KR101612853B1 - Photographing apparatus, controlling method of photographing apparatus, and recording medium storing program to implement the controlling method - Google Patents

Abstract

The present invention relates to an image pickup apparatus capable of processing an image signal for correcting a white balance without increasing a processing load, a control method for an image pickup apparatus, and a recording medium storing a program for executing a control method, A second dividing means for further dividing the first block into M second blocks, a position changing means for changing the second block to be calculated for each frame, a position changing means Calculating means for performing an arithmetic processing on the changed second block and performing arithmetic processing on the first block at the time of recording, arithmetic operation result of a rectilinear M frame for the second block of the integrating means, A light source estimating means for estimating a light source of an image signal using the calculation result, a control method for the photographing apparatus, and a program for executing the control method And a recording medium in which the grams are stored.

Description

[0001] The present invention relates to a photographing apparatus, a control method of a photographing apparatus, a recording medium storing a program for executing the control method,

The present invention relates to a photographing apparatus, a photographing apparatus control method, and a recording medium storing a program for executing the control method, and more particularly to a photographing apparatus capable of processing an image signal for correcting white balance without increasing the processing load, A control method of the photographing apparatus, and a recording medium storing a program for executing the control method.

BACKGROUND ART [0002] In an electronic photographing apparatus that photographs a subject electronically, such as a digital still camera, image signal processing (white balance correction processing) for correcting the white balance so that a white subject is photographed whatever the light source of the illumination is generally built in. There may be a color difference between the photographed image observed with the naked eye and the photographed image by the illumination light source. In this case, the white balance correction processing is a correction processing for causing a white subject to be reproduced in whiteness. For example, in natural light such as daylight and artificial light such as fluorescent light, there are differences in color temperature of two light sources, and as a result, white reproducibility of a photographed image is greatly influenced. Therefore, by performing the white balance correction processing, an uncomfortable feeling can be prevented from occurring in the image reproduced by the photographing apparatus.

The white balance is corrected by dividing the image signal obtained from the image pickup device into a plurality of blocks and obtaining the color integration values such as R (red), G (green), and B (blue) . It is general to perform white balance control so that the integrated value in the block determined as achromatic is R = G = B.

However, if color mixing occurs due to the presence of a plurality of colors in the divided blocks, it becomes impossible to correctly determine the chromatic color / achromatic color. Thus, a technology is disclosed in which the occurrence of color mixture is suppressed as much as possible by finely dividing a block, and white balance determination is normally performed. For example, Japanese Unexamined Patent Application Publication No. 2007-336107, Japanese Unexamined Patent Publication No. 2007-228516, Japanese Unexamined Patent Publication No. 2006-211440, Japanese Unexamined Patent Publication No. 2005-12763, and the like.

However, if the block to be subjected to the image signal processing is finely divided so as to suppress the occurrence of the color mixture, the white balance control processing time becomes longer and the processing can not be completed within one frame. Particularly, in live view in which an image obtained from an image pickup device is sequentially displayed on a monitor provided in a photographing apparatus, if the calculation time of the white balance gain increases, a time difference occurs in the scene displayed in live view do. Further, if the white balance control processing time is prolonged at the time of still image photographing, there is a problem that the time until the end of the photographing becomes long. In particular, in the case of continuous photographing in a short time, It goes without saying that it is desirable to shorten the processing time from the viewpoint of low power consumption in the case where an imaging device is provided in a portable terminal such as a cellular phone to have a camera function.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to finely divide a block to be subjected to image signal processing in a step before recording to suppress the occurrence of color mixture, And a program for executing a control method and a control method of a photographing apparatus capable of performing image signal processing for correcting white balance without increasing a processing load by using evaluation results of finely divided blocks of a photographing apparatus And an object of the present invention is to provide a recording medium on which a recording medium is stored.

The present invention is characterized by comprising first dividing means for dividing an image signal obtained from an image pickup device into a plurality of first blocks, second dividing means for further dividing the first block into M second blocks, Calculating means for performing arithmetic processing on the second block which has been changed by the position changing means before recording and arithmetic processing on the first block in the case of recording; And light source estimation means for estimating a light source of the image signal by using the calculation result of the M frame calculation means and the calculation result of the first block.

