provided.

According to a ninth aspect of the present invention, there is provided an automatic focus control device which picks up an image at an initial focus lens position, outputs image data, and corresponds to the point image radius stored in the storage means. Image data is restored using a plurality of restoration filters, AF evaluation values are calculated for the image data groups restored for each restoration filter, and the calculated AF evaluation values are collated to determine a focus position. In the automatic focus control apparatus described above, the storage means stores a corresponding restoration filter at an interval of a small point image radius at a close distance as compared with a long distance.

An automatic focus control device according to a tenth aspect captures an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
At least two or more AF areas; a focus index value calculating means for calculating a focus index value for each AF area; and a designating means for designating one of the at least two AF areas. The focusing operation is performed for the AF area that has been set.

The automatic focus control device according to the eleventh aspect picks up an image at an initial focus lens position, outputs image data, and applies a plurality of restoration filters corresponding to a point image radius to the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
First, image data is restored using the restoration filter, an AF evaluation value is calculated based on the restored image data, and the calculated AF evaluation value is collated to determine a temporary focus position. Then, scanning is performed by a hill-climbing servo method from a position before the temporary in-focus position to determine a final in-focus position.

According to a twelfth aspect of the present invention, there is provided an automatic focus control apparatus comprising: a Fourier transform unit for converting all or a part of image data captured at an initial focus lens position into a frequency component; Inverse Fourier transform means for inversely transforming all or part of the data into spatial frequency components, and filtering means for restoring the image data converted to the frequency components using a plurality of restoration filters corresponding to the point image radius And high-frequency component integrating means for calculating a high-frequency component integrated value by integrating a specific high-frequency component for all or a part of the image data restored by the restoration filter, and image data inversely transformed into the spatial frequency component Negative value integrating means for calculating a negative value integrated value for all or a part thereof, and the high frequency component integrated value and / or Based on the negative value cumulative value is obtained by including a focusing index calculating means for calculating the focus index value.

According to a thirteenth aspect of the present invention, in the automatic focus control device according to the twelfth aspect, at least one of the means is constituted by hardware.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment in which an automatic focus control device according to the present invention is applied to a digital still camera will be described below in detail with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 shows Embodiment 1 of the present invention.
1 is a configuration diagram of a digital still camera according to the present invention. The digital still camera shown in FIG.
A lens system 1 for forming an image on a CD, a diaphragm 2, a front end unit 3 for outputting image data corresponding to a subject image, and an image preprocessor (Imag) for performing various data processing of image data
e Pre-Processor, hereinafter referred to as “IPP”) Part 4
A CPU I / F 5, a CPU 6 for controlling the operation of each part of the digital still camera, a focus lens controller 7 for controlling the drive of the lens system 1, and an aperture controller 8 for controlling the aperture value (f-number) of the aperture 2. And

The lens system 1 includes an imaging lens and a focus lens. The front end unit 3 converts a subject image formed by the lens system 1 into an electric signal (analog image data) and outputs the converted signal, and performs noise removal and gain adjustment of the electric signal input from the CCD 31. A signal processing unit 32 and a CCD 31 via the signal processing unit 32
A / D converter 33 that converts analog image data input from the digital camera into digital image data and outputs the digital image data to IPP unit 4
And.

The IPP unit 4 separates the digital image data input from the front end unit 3 into R, G, and B components (RGB digital signals).
And an RGB gain adjustment unit 42 that adjusts the gain of each color component of the separated RGB digital signal to output to a luminance value generation unit 43, and converts an input RGB digital signal into a luminance signal to perform FFT (IFFT). A luminance value generating unit 43 to be output to the calculating unit 44; a spatial component of the luminance signal input from the luminance value generating unit 43 is converted into a frequency component to be output to the filtering unit 45; (IFFT) operation unit 44 that performs IFFT conversion, inversely converts the space component into a spatial component, and outputs the result to the negative value integration unit 48.

Further, the IPP unit 4 performs the following processing on the basis of the restoration filter stored in the restoration filter data ROM 46.
A filtering unit 45 for performing a restoration process of the signal converted to the frequency component by the FFT (IFFT) operation unit 44, a restoration filter data ROM 46 storing data of a plurality of restoration filters respectively corresponding to a plurality of point image radii, After filtering the signal converted to frequency component,
A high-frequency component integrator 4 that outputs to the CPU 6 a high-frequency component integrated value obtained by extracting and accumulating the specific high-frequency component.
7 and a negative value integrated value obtained by integrating the negative values of the spatial frequency components input from the FFT (IFFT) calculation unit 44 are represented by C
And a negative value accumulator 48 for outputting to the PU 6. Note that I
Although each function of the PP unit 4 can be realized by software, it is preferable that the PP unit 4 be configured by hardware as shown in the figure, because high-speed processing can be performed.

As described above, the CPU 6 controls the operation of each unit of the digital still camera. Specifically, for example, the CPU 6 calculates the input integrated value of the high-frequency component and / or the integrated value of the negative value. Based on this, the AF evaluation value is calculated (a detailed calculation method of the AF evaluation value will be described later), and AF control and the like are performed.

Next, an outline of the AF (one-shot AF) operation of the digital still camera having the above configuration will be described. First, RGB digital color signals obtained from the CCD 31 through the A / D converter 33 are input to the IPP unit 4 that performs image signal processing. In the IPP section 4, first, after being converted into a luminance signal by the luminance value generation section 43, the FFT (I
The spatial component is converted into a frequency component by the FFT (Calculation Unit) 44. In the filtering unit 45, a restoration filter data ROM
The restoration processing is performed based on the data (1 restoration filter) read from 46. The signal on which the filtering process has been performed is output to the high-frequency component integrator 47 and also to the FFT (IFFT) calculation unit 44.

The high-frequency component integrator 47 extracts a specific high-frequency component of the input signal, and outputs a high-frequency component integrated value obtained by accumulating the specific high-frequency component to the CPU 6 via the CPU I / F 5.

