JP2004191674A - Automatic focusing device and photographing device - Google Patents

Abstract

The present invention provides an automatic focusing device that uses a hill-climbing type and a phase difference type to obtain a high-speed and high-precision focusing result.
An imaging lens for electrically imaging a subject, a signal evaluation unit for evaluating image data obtained from the imaging lens, and an evaluation value evaluated by the signal evaluation unit being an extreme value A hill-climbing focusing means for driving the photographing lens so as to achieve focusing, an AF optical system 110 for re-focusing the subject light as a pair of images, and a phase difference AF for converting the pair of images into an electric signal. A phase difference type focus detection unit having an operation unit 113 for calculating the amount of defocus from the relative positional relationship between the pair of images by the sensor 111, the defocus amount calculated by the operation unit 113 is within a predetermined range. It is configured to determine the operation of the hill-climbing focusing unit based on the result of the defocus amount calculated by the evaluation / focus determination unit 114 that determines whether or not the calculation unit 113 is operating.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an automatic focusing device and a photographing device in a device for electrically photographing a subject, such as an electronic camera and a video camera.
[0002]
[Prior art]
2. Description of the Related Art In recent years, an electronic camera or the like that obtains a good image by focusing with an automatic focusing device when photographing a subject has been developed. There are several types of methods of the automatic focusing device. For example, a hill-climbing method used in a video camera or the like as disclosed in Patent Document 1 and a phase difference method used in a single-lens reflex camera or the like as disclosed in Patent Document 2 are used. Used.
[0003]
The hill climbing type and the phase difference type will be described with reference to FIGS.
[0004]
FIG. 7 is a block diagram of a hill-climbing automatic focusing device, and FIG. 8 is a diagram illustrating a relationship between a focus lens position and a focus evaluation signal. FIG. 9 is a configuration diagram of a phase difference type automatic focusing device, and FIG. 10 is a configuration diagram of a photographing lens and an AF module.
[0005]
The hill-climbing automatic focusing device extracts a high-frequency component through a high-pass filter (HPF) 502 from a video signal from a photoelectric conversion element 501 for capturing an image of a subject as shown in FIG. To obtain a high-frequency signal. At the same time, the signal evaluation unit 503 evaluates whether or not focusing is achieved, and if the result is not in focus, driving is continued further.
[0006]
If the defocus amount is large, the image on the photoelectric conversion element 501 is blurred, and the amplitude of the extracted high-frequency signal is also small. However, as the lens is driven and approaches the focal point, the image on the photoelectric conversion element 501 becomes out of focus. Since they match, the amplitude of the high-frequency signal also increases. As shown in FIG. 7, when the lens driving starts from P1, the signal amplitude increases as approaching the focal point P2. Then, after passing through the focal point P2, the image is blurred again, and the signal amplitude is reduced. When the distance becomes smaller, the lens is driven in the opposite direction, and the lens returns to the point P2 to reach focusing. This is the basic operation of the hill climbing type.
[0007]
Next, a phase difference type automatic focusing apparatus will be described. As shown in FIG. 9, an AF optical module 701 for detecting a phase difference is disposed at a position equivalent to the photoelectric conversion element 704 for imaging, and a photographing is performed on a subject side of an optical path. A lens 702 is arranged, and light passing through the photographing lens 702 is split by a prism 703 into an imaging photoelectric conversion element 704 and an AF optical module 701. This prism divides the subject light for phase difference AF and imaging.
[0008]
The AF optical module 701 will be described in more detail. As shown in FIG. 10, the basic configuration is composed of a field mask 801, a condenser lens 802, an aperture mask 803, a re-imaging lens 804, and a phase difference photoelectric conversion element 805. The light fluxes 806a and 806b that have passed through the specific emission surface are formed on the photoelectric conversion element 805 as a pair of images as shown in FIG.
[0009]
Then, focusing can be performed based on an interval between one of the pair of images displayed on the photoelectric conversion element 805 and the other.
[0010]
That is, the image interval at the time of focusing is determined by the design of the AF optical module. The image interval is widened when the focus is out of focus, and the image interval is narrow when the focus is out of focus. The amount of defocus and the direction of the defocus are calculated from the difference between the image interval at the time of focusing and the image interval at the time of defocus determined by design, and the focusing state can be obtained by driving the photographing lens 702.
