JP3864409B2 - Imaging apparatus and imaging result processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an imaging apparatus and an imaging result processing method, and can be applied to, for example, an electronic still camera. In the present invention, the brightness level of each area set in the imaging result is divided into a plurality of stages, and the area of the section that occupies the most area is detected on the basis of the distribution of the brightness level by this section. By detecting the region to be processed, the region to be processed can be easily and reliably detected with emphasis, for example, by applying it to exposure control.
[0002]
[Prior art]
Conventionally, in an imaging apparatus such as a video camera or an electronic still camera, a predetermined determination reference value is calculated on the basis of the luminance level of the imaging result, and a diaphragm or the like is controlled so that the determination reference value becomes a predetermined value. Automatic exposure control.
[0003]
In such a calculation method of the determination reference value, conventionally, there is a method of setting the determination reference value by calculating the integral value and average value of the luminance level in units of frames, and in the method using these integration value and average value, The exposure can be controlled by a simple process.
[0004]
On the other hand, the imaging result is divided into a plurality of areas. For example, the higher the weighting coefficient is set in the center area of the screen, the luminance level for one screen is weighted and added, and the determination reference value is determined by this weighted addition value. A calculation method is also adopted. In this method, exposure control can be performed with emphasis on the area corresponding to the setting of the weighting coefficient. For example, when the most weighting coefficient is set in the center area of the screen, the center area of the screen has an appropriate light amount. In addition, it is possible to perform automatic exposure control by effectively avoiding overexposure and underexposure of the peripheral portion by setting the coefficient.
[0005]
Further, when calculating the evaluation reference value by such weighted addition processing, exposure control is performed by switching the weighting coefficient assigned to each region according to the shooting mode, for example, when shooting a landscape or shooting a person. A method for switching the focus of an object has also been proposed. In this method, the intention of photographing by a user can be reflected in exposure control.
[0006]
[Problems to be solved by the invention]
However, in practice, in this type of shooting, various compositions are tried by the user, and when automatic exposure control is performed based on the judgment reference value by weighted addition in this way, setting of the area to be processed with emphasis is set. May not always be appropriate. In particular, an electronic still camera may be photographed by a composition with a vertically long screen in addition to a composition with a horizontally long screen as in a video camera, and there is a feature that an imaging result can be obtained by various compositions.
[0007]
Specifically, for example, when a weighting coefficient having a large value is set in the center portion of the imaging result and weighted addition is performed with emphasis on the center of the screen, the subject may be set at a position shifted from the center of the screen. In this case, it becomes difficult to appropriately control the exposure. Incidentally, in such a case, for example, a shooting target that is a person is set in a vast landscape, and in the imaging result, the amount of light is often insufficient for the person.
[0008]
As one method for solving this problem, for example, in the technique disclosed in Japanese Patent Application Laid-Open No. 5-56331, a luminance level is detected for each region, and the determination of the luminance level in units of this region is focused. A method of detecting a part for setting a weighting coefficient has been proposed. However, in the case of this method, there is a problem that the processing becomes complicated by detecting the luminance level distribution for each region.
[0009]
The present invention has been made in consideration of the above points. For example, in such exposure control, an imaging apparatus and an imaging result processing method capable of easily and reliably detecting an area to be processed with emphasis are proposed. It is something to try.
[0010]
[Means for Solving the Problems]
In order to solve such a problem, the invention of claim 1 is applied to an imaging apparatus, and for a plurality of areas set in the screen of the imaging result, the luminance level of each area is classified by a plurality of stages. Based on the luminance level distribution by the image, the region to be processed is detected with emphasis on the imaging result, and the imaging condition is controlled based on the detection result . A region of the section occupying the area is detected, and a region to be processed with the emphasis is detected .
[0011]
According to a fourth aspect of the present invention, the method is applied to a method of processing an imaging result, and for a plurality of areas set in the imaging result screen, the brightness level of each area is classified by a plurality of stages, Based on the distribution of luminance levels, the imaging result is processed so that processing is performed with emphasis on the area detection step for detecting an area for processing the imaging result with emphasis and the area detected in the area detection step. A processing area to be processed is detected, and a region of a section occupying the largest area is detected on the screen, and a region to be processed with the emphasis is detected .