According to this configuration, the first dividing means divides the image signal obtained from the image pickup device into a plurality of first blocks, and the second dividing means further divides the first block into M second blocks. The position changing means changes the second block to be calculated for each frame and the light source estimating means changes the position of the image signal by using the calculation result of the arithmetic means of the rectilinear M frame for the second block and the calculation result for the first block. Estimate the light source. As a result, in the step before the recording, the block to be subjected to the image signal processing is finely divided as the second block. In recording, the calculation result for the finely divided second block in the pre- By using the calculation result for one block, it is possible to process the image signal without increasing the processing load.

According to another aspect of the present invention, there is provided an image processing apparatus including: storage means for storing a light source estimation result of the light source estimation means for at least M frames; And gain calculation means for calculating a gain for correcting the white balance using the light source estimation result for the block.

According to still another aspect of the present invention, the gain calculating means determines a predetermined weight coefficient by using the light source estimation result during the rectilinear M frame for the second block, and adds the calculated weight to the calculation result for the first block The gain can be calculated by multiplying the coefficient.

According to still another aspect of the present invention, the predetermined weight coefficient can be such that the greater the number of small blocks determined as achromatic color as the result of the light source estimation in the light source estimation means, the larger the coefficient.

The present invention also provides a method of dividing an image signal obtained from an image pickup device into a first block, a second block, a second block, An arithmetic operation step of performing arithmetic processing on a second block changed in the position changing step before the recording and an arithmetic processing on the first block in the recording step; And a light source estimating step of estimating a light source of the image signal using the calculation result of the rectilinear M frame for the second block and the calculation result for the first block.

According to the recording medium storing the program for executing the photographing apparatus, the photographing apparatus control method, and the control method of the present invention as described above, in the pre-recording step, the block to be subjected to the image signal processing is suppressed And the image signal processing for correcting the white balance without increasing the processing load by using the evaluation results of the finely divided blocks in the pre-recording step at the time of recording is finely divided, It is possible to provide a recording medium storing a program for executing a control method and a control method of a photographing apparatus. Thus, during high-speed continuous shooting, the processing time can be shortened as much as possible to reduce the processing load of white balance correction at the time of still image shooting without being influenced by the time difference between screen display before shooting and still image shooting have.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description will be omitted.

First, before describing a preferred embodiment of the present invention, problems that may occur in white balance correction processing will be described with reference to the drawings.

Fig. 10 is an explanatory diagram for explaining the block division in the white balance correction processing. 10, an image signal extracted from an image pickup device such as a CCD or a CMOS is divided into a plurality of blocks, and the white balance correction process is performed for each block of R, G, And calculates the integrated values ([Sigma] R, [Sigma] G, [Sigma] B). When the integrated values (? R,? G,? B) of the pixels of the R, G, and B colors are calculated, whether the block is controlled as achromatic color or chromatic color is determined for each block, and the appropriate white balance gains (Kr, Kg , Kb).

Here, when a plurality of colors are mixed in the divided block, mixed color occurs and the white balance correcting process can not be correctly judged. When the area of the block to be divided is increased, the frequency of occurrence of color mixture increases.

11 is an explanatory view showing an example of an image obtained from an image signal extracted from an image pickup element such as a CCD or CMOS which is an object of the white balance correction processing, Fig. 12 shows an image signal obtained from the image shown in Fig. × vertical three blocks. FIG. 13 is an explanatory view showing a case where an image signal for obtaining the image shown in FIG. 11 is divided into "horizontal 12 blocks" × "vertical 9 blocks". In the white balance correction processing, the red petal portion and the green leaf portion in the image are not regarded as a light source but are judged to be chromatic colors. However, when red and green are mixed in the block in the integration process in each block, mixed color occurs (mixed red and green), and it is erroneously determined that the object is yellow. When the subject in yellow is a color balance such as a light source such as tungsten light, it is determined that the color of the light source is achromatic, and the white balance is erroneously judged. Therefore, there is a method of reducing the area of the block by increasing the number of blocks in order to reduce the frequency of occurrence of the color mixture.

Fig. 14 is an explanatory view showing the arrangement of blocks erroneously judged as yellow subjects by color mixing when the image signal is divided into "horizontal 4 blocks" x "vertical 3 blocks" Quot; x "vertical 9 blocks ". FIG.

In the case shown in Figs. 14 and 15, in the case of dividing into 4 × 3, 83% of the blocks are erroneously determined to be yellow subjects, whereas in the case of dividing into 12 × 9, 28% is erroneously judged to be yellow subjects . As described above, the number of blocks is increased to reduce the area per block, thereby suppressing the occurrence frequency of the color mixture.

