Patent Publication Number: US-2023164451-A1

Title: Information processing apparatus, method, medium, and system for color correction

Description:
BACKGROUND 
     Field 
     The present disclosure generally relates to a technique for generating information for color correction from captured images and, more particularly, to an information processing apparatus, method, medium, and system for color correction. 
     Description of the Related Art 
     There is a system that captures images using a plurality of imaging apparatuses (hereinafter, “cameras”), mixes or switches the plurality of images obtained by the plurality of cameras, and transmits the resulting images. 
     If the models, the manufacturers, or the grades of the plurality of cameras used at this time are different from each other, and there is a great difference in image creation between the cameras, and for example, when the cameras are switched, the color of even the same object may look different. Thus, a photographer or a video engineer (VE) needs to perform the work of adjusting the cameras in advance so that the colors of images of the plurality of cameras are the same as each other, which is a great burden. In response to this, the publication of Japanese Patent Application Laid-Open No. 2020-9162 discusses a technique for capturing images of the same object using cameras and correcting the difference in color between the captured images. This technique can reduce the burden of the work of adjusting cameras. 
     The difference in color between images of a plurality of cameras may also occur according to the recording modes of the cameras or the state of an object in the angles of view. For example, depending on the recording modes of the cameras or the state of the object in the angles of view, the compression ratio of a compression process performed on a captured image by each of the cameras may become high. In this case, the color of the object in the image may be different from the original color. In the technique of the publication of Japanese Patent Application Laid-Open No. 2020-9162, color correction data is created based on a captured image of a single frame. Thus, for example, if color correction data is created based on a color acquired from an image of which the compression ratio is high, a color that should not be corrected may be corrected based on the color correction data. 
     SUMMARY 
     According to an aspect of the present disclosure, an information processing apparatus includes a parameter acquisition unit configured to acquire imaging parameters of a first imaging apparatus and a second imaging apparatus, a number-of-images determining unit configured to, based on the imaging parameters, determine a number of first images to be captured by the first imaging apparatus and a number of second images to be captured by the second imaging apparatus, a color information acquisition unit configured to acquire first color information included in the first images and second color information included in the second images, and a generation unit configured to, based on the first color information and the second color information, generate color correction information for correcting a difference in color between the first and second images. 
     Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram illustrating an example of a general configuration of a system according to a first exemplary embodiment. 
         FIG.  2    is a diagram illustrating an example of a hardware configuration of an information processing apparatus. 
         FIG.  3    is a diagram illustrating an example of a functional configuration of the information processing apparatus according to the first exemplary embodiment. 
         FIG.  4    is a flowchart illustrating a flow of information processing according to the first exemplary embodiment. 
         FIG.  5    is a flowchart illustrating a flow of a color information acquisition process according to the first exemplary embodiment. 
         FIGS.  6 A and  6 B  are diagrams illustrating correspondence relationships between imaging conditions and the number of images to be captured. 
         FIGS.  7 A and  7 B  are diagrams used to describe an image area from which color information is acquired. 
         FIGS.  8 A to  8 C  are diagrams illustrating contents of pieces of color information. 
         FIG.  9    is a diagram illustrating an example of a functional configuration of an information processing apparatus according to a second exemplary embodiment. 
         FIG.  10    is a flowchart illustrating a flow of a color information acquisition process according to the second exemplary embodiment. 
         FIG.  11    is a flowchart illustrating a flow of information processing according to a third exemplary embodiment. 
         FIG.  12    is a flowchart illustrating a flow of a color information acquisition process according to the third exemplary embodiment. 
         FIGS.  13 A and  13 B  are diagrams each illustrating an example of a general configuration of a system according to another exemplary embodiment. 
         FIG.  14    is a flowchart illustrating a flow of information processing according to another exemplary embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     With reference to the drawings, exemplary embodiments of the present disclosure will be described below. The following exemplary embodiments do not limit the present disclosure, and not all the combinations of the features described in the present exemplary embodiments are essential for a method for solving the issues in the present disclosure. The configurations of the exemplary embodiments can be appropriately modified or changed depending on the specifications of an apparatus to which the present disclosure is applied, or various conditions (the use conditions and the use environment). A configuration may be obtained by appropriately combining parts of the following exemplary embodiments. In the following exemplary embodiments, similar components are described by designating the same reference signs. 
     A first exemplary embodiment is described taking as an example a system where an information processing apparatus and a plurality of imaging apparatuses are connected to each other via a network. Based on an imaging parameter of each of the imaging apparatuses connected to the information processing apparatus according to the present exemplary embodiment via the network, the information processing apparatus determines the number of images to be captured and acquires color information from image data obtained by capturing as many images as the number of images to be captured. Then, based on the color information acquired from the image data on the as many images as the number of images to be captured, the information processing apparatus according to the present exemplary embodiment generates a lookup table (LUT) for color correction information for correcting the difference in color between images captured by the imaging apparatuses. In the following description, for ease of description, image data will be referred to simply as an “image”, where appropriate. 
     For example, the system according to the present exemplary embodiment is applicable to a system that, in the broadcast of a television program or a live broadcast such as a sports broadcast, captures images using a plurality of cameras and mixes or switches the images captured by the plurality of cameras, thereby performing broadcasting. In a sports broadcast, such a broadcasting system can capture a bird&#39;s-eye view image of the entirety of a game venue using a certain camera, capture a player from various positions using other cameras, and generate images for relaying the state of a game. As a matter of course, the system according to the present exemplary embodiment is applied not only to such a broadcasting system. 
       FIG.  1    is a schematic diagram illustrating an example of the configuration of a system  10  including an information processing apparatus  300  according to the first exemplary embodiment. In the system  10  illustrated in  FIG.  1   , the information processing apparatus  300  according to the present exemplary embodiment and a plurality of imaging apparatuses such as a first imaging apparatus and a second imaging apparatus are connected to each other via a network  400 .  FIG.  1    illustrates a camera  100 A as an example of the first imaging apparatus and a camera  100 B as an example of the second imaging apparatus and illustrates only the two cameras  100 A and  100 B. The number of cameras, however, is not limited to two, and more cameras may be connected. 
     The network  400  connects the plurality of cameras  100 A and  100 B and the information processing apparatus  300  so that the plurality of cameras  100 A and  100 B and the information processing apparatus  300  can communicate with each other. The network  400  includes, for example, a plurality of routers, switches, and cables compliant with the Ethernet® communication standard. The communication standard, the scale, and the configuration of the network  400  do not matter so long as the network  400  is configured to enable communication between the cameras  100 A and  100 B and the information processing apparatus  300 . 
     The information processing apparatus  300  has a controller function for controlling the plurality of cameras  100 A and  100 B and the function of generating a correction LUT for correcting the difference in color between images of the cameras  100 A and  100 B. The controller function is the function of enabling the setting of imaging parameters (hereinafter occasionally referred to also as “imaging conditions”) for the cameras  100 A and  100 B, the acquisition of the imaging parameters, and control of imaging operations of the cameras  100 A and  100 B. The details of the imaging conditions of the cameras  100 A and  100 B and the acquisition of the imaging conditions will be described below. The LUT generation function is the function of acquiring color information (red, green, blue (RGB) values) from an image area of an object in images captured by each of the cameras  100 A and  100 B, generating degree-of-importance information at the same time, and generating an LUT for color correction information based on these pieces of information. The details of the acquisition of the color information and the generation of the LUT will be described below. The LUT generated by the information processing apparatus  300  is output to the cameras  100 A and  100 B via the network  400  and applied to the cameras  100 A and  100 B. This can acquire images obtained by correcting the difference in color between images of the cameras  100 A and  100 B. The information processing apparatus  300  can be composed of, for example, a terminal apparatus such as a personal computer (PC), a smartphone, or a tablet PC. 