On the other hand, the data subjected to the filtering processing is again input to the FFT (IFFT) calculating section 44, converted into a spatial component again, and output to the negative value integrating section 48. Here, the re-converted data (image data) may include a negative value. In the negative value integrating unit 48, a negative value integrated value obtained by integrating the negative values of the reconverted data is output to the CPU 6 via the CPU I / F5. That is, the high frequency component integrated value and the negative value integrated value corresponding to one restoration filter are input to the CPU 6.

The series of processing of filtering processing → high frequency component integration → IFFT → negative value integration is repeated by the number of restoration filters, and the high frequency component integration values and the negative value integration values by the number of restoration filters are output to the CPU 6. You.

The CPU 6 calculates an AF evaluation value based on the inputted high frequency component integrated value and / or negative value integrated value, and searches for a minimum value, for example. Then, the corresponding focus lens position (target position) is specified using the restoration filter number corresponding to the retrieved minimum value as the focus index. Then, the CPU 6 outputs control data for instructing the focus lens control unit 7 to move the focus lens to the target position. In response, the focus lens control unit 7 drives the focus lens to the target position. With the above operation, the AF operation ends.

(Embodiment 2) Embodiment 2 will be described with reference to FIG. In the second embodiment, a first method for specifying the focal point in the digital still camera having the configuration of the first embodiment will be described.

FIG. 2 is an explanatory diagram for explaining a first method for specifying the focal point. In particular, each restoration filter (N
o. 1 to No. 12 shows an example of the relationship between 12) and the negative integrated value. In the figure, the horizontal axis represents the restoration filter No., and the vertical axis represents the negative value integrated value of the image data restored by each restoration filter. When specifying the in-focus point, first, a negative integrated value of the AF area is calculated for each of the restored image data and used as an AF evaluation value.

Normally, in specifying the focal point, the negative value integrated value becomes the smallest at the focal point, so that point is often set as the focal point. In the second embodiment, a search is made for the minimum value from the calculated negative value integrated value group, and when there is one minimum value, it is set as the focal point. On the other hand, as shown in FIG. In this case, the point having the largest point image radius (filter number) is set as the focal point.

In the second embodiment, the AF evaluation value is calculated from the negative value integrated value in the AF area, the position of the minimum value of the negative value integrated value is set as the focal point, and a plurality of the minimum values exist. In such a case, the focal point is determined using the largest point image radius as the focal point, so that the focal point can be determined with high accuracy even when a pseudo peak exists in the negative integrated value. Becomes

(Embodiment 3) Embodiment 3 will be described with reference to FIG. In the third embodiment, a second method for specifying the focal point in the digital still camera having the configuration of the first embodiment will be described.

FIG. 3 is an explanatory diagram for explaining a second method for specifying the focal point. In particular, each restoration filter (N
o. 1 to No. 12) and an example of the relationship between the ratio of the negative value integrated value to the high frequency component integrated value. In the figure, the horizontal axis represents the restoration filter No., and the vertical axis represents the ratio between the negative value integrated value and the high frequency component integrated value of the image data restored by each restoration filter.

In the figure, when the focal point is specified, first, in each of the restored images, the negative value integrated value of the AF area and the high frequency component of the specific area are calculated. Next, the ratio between the calculated negative value integrated value group and the calculated high frequency component integrated value is calculated, and this is used as the AF evaluation value. The minimum value is searched for, and that is used as the focal point. The reason why the above-mentioned focus is set is that the negative value integrated value is the same as the reason described above, and that the high-frequency component integrated value has the largest high-frequency component at the focal point. When viewed from these ratios, at the focal point, the negative value integrated value becomes the minimum and the high frequency component integrated value becomes the maximum, so that the ratio becomes the minimum.

Here, the ratio between the negative value integrated value and the high frequency component integrated value can be calculated, for example, by the following equation (1).

(Ratio between negative value integrated value and high frequency component integrated value) = | 1000− (negative value integrated value) | / (high frequency component integrated value) (1) where || indicates an absolute value .

As described above, if the method of searching for the minimum value of (the ratio between the negative value integrated value and the high frequency component integrated value) is used, the case where there are a plurality of minimum values is smaller than in the first method. And the accuracy is improved. On the other hand, since the amount of calculation is smaller in the first method, the time required for specifying the focus position is better in the first method.

In the second method, when there are a plurality of minimum values of the ratio between the negative value integrated value and the high frequency component integrated value, the one having the largest point image radius (filter number) is set as the focal point. . Expression (1) is an example of the definition of the ratio between the negative value integrated value and the high frequency component integrated value, and the present invention is not limited to this.

As described above, in the third embodiment, the AF evaluation value is calculated by the ratio between the negative value integrated value and the high frequency component integrated value in the AF area, and the AF evaluation value is calculated based on the negative value integrated value and the high frequency component integrated value. When the minimum value of the ratio is the focal point, and when there are a plurality of the minimum values, the focal point is determined by using the largest point image radius as the focal point. Even if there is a peak, it is possible to calculate the focal point with high accuracy.

(Embodiment 4) Embodiment 4 will be described with reference to FIG. In the fourth embodiment, a third method for specifying the focal point in the digital still camera having the configuration of the first embodiment will be described.

FIG. 4 is an explanatory diagram for explaining a fourth method for specifying the focal point. In particular, each restoration filter (N
o. 1 to No. 12) and an example of the relationship between the ratio of the negative value integrated value to the high frequency component integrated value. In the figure, the horizontal axis represents the restoration filter No., and the vertical axis represents the ratio between the negative value integrated value and the high frequency component integrated value of the image data restored by each restoration filter.

In the figure, to specify the focal point, first, in each of the restored image data, the negative value integrated value of the AF area and the integrated value of the high frequency component in the specific area are calculated.
Then, the ratio between the calculated integrated value of the negative value and the integrated value of the high frequency component is calculated, and the calculated value is used as the AF evaluation value to search for the minimum value. Middle Fa). Also in the third method, the above equation (1) is used to define the ratio between the negative value integrated value and the high frequency component integrated value.