However, if the number of blocks is increased, the number of data to be processed at one time increases, and the processing time until the white balance gain is calculated increases, so that the processing can not be completed within one frame. Particularly, in live view in which an image obtained from an image pickup device is displayed on a monitor (real-time) on a monitor provided in the image pickup device, when the calculation time of the white balance gain is extended, There is a time difference in God.

Further, when the processing time of the white balance control is prolonged at the time of still image photographing, there is a problem that the time until the end of the photographing becomes long. In particular, in the case of continuous photographing in a short time, Throw away. It is needless to say that, in the case where a portable terminal other than a cellular phone is equipped with an image pickup device to have a camera function, the processing time can be shortened from the viewpoint of low power consumption.

Therefore, in a preferred embodiment of the present invention described below, a photographing apparatus and an image processing method that can suppress an increase in processing time while reducing the area of a block in order to suppress the occurrence frequency of color mixing are implemented.

First, the configuration of a photographing apparatus according to an embodiment of the present invention will be described. Fig. 1 is an explanatory view showing a configuration of a photographing apparatus 100 according to an embodiment of the present invention. Hereinafter, a configuration of a photographing apparatus 100 according to an embodiment of the present invention will be described with reference to FIG.

1, a photographing apparatus 100 according to an embodiment of the present invention includes a zoom lens 102, a diaphragm 104, a focus lens 106, a CCD (Charge Coupled Devices) element 108, An A / D converter 112, an image input controller 114, an image signal processing unit 116, a compression processing unit 120, an LCD (Liquid Crystal Display) driver 122, a CDS (Correlated Double Sampling) An LCD 124, a timing generator 126, motor drivers 142a, 142b and 142c, a CPU (Central Processing Unit) 128, an operation unit 132, a memory 134, a VRAM (Video Random Access Memory 136, a media controller 138, and a recording medium 140.

The zoom lens 102, the diaphragm 104, the focus lens 106, and the CCD element 108 constitute an exposure section. In this embodiment, the CCD element 108 is used to form the exposure unit. However, the present invention is not limited to this example, and a CMOS (Complementary Metal Oxide Semiconductor) element may be used instead of the CCD element. Since the CMOS device can convert the video image of the subject into an electric signal at a higher speed than the CCD device, it is possible to shorten the time until the image is recorded after the subject is photographed.

The zoom lens 102 is a lens in which the focal length continuously changes as it moves back and forth in the direction of the optical axis, and changes the size of the subject and photographs it. The diaphragm 104 adjusts the amount of light entering the CCD element 108 when capturing an image. The focus lens 106 adjusts the focus of the subject by moving back and forth in the direction of the optical axis.

The motor drivers 142a, 142b, and 142c control the motor that operates the zoom lens 102, the diaphragm 104, and the focus lens 106. [ The zoom lens 102, the diaphragm 104 and the focus lens 106 are operated via the motor drivers 142a, 142b and 142c to adjust the size of the subject, the amount of light, and the focus.

The CCD element 108 is an element for converting the light incident from the zoom lens 102, the diaphragm 104, and the focus lens 106 into an electric signal. In this embodiment, the time for extracting the electric signal is controlled by controlling the incident light by the electronic shutter. However, the time for extracting the electric signal by controlling the incident light by using a mechanical shutter may be adjusted.

The CDS circuit 110 is a circuit in which a CDS circuit, which is a kind of sampling circuit that removes noise of an electric signal output from the CCD element 108, and an amplifier that amplifies an electric signal after noise is removed, are integrated. In the present embodiment, the photographing apparatus 100 is configured by using a circuit in which the CDS circuit and the amplifier are integrated. However, the CDS circuit and the amplifier may be constituted by separate circuits.

The A / D converter 112 converts the electric signal generated by the CCD element 108 into a digital signal to generate raw data of an image.

The image signal processing unit 116 is a circuit for performing various signal processing on raw data of an image generated by the A / D converter 112. [

The compression processing unit 120 performs compression processing for compressing the data subjected to the signal processing in the image signal processing unit 116 into image data of an appropriate format. The compression format of the image may be reversible or irreversible. As an example of a suitable format, it may be converted into a Joint Photographic Experts Group (JPEG) format or a JPEG2000 format.