     In the present exemplary embodiment, a color chart in which color patches of a plurality of different colors are arranged is taken as an example of the object. In the present exemplary embodiment, the degree-of-importance information is a weight coefficient for each piece of color information. The weight coefficient can be assigned not only as an integer but also as a decimal. Color information having a high degree of importance is weighted to strengthen the tendency to make the difference in color between the plurality of cameras  100 A and  100 B as small as possible when an LUT is generated. 
     Each of the cameras  100 A and  100 B includes a lens group and an image sensor included in an imaging optical system. The lens group includes an optical lens that forms an optical image of the object on an image sensor. The image sensor is an element that converts light into an analog image signal. Examples of the image sensor can include a complementary metal-oxide-semiconductor (CMOS) element. Each of the cameras  100 A and  100 B is a camera that captures one or more still images or movies. 
     In the present exemplary embodiment, a camera capable of capturing an image of a target color that can be matched between the cameras  100 A and  100 B is referred to as a “reference camera”. Another camera that captures an image as a target to be corrected to the same color as the image of the reference camera is referred to as a “correction target camera”. In the present exemplary embodiment, the following description is given on the assumption that, for example, the camera  100 A in  FIG.  1    is a reference camera, and the camera  100 B is a correction target camera. 
       FIG.  2    is a diagram illustrating an example of the hardware configuration of the information processing apparatus  300 . 
     The information processing apparatus  300  includes a central processing unit (CPU)  201 , a random-access memory (RAM)  202 , a read-only memory (ROM)  203 , an auxiliary storage interface (I/F)  204 , a hard disk drive (HDD)  205 , an input I/F  206 , an output I/F  207 , and a network I/F  212 . The components of the information processing apparatus  300  are connected to each other by a system bus  208 . The information processing apparatus  300  is connected to an external storage device  209  and an operation device  211  via the input I/F  206  and connected to a display device  210  via the output I/F  207 . The information processing apparatus  300  is also connected to the network  400  illustrated in  FIG.  1    via the network I/F  212 . 
     The CPU  201  includes one or more processors, circuitry, or combinations thereof, and executes a control program stored in the ROM  203  using the RAM  202  as a work memory, thereby performing overall control of the components of the information processing apparatus  300  via the system bus  208 . The CPU  201  also executes an information processing program stored in the ROM  203 , thereby achieving information processing according to the present exemplary embodiment as described below. The HDD  205  is a storage device that stores various pieces of data including image data handled by the information processing apparatus  300 . The CPU  201  writes data to the HDD  205  and reads data stored in the HDD  205  via the system bus  208 . The storage device is not limited to the HDD  205 , and may include a device using various storage devices, such as an optical disc drive, a flash memory, or the like. 
     The input I/F  206  is a serial bus I/F based on, for example, Universal Serial Bus (USB) or the Institute of Electrical and Electronics Engineers (IEEE) 1394. The information processing apparatus  300  acquires data and a command from an external apparatus via the input I/F  206 . The external storage device  209  includes a storage medium such as a hard disk, a memory card, a CompactFlash (CF) card, a Secure Digital (SD) card, a USB memory, or the like. The information processing apparatus  300  acquires data from the external storage device  209  via the input I/F  206 . The operation device  211  is an input device which includes a mouse, a keyboard, and a touch panel and to which an instruction from a user is input. 
     The information processing apparatus  300  acquires an instruction from the user input to the operation device  211  via the input I/F  206 . 
     The output I/F  207  is a serial bus I/F based on USB or IEEE  1394 , similarly to the input I/F  206 . The output I/F  207  may be a video output terminal based on Digital Visual Interface (DVI) or High-Definition Multimedia Interface (HDMI®). The information processing apparatus  300  outputs data to an external apparatus via the output I/F  207 . In the present exemplary embodiment, examples of the external apparatus connected to the information processing apparatus  300  via the output I/F  207  include the display device  210  (various image display devices such as a liquid crystal display). The information processing apparatus  300  outputs image data and various pieces of message information processed or generated by the CPU  201  to the display device  210  via the output I/F  207 . 
     In the present exemplary embodiment, examples of data generated by the CPU  201  can include data indicating the result of generating an LUT. 
     The network I/F  212  includes a connector for connecting to a network such as Ethernet. The information processing apparatus  300  can acquire image data captured by each of the cameras  100 A and  100 B via the network  400  connected to the information processing apparatus  300  via the network I/F  212 . The CPU  201  of the information processing apparatus  300  stores the image data and information regarding an imaging condition in the RAM  202  or the HDD  205  via the system bus  208 . 
     The information processing apparatus  300  also includes components other than the components illustrated in  FIG.  2   , but these components are not illustrated or described here. 
     Under control of the CPU  201 , the information processing apparatus  300  according to the present exemplary embodiment having the above configuration acquires image data on the correction target camera  100 B and image data on the reference camera  100 A that are input to the network I/F  212  via the network  400 . Then, the information processing apparatus  300  acquires pieces of color information from the acquired pieces of image data, and based on the pieces of color information, generates an LUT for correcting the color of an image of the correction target camera  100 B to match the color of an image of the reference camera  100 A. 
     [Functional Configuration of Information Processing Apparatus] 
     With reference to a functional block diagram in  FIG.  3   , the functional configuration of the information processing apparatus  300  according to the present exemplary embodiment is described. The configuration illustrated in  FIG.  3    can be appropriately modified or changed. For example, a single function unit may be divided into a plurality of function units by function, or two or more function units may be integrated into a single function unit. The configuration in  FIG.  3    may be composed of two or more apparatuses. In this case, the apparatuses may be connected to each other via a circuit or a wired or wireless network and cooperatively operate by communicating data with each other, thereby achieving processes performed by the information processing apparatus  300  in the following description. 
     In the following description, the function units illustrated in  FIG.  3    perform processes. Actually, however, the functions of the function units are achieved by the CPU  201  executing an information processing program according to the present exemplary embodiment. The function units illustrated in  FIG.  3    may be implemented as hardware components. As used herein, the term “unit” generally refers to software, firmware, hardware, or combinations thereof that is used to effectuate a purpose. 
     The information processing apparatus  300  mainly includes an input data processing unit  301  and an LUT generation unit  302 . The input data processing unit  301  includes a condition acquisition unit  311 , a condition storage unit  313 , a number-of-images determining unit  314 , an image acquisition unit  315 , an image storage unit  317 , a color information generation unit  318 , and a relationship information storage unit  322 . The LUT generation unit  302  includes a correction information generation unit  319  and a format conversion unit  320 . 
