KR20100054702A - Photographing apparatus, controlling method of photographing apparatus, and recording medium storing program to implement the controlling method - Google Patents

Abstract

PURPOSE: A photographing apparatus, controlling method of photographing apparatus, and recording medium storing program to implement the controlling method are provided to compensate the white balance without expanding a processing load. CONSTITUTION: A first division unit(172) splits the picture signal of the image pickup device into several first blocks. A second division unit(174) splits first blocks more into M of the second blocks. A location changing unit(176) changes the second block of the operated target at every frame. An operation unit(178) performs the calculation of the changed second blocks at every frame. A light source estimator(182) presumes the light source of the picture signal by the result of the operation unit.

Description

Recording apparatus, controlling method of photographing apparatus, and recording medium storing program to implement the controlling method}

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

In an electronic photographing apparatus for photographing a subject electronically, such as a digital still camera, an image signal processing (white balance correction process) for correcting the white balance is generally built in so that a white subject is photographed white regardless of the light source of illumination. A color difference may occur between the subject image and the photographed image visually observed by the illumination light source. In this case, the white balance correction process is a correction process for reproducing a white subject in particular in white. For example, in natural light such as daylight and artificial light such as fluorescent lamps, there is a difference in the color temperature of the two light sources, and as a result, it has a great influence on the white reproducibility of the photographed image. Therefore, by performing the white balance correction process, it is possible to prevent discomfort in the image reproduced by the photographing apparatus.

The correction of the white balance is performed by dividing the image signal obtained from the image pickup device into a plurality of blocks, and calculating the color-specific integrated values such as R (red), G (green), and B (blue) for each divided block to control achromatic colors or chromatic colors. Determine whether to process Then, it is common to perform white balance control so that the integrated value in the block determined as achromatic is R = G = B.

By the way, when mixed color occurs because a plurality of colors exist in the divided block, it becomes impossible to judge chromatic and achromatic colors correctly. Therefore, a technique is disclosed in which white balance determination is normally performed by suppressing generation of mixed color as much as possible by dividing blocks finely. For example, Japanese Patent Laid-Open No. 2007-336107, Japanese Patent Laid-Open No. 2007-228516, Japanese Patent Laid-Open No. 2006-211440, Japanese Patent Laid-Open No. 2005-12763, and the like.

However, in order to suppress the occurrence of mixed color, finely dividing the block to be subjected to the image signal processing, there is a problem that the white balance control processing time is long, so that the processing cannot be completed within one frame. Particularly, in live view, in which images obtained from an image pickup device are sequentially displayed on a monitor provided in the photographing apparatus, when the calculation time of the white balance gain increases, a time difference occurs between the scene actually seen by the eye and the scene displayed by the live view on the monitor. do.

Disclosure of Invention The present invention has been made to solve various problems including the above problems, and the image signal processing for correcting the white balance without increasing the processing load even if the block to be subjected to the image signal processing is finely divided to suppress the generation of mixed color. It is an object of the present invention to provide a recording medium storing a new and improved photographing apparatus, a control method of the photographing apparatus, and a program for executing the method.

According to the present invention, first division means for dividing an image signal obtained by an image pickup device into a plurality of first blocks, second dividing means for further dividing the first block into M second blocks, and a second block as an operation target are provided. A position changing means for changing each frame, a calculating means for performing the calculation processing for the second block changed by the position changing means for each frame, and a light source for estimating the light source of the image signal using the calculation result of the calculating means. Provided is an imaging apparatus, comprising estimating means.

According to this configuration, the first dividing means divides the image signal obtained from the image pickup device into several 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 calculating means performs the calculation processing for the second block changed by the position changing means for each frame, and the light source estimating means uses an operation result of the calculating means to obtain an image. Estimate the light source of the signal. As a result, even if the block to be subjected to the image signal processing is finely divided as the second block to suppress the occurrence of mixed color, the image signal processing can be performed without increasing the processing load.