The LCD 124 performs live view display before the photographing operation, various setting screens of the photographing apparatus 100, and displays the photographed images. Display of image data and various kinds of information of the image pickup apparatus 100 on the LCD 124 is performed via the LCD driver 122. [

The timing generator 126 inputs a timing signal to the CCD element 108. [ The shutter speed is determined by the timing signal from the timing generator 126. [ That is, the driving of the CCD element 108 is controlled by the timing signal from the timing generator 126, and the video light from the subject is incident within the time the CCD element 108 is driven, A signal is generated.

The CPU 128 instructs the CCD element 108, the CDS circuit 110, and the like by a signal system or an operation system command for the operation of the operation unit 132. [ Although the present embodiment includes only one CPU, in the present invention, a command of the signal system and an instruction of the operating system may be executed by a separate CPU or a DSP (Digital Signal Processor).

The operation unit 132 includes a function as a photographing mode selection unit, and a member for operating the photographing apparatus 100 or performing various settings at the time of photographing is disposed. A member disposed in the operation section 132 is provided with a power button, a cross key and a selection button for selecting a photographing mode or a photographing drive mode and setting an effect parameter, and a shutter button for starting a photographing operation.

The memory 134 temporarily stores the photographed image or the image processed by the image signal processing unit 116. [ The memory 134 has a storage capacity sufficient to store a plurality of images. The image reading / writing into the memory 134 is controlled by the image input controller 114.

The VRAM 136 maintains the contents to be displayed on the LCD 124 and the resolution and the maximum number of colors of the LCD 124 depend on the capacity of the VRAM 136. [

The recording medium 140 records the photographed image. The input / output to / from the recording medium 140 is controlled by the media controller 138. The recording medium 140 may be a memory card that is a card-type storage device for recording data in a flash memory.

The configuration of the photographing apparatus 100 according to the embodiment of the present invention has been described above with reference to Fig. Next, the configuration of the image signal processing unit 116 included in the photographing apparatus 100 according to the embodiment of the present invention will be described.

Fig. 2 is an explanatory view for explaining a configuration of the image signal processing unit 116 included in the photographing apparatus 100 according to the embodiment of the present invention. Hereinafter, the configuration of the image signal processing unit 116 included in the image pickup apparatus 100 according to the embodiment of the present invention will be described with reference to FIG.

2, the image signal processing unit 116 according to an embodiment of the present invention includes an image front process unit 152, an image evaluation unit 154, a white balance gain calculation unit 156, A demosaicing processing unit 160, a color correction processing unit 162, and a gamma correction processing unit 164.

The image front-end processing unit 152 performs image front-end process such as defective pixel correction or black level correction on the image signal that is photoelectrically converted by the CCD element 108 and converted into a digital signal by the A / D converter. The image signal subjected to the image front process processing in the image front process processing unit 152 is sent to the image evaluation unit 154 and the white balance correction unit 158. [

The image evaluation unit 154 calculates the white balance gain for correcting the white balance in the white balance gain calculation unit 156 for the image signal subjected to the image front process processing in the image front process processing unit 152, And executes image evaluation processing. The image evaluation unit 154 divides the image signal subjected to the image front-end processing into a plurality of blocks, obtains the integrated values (? R,? G,? B) of the RGB pixels for each divided block, And estimates the light source based on the value. The configuration of the image evaluation unit 154 will be described later. The result of the image evaluation processing in the image evaluation unit 154 is sent to the white balance gain calculation unit 156. [

The white balance gain calculating unit 156 calculates white balance gains (Kr, Kg, Kb) based on the result of the image evaluation processing in the image evaluation unit 154. The white balance gain calculated by the white balance gain calculating section 156 is sent to the white balance correcting section 158.

The white balance correcting section 158 multiplies the white balance gain calculated by the white balance gain calculating section 156 with respect to the image signal subjected to the image front process processing in the image front process processing section 152. [ The white balance correcting process for the image signal can be executed by multiplying the image signal by the white balance gain by the white balance correcting section 158. [ The image signal subjected to the white balance correction processing is sent to the demosaic processing unit 160.

The de-mosaic processing unit 160 performs color complement processing (demosaicing processing) on the image signal subjected to the white balance correction processing. The demosaic processing unit 160 performs demosaicing processing on the image signal subjected to the white balance correction processing to generate a color image. The details of the demosaic processing are not directly related to the present invention, and thus a detailed description thereof will be omitted . The image signal subjected to the demosaic processing is sent to the color correction processing unit 162.