[0011]
Thus, an in-focus image can be captured by the hill-climbing focusing device or the phase difference focusing device.
[0012]
[Patent Document 1]
JP-A-7-143381
[Patent Document 2]
JP 2001-42206 A
[0013]
[Problems to be solved by the invention]
However, each hill-climbing and phase-difference focusing device has advantages and disadvantages. The advantage of the hill-climbing method is that the output signal of the image sensor itself is processed and used as an advantage. The effect can be eliminated. However, as a disadvantage, since the imaging is performed while driving the lens in small steps to obtain a defocus signal, the driving speed cannot be increased so much in relation to the imaging timing, and the peak position of the signal is reduced as shown in FIG. Since it is necessary to search, the user must pass the focusing point, and there is a problem that it takes time to focus.
[0014]
Further, in the phase difference method, the number of photoelectric conversion elements of the focusing device is at most several hundred pixels, which is far less than that of the imaging element, so that it does not take much time to read data. In addition, since the amount of defocus can be directly detected, the lens can be driven directly to the focal point, and focusing can be achieved at a higher speed than in a hill-climbing system. However, the disadvantage is that the focus accuracy in the phase difference type that is detected by an element different from the imaging element depends on the focus detection element, and the focus of the imaging result is not always appropriate depending on the element.
[0015]
The present invention has been completed as a result of intensive studies in view of the above description, and an object of the present invention is to provide an automatic focusing device that uses a hill-climbing focusing device and a phase-difference focusing device to obtain a high-speed and high-precision focusing result. It is an object to provide a focusing device.
[0016]
[Means for Solving the Problems]
The automatic focusing apparatus according to the present invention includes an imaging unit for electrically imaging a subject via a photographing lens, an evaluation unit for evaluating image data obtained from the imaging unit, and an evaluation evaluated by the evaluation unit. A first focusing unit for performing focusing based on the value, an optical unit for re-imaging a subject image via the photographing lens as a pair of images, and detecting a light amount distribution related to the pair of images to obtain an electric signal. A second focusing unit that has a conversion unit that converts the signal into a signal, and a calculation unit that detects the amount of defocus of the photographing lens based on the detection result of the conversion unit, and performs focusing based on the amount of defocus. Means for operating the first focusing means or the second focusing means in accordance with the defocus amount calculated by the calculating means.
[0017]
The automatic focusing apparatus according to the present invention includes an imaging unit for electrically imaging a subject via a photographing lens, an evaluation unit for evaluating image data obtained from the imaging unit, and an evaluation evaluated by the evaluation unit. A first focusing unit for performing focusing based on the value, an optical unit for re-imaging a subject image via the photographing lens as a pair of images, and detecting a light amount distribution related to the pair of images to obtain an electric signal. A second focusing unit that has a conversion unit that converts the signal into a signal, and a calculation unit that detects the amount of defocus of the photographing lens based on the detection result of the conversion unit, and performs focusing based on the amount of defocus. Means for switching from the second focusing means to the first focusing means in accordance with the defocus amount calculated by the calculating means, after the second focusing means is operated. .
[0018]
The automatic focusing apparatus according to the present invention includes: a collation degree determining unit that determines a collation degree of one of the pair of images and the other; and a signal amount determination unit that determines a magnitude of an input signal input from the conversion unit. It is characterized by having.
[0019]
The automatic focusing device according to the present invention, before the first focusing unit or the second focusing unit is operated, the first focusing unit corresponding to the evaluation of at least one of the comparison determination unit and the signal amount determination unit. Wherein said focusing means and said second focusing means are operated simultaneously.
[0020]
In the automatic focusing apparatus of the present invention, the collation degree judging means judges that the collation degree of one of the pair of images and the other image is smaller than a predetermined range to be set, or the predetermined amount set by the signal amount judgment means. The first focusing means and the second focusing means are activated based on the determination that the signal amount is smaller than the signal amount.