     The condition acquisition unit  311  acquires an imaging condition from the reference camera  100 A and also acquires an imaging condition from the correction target camera  100 B. An imaging condition in the present exemplary embodiment includes at least any of an International Organization for Standardization (ISO) sensitivity, a shutter speed, a stop value, and an image recording parameter. Examples of the image recording parameter include an image recording mode and an image bit rate, i.e., an encoding method and a bit rate, and an encoding parameter (a quantization parameter). In the present exemplary embodiment, the condition acquisition unit  311  acquires information regarding an imaging condition set for each of the reference camera  100 A and the correction target camera  100 B, but for example, may acquire information regarding an imaging condition input by the user. 
     The condition storage unit  313  stores the imaging condition of each of the cameras  100 A and  100 B acquired by the condition acquisition unit  311 . 
     The imaging condition stored in the condition storage unit  313  is referenced by the number-of-images determining unit  314 . 
     The relationship information storage unit  322  stores correspondence relationship information describing the relationships between the number of images to be captured that indicates how many images can be captured by each of the cameras  100 A and  100 B to obtain color information, and a plurality of different imaging conditions. The details of the correspondence relationship information stored in the relationship information storage unit  322  and describing the relationships between the number of images to be captured to obtain color information, and the imaging conditions will be described below. 
     Based on the imaging condition stored in the condition storage unit  313 , the number-of-images determining unit  314  references the correspondence relationship information stored in the relationship information storage unit  322  and determines the number of images to be captured that indicates how many images can be captured by each of the cameras  100 A and  100 B to obtain color information. That is, based on the imaging condition of each of the reference camera  100 A and the correction target camera  100 B, the number-of-images determining unit  314  references the correspondence relationship information and determines the number of first images to be captured by the reference camera  100 A and the number of second images to be captured by the correction target camera  100 B. The details of this number-of-images-to-be-captured determination process performed by the number-of-images determining unit  314  will be described below. Information regarding the number of images to be captured that is determined by the number-of-images determining unit  314  is sent to the image acquisition unit  315 . 
     The image acquisition unit  315  sends a command to capture images to each of the cameras  100 A and  100 B via the network  400  and acquires images captured by each of the cameras  100 A and  100 B according to the command. That is, the image acquisition unit  315  causes each of the reference camera  100 A and the correction target camera  100 B to capture as many images as the number of images to be captured that is determined by the number-of-images determining unit  314 , and acquires the as many captured images as the number of images to be captured. 
     The image storage unit  317  stores as many images as the number of images to be captured that are acquired from each of the cameras  100 A and  100 B by the image acquisition unit  315 . 
     From the images acquired from each of the reference camera  100 A and the correction target camera  100 B by the image acquisition unit  315  and stored in the image storage unit  317 , the color information generation unit  318  acquires color information for use in generating an LUT. In the present exemplary embodiment, first color information is acquired from an image area of the object in the first images captured by the reference camera  100 A, and second color information is acquired from the image area of the object in common with the first images in the second images captured by the correction target camera  100 B. Then, the color information generation unit  318  outputs the acquired first color information and second color information as a set to the correction information generation unit  319  of the LUT generation unit  302 . This color information acquisition process is performed by the color information generation unit  318  based on, for example, an instruction from the user. The details of the color information acquisition process performed by the color information generation unit  318  will be described below. 
     Based on the set of the pieces of color information generated by the color information generation unit  318 , the correction information generation unit  319  of the LUT generation unit  302  creates an LUT for correcting the color of an image acquired by the correction target camera  100 B. That is, based on the set of the first color information and the second color information acquired by the color information generation unit  318 , the correction information generation unit  319  creates an LUT for color correction information for correcting the difference in color between the first images captured by the reference camera  100 A and the second images captured by the correction target camera  100 B. As the LUT creation method, a method known generally may be used. 
     The format conversion unit  320  converts the LUT generated by the correction information generation unit  319  into a format that can be read by the correction target camera  100 B (e.g., a cube file), and outputs the converted LUT as LUT data  321 . The LUT data  321  is applied to the correction target camera  100 B, whereby the color of an image of the correction target camera  100 B matches the color of an image of the reference camera  100 A. 
     Next, with reference to a flowchart in  FIG.  4   , a description is given of the overall flow of information processing performed by the information processing apparatus  300  according to the present exemplary embodiment. 
     First, in step S 401 , the information processing apparatus  300  sets an imaging condition for each of the reference camera  100 A and the correction target camera  100 B using the above control function. Examples of the setting of the imaging condition for each of the cameras  100 A and  100 B include the setting of the image recording parameters such as the image recording mode and the image bit rate, and the setting of the ISO sensitivity, the shutter speed, and the stop value. Examples of the setting of the recording mode also include the setting of color gamut and gamma when an image is captured. The setting of the imaging condition for each of the reference camera  100 A and the correction target camera  100 B may be any of the setting based on an instruction from the user through the information processing apparatus  300 , the setting directly made on each of the cameras  100 A and  100 B by the user, and the setting automatically made by each of the cameras  100 A and  100 B. 
     Next, in step S 402 , the input data processing unit  301  of the information processing apparatus  300  acquires the imaging condition set for each of the reference camera  100 A and the correction target camera  100 B in step S 401 , and based on the imaging condition, determines the number of images to be captured to obtain color information. Further, the input data processing unit  301  causes the reference camera  100 A to acquire as many captured images as the number of images to be captured that is determined based on the imaging condition. Then, the input data processing unit  301  generates color information using the as many images as the number of images to be captured that are acquired by the reference camera  100 A. The details of the process of step S 402  will be described below. 
     In step S 403 , the input data processing unit  301  also causes the correction target camera  100 B to acquire as many captured images as the number of images to be captured that is determined based on the imaging condition. Then, the input data processing unit  301  generates color information using the as many images as the number of images to be captured that are acquired by the correction target camera  100 B. The process of step S 403  is similar to that of step S 402 , except that the camera that captures images changes from the reference camera  100 A to the correction target camera  100 B. The details of the process of step S 403  will be described below. 
     Next, in step S 404 , the correction information generation unit  319  of the LUT generation unit  302  acquires a set of the pieces of color information generated in steps S 402  and S 403  and performs a color correction information generation process using an optimization technique. In the present exemplary embodiment, the correction information generation unit  319  generates an LUT for color correction information for enabling the correction target camera  100 B to reproduce the color of an image of the reference camera  100 A. As the optimization technique, a DLS (damped least-squares) method, which is a known method, or a method discussed in the publication of Japanese Patent Application Laid-Open No. 2020-9162 can be used. 
     The DLS method is a method for obtaining a processing parameter so that the difference between a data stream obtained by processing a certain input data stream using a certain processing parameter and a target data stream corresponding to the data stream comes close to a target value stream. Examples of the processing parameter include a matrix. Examples of the target value stream include ΔE calculated from L*a*b* obtained based on red, green, and blue (RGB). 
     Next, in step S 405 , the format conversion unit  320  converts the LUT generated in step S 404  into a format applicable to the correction target camera  100 B, thereby generating the LUT data  321 . The LUT data  321  is applied to the correction target camera  100 B, whereby the color of an image of the correction target camera  100 B approximately matches the color of an image of the reference camera  100 A. 
     In the above description, the LUT is generated based on pieces of color information obtained from images captured by a single exposure. The present exemplary embodiment, however, is not limited to this, and the LUT may be generated using pieces of color information obtained from images captured by a plurality of exposures. In this case, the processes of steps S 401  to S 403  are repeatedly performed as many times as the number of imaging conditions with respect to each of the plurality of exposures. 