The color correction processing unit 162 performs color correction processing on the image signal subjected to the complementary processing (demosaic processing) in the demosaic processing unit 160. [ The color correction processing unit 162 can perform the color correction processing to generate an appropriate color image. The detail of the color correction processing is not directly related to the present invention, and thus a detailed description thereof will be omitted. The image signal subjected to the color correction processing is sent to the gamma correction processing unit 164.

The gamma correction processing unit 164 performs gamma correction processing on the image signal subjected to the color correction processing in the color correction processing unit 162. [ The details of the gamma correction process are not directly related to the present invention, and a detailed description thereof will be omitted. The image signal subjected to the gamma correction processing is sent to the compression processing unit 120 and subjected to compression processing, recording on the recording medium 140, or display on the LCD 124.

The configuration of the image signal processing unit 116 according to the embodiment of the present invention has been described above. Next, the configuration of the image evaluation unit 154 included in the image signal processing unit 116 according to the embodiment of the present invention will be described.

3 is an explanatory view for explaining the configuration of the image evaluation unit 154 included in the image signal processing unit 116 according to the embodiment of the present invention. Hereinafter, the configuration of the image evaluation unit 154 included in the image signal processing unit 116 according to the embodiment of the present invention will be described with reference to FIG.

3, the image evaluating unit 154 according to an embodiment of the present invention includes a first block dividing unit 172, a second block dividing unit 174, a block position changing unit 176, A memory unit 178, a storage unit 180, and a light source estimating unit 182.

The first block dividing section 172 divides the image signal sent to the image evaluation section 154 into blocks (large blocks) of a predetermined size. The first block dividing section 172 may divide the image signal into "horizontal 4 blocks" × "vertical 3 blocks" as described above, or may divide the image signal into "horizontal 12 blocks" × "vertical 9 blocks" do. It goes without saying that the number of divisions is not limited to this example. Further, the shape of the large block at the time of division may be a square, a rectangular shape, or any other shape.

The second block dividing unit 174 further divides each large block divided by the first block dividing unit 172 into blocks (small blocks) of a predetermined size. For example, in the first block dividing section 172, the image signal is divided into large blocks of "four horizontal blocks" x three vertical blocks, and the second block dividing section 174 divides the image signals into " Quot; horizontal 3-block "and" vertical 3-block " It goes without saying that the number of divisions is not limited to this example. The shape of the small block at the time of division may be a square, a rectangle, or any other shape. In the following description, it is assumed that one large block is divided into nine small blocks of "horizontal 3 blocks" × "vertical 3 blocks" for convenience.

FIG. 4 is an explanatory diagram showing a case where one large block is divided into small blocks of "horizontal 3 blocks" × "vertical 3 blocks" in the second block dividing section 174. In FIG. 4, alphabets A to I are attached to small blocks for convenience of explanation.

The block position changing unit 176 changes the small blocks to be processed by the integration processing unit 178 to be described later in a frame before the imaging processing (before the recording to the imaging apparatus 100) In the step of writing to the apparatus 100), a large block to be processed by the integration processing unit 178 is designated. For example, in the second block dividing section 174, one large block is divided into nine small blocks of "horizontal 3 blocks" × "vertical 3 blocks" as shown in FIG. 4. In the stage before the image pickup processing, The changing unit 176 cyclically selects one small block in the small blocks of A to I for each frame.

5 is an explanatory view for explaining the block position changing process in the block position changing unit 176 before the image pick-up process. 5 shows an example in which the small blocks to be processed are changed for each frame in the small blocks A to I divided by the second block dividing unit 174. [ In Fig. 5, the small blocks are denoted by A, E, G, C, H, F, B, D, I, The order is not limited to the one shown in Fig. 5, of course. In the present embodiment, the block position changing unit 176 cyclically changes the small frame, but in the present invention, the small block to be processed by the integration processing unit 178 may be changed at random.

Then, when the photographer operates the operation unit 132 of the photographing apparatus 100 to execute the image pick-up process, the block position changing unit 176 designates a large block to be processed by the integration processing unit 178. [ 6 is an explanatory view for explaining a block position changing process in the block position changing unit 176 before and after the image pickup process. In the stage before the image pickup processing, the block position changing unit 176 changes the small blocks to be processed in the small blocks of A to I divided by the second block dividing unit 174 for each frame, and when the image pick- The block position changing unit 176 specifies the large block J to be processed.