[0021]
An image capturing apparatus according to the present invention includes an image capturing unit for electrically capturing an image of a subject via a capturing lens, an evaluation unit that evaluates image data obtained from the image capturing unit, and an evaluation value evaluated by the evaluation unit. First focusing means for performing focusing based on the image data, optical means for re-focusing the subject image through the photographing lens as a pair of images, detecting a light amount distribution related to the pair of images, and converting the detected light amount distribution into an electric signal. A conversion unit for converting, and a calculation unit for detecting a defocus amount of the photographing lens based on a detection result of the conversion unit, and a second focusing unit for performing focusing based on the defocus amount; And operating the first focusing means or the second focusing means in accordance with the defocus amount calculated by the arithmetic means.
[0022]
An image capturing apparatus according to the present invention includes an image capturing unit for electrically capturing an image of a subject via a capturing lens, an evaluation unit that evaluates image data obtained from the image capturing unit, and an evaluation value evaluated by the evaluation unit. First focusing means for performing focusing based on the image data, optical means for re-focusing the subject image through the photographing lens as a pair of images, detecting a light amount distribution related to the pair of images, and converting the detected light amount distribution into an electric signal. A conversion unit for converting, and a calculation unit for detecting a defocus amount of the photographing lens based on a detection result of the conversion unit, and a second focusing unit for performing focusing based on the defocus amount; Wherein after the second focusing means is operated, the second focusing means is switched to the first focusing means according to the defocus amount calculated by the calculation means.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
(Automatic focusing device)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
FIG. 1 is a block diagram of an imaging device equipped with an automatic focusing device according to the present invention.
[0025]
First, light from a subject passes through a photographing lens 101 and is split by a prism 102 into an imaging photoelectric conversion element 103 and an AF optical system 110. Note that the light splitting ratio changes according to the specifications of the imaging device such as a camera, but here, the light is split equally at 5: 5. When the splitting ratio is changed, the response of the device to light increases when the light increases, and the response decreases when the light decreases.
[0026]
Here, control on the imaging photoelectric conversion element 103 side, which is one of the light division paths, will be described.
[0027]
A photoelectric conversion element driving unit 104 that sends out a drive signal to control the photoelectric conversion operation and the signal extraction, and a signal from the imaging photoelectric conversion element 103 that is subjected to A / D conversion when the image is actually captured. An image processing / storage unit 105 for processing and storing in a memory, and a high-frequency extraction unit 106 for extracting a high-frequency signal from the imaging photoelectric conversion element 103 are connected to the imaging photoelectric conversion element 103 such as a CCD area sensor or a CMOS area sensor. Connecting.
[0028]
Further, a signal evaluation unit 108 for evaluating whether the output of the high frequency extracted from the high frequency extraction unit 106 is in the increasing direction or the decreasing direction is connected to the high frequency extraction unit 106, and the photoelectric conversion element driving unit 104 and the image processing / storage are connected. A photographing control unit 107 for comprehensively controlling both is connected to the unit 105, and a monitor display 109 for displaying an image of a subject during a photographing operation of the imaging apparatus is connected to the control unit 107.
[0029]
Further, a focus control unit 115 for comprehensively evaluating a focus position is connected to the control unit 107 and the signal evaluation unit 108, and a lens drive control unit 116 for moving the photographing lens 101 is connected to the focus control unit 115. I have.
[0030]
Thus, according to the above configuration, light from a subject enters the imaging photoelectric conversion element 103 via the prism 102, is converted into a signal by the imaging photoelectric conversion element 103, and an image of the subject is displayed on the monitor display 109. At the same time, the high-frequency signal is extracted by the high-frequency signal extraction unit 106, the output is evaluated by the signal evaluation unit 108, the result is transmitted to the focus control unit 115, and hill-climbing focusing can be performed. An image can be recorded by the image processing / recording unit 105 or the like.
[0031]
Next, the AF optical system 110 side, which is the other light splitting path, will be described in detail.
[0032]
The light split by the prism 102 enters the AF optical system 110 and forms an image on the phase difference AF sensor 111.
[0033]
The configuration is the same as the conventional configuration shown in FIG. 9, and the AF optical system 110 is a configuration in which a conventional field mask 801, a condenser lens 802, an aperture mask 803, and a re-imaging lens 804 are combined. The sensor 111 is the photoelectric conversion element 805. Note that whether these members belong to the AF optical system 110 or the phase difference AF sensor 111 can be changed as appropriate.