Next, scanning is performed again from the provisional focal point toward the point image radius (filter number) which is larger. At this time, when the ratio between the negative value integrated value and the high frequency component integrated value is equal to or less than the specific threshold value (Rth) (Fb, Fc, F
In d), the in-focus point is calculated by, for example, the following equation (2) based on the temporary in-focus point and the filter number equal to or smaller than the threshold (Rth).

(Focus) = Fa + (c1 * Fb + c2 * Fc + c3 * Fd) / Num (2) where c1, c2, c3: coefficient c1 = c2 = c3 = 1.0 Fa: temporary focus ( Fb, Fc, Fd: Filter numbers below threshold Rth Num: Number of filter numbers below threshold Rth

The above equation (2) is used to calculate the focal point.
This is obtained by adding the weighted average value of the filter numbers that have become equal to or less than the threshold value Rth to the temporary focus point. The components to be considered are not limited to the above equation (2), and the coefficients are set to c1 = c2 = c3 = 1.0, but are not limited thereto.

As described above, in the fourth embodiment, the AF evaluation value is calculated by the ratio between the negative value integrated value and the high frequency component integrated value in the AF area, and the negative value integrated value and the high frequency component integrated value are calculated. The minimum value of the ratio is assumed to be a temporary focal point, and the ratio between the negative value integrated value and the high frequency component integrated value is re-scanned from the temporary focal point in the direction in which the point image radius increases, and the ratio is equal to or less than the specific threshold In this case, the point of focus at that time is used as a weight to determine the true focal point by focusing on the temporary focal point. Can be calculated.

(Fifth Embodiment) A fifth embodiment will be described with reference to FIG. In the fifth embodiment, a fourth method for specifying the focal point in the digital still camera having the configuration of the first embodiment will be described.

FIG. 5 is an explanatory diagram for explaining a fourth method for specifying the focal point. In particular, each restoration filter (N
o. 1 to No. 12) and an example of the relationship between the ratio of the negative value integrated value to the high frequency component integrated value. In the figure, the horizontal axis represents the restoration filter No., and the vertical axis represents the ratio between the negative value integrated value and the high frequency component integrated value of the image data restored by each restoration filter.

In the figure, to specify the focal point, first, in each of the restored image data, the negative value integrated value of the AF area and the integrated value of the high frequency component in the specific area are calculated.
Next, the ratio between the calculated negative value integrated value and high frequency integrated value is calculated and used as an AF evaluation value, and the minimum value is searched for and set as a temporary focal point (Fa in the figure). In the fifth embodiment, the above equation (1) is used to define the ratio of the ratio between the negative value integrated value and the high frequency integrated value.

Next, scanning is performed again from the temporary focal point to the point image having a larger radius (filter number). At this time, the ratio between the negative integrated value and the high frequency integrated value and the specific threshold value (R
th) and filter Nos (Fb, Fc, F in the figure) whose ratio between the negative value integrated value and the high frequency integrated value is equal to or less than the specific threshold value
The focal point is calculated in consideration of d). More specifically, when calculating the focal point, the difference between the filter number that is equal to or less than the threshold value Rth and the ratio value and the threshold value for each filter number, that is, the depth component (Db, Dc, D in the figure)
d) is set as a factor, and the focal point is calculated by, for example, the following equation (3).

(Focus) = Fa + (c1 * Fb * Db + c2 * Fc * Dc + c3 * Fd * Dd) / Num (3) where c1, c2, and c3 are coefficients c1 = c2 = c3 = 1.0. Fa: provisional focal point (filter number) Fb, Fc, Fd: filter number equal to or less than threshold value Rth Db: depth factor from threshold value Rth Db = 1−Rb
/ Rth Dc: Depth factor from threshold Rth Dc = 1−Rc
/ Rth Dd: Depth factor from threshold Rth Dd = 1−Rd
/ Rth Num: Number of filter numbers when the number is equal to or smaller than threshold value Rth

Equation (3) is used to calculate the focal point.
The weighted average value of the filter number that has become equal to or smaller than the threshold value Rth and the depth factor from the threshold value Rth is added to the temporary focus point. The components to be considered are not limited to the above equation (3), and the coefficients are expressed as c1 = c2 =
Although c3 = 1.0, the invention is not limited to this.

As described above, in the fifth embodiment, the AF evaluation value is calculated by the ratio between the negative value integrated value and the high frequency component integrated value in the AF area, and the value of the negative value integrated value and the high frequency component integrated value is calculated. The minimum value of the ratio is set as a temporary focus position, and the ratio between the negative value integrated value and the high frequency component integrated value is re-scanned from the temporary focus point in the direction in which the point image radius increases, and the ratio is set to a specific threshold value. If it is less than or equal to the value, the true focal point is specified by adding the weight of the point image radius at that time and the ratio of how much the ratio is below the threshold to the temporary focal point. It is possible to calculate the focal point with high accuracy even if there is a pseudo peak in the negative integrated value.

(Embodiment 6) Embodiment 6 will be described with reference to FIG. In the fifth embodiment, a fifth method for specifying the focal point in the digital still camera having the configuration of the first embodiment will be described. FIG. 6 is a flowchart for explaining a fifth method of specifying the focal point,
The outline of the one-shot AF operation of the sixth embodiment is shown.

In FIG. 6, first, at the initial focus lens position, an image is taken and image data (for example, image capture 8 bits / pixel) is captured (step S10), and AF is performed.
An area (for example, an area of 256 × 256 pixels) is cut out (step S11). Next, in this AF area, an average luminance (Yave) is calculated (step S1).
2) It is determined whether or not the average luminance (Yave) is within a specific luminance range (appropriate luminance range). Specifically, Ylo
w (eg, 100) ≦ Yave ≦ Yhigh (eg, 13
0) is determined (step S13). As a result of this determination, if Ylow ≦ Yave ≦ Yhigh,
The process proceeds to step S14 to start the substantial processing of the one-shot AF.