The integration processing unit 178 compares the RGB values of the small blocks for obtaining the white balance gain with respect to the pixels of the R, G, and B colors included in the small block or large block specified by the block position changing unit 176, The integrated values (? R,? G,? B) of pixels and the integrated values (? R2,? G2,? B2) of RGB pixels in the large block. The coloring in the corresponding small block or large block can be determined by obtaining the integrated values (? R,? G,? B,? R2,? G2,? B2) of RGB pixels. The integrated values (? R,? G,? B,? R2,? G2,? B2) of the RGB pixels obtained by the integration processing section 178 and the determination result of coloring in the corresponding small block or large block may be temporarily stored in the storage section 180 . The integrated values (? R,? G,? B,? R2,? G2,? B2) of RGB pixels obtained by the integration processing unit 178 .

The light source estimating unit 182 executes the light source estimating process of estimating the light source by using the integrated values (? R,? G,? B,? R2,? G2,? B2) of the RGB pixels obtained by the integration processing unit 178. The result of the light source estimation processing in the light source estimating section 182 may be temporarily stored in the storage section 180. [ The result of the light source estimation processing in the light source estimating section 182 is sent to the white balance gain calculating section 156 and used for calculation of the white balance gain.

7 is an explanatory view for explaining an example of a relationship between a block to be evaluated and a frame when the light source estimating unit 182 estimates the light source. In the example shown in Fig. 7, the light source estimation result of the small blocks (A to I) for nine rectilinear frames acquired at the stage before the image pickup processing and the light source estimation result of the large frame (J) And the light source estimation processing is executed.

Although the light source estimating section 182 is included in the image evaluating section 154 in this embodiment, the present invention is not limited to this example. For example, the function of the light source estimating section 182 may be included in the white balance gain calculating section 156.

The configuration of the image evaluation unit 154 included in the image signal processing unit 116 according to the embodiment of the present invention has been described above. Next, an imaging method according to an embodiment of the present invention will be described.

8 is a flowchart for explaining an imaging method according to an embodiment of the present invention. Hereinafter, an imaging method according to an embodiment of the present invention will be described with reference to FIG. Although the "end" step is not shown in FIG. 8, it is understood that the process can be terminated at any time if there is a termination signal from the user during execution of the flowchart as shown in FIG.

First, the block position changing unit 176 selects a small block to be subjected to white balance evaluation (step S102). As described above, the small block to be evaluated of the white balance selected by the block position changing unit 176 is changed every one frame.

When the block position changing unit 176 selects a small block to be subjected to white balance evaluation in step S102, the integrated values (? R,? G,? B) of the RGB pixels in the corresponding small block are stored in the accumulation processing unit 178 (Step S104). When the integrated values SIGMA R, SIG and GIGMA B of the RGB pixels are calculated by the integration processing unit 178 in step S104, the light source estimation unit 182 calculates And determines the coloring of the small block (step S106).

If the light source estimating unit 182 determines the color of the corresponding small block by using the integrated values (? R,? G,? B) of the RGB pixels in the above-described step S106, The light source estimating unit 182 estimates the light source of the small block and determines whether the small block is a chromatic color or an achromatic color (step S108). The information on whether it is a chromatic color or an achromatic color may be a binary value or a value of three or more. If the light source estimating unit 182 estimates the light source of the small block in step S108, the estimation result is stored in the storage unit 180 (step S110).

When the estimation result of the light source is stored in the storage unit 180 in the step S110, the white balance gain is calculated using the estimation result stored in the storage unit 180. [ First, the white balance gain calculating section 156 reads the estimation result in the rectangle frame stored in the storage section 180 (step S112). In this embodiment, one large block is divided into nine small blocks. Thus, in step S112, the white balance gain calculating unit 156 reads the estimation result of nine rectilinear frames from the storage unit 180. [

When the estimation result in the rectilinear frame stored in the storage unit 180 is read in step S112, the white balance gain calculation unit 156 weight-averages the read estimation result (step S114). An example of the weighted average is as follows. Assuming that the evaluation frame is f, the number of blocks to be treated as achromatic color in each frame is n, and the RGB integrated values of the block to be treated as achromatic color are r, g, and b, the color balance (Cr, Cg, Cb) Can be obtained by the following formula (1).

The white balance gain calculator 156 calculates the white balance gain Cr by using the obtained color balances Cr, Cg, and Cb as shown in Equation (1) And the balance gain is calculated (step S116). The white balance gains (Kr, Kg, Kb) can be obtained by the following equation (2).

The above equation (2) is a calculation formula in the case where the value of Cg is the largest among the color balances (Cr, Cg, Cb). When the values of the other colors are large, Modify the expression as appropriate.