     [Details of Color Information Acquisition Process] 
     Next, with reference to a flowchart in  FIG.  5   , a description is given of the flow of the processing from the determination of the number of images to be captured based on the imaging condition to the acquisition of color information in steps S 402  and S 403  in  FIG.  4   . 
     In steps S 402  and S 403 , similar processing is performed no matter which of the reference camera  100 A and the correction target camera  100 B is the camera that captures images. Thus, the reference camera  100 A and the correction target camera  100 B are referred to simply as a “camera” without identifying the reference camera  100 A and the correction target camera  100 B. 
     In step S 501 , the condition acquisition unit  311  of the input data processing unit  301  acquires the imaging condition of the camera set in step S 401 . Then, information regarding the imaging condition acquired by the condition acquisition unit  311  is stored in the condition storage unit  313 . 
     Next, in step S 502 , based on the imaging condition stored in the condition storage unit  313  and the correspondence relationship information stored in the relationship information storage unit  322 , the number-of-images determining unit  314  determines the number of images to be captured Fn. 
       FIG.  6 A  is a diagram illustrating an example of the correspondence relationship information stored in the relationship information storage unit  322 . The correspondence relationship information exemplified in  FIG.  6 A  is information indicating the relationship between the image recording parameters and the number of images to be captured Fn. That is, the correspondence relationship information illustrated in  FIG.  6 A  is information indicating the correspondence relationship between information regarding the recording mode (the encoding method) and the bit rate as the image recording parameters as an example of the imaging condition of the camera, and the number of images to be captured Fn. Based on the imaging condition acquired in step S 501 , the number-of-images determining unit  314  references the correspondence relationship information in  FIG.  6 A , thereby determining the number of images to be captured Fn. The number of images to be captured Fn is determined based on the encoding method and the bit rate as the imaging condition because the lower the bit rate is, the higher the compression ratio is. As a result, the compressed image is likely to be influenced by block noise and have an error in color with respect to the original image. In the correspondence relationship information exemplified in  FIG.  6 A , the lower the bit rate is, the greater the number of images to be captured Fn to be determined is. If the number of images to be captured Fn is determined using the correspondence relationship information in  FIG.  6 A , the lower the bit rate is, the greater the number of images to be captured Fn is. This can reduce the influence of an error in color. 
     The correspondence relationship information stored in the relationship information storage unit  322  may also include information indicating the relationship between the image recording parameter and the number of images to be captured Fn as illustrated in  FIG.  6 B , for example. The correspondence relationship information in  FIG.  6 B  is information indicating the correspondence relationship between the quantization parameter (the encoding parameter) based on H.264 as the image recording parameter as an example of the imaging condition of the camera, and the number of images to be captured Fn. Based on the imaging condition acquired in step S 501 , the number-of-images determining unit  314  references the correspondence relationship information illustrated in  FIG.  6 B , thereby determining the number of images to be captured Fn. That is, in the case of the quantization parameter, the greater the value of the quantization parameter is, the more likely the quantized image is to be influenced by noise and have an error in color with respect to the original image. Thus, in the correspondence relationship information in  FIG.  6 B , the greater the value of the quantization parameter is, the greater the number of images to be captured Fn to be determined is. If the number of images to be captured Fn is determined using the correspondence relationship information in  FIG.  6 B , the greater the value of the quantization parameter is, the greater the number of images to be captured Fn is. This can reduce the influence of an error. 
     Alternatively, the number-of-images determining unit  314  may determine the number of images to be captured Fn based on not only the image recording parameters exemplified in  FIG.  6 A or  6 B , but also the imaging condition such as the ISO sensitivity, the shutter speed, or the stop value. That is, an error in the color of the captured image with respect to the original color of the object may be influenced by noise generated due to the ISO sensitivity, the shutter speed, or the stop value. For example, if the ISO sensitivity is increased, noise in the captured image tends to be large. If the shutter speed is fast, noise tends to be small. If the stop value is great, noise tends to be small. Thus, the number-of-images determining unit  314  determines the number of images to be captured Fn so that the higher the ISO sensitivity is, the greater the number of images to be captured Fn is, and that the slower the shutter speed is, the greater the number of images to be captured Fn is, and that the smaller the stop value is, the greater the number of images to be captured Fn is. This can reduce the influence of noise due to the ISO sensitivity, the shutter speed, and the stop value. 
     The description returns to  FIG.  5   . In step S 503 , the image acquisition unit  315  causes the camera to capture a single image of the object and acquires the image. Then, the image storage unit  317  stores the image acquired by the image acquisition unit  315 . 
     Next, in step S 504 , based on specifying by the user, the color information generation unit  318  acquires color information from the image stored in the image storage unit  317 . 
     With reference to  FIGS.  7 A and  7 B , a description is given of the details of the color information acquisition process performed by the color information generation unit  318  based on the specifying by the user in step S 504 . 
       FIG.  7 A  is a diagram illustrating an example of a graphical user interface (GUI) window  701  displayed on the screen of the display device  210  in  FIG.  2   . In the GUI window  701 , the captured image is displayed. 
     In the present exemplary embodiment, since the color chart is used as the object, a color chart image  702  obtained by capturing the color chart is displayed in the GUI window  701 . In the color chart, a plurality of color patches composed of different colors is disposed. Thus, color patch images  703  of the respective colors appear in the color chart image  702  in the GUI window  701 . The user can select a desired color patch image  703 , i.e., a desired color, from the color chart image  702  by operating the mouse or the touch panel of the operation device  211 . In the example of  FIG.  7 A , an area  704  indicated by a dotted line is a position selected and specified by the user in the color chart image  702 . That is, in the present exemplary embodiment, the area  704  specified by the user is the position of an image area from which the color information generation unit  318  acquires the color information. 
     The color information generation unit  318  acquires as the color information a value obtained by acquiring the average pixel value of pixels in the area  704  specified by the user with respect to each of as many images as the number of images to be captured Fn and averaging the acquired average pixel values by the number of images to be captured Fn. If a plurality of areas is specified from the color chart image  702  in the GUI window  701 , numbers are assigned to the respective areas selected by the user as illustrated in  FIG.  7 B , whereby it is possible to indicate the correspondence relationships between a plurality of pieces of color information between the cameras  100 A and  100 B. 
     The description returns to  FIG.  5   . In step S 505 , the image acquisition unit  315  determines whether the number of the images acquired from the camera reaches the number of images to be captured Fn determined in step S 502 , i.e., whether the number of the images captured by the camera≥Fn. If the number of the images acquired from the camera reaches the number of images to be captured Fn (Yes in step S 505 ), the processing proceeds to step S 506 . If, on the other hand, the number of the images acquired from the camera does not reach the number of images to be captured Fn (No in step S 505 ), the image acquisition unit  315  increments the number of the images acquired from the camera, and then, the processing returns to step S 503 . Consequently, the image acquisition unit  315  causes the camera to capture one more image of the object and acquires the captured image. If the color information is acquired from the second or subsequent captured image, the specifying of the acquisition position of the color information in step S 504  may not be performed, and the color information may be acquired using information regarding the acquisition position specified in the previous image. 