On the other hand, if Ylow ≦ Yave ≦ Yhigh is not satisfied, the flow shifts to step S15, where the average luminance value (Yave)
Is adjusted so as to fall within a specific luminance range (Ylow ≦ Yave ≦ Yhigh). Specifically, this adjustment is performed arithmetically for all pixels in the AF area. That is, when the target average luminance value is 100 and the average luminance is 95, the difference of 5 is added (decreased) as an offset. In this embodiment, the threshold of the appropriate luminance range is set to Ylow = 100,
The target average luminance to be adjusted when the luminance exceeds the appropriate luminance range is set to 100. However, if the target average luminance is 40% to 50% with respect to the maximum luminance setting reference for A / D conversion, these values are Not limited. The average luminance value is not limited to the method of adjusting the average luminance value by arithmetic operation, and the photographing (image capturing) may be performed again by changing the photographing conditions and the like, and the average luminance value may be calculated. When the adjustment of the average luminance value is completed, the process proceeds to step S14, and the substantial processing of the one-shot AF is started.

Hereinafter, the substantial processing of the one-shot AF will be described. First, in step S14, a luminance signal corresponding to the image data in the AF area is converted to an FFT (IFFF).
T) The spatial component is converted into a frequency component by the calculation unit 44. Then, each restoration filter (for example, FiltN
o. A search for a focal point is performed for (0 to 120) (step S16). Specifically, first, the filtering unit 45 applies the signal converted to the frequency component to
The data (1 restoration filter) read from the restoration filter data ROM 46 is accessed (step S2).
4), a restoration process is performed (step S17). Then, the high frequency component integrator 47 extracts a specific high frequency component of the input signal and accumulates the specific high frequency component to calculate a high frequency component integrated value (step S18). Also, FFT
The (IFFT) calculation unit 44 converts the filtered data into spatial components (step S19). The negative value integrating unit 48 calculates the negative value integrated value by integrating the negative values of the reconverted data (step S20). The calculation of the high-frequency component integrated value and the negative value integrated value is performed for all restoration filters (Filt Nos. 0 to 120) (step S21).

Finally, based on the calculated high-frequency component integrated value group and negative value integrated value group, the in-focus position is calculated (step S22), and the focusing lens is driven to the in-focus position (step S23).

As described above, in the sixth embodiment, prior to performing a series of one-shot AF operations,
Calculate the average luminance in the AF area, and when the average luminance is out of the specific luminance range, adjust the luminance so that the average luminance in the AF area falls in the specific luminance range, and then enter the one-shot AF operation. Since the focal point is specified, the deviation from the original focal point caused by the brightness of the captured AF area can be prevented when calculating the focal point index by one-shot AF,
It is possible to determine the focal point with high accuracy.

(Seventh Embodiment) A seventh embodiment will be described with reference to FIGS. In the seventh embodiment, an example will be described in which, in the digital still camera having the configuration of the first embodiment, a window function process is performed on an AF area prior to performing one-shot AF to reduce the influence near the AF area. .

FIG. 7 shows an example of the relationship between the pixel position in the AF area and the relative intensity. In the figure, the horizontal axis indicates the pixel position in the AF area, and the vertical axis indicates the relative intensity. Although the drawing is shown in one dimension for simplicity, it is actually expanded to two dimensions.

First, photographing (image capture) is performed at the initial focus lens position, and an AF area is cut out. Here, the size is 256 × 256 pixels. In this AF area, window function processing as shown in the following equation (4)
Perform dimensionally.

V [i] = data [i] * {0.54-0.46 * cos (2.0 * 3.14 * i / N)} (4) where V: window function processing Pixel data at the subsequent pixel position i: Pixel position 0 to 255 data: Pixel data at the pixel position i before the window function processing N: Window size N = 256

This window function process is a so-called weighting based on the pixel position, and as shown in FIG. 7, shows that the weight as image information decreases as the edge of the AF area approaches. Then, after the window function processing is completed, the subroutine enters the substantial processing of the one-shot AF.
In this embodiment, a Hamming window is used as a window function, but the present invention is not limited to this.

FIG. 8 shows a configuration example of a window function processing unit for performing the window function processing. The window function processing unit illustrated in FIG. 8 includes a window function processing unit 20 that performs a window function process based on the window function selected by the selector 21, a window function data ROM 22 storing a plurality of types of window functions 1 to M,
A selector 21 for selecting an optimal window function from a plurality of window functions.

Next, the operation of the window function processing unit will be briefly described. First, the image data captured from the CCD is A / D converted and then converted into luminance data. Then, image data (luminance data) of the AF area is extracted and input to the window function processing unit 20. Window function processing unit 20
Calculates the window function data and the image luminance data read from the window function data ROM 22, and outputs the image data subjected to the window function processing. At this time, the window function data ROM 22
Stores a plurality of window functions, and the selector 21 selects which window function process is to be performed. The selector 21 may select a window function based on information from an interchangeable lens or information from a restoration filter, for example. In order to implement the seventh embodiment, the window function processing unit shown in FIG. 8 may be added to the digital still camera having the configuration of the first embodiment.

As described above, in the seventh embodiment, prior to performing a series of one-shot AF, the AF
Since the window function processing is performed on the area, the influence near the AF area can be reduced. In addition, generally, one of the processes when performing the one-shot AF process is described.
When the Fourier transform (FFT) processing is performed on the AF area, the vicinity of the side of the AF area becomes an edge, and unnecessary high-frequency components may be generated. In the one-shot AF, high-frequency component integration is performed to specify a focal point. Although the value may be used, if the unnecessary high-frequency components are mixed, the accuracy of the focus determination is reduced.
Since the window function processing is performed on the area, the influence can be prevented.

Embodiment 8 Embodiment 8 will be described with reference to FIG. In the eighth embodiment, an example of efficient arrangement of restoration filters in the digital still camera having the configuration of the first embodiment will be described.