According to another aspect of the present invention, it is possible to store the white light using the storage means for storing the light source estimation result of the light source estimating means for at least M frames and the light source estimation result for the rectilinear M frames stored by the storage means. The apparatus may further include a gain calculating means for calculating a gain for correcting the balance.

According to still another feature of the present invention, the gain calculating means may calculate the gain by weighted averaging the light source estimation result during the rectilinear M frames stored by the storage means.

According to still another feature of the present invention, there is further provided a storage means for storing the calculation result of the calculation means for at least M frames, wherein the light source estimating means uses the calculation result for the straight M frames stored in the storage means. Estimating a light source of the image signal.

The present invention also provides a first division step of dividing an image signal obtained by an image pickup device into a plurality of first blocks, a second division step of further dividing the first block into M second blocks, and a second operation target. A light source of the image signal is estimated using a position change step of changing a block from frame to frame, a calculation step of performing a calculation process on a frame-by-frame basis for the second block changed in the position change step, and a calculation result of the calculation step It provides a photographing apparatus control method comprising the step of estimating the light source.

The present invention also provides a recording medium storing a program for executing the above control method.

According to the recording medium of the present invention made as described above, the recording medium storing the control method and the program for executing the control method, even if the blocks to be processed image signal is finely divided to suppress the generation of mixed color A new and improved photographing apparatus capable of image signal processing for correcting white balance without increasing the processing load, a recording medium storing a control method and a program for executing the photographing apparatus can be provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration will be omitted by the same reference numerals.

First, the problems of the prior art will be described with reference to the drawings before describing preferred embodiments of the present invention.

7 is an explanatory diagram for explaining block division in the white balance correction process. As shown in Fig. 7, the white balance correction processing divides an image signal taken out of an image pickup device such as a CCD or a CMOS into several blocks, and integrates pixels of R, G, and B colors for each of the divided blocks. The values ΣR, ΣG, ΣB are calculated. When the integrated values (ΣR, ΣG, ΣB) of the pixels of each of the R, G, and B colors are calculated, the appropriate white balance gain (Kr, Kg) is determined by determining whether the block is controlled as achromatic or chromatic color for each block. , Kb) is a common method.

In the case where multiple colors are mixed in the divided block here, mixed color occurs and the white balance correction process cannot be judged correctly. Increasing the area of the divided blocks increases the frequency of mixing.

FIG. 8 is an explanatory diagram showing an example of an image obtained from an image signal taken out of an image pickup device such as a CCD or CMOS, which is a white balance correction process, and FIG. 9 is an image signal capable of obtaining the image shown in FIG. An explanatory diagram showing a case where the image is divided into "4 horizontal blocks" x "3 vertical blocks", and FIG. 10 divides the image signal capable of obtaining the image shown in FIG. 8 into "12 horizontal blocks" x "9 vertical blocks". It is explanatory drawing which showed one case. In the normal white balance correction process, the red petal portion and the green leaf portion in the image are not regarded as a light source and are determined as colored colors. However, if red and green are mixed in the block during the integration process in each block, mixed color occurs (mixed red and green) and is mistaken as a yellow subject. When the yellow subject is in the same color balance as a light source such as tungsten light, it is determined as the light source color (achromatic color), and the white balance is judged incorrectly. Therefore, to reduce the frequency of color mixing, increase the number of blocks to reduce the area of blocks.

Fig. 11 is an explanatory diagram showing the arrangement of blocks erroneously determined to be yellow subjects by color mixing when the image signal is divided into "4 horizontal blocks" x "3 vertical blocks", and Fig. 12 is a horizontal view of the image signal "horizontal". It is explanatory drawing which shows the arrangement | positioning of the block erroneously determined to be a yellow subject by mixing color when it divides into 12 blocks "x" 9 blocks long. "

In the cases shown in Figs. 11 and 12, 83% of blocks are incorrectly judged as yellow subjects when divided into 4x3, whereas 28% are incorrect as yellow subjects when divided into 12x9. By increasing the number of blocks in this way, the frequency of mixing can be suppressed by reducing the area per block.