     In step S 506 , the color information generation unit  318  generates as color information a value obtained by obtaining the average pixel value from the area in each of the as many images as the number of images to be captured Fn in step S 504  and further averaging the obtained average pixel values by the number of images to be captured Fn. For example, if the number of images to be captured Fn is four, the color information generation unit  318  generates as the color information a value calculated by obtaining the average pixel value from the image area specified by the user in each of four images in step S 504  and further averaging the obtained average pixel values by the four images. 
     Then, the color information generation unit  318  outputs the generated color information to the correction information generation unit  319  of the LUT generation unit  302 . 
     The color information obtained from the image area specified in the as many images as the number of images to be captured Fn that are obtained as described above is data in which the image area and the pixel value are associated with each other with respect to each of the cameras  100 A and  100 B. In the as many images as the number of images to be captured Fn, pieces of color information regarding an image area of a color patch at the same position in the color chart can normally have the same value, and can also have the same value between the plurality of cameras  100 A and  100 B. These colors, however, may differ depending on the imaging conditions of the cameras  100 A and  100 B.  FIGS.  8 A to  8 C  are diagrams illustrating examples of pieces of color information regarding the same image areas of the same color patches with respect to each camera in a case where the image areas of the color patches in the color chart are numbered in order from the upper left to the right, for example. Specifically,  FIGS.  8 A to  8 C  illustrate pieces of color information obtained from the image areas of color patches at the same positions in the same color chart in a case where the color chart is captured by respective cameras A to C as a plurality of cameras. The pieces of color information regarding the cameras A to C, however, have different values in the image areas of the same color patches assigned the same numbers due to the differences between the imaging conditions. 
     The correction information generation unit  319  of the LUT generation unit  302  generates an LUT for color correction information that enables the correction of the color of an image of the correction target camera  100 B so that the color of the image area of a color patch at the same position in the color chart image captured by the correction target camera  100 B matches the color of the image area of the same color patch captured by the reference camera  100 A. 
     As described above, based on the information processing apparatus according to the present exemplary embodiment, regardless of imaging conditions such as the recording modes of cameras, an LUT that enables the correction of the difference in color between images of the cameras is generated. Consequently, the cameras can generate images in which the same object has the same color. 
     Next, a second exemplary embodiment is described. Processing according to the second exemplary embodiment is different from the processing described in the first exemplary embodiment in the color information acquisition process performed by the reference camera  100 A in step S 402  and the color information acquisition process performed by the correction target camera  100 B in step S 403 . 
     The information processing apparatus  300  according to the second exemplary embodiment determines noise in images captured by the reference camera  100 A and the correction target camera  100 B. In the second exemplary embodiment, it is determined whether the first color information acquired from the first images captured by the reference camera  100 A and the second color information acquired from the second images captured by the correction target camera  100 B include color noise exceeding a predetermined color noise threshold. Then, based on the result of determining color noise, the information processing apparatus  300  determines whether to add a predetermined number of images to the number of images to be captured Fn. That is, if the first color information and the second color information include color noise exceeding the color noise threshold, the information processing apparatus  300  according to the second exemplary embodiment adds the predetermined number of images to the number of images to be captured Fn. 
     The information processing apparatus  300  according to the second exemplary embodiment also calculates the amount of noise included in as many images as the number of images to be captured Fn that is determined similarly to the first exemplary embodiment. In the present exemplary embodiment, the information processing apparatus  300  acquires the amount of block noise as the amount of noise. Then, based on the amount of block noise obtained by this amount-of-noise acquisition process, the information processing apparatus  300  makes an adoption determination regarding whether to adopt the as many captured images as the number of images to be captured Fn as images from which the first color information and the second color information are to be acquired, i.e., whether to adopt the as many captured images as the number of images to be captured Fn to generate an LUT. If the amount of block noise obtained by the amount-of-block-noise acquisition process is greater than or equal to a predetermined block noise threshold, the information processing apparatus  300  does not adopt the as many captured images as the number of images to be captured Fn as the images from which the first color information and the second color information are to be acquired. Then, the information processing apparatus  300  adds the predetermined number of images again to the number of images to be captured Fn. Then, using captured images acquired by adding the predetermined number of images again, the information processing apparatus  300  attempts to acquire color information. Further, the information processing apparatus  300  according to the present exemplary embodiment can set a predetermined upper limit number of images for the number of images to be captured Fn, and performs the process of confirming the number of images to be captured so that the number of images to be captured Fn does not exceed the upper limit number of images. 
     The reason for determining the amount of block noise is to take measures against a case where, when the object (the color chart) is captured, block noise is generated more than normally assumed in the compressed image by a moving object suddenly cutting into the angle of view or the object or the camera itself shaking. As described above, in the second exemplary embodiment, based on the result of determining the amount of block noise, it is determined whether to acquire color information from captured images, i.e., whether an LUT can be optimized. If it is difficult to optimize the LUT, an attempt is made to acquire color information using captured images obtained by further adding the predetermined number of images to the number of images to be captured Fn. Then, if the amount of block noise in images obtained by additionally capturing images is less than the threshold, the information processing apparatus  300  acquires color information from the images and generates an LUT. In the present exemplary embodiment, the predetermined upper limit number of images is set for the additional capturing of images. If the amount of block noise in additionally captured images within the upper limit number of images is less than the threshold, the information processing apparatus  300  acquires color information from the captured images and generates an LUT. If color information as assumed cannot be obtained from the additionally captured images within the upper limit number of images, for example, the information processing apparatus  300  displays a warning message and ends the processing. 
       FIG.  9    is a diagram illustrating an example of the functional configuration of the input data processing unit  301  and the LUT generation unit  302  of the information processing apparatus  300  according to the second exemplary embodiment. In the second exemplary embodiment, the configuration illustrated in  FIG.  9    can be appropriately modified or changed. For example, a single function unit may be divided into a plurality of function units by function, or two or more function units may be integrated into a single function unit. The configuration in  FIG.  9    may be composed of two or more apparatuses. In this case, the apparatuses may be connected to each other via a circuit or a wired or wireless network and cooperatively operate by communicating data with each other. Further,  FIG.  10    is a flowchart illustrating the flow of the color information acquisition process in steps S 402  and S 403  in  FIG.  4    performed by the input data processing unit  301  according to the second exemplary embodiment. Components and processes similar to those in the first exemplary embodiment are not described, and only components and processes different from those of the first exemplary embodiment are described here. 
     First, in the functional configuration illustrated in  FIG.  9   , function units different from those of the first exemplary embodiment are described. 
     An amount-of-noise calculation unit  323  calculates the amount of noise included in each of the images acquired by the image acquisition unit  315 . In the present exemplary embodiment, the amount of noise calculated by the amount-of-noise calculation unit  323  is the amount of block noise. The details of this amount-of-block-noise calculation process will be described below. 
     Based on the result of the amount-of-noise calculation unit  323  calculating the amount of block noise, an image quality determination unit  316  determines whether the image acquired by the image acquisition unit  315  has such an image quality that the image can be used to acquire color information. In the second exemplary embodiment, the relationship information storage unit  322  also stores a block noise threshold Th, and the block noise threshold Th read from the relationship information storage unit  322  is input to the image quality determination unit  316  via the number-of-images determining unit  314 . Then, the image quality determination unit  316  compares the amount of block noise calculated by the amount-of-noise calculation unit  323  and the block noise threshold Th read from the relationship information storage unit  322 . If the calculated amount of block noise is greater than or equal to the block noise threshold Th, the image quality determination unit  316  determines that the image acquired by the image acquisition unit  315  does not have such an image quality that the image can be adopted to acquire color information. The details of this process will be described below. 