When the white balance gain is calculated in step S116, it is determined whether or not the photographing operation by the photographer has been executed (step S118). The photographing operation by the photographer may be a pressing of the shutter button included in the operation unit 132. [ Further, the CPU 128 may determine whether or not the photographing operation by the photographer has been executed.

If it is determined in step S118 that the photographing operation has not been performed by the photographer, the process returns to step S102, and the block position changing unit 176 selects a small block to be subjected to white balance evaluation. On the other hand, if it is determined in step S118 that the photographing operation has been performed by the photographer, the block position changing unit 176 selects a large block to be subjected to white balance evaluation (step S120).

When the large block to be subjected to the white balance evaluation is selected by the block position changing unit 176 in the step S120, the integrated values SIGMA R2, SIGMA G2 and SIGMA B2 of the RGB pixels in the corresponding large block are then output to the accumulation processing unit 178, (Step S122). When the integrated values SIGMA R2, SIGMA G2 and SIGMA B2 of the RGB pixels are calculated by the integration processing unit 178, the light source estimation unit 182 then uses the integrated values SIGMA R2, SIGMA G2 and SIGMA B2 of the RGB pixels in the corresponding large block And determines the coloring of the corresponding large block (step S124).

When the light source estimating unit 182 determines the coloring of the large block in the step S124, the light source estimation result of the small block stored in the storage unit 180 in the step S110 is read by nine rectilinear frames (step S126) . Then, the white balance gain calculator 156 calculates the white balance gain using the light source estimation result for nine rectilinear frames read in step S126.

To calculate the white balance gain at the white balance gain calculating unit 156, the weight for the operation result of the large block is determined first (step S128). The weight of the arithmetic processing result of the large block may be determined according to the number of small blocks determined to be achromatic. 9 is an explanatory diagram showing in graph form an example of the relationship between the number of small blocks judged to be achromatic and the weighting coefficient for the calculation result of the large block. In the graph shown in Fig. 9, the abscissa represents the number of small blocks determined to be achromatic, and the ordinate represents the weight coefficient for the arithmetic processing result of the large block. In the example shown in Fig. 9, when the number of small blocks judged to be achromatic is increased, the weight coefficient is increased in a quadratic function. It goes without saying that the relationship between the number of small blocks determined to be achromatic and the weighting coefficient is not limited to the example shown in Fig.

Referring to the graph shown in Fig. 9, when the maximum number of small blocks determined as achromatic is nine, the weight coefficient is maximized to 1.0. When the number of small blocks determined to be achromatic is 8, the weight coefficient is 0.75, and when there are 7 small blocks determined to be achromatic, the weight coefficient is 0.5. As described above, by applying the weight coefficient indicating the reliability of whether or not the large block is achromatic at the time of photographing the still image, it is possible to reduce the influence of the operation processing result on the large block in the large block, Can be reduced.

If the weight of the operation result of the large block is determined in step S128, the light source in the large block selected in step S120 is estimated using the determined weight (step S130). The white balance gain calculator 156 calculates the white balance gain using the information of the light source estimated in step S130 (step S132). The photographing apparatus 100 corrects the white balance by applying the calculated white balance gain to the white balance correction section 158. [

The imaging method according to the embodiment of the present invention has been described above with reference to Fig. As described above, the signal processing for the small blocks whose positions are different over a plurality of frames is performed at the time point before shooting, and the signal processing results for the small blocks in the immediately preceding frame and the signals By using the processing result, smaller block division is possible without increasing the processing load per one frame, and the occurrence of color mixture can be suppressed.

As described above, according to the embodiment of the present invention, a block to be subjected to image signal processing is finely divided as a small block in order to suppress the occurrence of color mixture, and a plurality of small blocks It is possible to execute the image signal processing for correcting the white balance without increasing the processing load by using the evaluation result for the large block and the evaluation result for the finely divided small block in the rectilinear frame before recording. Since the gain for correcting the white balance is calculated on the basis of the integrated value of the pixels at the time of photographing and the data calculated in the past frame is used only for determination of the weight coefficient, The worst caused by the calculation delay does not occur. In particular, during high-speed continuous shooting in which a plurality of still images are continuously shot in a short time, the processing load of the white balance correction is reduced at the time of still image shooting without being affected by the time difference between the screen display before shooting and the still image shooting The processing time can be shortened as much as possible.