However, increasing the number of blocks increases the number of data that needs to be processed at one time, and increases the processing time until the white balance gain is calculated, thereby preventing processing in one frame. Particularly during live view, in which images obtained from an image pickup device (which can be called a real-time video) are sequentially displayed on a monitor equipped with a photographing device, when the calculation time of the white balance gain is increased, the live view is displayed on the scene and the monitor that are actually visible. There is a time difference in the scene.

Therefore, in the preferred embodiment of the present invention described below, it is possible to suppress the increase in processing time while reducing the block area in order to suppress the frequency of mixing.

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

As shown in FIG. 1, the photographing apparatus 100 according to an exemplary embodiment includes a zoom lens 102, an aperture 104, a focus lens 106, and a charge coupled device (CCD) device 108. And an amplifier integrated CDS (Correlated Double Sampling) circuit 110, an A / D converter 112, an image input controller 114, an image signal processor 116, a compression processor 120, and an LCD. (Liquid Crystal Display) driver 122, LCD 124, timing generator 126, motor drivers 142a, 142b, 142c, CPU (Central Processing Unit) 128, The operation unit 132, a memory 134, a VRAM (Video Random Access Memory) 136, a media controller 138, and a recording medium 140 are included.

An exposure part is constituted by a zoom lens 102, an aperture 104, a focus lens 106, and a CCD element 108. In the present embodiment, the exposure unit is configured by using the CCD element 108. The present invention is not limited to the above example, but a Complementary Metal Oxide Semiconductor (CMOS) element may be used instead of the CCD element. Since the CMOS element can convert the video light of the subject into an electrical signal at a higher speed than the CCD element, the time from photographing the subject to recording the image can be shortened.

The zoom lens 102 is a lens in which the focal length is continuously changed by moving in the optical axis direction. The diaphragm 104 adjusts the amount of light entering the CCD element 108 when the image is taken. The focus lens 106 adjusts the focus of the subject by moving in the optical axis direction.

The motor drivers 142a, 142b, and 142c control the motor for operating the zoom lens 102, the aperture 104, and the focus lens 106. By operating the zoom lens 102, the aperture 104, and the focus lens 106 through the motor drivers 142a, 142b, and 142c, the size, amount of light, and focus of the subject are adjusted.

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

The CDS circuit 110 is a circuit in which a CDS circuit, which is a kind of sampling circuit for removing noise of an electrical signal output from the CCD element 108, and an amplifier for amplifying the electrical signal after removing the noise, are integrated. In the present embodiment, the photographing apparatus 100 is configured using a circuit in which the CDS circuit and the amplifier are integrated, but the CDS circuit and the amplifier may be configured as separate circuits.

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

The image signal processing unit 116 performs various signal processing on the raw data of the image generated by the A / D converter 112.

The compression processing unit 120 performs compression processing for compressing the data processed by the image signal processing unit 116 into image data of an appropriate format. The compressed format of the image may be a reversible format or an irreversible format. Examples of suitable formats may be converted to the JPEG (Joint Photographic Experts Group) format or JPEG2000 format.

The LCD 124 displays the live view display before the photographing operation, various setting screens of the photographing apparatus 100, and the photographed image. Displaying image data or various information of the photographing apparatus 100 on the LCD 124 is performed through 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 electric signal serving as the basis of the image data is generated by injecting image light from the subject within the time that the CCD element 108 is driven. Is generated.

The CPU 128 issues a signal system command to the CCD element 108, the CDS circuit 110, or the like, or issues an operation system command for the operation of the operation unit 132. In the present embodiment, only one CPU is included. In the present invention, the signal system command and the operation system command may be executed by the CPU or the digital signal processor (DSP), respectively.

