JP2002171441A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device that picks up an object in a short time without increasing the cost even when the light quantity of the object is subject to change. SOLUTION: A controller 14 sets a plurality of exposures when outputting one image externally to an image pickup section 11. The image pickup section 11 picks up an object by each setting of the exposure to generate image data. An image processing section 12 compresses the image data to supply the compressed image data to a size comparator 13. The size comparator 13 outputs the image data having the largest data size among the image data sequentially received from the image processing section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device,
In particular, the present invention relates to an imaging device suitable for imaging a subject whose light amount changes.

[0002]

2. Description of the Related Art Conventionally, an image pickup apparatus performs image processing for setting an exposure amount and image processing for compressing an image in separate systems. For example, as shown in FIG. 3, a conventional imaging apparatus includes an imaging unit 31 that captures an image of a subject and outputs image data, and a selector 32 that selects exposure or compression image data captured by the imaging unit 31. A first image processing unit 33 for compressing image data for compression, and an imaging unit 3
A second image processing unit 34 for performing image processing for setting the first exposure amount.

The selector 32 distinguishes image data from the imaging unit 31 for compression and exposure, supplies image data for compression to the first image processing unit 33, and outputs image data for exposure to the second image processing unit 33. Is supplied to the image processing unit 34.

[0004] The second image processing section 34 performs an evaluation operation to determine whether or not the exposure amount of the image data supplied from the selector 32 is correct. When the second image processing unit 34 determines that the exposure amount of the image data is not correct, the second image processing unit 34
Reset the exposure of. The imaging unit 31 captures an image of the subject again based on the reset exposure amount, and outputs image data. The selector 32 supplies the image data to the first image processing unit 33 when the exposure amount of the image data becomes an optimal value as a result of repeating such an operation. And the first
Image compression unit 33 compresses the image data with the appropriate exposure amount by, for example, the JPEG method and outputs the image data to the outside.

[0005]

When the light amount of the subject changes, the imaging apparatus needs to set the exposure amount according to the change in the light amount. However, since the image processing time of the second image processing unit 34 for adjusting the exposure amount is different from the image processing time of the first image processing unit 33 for compressing the image, the light amount of the subject is If it changes, there is a problem that the imaging time becomes longer.

On the other hand, it is conceivable to increase the processing speed of the second image processing section 34 in order to set the exposure amount and the processing for image compression almost simultaneously. However, when the speed of the second image processing unit 34 is increased, there arises a problem that a circuit scale becomes large and power consumption becomes large.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problem, and an image pickup apparatus for imaging a subject in a short time without increasing the cost even when the amount of light of the subject changes. The purpose is to provide.

[0008]

According to the first aspect of the present invention,
An exposure amount setting unit configured to set a plurality of exposure amounts when one image is output to the outside; and each time an exposure amount is set by the exposure amount setting unit, an image of a subject is taken based on the set exposure amount. Imaging means for generating image data by means of an image, image compression means for compressing image data generated by the imaging means, and image data having a maximum data amount among image data having different exposure amounts compressed by the image compression means. And an output unit for outputting

[0009] The exposure amount setting means sets a plurality of exposure amounts when outputting one image to the outside when an image of a subject is instructed. One image is, for example, one still image when capturing a still image, and 1 when capturing a moving image.
Preferably it is a frame. The imaging unit generates image data having different exposure amounts each time the exposure amount is set by the exposure amount setting unit. The image compression means compresses image data having different exposure amounts by a predetermined compression method. Here, as the exposure amount becomes an optimal value, the outline of the object in the image data tends to be clear, and the data amount of the compressed image data tends to increase. Therefore, the output unit outputs the image data having the largest data amount from the compressed image data having different exposure amounts as the optimal image data having the exposure amount.

According to a second aspect of the present invention, there is provided an exposure amount setting means for setting a plurality of exposure amounts for outputting one image to the outside, and each time an exposure amount is set by the exposure amount setting means. Imaging means for imaging a subject based on a set exposure amount to generate image data; image compression means for compressing image data generated by the imaging means; and images compressed by the image compression means. Exposure amount output means for selecting a maximum data amount of data and outputting an exposure amount of the image data having the maximum data amount, wherein the exposure amount setting means determines the exposure amount from the exposure amount output by the exposure amount output means. The exposure amount shifted by a fixed amount is reset, the imaging unit captures an image of a subject based on the exposure amount reset by the exposure amount setting unit to generate image data, and the image compression unit includes the imaging unit. Or And outputting the image data of the re-set exposure amount to the outside compression.

The image pickup means generates image data having different exposure amounts each time an exposure amount is set by the exposure amount setting means in outputting one image to the outside. It is preferable that one image is, for example, one still image when capturing a still image, and one frame when capturing a moving image. The image compression means compresses image data having different exposure amounts by a predetermined compression method. Exposure output means
The maximum data amount of the image data compressed by the image compression means is selected, and the exposure amount of the image data having the maximum data amount is output. Here, the image data having the maximum data amount among the compressed image data is image data obtained when the exposure amount is set to an optimum value. Therefore, the exposure amount output from the exposure amount output means indicates the optimal exposure amount for the light amount of the subject at the time of imaging.