     If the image quality determination unit  316  obtains the determination result that the image does not have such an image quality that the image can be adopted to acquire color information, the image stored in the image storage unit  317  is not used when the color information generation unit  318  generates color information. In this case, the number-of-images determining unit  314  adds a predetermined number of images to the number of images to be captured. Consequently, the image acquisition unit  315  causes the camera to acquire as many images as the added number of images. At this time, the number-of-images determining unit  314  also performs a number-of-images confirmation process for preventing the number of images to be captured from exceeding a predetermined upper limit number of images due to the addition of the number of images. The details of this process will be described below. 
     A color noise calculation unit  324  performs a color noise acquisition process for calculating the amount of color noise included in the color information generated by the color information generation unit  318 . 
     A color noise determination unit  325  determines whether the amount of color noise calculated by the color noise calculation unit  324  exceeds a color noise threshold Thc. In the second exemplary embodiment, the relationship information storage unit  322  also stores the color noise threshold Thc, and the color noise threshold Thc read from the relationship information storage unit  322  is input to the color noise determination unit  325  via the number-of-images determining unit  314 . Then, the color noise determination unit  325  compares the amount of color noise calculated by the color noise calculation unit  324  and the color noise threshold Thc read from the relationship information storage unit  322 . That is, the color noise determination unit  325  determines whether the calculated amount of color noise exceeds the color noise threshold Thc. The details of this process will be described below. 
     If the color noise determination unit  325  obtains the determination result that the calculated amount of color noise exceeds the color noise threshold Thc, the number-of-images determining unit  314  adds the predetermined number of images again to the number of images to be captured. Consequently, the image acquisition unit  315  causes the camera to acquire as many images as the number of images added again. The details of this process will be described below. 
     In the number-of-images confirmation process performed by the number-of-images determining unit  314 , if it is determined that the number of images to be captured exceeds the upper limit number of images, the message generation unit  330  outputs message information for warning the user about this state to the display device  210 , for example. The message information may be text information or an icon, or may be in any other format. The same applies to other message information described below. 
     With reference to a flowchart in  FIG.  10   , a description is given of the flow of information processing according to the second exemplary embodiment. In the second exemplary embodiment, after step S 501 , the processes of steps S 1301  and S 1302  are performed, and then, the processing proceeds to step S 503 . After the process of step S 503 , a determination process in step S 1303  is performed, and based on the result of the determination, the process of either of steps S 504  and S 1304  is performed. After the process of step S 504  or S 1304 , a determination process in step S 1305  is performed, and based on the result of the determination, the process of either of steps S 505  and S 1306  is performed. Further, after the process of step S 506 , a determination process in step S 1307  is performed, and based on the result of the determination, the processing of the flowchart ends, or the process of step S 1308  is performed. Then, after the process of step S 1308 , the processing returns to step S 503 . After the process of step S 1306 , the processing of the flowchart ends. 
     After step S 501 , then in step S 1301 , based on the imaging condition obtained in step S 501  and the correspondence relationship information stored in the relationship information storage unit  322 , the number-of-images determining unit  314  determines the number of images to be captured Fn. Further, in step S 1301 , the number-of-images determining unit  314  acquires from the relationship information storage unit  322  an upper limit number of images Lim for a number-of-images-to-be-captured confirmation process performed when images are additionally captured. The upper limit number of images Lim is a value set to, when images need to be captured again due to the influence of noise, prevent the number of images to be captured again from increasing unlimitedly. In the present exemplary embodiment, the upper limit number of images Lim is set to  120 , for example. 
     Next, in step S 1302 , the number-of-images determining unit  314  reads the block noise threshold Th and the color noise threshold Thc stored in the relationship information storage unit  322 . Specifically, examples of the block noise threshold Th include the number of gradation levels found by detecting block noise. The relationship information storage unit  322  stores the block noise threshold Th obtained in advance. Examples of the color noise threshold Thc include a standard deviation from the average value of color information with respect to each image. For example, if the number of images to be captured Fn is set to eight, the color information generation unit  318  acquires the average value of pieces of color information regarding each image area in eight images. Thus, the relationship information storage unit  322  stores as the color noise threshold Thc a standard deviation obtained from pieces of color information obtained with respect to each image area in eight images acquired by capturing the color chart in advance. The number-of-images determining unit  314  sends information regarding the block noise threshold Th read from the relationship information storage unit  322  to the image quality determination unit  316  and sends information regarding the color noise threshold Thc to the color noise determination unit  325 . 
     After step S 503 , then in step S 1303 , the amount-of-noise calculation unit  323  calculates the amount of block noise in the image acquired in step S 503 . For the calculation of the amount of block noise, for example, a method discussed in the publication of Japanese Patent Application Laid-Open No. 2001-218210 can be used. The method discussed in Japanese Patent Application Laid-Open No. 2001-218210 is known, and therefore is not described. 
     Further, in step S 1303 , the image quality determination unit  316  compares the amount of block noise calculated by the amount-of-noise calculation unit  323  and the block noise threshold Th and determines whether the amount of block noise is greater than or equal to the block noise threshold Th (block noise≥Th). If the amount of block noise is less than the block noise threshold Th (No in step S 1303 ), the image quality determination unit  316  determines that the image acquired in step S 503  can be adopted as an image for use in generating color information. That is, in this case, the image acquired in step S 503  is used in a color information generation process performed by the color information generation unit  318 . Then, the processing proceeds to step S 504 . If, on the other hand, the amount of block noise is greater than or equal to the block noise threshold Th (Yes in step S 1303 ), the image quality determination unit  316  determines that the image acquired by the image acquisition unit  315  cannot be adopted as an image for use in generating color information. That is, in this case, the image acquired in step S 503  is not used in the color information generation process performed by the color information generation unit  318 . Then, the processing proceeds to step S 1304 . 
     In step S 1304 , the number-of-images determining unit  314  adds a predetermined number of images to the number of images to be captured Fn, and the image acquisition unit  315  acquires as many images as the added number of images. In the present exemplary embodiment, the number-of-images determining unit  314  adds 1 to the number of images to be captured Fn (adds a single image to the number of images to be captured Fn), and the image acquisition unit  315  causes the camera to capture an image corresponding to the added single image and acquires the image. 
     After step S 504  or S 1304 , then in step S 1305 , the number-of-images determining unit  314  performs a number-of-images-to-be-captured confirmation process for determining whether the number of captured images Fn is greater than or equal to the upper limit number of images Lim (the number of images to be captured Fn≥Lim). For example, if it is determined in step S 1301  that the number of images to be captured Fn is eight, and the number of images (the number of frames) in which the amount of block noise calculated in step S 1303  is greater than or equal to the block noise threshold Th is  121 , the number of images to be captured Fn is greater than or equal to the upper limit number of images Lim. In this case, the number-of-images determining unit  314  determines that the amount of noise is greater than assumed and it is less likely that an image that can be adopted to generate color information can be captured. In this case (Yes in step S 1305 ), the processing proceeds to step S 1306 . If, on the other hand, the number-of-images determining unit  314  determines that the number of images to be captured Fn is not greater than or equal to the upper limit number of images Lim (No in step S 1305 ), the processing proceeds to step S 505 . The upper limit number of images Lim is  120  in the present exemplary embodiment, but is not particularly limited to this value. The value may be changed according to the imaging condition. 