[0012]
According to the configuration of claim 1, the luminance level of each area is divided into a plurality of stages for a plurality of areas set in the imaging result screen when applied to an imaging apparatus, and distribution based on the detect the area to be treated emphasis from the imaging results, based on the detection result, so as to control the condition of imaging, from sections most occupy large area, most emphasis Ru can be easily and reliably detect the area to be treated at a. According This ensures the configuration of the first aspect, it is possible to execute processing such as an automatic exposure adjustment, for example.
[0013]
According to the configuration of the fourth aspect , it is possible to provide an imaging result processing method capable of detecting an area to be processed with emphasis simply and surely.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
[0015]
(1) Configuration of Embodiment FIG. 1 is a block diagram showing an electronic still camera according to an embodiment of the present invention. In the electronic still camera 1, the lens 2 condenses incident light on an imaging surface of a CCD solid-state imaging device (CCD: Charge Coupled Device) 3. The CCD solid-state image pickup device 3 is a single-plate solid-state image pickup device for color images. The CCD solid-state image pickup device 3 operates in accordance with various drive signals output from a timing generator (TG) 4 to detect an object formed on an image pickup surface by an optical system (not shown). The image is subjected to photoelectric conversion, and an imaging signal as an imaging result is output.
[0016]
The timing generator 4 generates and outputs various drive signals for the CCD solid-state imaging device 3. In this processing, the timing generator 4 varies the timing of the drive signal so as to vary the charge accumulation time of the CCD solid-state imaging device 3 under the control of the microcomputer 5. As a result, the electronic still camera 1 can control exposure by varying the shutter speed by the electronic shutter under the control of the microcomputer 5.
[0017]
A CDS (Correlated Double Sampling) 6 performs correlated double sampling on the imaging signal output from the CCD solid-state imaging device 3 and outputs a color signal corresponding to a color filter arranged on the CCD solid-state imaging device 3.
[0018]
The AGC circuit 7 receives the color signal output from the CDS 6, amplifies the color signal with a predetermined gain, and outputs it. The gain of the AGC circuit 7 is varied by the control of the microcomputer 5, whereby the exposure control process by the AGC is executed together with the microcomputer 5 and the DSP (Digital Signal processor) 8.
[0019]
An analog-to-digital converter (A / D, analog to digital converter) 9 performs an analog-to-digital conversion process on the output signal of the AGC circuit 7 and outputs image data as a result of the process.
[0020]
The DSP 8 outputs this image data to a display means (not shown) after knee processing, gamma correction processing, etc., and further compresses the data under the control of the microcomputer 5 and outputs it to a recording means (not shown). When the CCD solid-state image sensor 3 is an image sensor in which a complementary color filter is arranged, the DSP 8 performs image data processing to generate primary color image data, and then executes knee processing and the like using this image data. To do. In these processes, the DSP 8 performs arithmetic processing on the image data to generate luminance data DY, which is image data corresponding to the luminance signal, and outputs the luminance data DY.
[0021]
The microcomputer 5 is a controller that controls the operation of the electronic still camera 1, and outputs image data DV to a display device (not shown) to display the imaging result by controlling the operation of the DSP 8 or the like in response to various operations by the user. Further, the image data DV obtained by data compression is recorded on a predetermined recording medium.
[0022]
Further, the microcomputer 5 detects the brightness of the imaging result by weighted addition of the luminance data DY output from the DSP 8. Further, the microcomputer 5 controls the operation of the timing generator 4 based on the weighted addition value thus obtained, thereby adjusting the shutter speed of the electronic shutter so that the brightness of the imaging result becomes a predetermined brightness. To do. Further, when the brightness of the imaging result cannot be ensured even by such electronic shutter control, the AGC circuit 7 is instructed to increase the gain, and thereby exposure control is performed by the AGC.
[0023]
In this series of exposure control, for example, as shown in FIG. 2, the microcomputer 5 divides one screen based on the imaging result into a plurality of regions in the horizontal direction and the vertical direction, and divides the luminance level of each region. The exposure control process is executed with reference to the above. In FIG. 2, the imaging result is divided into four in the horizontal direction and the vertical direction, and one screen is divided into 16 areas.