FIGS. 9A and 9B are diagrams for explaining a restoration filter according to the eighth embodiment. FIG. 9A shows an example of the arrangement of a conventional restoration filter, and FIG. 9B shows the restoration according to the eighth embodiment. The example of arrangement of a filter is shown. FIG. 9 shows the case where the initial focus lens position is set to infinity. However, FIG. 3 shows the structure of the restoration filter in an easily understandable manner, and this filter does not necessarily exist at an actual distance.

In the configuration of the conventional restoration filter shown in FIG. 9A, 120 filters are used, and in the configuration of the restoration filter of the present embodiment shown in FIG. 9B, 60 restoration filters are used. And the restoration filter is 30 [cm] ~
It is assigned to a distance of 300 [cm] ∞.

When the focal point is specified, actually, the focal point is not only one point, but has a certain range of width in consideration of the depth of field and the like. Is determined within the range considered to be In particular, the farther the subject is, the wider the allowable focus range becomes, and it is meaningless to arrange a plurality of corresponding restoration filters in this range. On the other hand, the closer the distance is, the narrower the allowable focus range becomes. Therefore, more corresponding restoration filters must be arranged.

In the eighth embodiment, as shown in FIG. 9B, the restoration filters are arranged so as to be dense on the near side and coarse on the far side. As a result, highly accurate one-shot AF can be realized. In this embodiment, in terms of speed, cost, and mounting, the number of restoration filters is reduced as much as
Although 0 to 60 sheets are allocated to each distance, the present invention is not limited to this, and the number of restoration filters is 12
It is also possible to assign the number of sheets without changing them. Also, the number of restoration filters is not limited to those listed here.

As described above, in the eighth embodiment, the restoration filter used for the one-shot AF is
Since the density of the number of restoration filters corresponding to the closest distance is relatively large with respect to the density of the number of restoration filters corresponding to the long distance, the restoration filters can be efficiently arranged without waste, and one-shot with high accuracy AF can be realized.

(Embodiment 9) Embodiment 9 will be described with reference to FIG. In the tenth embodiment, an example of an operation in which a plurality of AF areas are provided for focusing in the digital still camera having the configuration of the first embodiment will be described.

FIG. 10 is an explanatory diagram for explaining an AF area according to the ninth embodiment. FIG. 10A shows a case where AF areas are set at several places near the center of an image frame. 10B shows an AF area obtained by equally dividing the entire image frame.

FIG. 10A shows a case where the image frame is 1280.
× 1024 pixels, and three AF areas (256 × 256 pixels) are set in parallel near the center of the image frame. For convenience, the left AF area and the central AF area are arranged in order from the left.
Area, right AF area. FIG. 10 (b)
The image frame is 1280 × 1024 pixels, and an AF area is set by equally dividing the image frame into 5 × 4. For convenience, the AF area 11, the AF area 12,. .., AF area 21,
The AF area 22,...

In FIG. 10A, it is assumed that there are a plurality of subject candidates, and the photographer selects which subject is the target. First, in a digital still video camera, a left AF area, a central AF area,
An area corresponding to the right AF area is cut out, and a focus index value is calculated for each area.

The photographer operates an operation button (not shown) to select an AF area including a target subject. In response, the digital still video camera retrieves the focus index value of the selected AF area and controls the focus lens to move to a predetermined position based on the value. Accordingly, when there is only one AF area, a redundant operation in which the AF area is sequentially adjusted to the subject candidate and the one-shot AF operation is repeated each time is avoided, and a high-speed one-shot AF operation is obtained. .

In FIG. 10 (b), FIG.
The same operation as described in (a) is performed. However,
In this case, when calculating the focus index value, all A
It may not be the F area, but may be performed only for some AF areas picked up by the photographer. When the focus index value is calculated for all AF areas, if the subject distance information is stored together with the image information, appropriate image processing means typified by a personal computer and application software can be used as post processing. Thereby, it is also possible to generate an in-focus image from near to far.

In the present invention, the size, shape, and arrangement of the AF areas shown in FIG. 10 are not limited, and each AF area may have an overlapping portion.

As described above, in the ninth embodiment, at least two or more AF areas are provided, the focus index value for each AF area is calculated, and only the AF area designated by the operator is calculated. Since the focusing operation is performed, a high-speed one-shot AF can be realized by eliminating redundant operations.

(Embodiment 10) Embodiment 10 will be described with reference to FIG. 11 and FIG. Embodiment 1
0, an operation example in which the one-shot AF is used for coarse adjustment and the hill-climbing servo method is used for fine adjustment in the digital still camera having the configuration of the first embodiment will be described.

In the tenth embodiment, first, a rough subject position is determined by using one-shot AF for coarse adjustment.
The focus lens is moved to the corresponding position, and then fine adjustment is performed by the hill-climbing servo method to move the focus lens to the final focus position.

FIG. 11 is an explanatory diagram for explaining the conventional one-shot AF and hill-climbing servo method, and FIG. 12 is an explanatory diagram for explaining the one-shot AF and the hill-climbing servo method according to the tenth embodiment. . 11 and FIG.
FIG. 2 shows a diagram for explaining the one-shot AF operation (the diagram shown in the upper part of the figure) and a figure for explaining the hill-climbing servo method (the figure shown in the lower part of the figure) in association with each other.

In FIG. 12, a diagram for explaining the one-shot AF operation shows a relationship among a lens position, a subject position, a restoration filter, and a one-shot AF evaluation value. As shown in the drawing, when the focal position is between ∞ and Near (closest), seven restoration filter Nos. Each corresponding to each distance. 1 to No. 7 (filter group).
Each restoration filter No. 1 to No. 7, the image is restored, and the AF evaluation value is obtained. Here, the focal point is a filter number indicating the minimum value of the AF evaluation value. In the case of the example shown in FIG. At 6, the AF evaluation value is output to indicate that it is the in-focus position. Based on this signal, the focus lens is set to the filter No. Move to the position corresponding to 5. Conventionally, as shown in FIG. Had moved to 6.