     If the number-of-images determining unit  314  determines that the number of images to be captured Fn is greater than or equal to the upper limit number of images Lim, then in step S 1306 , the message generation unit  330  generates message information indicating that the number of images to be captured that is greater than or equal to assumed is used to acquire color information in the current situation, and it is difficult to acquire color information. Then, the message information generated by the message generation unit  330  is sent to and displayed on the display device  210 . This enables the user to recognize that it is difficult to acquire color information. After step S 1306 , the processing of the flowchart in  FIG.  10    ends. 
     In step S 1307 , the color noise calculation unit  324  calculates the amount of color noise included in the color information generated by the color information generation unit  318 . The color noise determination unit  325  determines whether the calculated amount of color noise is greater than the color noise threshold Thc. Then, if the color noise determination unit  325  determines that the calculated amount of color noise is greater than the color noise threshold Thc (Yes in step S 1307 ), the processing proceeds to step S 1308 . If, on the other hand, the color noise determination unit  325  determines that the calculated amount of color noise is less than or equal to the color noise threshold Thc (color noise≤Thc) (No in step S 1307 ), the color information generated in step S 506  is output to the LUT generation unit  302 . Then, the processing of the flowchart in  FIG.  10    ends. 
     In step S 1308 , to improve color noise, the number-of-images determining unit  314  adds the predetermined number of images again to the number of images to be captured Fn. For example, if it is determined in step S 1301  that the number of images to be captured Fn is eight, the number-of-images determining unit  314  adds four images as the addition of the predetermined number of images to the number of images to be captured Fn performed again. Then, the processing proceeds to step S 503 . 
     As described above, according to the second exemplary embodiment, regardless of imaging conditions of cameras or the state of an object, it is possible to correct the difference in color between images of the cameras. When color information is acquired, it is possible to acquire color information also corresponding to abrupt noise fluctuation when an image is captured. According to the second exemplary embodiment, it is possible to confirm whether generated color information is obtained as assumed. Thus, it is possible to generate an LUT for correcting the colors of images of the cameras with higher accuracy. 
     Next, a third exemplary embodiment is described. The third exemplary embodiment is different from the above exemplary embodiments in the color information acquisition method of the reference camera  100 A in step S 402  and the color information acquisition method of the correction target camera  100 B in step S 403 . Specifically, based on an imaging condition, the information processing apparatus  300  according to the third exemplary embodiment performs a generation determination process for determining whether much noise is likely to be generated. Then, as the result of the generation determination process, if it is highly likely that much noise is generated, the information processing apparatus  300  displays a message for notifying the user of this state. Only if the processing is to be continued nonetheless, the information processing apparatus  300  generates an LUT for color correction. Components and processes similar to those in the above exemplary embodiments are not described, and only components and processes different from those of the above exemplary embodiments are described. 
     The functional configuration of the information processing apparatus  300  according to the third exemplary embodiment is approximately similar to that described above in  FIG.  3   , except that the input data processing unit  301  includes a message generation unit  330 . Although the details will be described below, in the third exemplary embodiment, based on an acquired imaging condition, the input data processing unit  301  performs a generation determination process for determining whether it is highly likely that much noise is generated and it becomes difficult to acquire color information. Then, if the input data processing unit  301  determines that it is highly likely that it becomes difficult to acquire color information, the message generation unit  330  outputs message information for notifying the user of this state and further outputs message information for inquiring whether to change the setting of the imaging condition. The details of this process will be described below. 
       FIG.  11    is a flowchart illustrating the overall flow of processing performed by the information processing apparatus  300  according to the third exemplary embodiment. In the flowchart in  FIG.  11   , the processes of steps S 404  and S 405  are similar to those of steps S 404  and S 405  in the flowchart in  FIG.  4   , and therefore are not described. 
     First, in step S 1001 , the information processing apparatus  300  sets an imaging condition for the reference camera  100 A. The specific content of the setting process for setting the imaging condition is similar to that of the process described above in step S 401 . 
     Next, in step S 1002 , the input data processing unit  301  acquires the imaging condition of the reference camera  100 A, and based on the imaging condition, determines the number of images to be captured to obtain color information. Further, the input data processing unit  301  acquires as many images as the number of images to be captured and generates color information. At this time, however, based on the imaging condition, the input data processing unit  301  determines whether it is highly likely that much noise is generated and it becomes difficult to acquire color information. Then, the input data processing unit  301  generates and outputs message information according to the result of the determination. The details of the process of step S 1002  will be described below with reference to a flowchart in  FIG.  12   . 
     Next, in step S 1003 , the input data processing unit  301  determines whether the acquisition of color information is successful in the process of step S 1002 . Then, if it is determined that the acquisition of color information is successful (Yes in step S 1003 ), the processing proceeds to step S 1005 . If, on the other hand, it is determined that the acquisition of color information fails (No in step S 1003 ), the processing proceeds to step S 1004 . 
     In step S 1004 , the input data processing unit  301  determines whether the imaging setting of the reference camera  100 A can be reviewed. For example, the input data processing unit  301  generates message information for inquiring of the user about whether to review the setting, displays the message information on the display device  210 , and makes the determination based on an input from the user. Then, if an instruction to review the setting is input by the user (Yes in step S 1004 ), the processing returns to step S 1001 . If the setting is not to be reviewed (No in step S 1004 ), the processing of the flowchart in  FIG.  11    ends. 
     In step S 1005 , the information processing apparatus  300  sets an imaging condition for the correction target camera  100 B. The specific content of the setting process for setting the imaging condition is similar to that of the process described above in step S 401 . 
     Next, in step S 1006 , the input data processing unit  301  acquires the imaging condition of the correction target camera  100 B, and based on the imaging condition, determines the number of images to be captured to obtain color information. Further, the input data processing unit  301  acquires as many images as the number of images to be captured and generates color information. At this time, however, based on the imaging condition, the input data processing unit  301  determines whether it is highly likely that much noise is generated and it becomes difficult to acquire color information. Then, the input data processing unit  301  generates and outputs message information according to the result of the determination. The details of the process of step S 1006  will be described below with reference to the flowchart in  FIG.  12   . 
     Next, in step S 1007 , the input data processing unit  301  determines whether the acquisition of color information is successful in the process of step S 1006 . Then, if it is determined that the acquisition of color information is successful (Yes in step S 1007 ), the processing proceeds to step S 404 , which is performed by the LUT generation unit  302  of the information processing apparatus  300 . If, on the other hand, it is determined that the acquisition of color information fails (No in step S 1007 ), the processing proceeds to step S 1008 . 
     In step S 1008 , the input data processing unit  301  determines whether the imaging setting of the correction target camera  100 B can be reviewed. Also in this step, similarly to step S 1004 , the input data processing unit  301  generates message information for inquiring of the user about whether to review the setting, displays the message information on the display device  210 , and makes the determination based on an input from the user. Then, if an instruction to review the setting is input by the user (Yes in step S 1008 ), the processing returns to step S 1005 . If the setting is not to be reviewed (No in step S 1008 ), the processing of the flowchart in  FIG.  11    ends. 