[0034]
The phase difference AF sensor 111 includes a CCD or CMOS line sensor, an area sensor, or the like, is connected to the sensor control unit 112, and operates with a drive signal transmitted to the sensor control unit 112.
[0035]
The phase difference AF sensor 111 is also connected to a calculation unit 113 for calculating an image interval, in addition to the sensor control unit 112, and the calculation unit 113 is provided with a defocus amount and a light amount distribution of light incident on the sensor control unit 112. A calculation unit 113 for calculating the state and the like is connected, and from the result of the light amount distribution and the like calculated by the calculation unit 113, it is evaluated how much the focus shift amount has an error due to the influence of noise or the like. The evaluation / focus determination unit 114 that also determines whether the result is within the focus range of the defocus amount is connected, and the focus control unit 115 is connected to the evaluation / focus determination unit 114 and the sensor control unit 112. Then, a lens drive control unit 116 is connected to the focus control unit 115, and the lens is driven by the focus control unit 116 based on the determination result of the evaluation / focus determination unit 114. Impatience It can be carried out.
[0036]
Although the evaluation and focus determination unit 114 evaluates the amount of defocus and the amount of defocus, it may be performed independently.
[0037]
Here, the method of obtaining the image interval and the evaluation of the defocus amount will be described.
[0038]
In the phase-difference focus detection device, the same image divided into two by the re-imaging lens is formed on the sensor, and the output data output from the phase-difference AF sensor 111 are represented by Ai, Bi (i = 1 to n). I do. Since the same image is formed, the A data string and the B data string coincide at some point. It is found out by the calculation of Expression 1, and the image interval at the time of matching is found.
[0039]
SXj = ΣAk + 1-Bj + 1 (l = 0 to m, j = 1 to mm) Equation 1
Equation 1 subtracts m data from the k-th data in column A one by one from the first data in column B and adds the results. One SX is obtained at the time when the processing for m pieces is completed. Next, while the column A data remains the same, the start position of the column B data is shifted by one data, subtracted m times in the same manner, and the result is added. This is repeated mm times. When an area corresponding to m data in the A column matches the data in the B column, the SX value at that time is zero in an ideal state, and the value of mm at this time indirectly represents the image interval. Although the SX value is described to be zero when they match, it does not become zero due to error factors such as sensor noise. Therefore, the part having the minimum value is regarded as a coincidence point.
[0040]
The value of mm is only the resolution determined by one pixel pitch of the sensor data, and this is insufficient for focus detection accuracy. Therefore, interpolation calculation is performed using the SX value of mm and the SX value of about mm to improve the accuracy. The interpolation formula is omitted.
[0041]
In the present invention, it is also used to determine whether to operate the hill-climbing type focusing device or to adopt the result of the phase difference type according to the determination result. The determination value serving as the basis for the determination is obtained from the SX value.
[0042]
FIG. 2 is a graph showing a change in the SX value.
[0043]
In this example, the total number of mm is 7, and the minimum is 3 when mm = 3. The judgment values are kmax and sxmin in the figure. In a subject in which the subject has a contrast and a sufficient sensor signal can be obtained, kmax increases and sxmin decreases. If the subject has low contrast or darkens, the sensor signal will not be sufficient, and kmax will be small and sxmin will be large. Although sxmin is small depending on the state of the subject, kmax may be small.
[0044]
Therefore, if the sensor signal and the contrast are sufficiently obtained by the light from the subject from the determination value of kmax or sxmin, the magnitude of the calculation error of the defocus amount becomes small, and conversely, the sensor signal and the contrast are sufficiently obtained. If not, the magnitude of the calculation error of the defocus amount becomes large. Therefore, kmax and sxmin are used to evaluate whether the error of the defocus amount is large.
[0045]
Here, the focus detection operation of the present invention using both the hill-climbing focusing device and the phase difference focusing device will be described with reference to a flowchart. FIG. 3 is a flowchart of the basic operation of the present invention.