Thereafter, the control is switched to the control of the hill-climbing servo method to perform fine adjustment. In the related art, as shown in FIG. 11, in order to detect the direction of the focal point, it is necessary to move at least two points to acquire data and to know whether the AF evaluation value is in the inclination direction (a hollow slope or a rising slope). . On the other hand, in the present embodiment, as shown in FIG. 12, the focus lens is moved to the index value immediately before the in-focus index value of the coarse adjustment, and then the No. 1 lens is moved by the hill-climbing servo method. 5 to No. 5 6 to move to the final focus position. In the hill-climbing servo method, the position at which the AF evaluation value becomes maximum is detected as the focus position. That is, the scanning direction by the hill-climbing servo method is determined to be one direction (in this embodiment, the direction in which the filter number increases). Therefore, a redundant operation for detecting a new focusing direction as in the related art is unnecessary.

Although the seven restoration filters are provided for one-shot AF coarse adjustment, the invention is not limited to this.

As described above, in the tenth embodiment, a tentative focus position is determined by one-shot AF, and scanning is performed by a hill-climbing servo method from a position before the tentative focus position. As a result, the number of restoration filters can be reduced, the memory cost can be reduced, and a high-precision and high-speed one-shot AF can be realized with an inexpensive configuration. It becomes possible.

In the tenth embodiment, the high-frequency component used in the hill-climbing servo method is a one-shot AF
Since the FFT engine (FFT (IFFT) calculation unit 44 and high-frequency component integrator 47, etc.) used in the above can be used,
No new device is required for the hill climbing servo method.

The present invention is not limited to the above-described embodiment, but can be appropriately changed without changing the gist of the present invention.

The automatic focus control device of the present invention can be widely applied to image input devices using an image pickup device such as a video camera and a still video camera.

[0101]

According to the first aspect of the present invention, there is provided an automatic focus control device which picks up an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. Each of the image data groups restored for each restoration filter by restoring the image data
In an automatic focus control device that calculates an F evaluation value and determines the in-focus position by comparing the calculated AF evaluation values,
Negative value integrated value calculating means for calculating each negative value integrated value of the restored image data group in the area;
The F evaluation value is set, and the minimum value of each of the AF evaluation values is focused. If there are a plurality of the minimum values, the focus point is set to the largest of the point image radii of the plurality of minimum values. Since the focus determining means is provided, it is possible to determine the focal point with high accuracy even when a pseudo peak exists in the negative integrated value.

Further, the automatic focus control device according to claim 2 captures an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Negative value integrated value calculating means for calculating each negative value integrated value of the restored image data group in the AF area; high frequency component calculating means for calculating each high frequency component integrated value of the restored image data group in the AF area; Based on the ratio of the negative value integrated value and high frequency component integrated value corresponding to each restored image data,
Each of the AF evaluation values of the image data group is calculated, and the minimum value among the calculated AF evaluation values is used as the focal point. Since it is provided with the focusing point specifying means for focusing on the largest image radius, it is possible to calculate the focusing point with high accuracy even if the negative integrated value has a pseudo peak.

The automatic focus control device according to claim 3 captures an image at the initial focus lens position, outputs image data, and applies a plurality of restoration filters corresponding to the point image radius to the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Negative value integrated value calculation means for calculating each negative value integrated value of the restored image data group in the AF area; and high frequency component calculation means for calculating each high frequency component integrated value of the restored image data group in the AF area; And calculating each AF evaluation value of the image data group based on the ratio between the negative value integrated value and the high frequency component integrated value corresponding to each image data.
A temporary focus specifying means that sets the minimum value among the evaluation values as a temporary focus, and a ratio between the negative value integrated value and the high frequency component integrated value in the direction in which the point image radius increases from the temporary focus. Scan again and add a point image radius when the ratio of the scanned negative value integrated value to the high frequency component integrated value is equal to or less than a specific threshold value to a temporary focus point as a weight to specify a true focus point. And the in-focus point specifying means, it is possible to calculate the in-focus point with high accuracy even if there is a pseudo peak in the negative integrated value.

The automatic focus control device according to claim 4 captures an image at an initial focus lens position, outputs image data, and applies a plurality of restoration filters corresponding to a point image radius to the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Negative value integrated value calculating means for calculating each negative value integrated value of the restored image data group in the AF area; high frequency component calculating means for calculating each high frequency component integrated value of the restored image data group in the AF area; Each AF evaluation value of the image data group is calculated based on the ratio between the negative value integrated value and the high frequency component integrated value corresponding to each image data, and the minimum value among the calculated AF evaluation values is provisionally calculated. The provisional in-focus specifying means to be the focus, and from the provisional in-focus point, the ratio between the negative value integrated value and the high-frequency component integrated value is re-scanned in the direction in which the point image radius increases, and the scanned negative value integrated value and When the ratio with the high-frequency component integrated value is equal to or less than the specific threshold, the difference between the point image radius and the ratio between the negative-value integrated value and the high-frequency component integrated value and the specific threshold is used as a weight for the temporary focus point. True focal point specifying means to additionally specify the true focal point Since it was decided with a, it is possible to calculate the focus even with high accuracy a pseudo peak negative value integrated value.

The automatic focus control device according to claim 5 captures an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Before performing the focusing operation, the average luminance of the image data in the AF area is calculated, and if the calculated average luminance is not within the specific luminance range, the luminance is adjusted so that the average luminance falls within the specific luminance range. Since the focusing operation is performed after the adjustment, the deviation from the original focal point due to the brightness of the captured AF area can be prevented when the focusing index is calculated by the one-shot AF. It is possible to determine the focal point with accuracy.

According to a sixth aspect of the present invention, in the automatic focus control device according to the fifth aspect, the specific luminance range is 40% to 50% of the maximum luminance setting criterion for A / D conversion. %, It is possible to determine the focal point with higher accuracy.

The automatic focus control device according to claim 7 captures an image at an initial focus lens position, outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
Before performing image restoration, a window function processing unit that performs one-dimensional or two-dimensional window function processing on the image data in the AF area is provided, so that the influence near the AF area can be reduced. It is possible to determine the focal point with high accuracy.