In general, in the image recognition processing, it is preferable to use image data in which the outline of an object is clear, and such image data is often shifted by a predetermined amount from the optimal exposure amount. Therefore, the exposure amount setting unit can obtain an exposure amount suitable for the image recognition process by resetting the exposure amount shifted by a predetermined amount from the exposure amount output by the exposure amount output unit.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] As shown in FIG.
The imaging apparatus according to the first embodiment of the present invention includes an imaging unit 11 that captures an image of a subject, an image processing unit 12 that compresses image data, and a size that compares the data sizes of image data with different exposure amounts. A comparator 13 and a controller 14 for controlling the exposure setting of the imaging unit 11 are provided.

The imaging unit 11 receives light from a subject to generate image data, and supplies the generated image data to the image processing unit 12. The image processing unit 12 performs JPEG compression processing on the image data from the imaging unit 11 and supplies the compressed image data to the size comparator 13.

The size comparator 13 stores the image data compressed by the image processing unit 12 and its data size.
The size comparator 13 compares the data size each time compressed image data with a different exposure amount is supplied from the image processing unit 12, and stores the larger image data and the data size.

The controller 14 outputs a plurality of exposure amounts prepared in advance to output one image to the outside.
Are sequentially set to indicate the start of imaging.

The imaging apparatus configured as described above captures an image of a subject every time the exposure amount changes, and outputs the optimal image data of the exposure amount among the compressed image data having the largest data size. Perform the operation of

First, the controller 14 instructs the image pickup section 11 to set an exposure amount and to start image pickup. Imaging unit 11
Receives an image projected through a lens (not shown), performs sensitivity adjustment according to a set exposure amount, generates image data, and supplies the image data to the image processing unit 12 when an imaging start is instructed . The image processing unit 12 compresses the image data supplied from the imaging unit 11 by the JPEG method, and supplies the compressed image data to the size comparator 13.

The size comparator 13 stores the first compressed image data and its data size. When new image data is supplied from the image processing unit 12, the size comparator 13 compares the data size of the stored image data with the data size of the new image data, and determines the larger data size. And image data only. The size comparator 13 discards the smaller data size and image data.

Here, as the exposure value becomes an optimum value, the outline of the object of the image data becomes clearer, and the data size of the compressed image data becomes larger. Therefore, the size comparator 13 obtains image data having the optimum exposure amount by storing image data having a large data size.

When the data size comparison process in the size comparator 13 is completed, the controller 14 sets the next different exposure amount in the imaging unit 11 and instructs the start of imaging. Then, when outputting one image to the outside, the above-described processing is repeated for all of the plurality of exposure amounts prepared in advance.

When the comparison of the data sizes of all the image data having different exposure amounts is completed, the size comparator 13 outputs the last stored image data to the outside.

As described above, the imaging apparatus selects the image data having the largest data size from among the compressed image data without performing any special image processing, thereby obtaining an image with the optimum exposure amount. Image data can be obtained. As a result, without increasing the circuit scale,
An optimal exposure amount can be set with low power consumption.

Further, since the image pickup apparatus picks up an image of a subject with a plurality of exposure amounts prepared in advance by the controller 14, it is possible to save time for image processing for exposure, and as a result,
Even when the light amount of the subject changes, the subject can be imaged in a short time.

[Second Embodiment] Next, a second embodiment of the present invention will be described. The imaging device according to the second embodiment performs a process of shifting the exposure by a predetermined amount in order to easily determine the contour of the object.

As shown in FIG. 2, an image pickup apparatus according to the second embodiment includes an image pickup section 21 for picking up an object, an image processing section 22 for compressing image data, and an image processing section 22 for compressing image data. A selector 23 for selecting image data to be output from the inside to the outside, a size comparator 24 for comparing the data sizes of compressed image data with different exposure amounts, and a controller 25 for controlling the exposure setting of the imaging unit 11. Have.

The imaging unit 21 receives image light from a subject, generates image data, and supplies the generated image data to the image processing unit 22. The image processing unit 22 performs JPEG compression processing on the image data from the imaging unit 21, and supplies the compressed image data to the selector 23.

The selector 23 switches the output destination of the image data in accordance with an instruction from the controller 25. For example, the selector 23 outputs the image data from the image processing unit 22 to the outside or supplies the image data to the size comparator 24.

The size comparator 24 stores the data size and the exposure amount of the image data compressed by the image processing unit 22. Then, the size comparator 24 compares the data size each time new image data is supplied from the selector 23, and stores the larger data size and the exposure amount. Further, the size comparator 24 supplies the exposure amount stored last to the controller 25.

The controller 25 controls the amount of exposure of the image pickup unit 21, and sets a predetermined amount of exposure in the image pickup unit 21 in order to output one image to the outside.
Instructs the start of imaging. Further, the controller 25 can set the exposure amount supplied from the size comparator 24 as a basic value, and set the exposure amount arbitrarily shifted from the basic value by a predetermined amount in the imaging unit 11.