[0046]
First, the incident light is accumulated by the phase difference AF sensor 111 (step 301), and sensor data is obtained (step 302). The calculation unit 113 calculates the SX value from the data using the above-described formula 1 (step 303), extracts the defocus amount, sxmin, and kmax from the calculated SX value, and enters the phase difference AF sensor 111 from the sxmin. The collation degree between one light and the other light of the pair of lights is determined (step 304), and it is determined whether a sensor signal is sufficiently obtained from the amount of incident light based on kmax (step 305). In this embodiment, when sxmin is 50 or more or kmax is 150 or less, an impossible flag is set (step 306). The processing at the time of disabling will be described later.
[0047]
If it is not impossible, the process proceeds to step 307, and the focus control unit 115 determines whether or not the subject is in focus. Here, if the amount of defocus is within (open focal depth / 2) of the attached lens, it is determined that the lens is focused. The open focal depth is generally referred to as a value obtained by multiplying an open aperture value of a mounted lens by a minimum circle of confusion. In the case of a 35 mm film, the minimum circle of confusion is said to be about 30 μm, but in the case of a digital camera, it is often referred to as the pixel size of an image sensor.
[0048]
If the focus position comes within this depth of focus, the out-of-focus state will not be felt on the photograph. However, since the degree of blur before and after is different, it is desirable that the detection accuracy of the focus detection device is aimed at the center of the depth as much as possible. Therefore, in this embodiment, the determination is made at a half depth. If it is more severe, it may be 1/3 or 1/4.
[0049]
If the in-focus state can be determined in step 407, the in-focus flag is set (step 308), and the focus detection operation ends.
[0050]
On the other hand, if it is not in focus, the focus control unit 116 determines in step 309 whether to drive the lens by the lens drive control unit 116 or switch to the hill-climbing type based on the phase difference type focus detection result. I do. The criterion is evaluated based on the open focal depth. If the open focal depth is smaller than the defocus amount, the hill-climbing focusing device is activated (step 313).
[0051]
This is because the lens does not need to be driven if the lens is in focus from the beginning, but if the lens is driven, it is necessary to use a hill-climbing focusing device to firmly catch the peak of focus. However, when the driving amount is large, it is preferable to perform AF using a fast phase difference method until near the in-focus state. Therefore, if NO is determined in step 309, lens driving is performed based on the result of the defocus amount of the phase difference method. The control unit 116 drives the lens, returns to the first step, and continues the phase difference type focus detection (steps 310, 311 and 312), and repeats the above steps. And the switching from the phase difference type focusing to the phase difference type and hill-climbing type focusing is performed.
[0052]
Although the open criterion is used as the criterion as described above, the open focal depth may be doubled or tripled in accordance with the detection accuracy of each of the phase difference type and the hill-climbing type to increase the accuracy.
[0053]
Preferably, when focusing, a phase difference method is first performed, and a hill-climbing type focusing operation is performed only near the final focal point, so that the focusing time can be reduced.
[0054]
Next, a process in a case where the phase difference type focus detection result is impossible will be described.
[0055]
If it is impossible, an impossible search drive is performed, in which the focus detection operation is performed while operating the lens. In this case, both the phase difference type and the hill-climbing type are operated to increase the focus detection probability.
[0056]
In other words, by using a hill-climbing focusing device, it is possible to know the lens moving direction up to the focal point, and to quickly determine the moving distance of the lens to the focusing point using a phase-difference focusing device. Focus can be obtained.
[0057]
If the result of the phase difference is obtained during the impossible search, the control is shifted to the flow shown in FIG. 3 or FIG.
[0058]
The hill-climbing focusing device performs the operation described with reference to FIGS. 6 and 7, and thus the description of the operation is omitted here.
[0059]
Note that when the focus control unit 115 determines that the relationship between the defocus amount and the open depth of focus has reached the relationship in step 307 while the hill-climbing focusing device is operating, the phase difference type The focusing device may be activated.
[0060]
Thus, according to the automatic focusing apparatus having the above configuration, the light from the subject is split by the prism 102 and made incident on the phase difference AF sensor 111, and the defocus amount is calculated by the calculation unit 113. By making the focus control unit 115 determine whether or not to perform the focusing in the formula, the focusing speed of the lens can be improved, and the focusing accuracy can be improved. An improved automatic focusing device could be provided.