The operation unit 132 includes a function for operating a photographing apparatus 100 including a function as a photographing mode selector, or for arranging various settings when photographing. On the member disposed on the operation unit 132, a power button, a cross key for selecting a shooting mode or a shooting drive mode and setting effect parameters, a selection button, a shutter button for starting a shooting operation, and the like are disposed.

The memory 134 (temporarily) stores the captured image or the image processed by the image signal processing unit 116. The memory 134 has a storage capacity capable of storing several images. Reading and writing an image to the memory 134 is controlled by the image input controller 114.

The VRAM 136 retains the contents displayed on the LCD 124, and the resolution or maximum number of colors of the LCD 124 depends on the capacity of the VRAM 136.

The recording medium 140 records the photographed image. Input / output to the recording medium 140 is controlled by the media controller 138. As the recording medium 140, a memory card that is a card-type storage device for recording data in the proxy memory can be used.

The configuration of the photographing apparatus 100 according to an exemplary embodiment of the present invention has been described above with reference to FIG. 1. Next, a configuration of the image signal processing unit 116 included in the photographing apparatus 100 according to an embodiment of the present invention will be described.

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

As shown in FIG. 2, the image signal processor 116 according to an embodiment of the present invention may include an image front process processor 152, an image evaluator 154, a white balance gain calculator 156, A white balance correction unit 158, a de-mosaic processing unit 160, a color correction processing unit 162, and a gamma correction processing unit 164 are included.

The image front process processor 152 performs image front process processing such as defective pixel correction or black level correction on an image signal that is photoelectrically converted by the CCD element 108 and converted into a digital signal by an A / D converter. The image signal processed by the image front process processor 152 is sent to the image evaluator 154 and the white balance corrector 158.

The image evaluator 154 performs image evaluation processing to calculate the white balance gain for correcting the white balance in the white balance gain calculator 156 for the image signal processed by the image front process processor 152. Run. The image evaluator 154 divides the image signal processed by the image front process into a plurality of blocks, and calculates the integrated values (ΣR, ΣG, ΣB) of the RGB pixels for each of the divided blocks, or calculates the integrated values of the RGB pixels. Estimate the light source based on that. The structure of the image evaluation part 154 is mentioned later. The image evaluation processing result in the image evaluation unit 154 is sent to the white balance gain calculation unit 156.

The white balance gain calculation unit 156 calculates the white balance gains Kr, Kg, and Kb based on the image evaluation processing result in the image evaluation unit 154. The white balance gain calculated by the white balance gain calculator 156 is sent to the white balance corrector 158.

The white balance correction unit 158 multiplies the image signal processed by the image front process processor 152 with the white balance gain calculated by the white balance gain calculator 156. The white balance correction unit 158 multiplies the image signal with the white balance gain to execute white balance correction processing on the image signal. The white balance corrected image signal is sent to demosaicing processor 160.

The demosaicing processor 160 performs color complementary processing (demosaic processing) on the white balance corrected image signal. Although the demosaicing processing can be performed by the demosaicing processing unit 160 on the image signal subjected to the white balance correction processing, the color image can be generated. However, since the details of the demosaicing processing are not directly related to the present invention, detailed description thereof will be omitted. . The demosaiced image signal is sent to the color correction processing unit 162.

The color correction processing unit 162 performs color correction processing on the image signal complemented by the demosaicing processing unit 160 (de-mosaic processing). The color correction processing unit 162 can generate an appropriate color image by performing color correction processing. However, since the details of the color correction processing are not directly related to the present invention, detailed description thereof will be omitted. The color correction processed image signal 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 color correction processing by the color correction processing unit 162. The details of the gamma correction process are not directly related to the present invention, and thus detailed description thereof is omitted. The gamma corrected image signal is sent to the compression processing unit 120 to be compressed or recorded on the recording medium 140 or displayed 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 evaluator 154 included in the image signal processor 116 according to an embodiment of the present invention will be described.

3 is an explanatory diagram 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 image evaluator 154 included in the image signal processor 116 according to the exemplary embodiment of the present invention will be described with reference to FIG. 3.