The automatic focus control device according to claim 8 is the automatic focus control device according to claim 7, wherein the window function processing means includes: a window function holding means for storing or generating a plurality of window functions; Window function selecting means for selecting an optimum window function from window functions; and A based on the selected window function.
Since window function execution means for performing window function processing on image data in the F area is provided, the window function processing can be performed with a simple configuration.

The automatic focus control device according to the ninth aspect of the present invention picks up an image at an initial focus lens position and outputs image data, and the image data corresponds to the point image radius stored in the storage means. Image data is restored using a plurality of restoration filters, AF evaluation values are calculated for the image data groups restored for each restoration filter, and the calculated AF evaluation values are collated to determine a focus position. In the automatic focus control device, the corresponding restoration filter is stored in the storage means at an interval of a small point image radius at a short distance as compared with a long distance, so that the restoration filter can be efficiently stored without waste. The one-shot AF with high accuracy can be realized.

The automatic focus control device according to the tenth aspect captures an image at an initial focus lens position and outputs image data, and uses a plurality of restoration filters corresponding to a point image radius for the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
At least two or more AF areas, focusing index value calculating means for calculating a focusing index value for each AF area, and specifying means for specifying one of the at least two AF areas. Since the focusing operation is performed with respect to the AF area, redundant operations are eliminated, and a high-speed one-shot A
F can be realized.

The automatic focus control device according to the eleventh aspect picks up an image at an initial focus lens position, outputs image data, and applies a plurality of restoration filters corresponding to a point image radius to the image data. In an automatic focus control device that calculates an AF evaluation value for each image data group restored for each restoration filter by performing restoration of image data, and compares the calculated AF evaluation values to determine a focus position,
First, the image data is restored using the restoration filter.
An AF evaluation value is calculated based on the restored image data, the calculated AF evaluation value is collated to determine a temporary focus position, and then a hill-climbing is performed from a position before the temporary focus position. Since the final focus position is determined by scanning using the servo method, the number of restoration filters can be reduced, so that the memory cost can be reduced. AF becomes possible.

The automatic focus control device according to claim 12 is a Fourier transform means for converting all or a part of the image data captured at the initial focus lens position into a frequency component, and an image converted into a frequency component. Inverse Fourier transform means for inversely transforming all or a part of the data into spatial frequency components, and filtering means for restoring image data converted to frequency components, using a plurality of restoration filters corresponding to the point image radius. A high-frequency component integrating means for calculating a high-frequency component integrated value by integrating a specific high-frequency component for all or a part of the image data restored by the restoration filter, and all or all of the image data inversely transformed into spatial frequency components A negative value integrating means for calculating a negative integrated value for a part thereof, and a high frequency component integrated value and / or a negative integrated value based on the negative integrated value. Come, and the focus index calculation means for calculating the focus index value, since it was decided with a, it is possible to highly accurate, high-speed one-shot AF.

Further, in the automatic focus control device according to the thirteenth aspect, since at least one of the respective means is configured by hardware in the automatic focus control device according to the twelfth aspect, one-shot AF at a higher speed can be performed. Becomes

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a digital still camera to which an automatic focus control device according to a first embodiment is applied.

FIG. 2 is a diagram illustrating a first example of specifying a focal point according to the second embodiment.
FIG. 4 is an explanatory diagram for describing the method.

FIG. 3 is a diagram illustrating a second example of specifying a focal point according to the third embodiment.
FIG. 4 is an explanatory diagram for describing the method.

FIG. 4 is a diagram illustrating a third example of specifying a focal point according to the fourth embodiment.
FIG. 4 is an explanatory diagram for describing the method.

FIG. 5 relates to a fifth embodiment, and is a fourth example for specifying a focal point.
FIG. 4 is an explanatory diagram for describing the method.

FIG. 6 relates to a sixth embodiment, and relates to a fifth embodiment for specifying a focal point.
FIG. 4 is an explanatory diagram for describing the method.

FIG. 7 relates to the seventh embodiment and performs a window function process on the AF area before performing one-shot AF;
FIG. 9 is an explanatory diagram for describing an operation example in which the influence near the F area is reduced.

FIG. 8 is a block diagram showing a configuration of a window function processing unit according to the seventh embodiment.

FIG. 9 is an explanatory diagram illustrating an example of arrangement of a restoration filter according to the eighth embodiment.

FIG. 10 is an explanatory diagram for describing an AF area according to the ninth embodiment.

FIG. 11 is an explanatory diagram illustrating a one-shot AF and a hill-climbing servo method according to the related art.

FIG. 12 is a view illustrating one shot A according to the tenth embodiment.
It is explanatory drawing for demonstrating F and a hill climbing servo method.

[Explanation of symbols]

 Reference Signs List 1 lens system 2 aperture 3 front end section 4 image preprocessor (IPP) section 5 CPU I / F 6 CPU 7 focus lens control section 8 aperture control section 31 CCD 32 signal processing section 33 A / D converter 41 RGB separation section 42 RGB gain Adjustment unit 43 Luminance value generation unit 44 FFT (IFFT) calculation unit 45 Filtering unit 46 Restoration filter ROM 47 High frequency component integrator 48 Negative value integration unit 20 Window function processing unit 21 Selector 22 Window function data ROM

Claims (13)