[0024]
In other words, the microcomputer 5 detects the maximum value and the minimum value of the luminance level from one screen, and uses the maximum value and the minimum value as a reference, and the average value as a reference if necessary. First and second threshold values are set to divide into three levels of low luminance level, luminance level, and high luminance level.
[0025]
The microcomputer 5 determines the value of the luminance data DY for each area on the basis of the first and second threshold values, and totals the determination results for each section. Further, the microcomputer 5 detects the division in which the total value having the largest value is obtained in each region, and thereby divides the luminance level of each region into three stages as shown in FIG.
[0026]
Thereby, the microcomputer 5 detects the distribution of the luminance level in units of areas. In the luminance level distribution thus detected, the position of the subject can be confirmed by the correlation between the sections. That is, by comparing the segments between adjacent regions, if the regions of the same segment are continuous, it can be determined that the same object, background, etc. are captured in this region. Similarly, it is possible to determine that the region belonging to the category occupying the largest area by such a category is the subject intended by the user.
[0027]
Thus, for example, as shown in FIG. 3, the upper and lower left and right regions of the screen are divided into high luminance level regions, and the lower and lower left and right regions of the screen are low luminance level regions. If the remaining area is divided into areas of medium luminance level, the medium luminance level area in the center of the screen is the area where the same object is imaged. It is thought that the composition is set for the subject. In practice, such a pattern can be obtained, for example, when the face of a person is photographed up. In this case, the user obtains an imaging result in which the central portion is appropriately exposed. Is what you want.
[0028]
Also, as shown in FIG. 4, the upper part of the screen is divided into areas of high luminance level, the area below the upper part, the left and right end areas are divided into areas of medium luminance level, and the remaining areas are low luminance. When divided into level areas, the high brightness level area at the top of the screen captures the same object, such as the sky, and this area is the same object in the low brightness level area. In this case, since this area occupies the most area and occupies the central part of the screen, the user is appropriately exposed in this low luminance level region. It is thought that the imaging result is desired. In practice, such a luminance distribution is obtained when a person or the like is imaged outdoors. In such a case, an imaging result obtained by optimally exposing the person or the like is desired.
[0029]
In such a case, since the subject has a low luminance level, it can be considered that the image is captured in a backlight state. In this case, it is necessary to set a longer exposure time.
[0030]
On the other hand, as shown in FIG. 5, when the area above the center of the screen is divided into high luminance levels and the remaining area is divided into medium luminance levels, the high luminance level portions are empty or the like. It is a region where the same object is imaged, and it can be determined that the region of medium luminance level is also a region where the same object is imaged. However, in this medium luminance level region, the difference in luminance level is small compared to the region of high luminance level, so that, in contrast to the distribution in FIG. It can be determined that the image is being taken. Thereby, in this case, exposure control is performed with an appropriate amount of light for the entire screen, and an imaging result desired by the user can be obtained.
[0031]
Based on these determination principles, the microcomputer 5 detects an area that needs to be subjected to exposure control with emphasis by comparison with a plurality of determination reference patterns 10 (FIG. 1) held in a memory.
[0032]
Here, the determination reference pattern 10 is a pattern in which the distribution of the divisions thus detected is recorded together with the weighting coefficient of each region. In the microcomputer 5, the highest is obtained by comparison with the determination reference pattern 10. A determination reference pattern 10 that matches with accuracy is detected. As a result, the microcomputer 5 detects the area to be processed with the most emphasis by the weighting coefficient set in the determination reference pattern 10 thus detected. The microcomputer 5 sequentially weights and adds luminance data of one screen by using this weighting coefficient, and sets a reference value for exposure control using this added value.
[0033]
The microcomputer 5 executes the exposure control process by the electronic shutter and AGC so that the determination reference value calculated in this way becomes a predetermined value, and thereby the optimum imaging condition for the subject desired by the user is obtained. An imaging result is acquired under one optimum exposure condition.
[0034]
(2) Operation of Embodiment In the above-described configuration, in the electronic still camera 1, after the imaging result obtained from the CCD solid-state imaging device 3 is processed by the CDS 6 and amplified by the AGC circuit 7 with a predetermined gain, analog digital The image data is converted into image data by the conversion circuit 9, and this image data is subjected to knee processing, gamma processing, and the like by the DSP 8. In the electronic still camera 1, the image data DV processed in this way is displayed on a display device, and the data is compressed and recorded on a predetermined recording medium.