[0061]
Next, another embodiment of the present invention will be described with reference to the drawings. 4 and 5 show another basic operation flow of the present invention.
[0062]
Steps that perform the same steps as those in FIG. 3 are denoted by the same reference numerals.
[0063]
In the flow of FIG. 4, most of the processing flow is the same as that of FIG. 3, but the focus is determined in step 307, and the phase difference and the hill-climbing selection are determined in step 309. The evaluation of the degree is done again. In this determination, when the degree of the error of the defocus amount is smaller than the predetermined range, the lens is driven to the focal point based on the result of the phase difference without activating the hill-climbing focusing device. By adding this determination, it is possible to focus without spending time unnecessarily and without reducing accuracy. In the embodiment, the determination criterion is a case where both kmax is 500 or more and sxmin is 20 or less. For this value, the best value may be selected according to the capability of each focus detection device.
[0064]
In FIG. 5, another process is added to FIG. 4. After it is determined in step 311 whether the lens is being driven, if the lens is being driven, in step 402, if the number of remaining drive pulses is less than the open focal depth, A hill-climbing focusing device is operated. In FIG. 3, the determination is made only based on the result of the phase difference type. However, the hill-climbing type startup determination can be performed with the remaining drive pulses.
[0065]
That is, the remaining drive pulse determines the remaining movement amount of the lens up to the focal point. If the remaining movement amount is less than the open focal depth, the hill-climbing focusing operation is performed without performing the phase-difference focusing operation. Perform the operation.
[0066]
Therefore, the focusing time can be shortened, and the operator can immediately take a picture of the subject. Step 402 can be added to the configuration shown in FIG.
[0067]
In the above-described flow, when the determination is NO in step 309 and the process returns to the beginning and repeats, if the in-focus point is not specified even after performing a plurality of steps from the beginning to step 309, the process returns to step 313 when the required number of times is reached. Can be set to proceed.
[0068]
If it is determined in step 307 that the object is in focus, the process may proceed to step 312 if the focus shift amount is to be further reduced.
[0069]
Thus, according to the focusing device of the present invention, the evaluation / focus determination unit 114 that determines whether or not to operate the hill-climbing focusing unit according to the defocus amount calculated by the calculation unit 113 is provided. With this arrangement, if the phase-difference focus detection result is in focus, the focusing operation does not have to be performed. Thereby, the accuracy of focusing can be improved, and the focusing speed can be improved.
[0070]
Further, when the phase difference type focus detection result is not possible, the phase difference type and the hill-climbing type can be simultaneously operated at the time of the impossible search drive to increase the detection probability.
[0071]
As described above, by combining the phase difference type and the hill-climbing type according to the situation based on the phase difference type focus detection result, a high-speed and high-accuracy focus detection device can be provided.
[0072]
(Photographing device)
Next, the photographing apparatus of the present invention will be described with reference to FIG.
[0073]
FIGS. 6A and 6B are top views of a camera showing the photographing apparatus of the present invention, in which FIG. 6A shows when the power is turned off, FIG. 6B shows when the power is turned on, and FIG. 6C shows when the lens is extended corresponding to the subject. .
[0074]
On the camera upper surface 401, a release button 406, a main switch 407, a display panel 402, a menu button 404, and a flash mode button 403 are provided. When a menu button 404 is pressed, an exposure correction mode, a self mode, a long time (LT) mode, and a mode of MF / AF setting are sequentially displayed on the display panel 402, and each mode can be selected. When the MF / AF setting is selected with the menu button 404, only the AF characters blink on the display panel 402, and when the JOG dial 405 is rotated, the MF characters blink and the first set distance is displayed. The JOG dial 405 is selected by the menu button 404 and displayed on the display panel (LCD) 2 as described above. The exposure correction mode, the self mode, the long time mode, the MF / AF setting mode, the shooting data editing mode and the shooting mode This is a dial for displaying each value, such as a mode, one by one in order.
[0075]
When the MF / AF setting is set to AF in the MF / AF setting by the menu button 404, the AF mode is selected by the JOG dial 405, and shooting suitable for the environment is performed.