[Claims] An image is output at an initial focus lens position, and image data is output. The image data is restored using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
An automatic focus control device that determines an in-focus position by comparing an F evaluation value; a negative value integrated value calculating unit that calculates each negative value integrated value of the restored image data group in an AF area; The integrated value is used as each AF evaluation value, and the minimum value of each AF evaluation value is focused. If a plurality of the minimum values exist, the one with the largest point image radius among the plurality of minimum values is combined. An automatic focus control device, comprising: 2. An image pickup device that outputs an image data by capturing an image at an initial focus lens position, and restores the image data using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
An automatic focus control device that determines an in-focus position by comparing an F evaluation value; a negative value integrated value calculating unit that calculates each negative value integrated value of the restored image data group in an AF area; High-frequency component calculating means for calculating each high-frequency component integrated value of the restored image data group, based on a ratio of the negative value integrated value and the high-frequency component integrated value corresponding to each restored image data, Each of the AF evaluation values of the image data group is calculated, and the minimum value among the calculated AF evaluation values is used as the focal point. An automatic focus control device, comprising: a focus determining unit that focuses on the largest image radius. 3. An image pickup device at an initial focus lens position, outputs image data, and restores the image data using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
An automatic focus control device that determines an in-focus position by comparing an F evaluation value; a negative value integrated value calculating unit that calculates each negative value integrated value of the restored image data group in an AF area; High-frequency component calculation means for calculating each high-frequency component integrated value of the restored image data group; and the image data group based on a ratio of the negative value integrated value and the high-frequency component integrated value corresponding to each image data. Each AF
Tentative in-focus specifying means for calculating an evaluation value and setting the minimum value among the calculated AF evaluation values as a tentative focal point; and the negative value from the tentative in-focus point in a direction in which a point image radius increases. The ratio between the integrated value and the high-frequency component integrated value is again scanned, and the point image radius when the ratio of the scanned negative value integrated value and the high-frequency component integrated value is equal to or less than a specific threshold is used as a weight. An automatic focus control device, comprising: a true in-focus specifying means for specifying a true in-focus point in addition to the in-focus point. 4. An image pickup device at an initial focus lens position and outputs image data. The image data is restored using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
An automatic focus control device that determines an in-focus position by comparing an F evaluation value; a negative value integrated value calculating unit that calculates each negative value integrated value of the restored image data group in an AF area; High-frequency component calculation means for calculating each high-frequency component integrated value of the restored image data group; and the image data group based on a ratio of the negative value integrated value and the high-frequency component integrated value corresponding to each image data. Each AF
Tentative in-focus specifying means for calculating each of the evaluation values and setting the minimum value among the calculated AF evaluation values as a tentative in-focus; and the negative in the direction in which the point image radius increases from the tentative in-focus. The ratio between the value integrated value and the high-frequency component integrated value is again scanned, and when the ratio between the scanned negative value integrated value and the high-frequency component integrated value is equal to or less than a specific threshold, the point image radius in that case is reduced. And a true focal point specifying means for adding a difference between the ratio of the negative value integrated value and the high frequency component integrated value and the specific threshold value as a weight to the temporary focal point to specify a true focal point, An automatic focus control device, comprising: 5. An image pickup device which picks up an image at an initial focus lens position, outputs image data, and restores the image data using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
In an automatic focus control device that determines an in-focus position by comparing an F evaluation value, before performing a focusing operation, an average luminance of image data in an AF area is calculated, and the calculated average luminance is within a specific luminance range. If not, an automatic focus control device performs a focus operation after adjusting the luminance so that the average luminance is within a specific luminance range. 6. The automatic focus control device according to claim 5, wherein the specific luminance range is 40% to 50% with respect to a maximum luminance setting criterion for A / D conversion. 7. Image restoration is performed by imaging at an initial focus lens position, outputting image data, and restoring the image data using a plurality of restoration filters corresponding to a point image radius. An AF evaluation value is calculated for each of the image data groups restored for each
An automatic focus control device that determines an in-focus position by comparing an F evaluation value, wherein a window function process that performs one-dimensional or two-dimensional window function processing on image data in an AF area before performing the image restoration. An automatic focus control device comprising: 8. The window function processing unit includes: a window function holding unit that stores or generates a plurality of window functions; a window function selection unit that selects an optimal window function from the plurality of window functions; 8. The automatic focus control device according to claim 7, further comprising: a window function executing unit that performs a window function process on the image data of the AF area based on the window function. 9. An image is picked up at an initial focus lens position and image data is output. The image data is output from the image data by using a plurality of restoration filters corresponding to a point image radius stored in a storage means. An automatic focus control device that calculates an AF evaluation value for each of the image data groups restored for each restoration filter by performing restoration, and compares the calculated AF evaluation values to determine an in-focus position; Wherein a corresponding restoration filter is stored at an interval of a point image radius which is finer at a close distance than at a long distance. 10. An image pickup device at an initial focus lens position and outputs image data. The image data is restored using a plurality of restoration filters corresponding to a point image radius. In an automatic focus control device that calculates an AF evaluation value for each of the image data groups restored for each and determines the in-focus position by comparing the calculated AF evaluation values, at least two or more AF areas, Focusing index value calculating means for calculating a focusing index value for each area, and specifying means for specifying one of the at least two or more AF areas, and performing a focusing operation on the specified AF area. An automatic focus control device characterized by the above-mentioned. 11. Image data is output at an initial focus lens position, and image data is output. The image data is restored using a plurality of restoration filters corresponding to a point image radius. The AF evaluation value is calculated for each of the image data groups restored to
In an automatic focus control device that determines an in-focus position by comparing an F evaluation value, first, image data is restored using the restoration filter, and an AF evaluation value is calculated based on the restored image data. Determining a temporary focus position by comparing the calculated AF evaluation values, and then scanning by a hill-climbing servo method from a position before the temporary focus position to determine a final focus position. An automatic focus control device characterized by the above-mentioned. 12. Fourier transform means for converting all or a part of image data captured at an initial focus lens position into a frequency component, and converting all or a part of the image data converted into a frequency component into a spatial frequency component Inverse Fourier transform means for inversely transforming the image data, filtering means for restoring the image data converted to the frequency component using a plurality of restoration filters corresponding to the point image radius, image data restored by the restoration filter A high-frequency component integrating means for calculating a high-frequency component integrated value by integrating a specific high-frequency component for all or a part of the image data; and a negative-value integrated value for all or a part of the image data inversely converted to the spatial frequency component. Negative value integrating means for calculating a focus index value based on the high frequency component integrated value and / or the negative value integrated value Automatic focus control apparatus characterized by comprising; and the focus index calculation means for calculating. 13. An automatic focus control device according to claim 12, wherein at least one of said means is constituted by hardware.