[0035]
In the electronic still camera 1, in these processes, the luminance data DY generated by the DSP 8 is weighted and added by the microcomputer 5 for each region generated by dividing one screen of the imaging result, and is used for exposure control. A determination reference value is generated, and automatic exposure control, which is one of imaging conditions, is executed by the electronic shutter and AGC so that the determination reference value becomes a predetermined value. That is, in the electronic still camera 1, when the imaging result is too bright according to the evaluation reference value detected in this way, the charge accumulation time in the CCD solid-state imaging device 3 is short under the control of the timing generator 4 by the microcomputer 5. Can be switched to. On the other hand, if the imaging result is too dark, the charge generation time in the CCD solid-state imaging device 3 is switched to a longer time by the same control of the timing generator 4 by the microcomputer 5. When the brightness is insufficient, the gain of the AGC circuit 7 is increased, and the image pickup result is automatically adjusted for exposure.
[0036]
In the electronic still camera 1, in the generation process of the determination reference value based on the luminance data DY, first, threshold values for dividing the luminance level into three stages of a high luminance level, a medium luminance level, and a low luminance level are set. After the calculation, the luminance data DY is divided and aggregated for each area by this threshold value, so that the luminance level of each area is divided into three levels: a high luminance level, a medium luminance level, and a low luminance level. The luminance distribution is detected in units of areas based on these sections.
[0037]
In the electronic still camera 1, the determination reference pattern 10 that matches the luminance distribution is detected, and the above-described weighting addition processing of the luminance data DY is performed by the weighting coefficient set in the determination reference pattern 10, thereby determining exposure control. A reference value is generated. As a result, the electronic still camera 1 can easily and reliably detect a region to be processed with more emphasis than the segment showing the largest area due to the correlation of the segments between adjacent regions.
[0038]
That is, for example, when a moderate brightness level is concentrated in the center of the screen, a subject intended by the user is arranged in the center of the screen. According to this embodiment, such a user Thus, it is possible to easily and reliably detect an area to be focused on, flexibly corresponding to the intended composition. As a result, the electronic still camera 1 automatically processes the luminance data DY obtained from the area to be focused with a large weighting factor so that the area to be focused has an appropriate brightness. Can be adjusted.
[0039]
(3) Effects of the embodiment According to the above configuration, the luminance level of each region set in the imaging result is divided into a plurality of stages, and the imaging result is focused on the basis of the luminance level distribution by this division. By detecting the area to be processed automatically, it is possible to easily and reliably detect the area to be focused, for example, by applying it to exposure control. In addition, by detecting the area belonging to the section that occupies the most area on the screen and detecting the area to be focused on, the user's desired subject can be detected by simple processing. Can be appropriately reflected in the imaging result.
[0040]
At this time, this kind of processing is executed by simple processing by detecting a region to be processed with a large weighting coefficient set by comparison with a plurality of reference patterns registered in advance. can do.
[0043]
In addition, since such a division is a three-level division of the luminance level, this type of processing can be executed by simple processing.
[0044]
(4) Other Embodiments In the above-described embodiment, a case has been described in which a region to be preferentially processed is detected by comparison with a predetermined determination reference pattern, but the present invention is not limited to this. A luminance distribution may be appropriately determined by a calculation process by a microcomputer, and a region to be processed with priority may be detected.
[0045]
In the above-described embodiment, the case where the threshold value is set based on the maximum value and the minimum value of the luminance data and the luminance level is classified has been described. However, the present invention is not limited to this, for example, the average value of the luminance data. The threshold value may be set according to the above, and further, the threshold value may be classified according to a preset threshold value. In addition, in the case of classifying according to the threshold value set in advance in this way, for example, the luminance level is classified in a state where the entire screen or the predetermined area is set to the predetermined brightness by the average value and the integral value of the luminance level. Is required.
[0046]
Further, in the above-described embodiment, the case where one screen is divided into four areas in the horizontal direction and the vertical direction is set. However, the present invention is not limited to this, and is set by various division numbers. The same effect as the above-described embodiment can be obtained. In this way, when the area is set by dividing the screen in the horizontal direction and the vertical direction, if the number of divisions is set to be the same in the horizontal direction and the vertical direction, the imaging result on the vertical screen and the horizontal screen are used. The determination reference pattern can also be used with the imaging result.