As shown in FIG. 3, the image evaluator 154 according to an exemplary embodiment of the present invention includes a first block divider 172, a second block divider 174, and a block position changer 176. And an integration processing unit 178, a storage unit 180, and a light source estimating unit 182.

The first block dividing unit 172 divides the image signal sent to the image evaluating unit 154 into blocks (large blocks) of a predetermined size. The first block dividing unit 172 may divide the image signal into, for example, "4 horizontal blocks" x "3 vertical blocks" or "12 horizontal blocks" x "9 vertical blocks" as described above. Of course, the number of divisions is not limited to these examples. Moreover, the shape of the large block at the time of dividing may be square, rectangular, or another shape may be sufficient as it.

The second block dividing unit 174 further divides each large block divided by the first block dividing unit 172 into blocks of a predetermined size (small blocks). For example, the first block dividing unit 172 divides the image signal into large blocks of "4 horizontal blocks" x "3 vertical blocks" and "horizontal" in the second block dividing unit 174 for each large block. It is divided into three blocks "X" three blocks long. Of course, the number of divisions is not limited to the above example. Moreover, the shape of the small block at the time of dividing may be square, rectangular, or another shape may be sufficient as it. In the following description, a case in which one large block is divided into nine small blocks of "three horizontal blocks" x "three vertical blocks" will be described.

FIG. 4 is an explanatory diagram showing a case where one large block is divided into small blocks of "horizontal three blocks" x "three vertical blocks" in the second block dividing unit 174. As shown in FIG. In FIG. 4, for convenience of description, small letters A to I are shown.

The block position changing unit 176 changes the small blocks to be processed by the integration processing unit 178, described later, for each frame. For example, in the second block dividing unit 174, if one large block is divided into nine small blocks of "three horizontal blocks" x "three vertical blocks" as shown in FIG. 4, the block position changing unit 176 One small block is cyclically selected from small blocks A to I for each frame.

5 is a conceptual diagram illustrating a process of changing a block position in the block position changing unit 176. FIG. 5 shows an example in which the small block to be processed is changed from frame to frame in blocks A to I divided by the second block divider 174. FIG. In FIG. 5, small blocks are represented by A → E → G → C → H → F → B → D → I → A →. The case where it changes in order of is shown. Of course, the order is not limited to that shown in FIG. In addition, in the present embodiment, the block position changing unit 176 changes the small frame cyclically. In the present invention, the small block to be processed by the integration processing unit 178 may be changed randomly.

The integration processing unit 178 calculates the integrated values (? R,? G, and?) Of the RGB pixels for obtaining the white balance gain for the pixels of each of the R, G, and B colors included in the small block designated by the block position changing unit 176. ΣB) is obtained. The color in the small block can be determined by obtaining the integrated values (ΣR, ΣG, ΣB) of the RGB pixels. The integrated values (? R,? G,? B) of the RGB pixels obtained by the integration processing unit 178 and the color determination result in the small block may be temporarily stored in the storage unit 180. The integrated values ΣR, ΣG, and ΣB of the RGB pixels obtained by the integration processing unit 178 are sent to the light source estimating unit 182 and used for the light source estimation process in the light source estimating unit 182.

The light source estimating unit 182 executes a light source estimating process of estimating the light source using the integrated values ΣR, ΣG, and ΣB of the RGB pixels obtained by the integration processing unit 178. The light source estimation processing result in the light source estimating unit 182 may be temporarily stored in the storage unit 180. The result of the light source estimation process in the light source estimating unit 182 is sent to the white balance gain calculating unit 156 and used for calculating the white balance gain.

In the present embodiment, the configuration in which the light source estimating unit 182 is included in the image evaluating unit 154 has been described, but the present invention is not limited to the above example. For example, the function of the light source estimating unit 182 may be included in the white balance gain calculating unit 156.