[0076]
Next, the operation of the camera will be described. When the power of the apparatus is turned on by the main switch 407, as shown in FIG. 6, the lens is extended from the apparatus main body, and the display panel 402 sets the number of shots, MF / AF, etc. The status is displayed.
[0077]
At this time, if the shooting mode is set by the JOG dial 405, the subject is displayed on a display panel or the like provided on the back side of a lens of a shooting device (not shown), settings of various devices, exposure settings, and the like are displayed. When pressed, a photograph is taken, and the photographing data is stored in a storage device that is internal to the photographing device or that can be detachably attached to the device main body from outside. When the release button 406 is a two-stage push button, the lens is operated as shown by the arrow as shown in FIG. Of course, at this time, the MF / AF setting is the AF mode.
[0078]
Here, the operation according to the AF mode setting will be described in detail.
[0079]
The AF mode is set in three modes: operation of only the hill-climbing focusing means, operation of only the phase-difference focusing means, and operation of both the hill-climbing focusing means and the phase-difference focusing means depending on the environment or the like. Yes, the device is focused by selecting this.
[0080]
First, as shown in FIG. 1, the hill-climbing focusing means stops the power supply to the device relating to the phase difference focusing means or sets the apparatus to the power saving mode. I do. For example, during the hill-climbing detection operation, the operation of the phase difference AF sensor 111 and the operation of the calculation unit 113 and the like are not performed.
[0081]
Also, in the phase type focusing means, similarly, by stopping power supply to the device relating to the hill-climbing type focusing means and setting a power saving mode, focusing by the above-described method is performed without performing the hill-climbing focusing operation. Do. For example, the operation of the high-frequency signal extraction unit 106 and the like are stopped.
[0082]
When a hill-climbing type and a phase difference type focusing device are used, the focusing operation is performed by performing the above-described operations of FIGS.
[0083]
Thus, in the photographing apparatus of the present invention, the user can quickly photograph a subject to be photographed according to the environment because the focusing unit can be changed according to the environment.
[0084]
In addition, since power consumption differs depending on the focusing mode, it is possible to provide an imaging apparatus capable of suppressing power consumption by selecting the focusing mode and enabling long-time imaging.
[0085]
It should be noted that the present invention is not limited to the above embodiment, and various improvements and changes may be made without departing from the scope of the present invention.
[0086]
For example, in the present embodiment, sxmin and kmax obtained from the result of the correlation operation are defined in the evaluation of the magnitude of the error of the defocus amount, but in addition to these values, the defocus such as the amplitude and the frequency component of the sensor data itself. The determination can also be made by combining values capable of measuring the quantity.
[0087]
The automatic focusing device of the present invention can also be used for a communication terminal such as a mobile phone or a PDA provided with an imaging terminal.
[0088]
Further, the configuration of the imaging apparatus is not limited to the embodiment, and for example, the settings and modes displayed on the panel at the time of recreation, and the settings of each mode performed by various switches can be appropriately changed.
[0089]
【The invention's effect】
As described above, according to the present invention, the determination means for determining whether or not to operate the hill-climbing focusing means in accordance with the defocus amount calculated by the calculation means is provided at a high speed. A high-precision focusing device could be provided.
[0090]
In addition, a high-precision photographing device capable of taking a photograph quickly according to the environment of the photographing device can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram of an imaging device equipped with an automatic focusing device according to the present invention.
FIG. 2 is a graph showing a change in an SX value.
FIG. 3 is a flowchart of a basic operation of the present invention.
FIG. 4 is a flowchart of another basic operation of the present invention.
FIG. 5 is a flowchart of still another basic operation of the present invention.
FIGS. 6A and 6B are top views of a camera showing the photographing apparatus of the present invention, in which FIG. 6A shows when the power is turned off, FIG. 6B shows when the power is turned on, and FIG. 6C shows when the lens is extended corresponding to the subject. is there.
FIG. 7 is a block diagram of a hill-climbing automatic focusing device.
FIG. 8 is a diagram illustrating a relationship between a focus lens position and a focus evaluation signal.
FIG. 9 is a configuration diagram of a phase difference type automatic focusing device.