The image pickup apparatus configured as described above performs the following operation to set an exposure amount suitable for face recognition and image recognition.

The controller 25 instructs the image pickup section 21 to set an exposure amount and to start image pickup. When the start of imaging is instructed, the imaging unit 21 receives light projected through a lens (not shown), performs sensitivity adjustment according to the set exposure amount, generates image data, and generates an image data. To supply.

The image processing unit 22 converts the image data into JPEG
And compresses the compressed image data into the selector 23.
To supply. The selector 23 is controlled to switch the output destination of the image data by the controller 25, and supplies the image data to the size comparator 24 here.

The size comparator 24 stores the data size and exposure amount of the first compressed image data. In addition,
The exposure amount here may be data indicating the exposure amount indirectly, such as an exposure setting number. When new image data is supplied from the selector 23, the size comparator 24 compares the stored data size with the data size of the new image data, and stores the larger data size and the exposure amount. Then, the smaller data size and exposure amount are discarded.

When the data size comparison process in the size comparator 24 is completed, the controller 25 sets a new exposure amount in the image pickup section 21 and issues an instruction to start the next image pickup. Then, when outputting one image to the outside, the above-described processing is repeated for all of the plurality of exposure amounts prepared in advance.

When the size comparator 24 completes the data size comparison judgment for all the image data having different exposure amounts, it supplies the controller 25 with the exposure amount stored last.

The controller 25 sets the exposure amount supplied from the size comparator 24 as a basic value, and sets an exposure amount shifted from the basic value by a predetermined amount in the imaging unit 21. At the same time, the controller 25
Controls the switching of the image data output destination of the selector 23 to the outside.

The image pickup section 21 picks up an image of a subject based on the exposure amount set to be shifted from the basic value by a predetermined value, and generates image data. The image processing unit 22 compresses the image data from the imaging unit 21 by the JPEG method,
, And outputs the compressed image data to the outside.

As described above, the imaging apparatus uses the exposure value set to the optimum value as the reference value and shifts the exposure value by a predetermined amount from the reference value, thereby facilitating the contour of the object in face recognition or image recognition. It is possible to obtain image data that can be determined as follows.

Further, as in the first embodiment, the image pickup apparatus does not need to perform special image processing for setting the exposure amount, so that the circuit scale is not increased and the power consumption is small. The above-described image data can be obtained.

Although the controller 25 sets the exposure amount by deviating from the basic value by a predetermined amount, the operator may operate an operation unit (not shown) to set the predetermined amount to an arbitrary value. The container 25 may automatically set the predetermined amount.

In the first and second embodiments, the case where the JPEG system is used as the image compression system has been described, but the present invention is not limited to this. For example, another image compression method such as intra-frame compression of the JBIG method or the MPEG method may be used.

[0044]

As described above, according to the present invention, even if the light amount of the subject changes, the image data with the optimum exposure value can be obtained in a short time with small power consumption without increasing the circuit scale. Obtainable.

Further, according to the present invention, even when the light amount of the subject changes, the image data set to the exposure amount suitable for the image recognition processing can be shortened with small power consumption without increasing the circuit scale. You can get in time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an imaging device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an imaging device according to a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a conventional imaging device.

[Explanation of symbols]

 10, 20 imaging device 11, 21, imaging unit 12, 22, image processing unit 13, 24 size comparator 14, 25 controller 23 selector

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/92 H04N 5/91 J // H04N 101: 00 5/92 H

Claims (3)

[Claims] 1. An exposure amount setting unit for setting a plurality of exposure amounts when one image is output to the outside, and each time an exposure amount is set by the exposure amount setting unit, the exposure amount is set based on the set exposure amount. Imaging means for imaging the subject to generate image data, image compression means for compressing the image data generated by the imaging means, and image data having different exposure amounts compressed by the image compression means. An image pickup apparatus comprising: an output unit that outputs image data of a data amount. 2. An exposure amount setting unit for setting a plurality of exposure amounts when one image is output to the outside, and each time the exposure amount is set by the exposure amount setting unit, the exposure amount is set based on the set exposure amount. An image capturing unit that captures an image of a subject to generate image data, an image compressing unit that compresses the image data generated by the image capturing unit, and a maximum data amount of the image data compressed by the image compressing unit. Exposure amount output means for outputting an exposure amount of image data having a maximum data amount, wherein the exposure amount setting means resets an exposure amount shifted by a predetermined amount from the exposure amount output by the exposure amount output means. The imaging unit captures a subject based on the exposure amount reset by the exposure amount setting unit to generate image data, and the image compression unit determines the reset exposure amount from the imaging unit. Imaging device and outputs to compress the image data to the outside. 3. An operation means for operating and inputting the value of the predetermined amount, wherein the exposure amount setting means determines a predetermined amount operated and input by the operation means from the exposure amount output by the exposure amount output means. The imaging apparatus according to claim 2, wherein the shifted exposure amount is reset.