The configuration of the image evaluator 154 included in the image signal processor 116 according to the exemplary embodiment of the present invention has been described above. Next, an image processing method (imaging device control method) according to an embodiment of the present invention will be described.

6 is a flowchart schematically showing an image processing method (imaging device control method) according to an embodiment of the present invention. FIG. 6 shows a case where the imaging apparatus 100 displays the image signal obtained by the CCD element 108 on the LCD 124 in a live view. Hereinafter, an image processing method according to an embodiment of the present invention will be described with reference to FIG. 6.

First, the block position changing unit 176 selects a small block to be evaluated for white balance (step S102). As described above, the small block that is the evaluation target of the white balance selected by the block position changing unit 176 may change every frame.

In step S102, when the block position changing unit 176 selects a small block to be evaluated for white balance, the integration processing unit 178 calculates the integrated values ΣR, ΣG, and ΣB of the RGB pixels in the small block. (Step S104). In step S104, the integrated values ΣR, ΣG, and ΣB of the RGB pixels are calculated by the integration processor 178, and then the corresponding small blocks are obtained using the integrated values (ΣR, ΣG, ΣB) of the RGB pixels in the light source estimating unit 182. Is determined (step S106).

In step S106, the light source estimating unit 182 determines the color of the small block using the integrated values ΣR, ΣG, and ΣB of the RGB pixels, and then uses the color determination result of the small block to determine the color of the small block. The light source is estimated by the light source estimating unit 182 to determine whether the corresponding small block is colored or achromatic (step S108). The information of whether it is colored or achromatic may be two values or the value of three or more steps may be sufficient. When the light source of the small block is estimated by the light source estimating unit 182 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 step S110, the white balance gain is calculated using the estimation result stored in the storage unit 180. First, the white balance gain calculator 156 reads the estimation result in the frame of the rectus stored in the storage unit 180 (step S112). In the present embodiment, the case where one large block is divided into nine small blocks is explained. In step S112, the white balance gain calculating unit 16 reads the estimation result of the straight nine frames from the storage unit 180. do.

When the estimation result in the frame of the straight root stored in the storage unit 180 is read in step S112, the white balance gain calculator 156 weights the average of the read estimation result (step S114). Here, an example of the weighted average will be described. If the evaluation frame is f, the number of blocks to be treated as achromatic in each frame is n, and the RGB integrated values of blocks to be treated as achromatic are r, g, and b, the color balance for each frame (Cr, Cg, Cb) is as follows. Can be obtained from Equation 1.

When the color balance (Cr, Cg, Cb) for nine frames is obtained as shown in Equation 1, the white balance gain calculating unit 156 continuously uses the obtained color balance (Cr, Cg, Cb) for the white signal. The balance gain is calculated (step S116). White balance gains (Kr, Kg, Kb) can be obtained by the following expression (2).

Equation 2 is a calculation equation when the value of Cg is the largest among the color balances Cr, Cg, and Cb, and when the value of another color is large, the above equation is suitably adjusted so that the white balance gain of the color becomes 1. Change it.

When the white balance gain is calculated in step S116, the process returns to step S102 and the block position changing unit 176 selects the small block to be evaluated for white balance.

As such, by performing signal processing for blocks having different positions over several frames, smaller block division is possible without increasing the processing load per frame, thereby suppressing the occurrence of mixed color.

The calculation method of the white balance gain mentioned above is an example of the image processing method (imaging device control method) of this invention, and it cannot be overemphasized that it is not limited to the said example in this invention. For example, as a result of the determination processing in step S108, the small block determined to be chromatic color may be subjected to a process of applying a gain of a reference previously obtained. For example, in the above Equation 1, the color balance (Cr, Cg, Cb) is obtained from a weighted average that simply adds the RGB integrated values for 9 frames and takes an average, but the present invention is not limited to the above examples. For example, the past frame may have a smaller value and multiply the RGB weight by a weight that increases as the frame becomes a straight frame, and obtain the color balance (Cr, Cg, Cb) by the weighted addition weighted average. In this case, the weight may be increased secondarily.