FIG. 10 is a configuration diagram of a photographing lens and an AF module.
[Explanation of symbols]
101 ... photographic lens
102 ... Prism
103 ... Photoelectric conversion element for imaging
104: photoelectric conversion element driving unit
105 ・ ・ ・ Image processing / recording unit
106 ··· High frequency signal extraction unit
107: Shooting control unit
108 ... Signal evaluation unit
109 ・ ・ ・ Monitor display
110 ・ ・ ・ AF optical system
111 ・ ・ ・ Phase difference AF sensor
112 ・ ・ ・ Sensor control unit
113 ··· Defocus amount calculation unit
114 ・ ・ ・ Evaluation / focus determination unit
115: Focus control unit
116 ... Lens drive control unit

Claims (7)

An imaging unit for electrically imaging a subject via a photographing lens; an evaluation unit for evaluating image data obtained from the imaging unit; and a focusing unit for performing focusing based on the evaluation value evaluated by the evaluation unit. 1 focusing means,
Optical means for re-imaging a subject image via the photographing lens as a pair of images; converting means for detecting a light amount distribution relating to the pair of images and converting the distribution into an electric signal; Computing means for detecting the amount of defocus of the photographing lens, and second focusing means for performing focusing based on the amount of defocus,
An automatic focusing device, wherein the first focusing means or the second focusing means is operated in accordance with the defocus amount calculated by the calculating means. An imaging unit for electrically imaging a subject via a photographing lens; an evaluation unit for evaluating image data obtained from the imaging unit; and a focusing unit for performing focusing based on the evaluation value evaluated by the evaluation unit. 1 focusing means,
Optical means for re-imaging a subject image via the photographing lens as a pair of images; converting means for detecting a light amount distribution relating to the pair of images and converting the distribution into an electric signal; Computing means for detecting the amount of defocus of the photographing lens, and second focusing means for performing focusing based on the amount of defocus,
An automatic focusing device, wherein after the second focusing means is operated, the second focusing means is switched to the first focusing means according to the defocus amount calculated by the computing means. 2. The image processing apparatus according to claim 1, further comprising: a matching level determining unit configured to determine a matching level between one and the other of the pair of images; and a signal amount determining unit configured to determine a magnitude of an input signal input from the converting unit. Or the automatic focusing device according to claim 2. Before at least the operation of the first focusing means or the second focusing means, the first focusing means and the second focusing means correspond to the evaluation of at least one of the collation determination means and the signal amount determination means. 4. The automatic focusing apparatus according to claim 3, wherein said focusing means are operated simultaneously. For the determination that the collation degree of one of the pair of images is smaller than a predetermined range set by the collation degree determination unit, or that the collation degree is smaller than a predetermined signal amount set by the signal amount determination unit. 5. The automatic focusing apparatus according to claim 4, wherein the first focusing means and the second focusing means are operated based on the information. An imaging unit for electrically imaging a subject via a photographing lens; an evaluation unit for evaluating image data obtained from the imaging unit; and a focusing unit for performing focusing based on the evaluation value evaluated by the evaluation unit. 1 focusing means,
Optical means for re-imaging a subject image via the photographing lens as a pair of images; converting means for detecting a light amount distribution relating to the pair of images and converting the distribution into an electric signal; Computing means for detecting the amount of defocus of the photographing lens, and second focusing means for performing focusing based on the amount of defocus,
An imaging apparatus, wherein the first focusing means or the second focusing means is operated in accordance with the defocus amount calculated by the calculating means. An imaging unit for electrically imaging a subject via a photographing lens; an evaluation unit for evaluating image data obtained from the imaging unit; and a focusing unit for performing focusing based on the evaluation value evaluated by the evaluation unit. 1 focusing means,
Optical means for re-imaging a subject image via the photographing lens as a pair of images; converting means for detecting a light amount distribution relating to the pair of images and converting the distribution into an electric signal; Computing means for detecting the amount of defocus of the photographing lens, and second focusing means for performing focusing based on the amount of defocus,
A photographing apparatus characterized in that after the second focusing means is operated, the second focusing means is switched to the first focusing means in accordance with the defocus amount calculated by the calculation means.

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