     Next, with reference to the flowchart in  FIG.  12   , the details of the processes of steps S 1002  and S 1006  in  FIG.  11    are described. In steps S 1002  and S 1006  in  FIG.  11   , the camera that captures images for use in generating color information is either of the reference camera  100 A and the correction target camera  100 B. Similar processing is performed no matter which of the reference camera  100 A and the correction target camera  100 B is the camera. Thus, the reference camera  100 A and the correction target camera  100 B are referred to simply as a “camera” without identifying the reference camera  100 A and the correction target camera  100 B. With reference to  FIG.  12   , only processing steps different from  FIG.  5    are described. In the flowchart in  FIG.  12   , after the process of step S 502 , the processes of steps S 901  to S 903  are performed, and then, the processing proceeds to the processes of step S 503  and the subsequent steps. 
     After step S 502 , then in step S 901 , based on the imaging condition acquired in step S 501 , the condition acquisition unit  311  determines whether it is highly likely that much noise is generated in images. With reference to the example of  FIG.  6 B , for example, if the quantization parameters as the imaging condition are greater than or equal to 40, the condition acquisition unit  311  determines that it is highly likely that noise is generated. Then, if the condition acquisition unit  311  determines that it is highly likely that noise is generated (Yes in step S 901 ), the processing proceeds to step S 902 . If, on the other hand, the condition acquisition unit  311  determines that it is not highly likely that noise is generated (No in step S 901 ), the processing proceeds to step S 503 . 
     In step S 902 , the message generation unit  330  generates message information indicating that it is highly likely that much noise is generated and it becomes difficult to acquire color information, i.e., message information indicating that noise is generated and it is difficult to obtain effective data. Then, the message generation unit  330  outputs the message information to the display device  210 . 
     This enables the user to recognize that in the current imaging condition, noise is generated and it is difficult to obtain effective data. 
     Further, in step S 902 , the message generation unit  330  generates message information for inquiring whether to continue the processing in the current imaging condition. Then, the message generation unit  330  outputs the message information to the display device  210 . 
     Next, in step S 903 , the message generation unit  330  determines whether an instruction to continue the processing is input by the user. If an instruction to continue the processing is input by the user (Yes in step S 903 ), the processing proceeds to step S 503 . If, on the other hand, an instruction not to continue the processing is input by the user (No in step S 903 ), the processing of the flowchart in  FIG.  12    ends. 
     In the processes of step S 503  and the subsequent steps, similarly to the above, the processes of acquiring an image and acquiring color information are performed. Then, the color information generated in the process of step S 506  is output to the LUT generation unit  302 . 
     As described above, according to the third exemplary embodiment, based on imaging conditions of cameras, if it is determined whether noise is likely to be generated, and further, it is determined that processing is to be continued, the processes of generating color information and generating an LUT are performed. 
     [Other Exemplary Embodiments] 
     Other exemplary embodiments are described below. 
       FIGS.  13 A and  13 B  are schematic diagrams each illustrating an example of the configuration of an information processing system according to another exemplary embodiment. 
       FIG.  13 A  is a diagram illustrating an example of the configuration of an information processing system  1000  including an information processing apparatus  200 A dedicated to receiving an output image from the camera  100 A, and an information processing apparatus  200 B dedicated to receiving an output image from the camera  100 B. A controller  500  sets an imaging condition for each of the reference camera  100 A and the correction target camera  100 B. The information processing apparatus  200 A acquires the imaging condition of the reference camera  100 A, and the information processing apparatus  200 B acquires the imaging condition of the correction target camera  100 B. The information processing apparatuses  200 A and  200 B may acquire the imaging conditions of the cameras  100 A and  100 B, respectively, from the controller  500  via the network  400 , or may acquire the imaging conditions of the cameras  100 A and  100 B from the cameras  100 A and  100 B connected to the information processing apparatuses  200 A and  200 B, respectively. The information processing apparatus  200 A performs the processes of setting the number of images to be captured for the reference camera  100 A, acquiring first images captured by the reference camera  100 A, and generating first color information. The information processing apparatus  200 B performs the processes of setting the number of images to be captured for the correction target camera  100 B, acquiring second images captured by the correction target camera  100 B, and generating second color information. Then, for example, the information processing apparatus  200 B generates an LUT using the first color information and the second color information and applies the LUT to the correction target camera  100 B. Alternatively, the information processing apparatus  200 A may generate an LUT, and the information processing apparatus  200 B may apply the LUT to the correction target camera  100 B. Yet alternatively, the controller  500  as an external apparatus connected to the information processing apparatuses  200 A and  200 B may generate an LUT. 
       FIG.  13 B  is a diagram illustrating an example of the configuration of a system  1000  in a case where the cameras  100 A and  100 B are connected to the information processing apparatus  300  not by the cameras  100 A and  100 B connecting to the network  400  at the same time, but by the cameras  100 A and  100 B connecting to the network  400  one by one. In the system configuration illustrated in  FIG.  13 B , the flow of the entirety of processing performed by the information processing apparatus  300  is illustrated in a flowchart in  FIG.  14   . 
     In the flowchart in  FIG.  14   , after the process of step S 402 , the process of step S 1201  is performed, and then, the processing proceeds to the processes of step S 403  and the subsequent steps. In step S 1201 , the information processing apparatus  300  first switches the connection state between the network  400  and the cameras  100 A and  100 B to the state where the reference camera  100 A is connected to the network  400 . Then, if the processes of acquiring the imaging condition of the reference camera  100 A, acquiring first images, and further generating first color information are performed, the information processing apparatus  300  makes a switching connection for changing the camera connected to the network  400  to the correction target camera  100 B. Then, if the processes of acquiring the imaging condition of the correction target camera  100 B, acquiring second images, and further generating second color information are performed, the information processing apparatus  300  generates an LUT based on the first color information and the second color information and applies the LUT to the correction target camera  100 B. 
     The present disclosure can also be achieved by the process of supplying a program for achieving one or more functions of the above exemplary embodiments to a system or an apparatus via a network or a storage medium, and of causing one or more processors of a computer of the system or the apparatus to read and execute the program. 
     The present disclosure can also be achieved by a circuit (e.g., an application-specific integrated circuit (ASIC)) for achieving the one or more functions. 
     All the above exemplary embodiments merely illustrate specific examples for carrying out the present disclosure, and the technical scope of the present disclosure should not be interpreted in a limited manner based on these exemplary embodiments. 
     That is, the present disclosure can be carried out in various ways without departing from the technical idea or the main feature of the present disclosure. 
     According to the present disclosure, regardless of the recording modes of imaging apparatuses or the state of an object, it is possible to appropriately correct the difference in color between images of the imaging apparatuses. 
     Other Embodiments 
     Embodiment(s) of the present disclosure can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors, circuitry, or combinations thereof (e.g., central processing unit (CPU), micro processing unit (MPU), or the like), and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)TM), a flash memory device, a memory card, and the like. 
     While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of priority from Japanese Patent Application No. 2021-190189, filed Nov. 24, 2021, which is hereby incorporated by reference herein in its entirety.