As described above, according to the exemplary embodiment of the present invention, the image signal is divided into a plurality of large blocks, and the large block is further divided into several small blocks to correct the white balance. The light source is estimated for each of the divided small blocks, at which time the small blocks of the object to be processed are changed by one frame. The white balance gain is calculated using the light source estimation results for all the small blocks in one large block. By calculating the white balance gain in this manner, two effects can be obtained: reduction in the frequency of occurrence of mixed colors and prevention of increase in processing load by miniaturizing the block.

In addition, the above-described operation of the photographing apparatus 100 may be performed by storing a computer program in the photographing apparatus 100 and reading out the computer program and executing the computer program in sequence.

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

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

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

2 is an explanatory diagram for explaining the configuration of the image signal processing unit 116.

3 is an explanatory diagram for explaining the configuration of the image evaluation unit 154.

FIG. 4 is an explanatory diagram showing a case where one large block is divided into small blocks of "three horizontal blocks" x "three vertical blocks".

5 is an explanatory diagram for explaining a process of changing a block position in the block position changing unit 176.

6 is a flowchart for explaining an imaging method (imaging device control method) according to an embodiment of the present invention.

7 is an explanatory diagram for explaining block division in the white balance correction process.

FIG. 8 is an explanatory diagram showing an example of an image obtained from an image signal extracted by an image pickup device such as a CCD or CMOS, which is a target of white balance correction processing.

FIG. 9 is an explanatory diagram showing a case where the image signal from which the image shown in FIG. 8 is obtained is divided into "4 horizontal blocks" x "3 vertical blocks".

FIG. 10 is an explanatory diagram showing a case where the image signal from which the image shown in FIG. 8 is obtained is divided into "12 horizontal blocks" x "9 vertical blocks".

FIG. 11 is an explanatory diagram showing an example of mixed color generation when the image signal is divided into "4 horizontal blocks" x "3 vertical blocks".

FIG. 12 is an explanatory diagram showing an example of mixed color generation when the image signal is divided into "12 blocks horizontally" x "9 blocks vertically".

<Explanation of symbols for the main parts of the drawings>

100: recording device 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: control panel 134: memory

138: media controller 140: recording media

142a, 142b, and 142c: Motor Driver 152: Image Front Process Processing Unit

154: Image evaluation unit 156: White balance gain calculation unit

158: white balance correction unit 160: demosaicing processing unit

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

172: first block divider 174: second block divider

176: block position changing unit 178: integration processor

180: storage unit 182: light source estimating unit

Claims (6)

First dividing means for dividing the image signal obtained by the image pickup device into a plurality of first blocks; Second dividing means for further dividing the first block into M second blocks; Position changing means for changing the second block to be calculated for each frame; Arithmetic means for executing arithmetic processing for the second block changed by the position changing means for each frame; And And light source estimating means for estimating a light source of the image signal by using the calculation result of the calculating means. The method of claim 1, Storage means for storing a light source estimation result of the light source estimation means for at least M frames; And And a gain calculating means for calculating a gain for correcting the white balance using the light source estimation result for the rectilinear M frames stored by the storage means. The method of claim 2, And the gain calculating means calculates the gain by weighted averaging the light source estimation result during the rectilinear M frames stored by the storage means. The method of claim 1, Storage means for storing an arithmetic result of said computing means for at least M frames, And the light source estimating means estimates a light source of the image signal using a result of the calculation during the rectilinear M frames stored in the storage means. A first division step of dividing the image signal obtained by the image pickup device into a plurality of first blocks; Dividing the first block into M second blocks; A position changing step of changing the second block, which is a calculation target, for each frame; An arithmetic step of executing arithmetic processing for each frame on the second block changed in the position changing step; And And a light source estimating step of estimating a light source of the image signal by using the calculation result of the calculating step. A recording medium storing a program for executing the control method of claim 5.

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