The above-described operation of the photographing apparatus 100 may be realized by storing a computer program in the photographing apparatus 100 and reading the computer program by the CPU 128 and sequentially executing the computer program.

The program for executing the control method according to the embodiments and the modifications described above in the photographing apparatus can be stored in the recording medium. Here, the recording medium may be, for example, a memory as shown in FIG. 1, a VRAM as shown in FIG. 1, a recording medium, or a separate recording medium. The storage medium may be a storage medium such as a magnetic storage medium (e.g., ROM, floppy disk, hard disk, etc.) and an optical reading medium (e.g., CD-ROM, DVD (Digital Versatile Disc) .

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Fig. 1 is an explanatory view showing a configuration of a photographing apparatus 100 according to an embodiment of the present invention.

Fig. 2 is an explanatory view for explaining a configuration of the image signal processing section 116. Fig.

3 is an explanatory view for explaining the configuration of the image evaluation section 154. [

FIG. 4 is an explanatory view showing a case where one large block is divided into small blocks of 3 blocks by 3 blocks.

5 is an explanatory view for explaining the block position changing process in the block position changing unit 176 in the stage before the imaging process.

Fig. 6 is an explanatory view for explaining the block position changing process in the block position changing unit 176 before and after the imaging process.

7 is an explanatory view for explaining an example of the relationship between a block to be evaluated and a frame when the light source estimating unit 182 estimates the light source.

8 is a flowchart for explaining an imaging method according to an embodiment of the present invention.

Fig. 9 is an explanatory diagram graphically showing an example of the relationship between the number of small blocks judged to be achromatic and the weight of the light block estimated by the small block.

Fig. 10 is an explanatory diagram for explaining the block division in the white balance correction processing.

11 is an explanatory diagram showing an example of an image obtained from an image signal extracted by an image pickup element such as a CCD or CMOS, which is subjected to white balance correction processing.

Fig. 12 is an explanatory diagram showing a case where an image signal obtained by the image shown in Fig. 11 is divided into 4 horizontal blocks by 3 vertical blocks.

13 is an explanatory diagram showing a case where an image signal obtained by the image shown in Fig. 11 is divided into 12 horizontal blocks and 9 vertical blocks.

14 is an explanatory view showing an example of occurrence of color mixture when an image signal is divided into 4 blocks by 3 blocks.

Fig. 15 is an explanatory view showing an example of occurrence of color mixture when an image signal is divided into 12 blocks x 9 blocks.

Description of the Related Art

100: photographing apparatus 102: zoom lens

104: Aperture 106: Focus lens

108: CCD element 110: CDS circuit

112: A / D converter 114: Image input controller

116: image signal processing unit 120: compression processing unit

122: LCD driver 124: LCD

126: timing generator 128: CPU

132: Operation section 134: Memory

138: Media controller 140: Recording media

142a, 142b, 142c: motor driver 152: image front process processor

154: image evaluation unit 156: white balance gain calculation unit

158: white balance correction unit 160: demosaicing unit

162: color correction processing unit 164: gamma correction processing unit

172: first block dividing section 174: second block dividing section

176: Block position changing unit 178:

180: storage unit 182: light source estimation unit

Claims (6)

First dividing means for dividing an image signal obtained from the image pickup device into a plurality of first blocks; Second dividing means for further dividing each of the first blocks into M (M > 1, and M is a natural number) second blocks; Position changing means for selecting any one of the M second blocks as an operation subject in accordance with a predetermined condition every frame and changing the operation subject for each frame; Calculating means for performing an arithmetic process on the second block in which the position changing means has been changed before the recording and executing an arithmetic process on the first block in the recording; And A second block which is changed by the position changing means by using the calculation result for the second block and the calculation result for the first block in the M near- And light source estimation means for estimating the light source. The method according to claim 1, Storage means for storing a light source estimation result of the light source estimation means during at least the M frames; And gain calculating means for calculating a gain for correcting white balance using the light source estimation result for the M straight frames of the second block and the light source estimation result for the first block stored in the storage means and, Wherein the gain calculation unit determines a predetermined weight coefficient using the light source estimation result during the M rectilinear frames of the second block and multiplies the calculation result for the first block by the predetermined weight coefficient to obtain a gain Calculating device. delete 3. The method of claim 2, Wherein the predetermined weight coefficient is a larger coefficient as a result of the light source estimation in the light source estimation means, the greater the number of second blocks determined to be achromatic in the M rectilinear frames. delete delete

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