[0047]
In the above-described embodiment, the case where the luminance level is divided into three stages has been described. However, the present invention is not limited to this, and the same effect can be obtained by dividing the luminance level into various stages.
[0048]
In the above-described embodiment, the case where the present invention is applied to the automatic exposure control by the electronic shutter and the AGC has been described. However, the present invention is not limited to this, and in addition to the electronic shutter or in addition to the electronic shutter. The present invention can be widely applied to automatic exposure control using a diaphragm and AGC, automatic exposure control using a mechanical shutter and AGC, and automatic exposure control using a diaphragm and mechanical shutter and AGC.
[0049]
In the above-described embodiment, the case where the present invention is applied to automatic exposure control to detect an area to be processed with emphasis has been described. However, the present invention is not limited thereto, and, for example, automatic focus adjustment, etc. The present invention can be widely applied to the detection of a region to be processed with emphasis by applying to various imaging condition setting processing and imaging result processing.
[0050]
In the above-described embodiment, the case where the present invention is applied to a single-plate type imaging apparatus has been described. However, the present invention is not limited to this and can be widely applied to a three-plate type imaging apparatus.
[0051]
In the above embodiment, the case where the present invention is applied to an electronic still camera has been described. However, the present invention is not limited thereto, and an imaging apparatus having a recording function such as a camera-integrated video tape recorder, The present invention can be widely applied to an image pickup apparatus having a communication function such as a mobile phone, and an image pickup apparatus integrated with a personal computer.
[0052]
In the above-described embodiment, the case where the present invention is applied to the imaging apparatus has been described. However, the present invention is not limited to this, and may be widely applied to, for example, image processing of imaging results in a personal computer. it can.
[0053]
【The invention's effect】
As described above, according to the present invention, the luminance level of each region set in the imaging result is divided into a plurality of stages, and the region to be processed with emphasis is detected based on the luminance level distribution by this division. In this way, by detecting the area of the section that occupies the most area in the screen and detecting the area to be processed with the emphasis , for example, it is applied to exposure control and the process is performed with emphasis. The area to be detected can be detected easily and reliably.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an electronic still camera according to an embodiment of the present invention.
FIG. 2 is a plan view for explaining region setting in the electronic still camera of FIG. 1;
FIG. 3 is a plan view showing a luminance level classification result;
4 is a plan view showing a luminance level classification result in an imaging result different from FIG. 2. FIG.
FIG. 5 is a plan view showing a luminance level classification result in an imaging result different from those in FIGS. 2 and 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electronic still camera, 3 ... CCD solid-state image sensor, 4 ... Timing generator, 5 ... Microcomputer, 7 ... AGC circuit, 8 ... DSP, 10 ... Judgment reference pattern

Claims (4)

Imaging means for outputting imaging results;
Signal processing means for signal-processing and outputting the imaging result;
Control means for controlling the imaging conditions by at least the imaging means based on the imaging result,
The control means includes
For a plurality of areas set in the screen of the imaging result, the brightness level of each area is divided by a plurality of stages,
And a distribution of luminance levels by said section to the criteria, to detect the area to be treated emphasis than the imaging result,
Control the imaging conditions based on the detection result ,
An imaging apparatus , wherein a region of a section occupying the largest area is detected on a screen, and a region to be processed with the emphasis is detected . The control means includes
The imaging apparatus according to claim 1, wherein a region to be processed with the emphasis is detected by comparison with a plurality of reference patterns registered in advance. The division is
The imaging apparatus according to claim 1 , wherein the brightness level is divided into three stages. An imaging result processing method for processing an imaging result,
For a plurality of areas set in the screen of the imaging result, dividing the luminance level of each area by a plurality of stages;
A step of detecting a region for detecting a region to be processed with emphasis on the imaging result on the basis of a distribution of luminance levels by the section;
A processing step of processing the imaging result so as to process with emphasis on the region detected in the region detection step ;
The region detecting step includes:
In the screen, the area of the section that occupies the most area is detected, and the area to be processed with the emphasis is detected.
Method of processing an imaging result, wherein the this.

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