Patent Publication Number: US-9906749-B2

Title: Image capturing apparatus capable of generating and adding pixel region information to image data, method of controlling the same, and image sensor

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an image capturing apparatus, a method of controlling the same, and an image sensor. 
     Description of the Related Art 
     In recent years, in conjunction with an increase in pixels in image sensors, and optimization of speeds for reading out from image sensors, a required transmission capacity between an image sensor and a circuit (DSP, Digital Signal Processor) for signal processing connected thereto is increasing. In response to such a requirement, Japanese Patent Laid-Open No. 2012-120158 discloses a technique for optimizing data transmission/reception between circuits by transmitting packets divided into a plurality of transmission channels in transmission/reception of data between an image sensor and a DSP. 
     However, in an image capturing system having an image sensor, a circuit for signal processing, and a control unit (for example, a CPU), it is necessary to transfer control information (for example, coordinate information) to each circuit from the control unit. In particular, because the circuit for signal processing processes image data in accordance with a size of an image output from the image sensor, when the image size of the image data output from the image sensor is changed, it is necessary for the circuit for signal processing to receive control information such as coordinate information from the control unit. Additionally, when there is a pixel of an optical black area for which the image sensor is light-shielded, for example, and the circuit for signal processing corrects pixel data of an effective pixel region using pixel data of that region, it is necessary for the circuit to receive coordinate information for the above-described two regions from the control unit. Because at this time the control unit transmits similar control information for the image sensor and the circuit for signal processing, it is envisioned that the system will become more complicated because, accompanying the increase in processing performed by the circuit for signal processing, the control information respectively transmitted from the control unit will increase. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in consideration of the aforementioned problems, and realizes a technique that provides an image capturing apparatus, a method of controlling the same, and an image sensor capable of reducing control information transmitted from a control unit to a circuit for signal processing. 
     In order to solve the aforementioned problems, the present invention provides an image capturing apparatus, comprising: a pixel portion comprising a first pixel region and a second pixel region; an output unit configured to output a result of adding region information indicating the first pixel region and the second pixel region to image data obtained from the pixel portion; and a signal processing unit configured to correct pixel data of the first pixel region using pixel data of the second pixel region for image data read out from the pixel portion, wherein the signal processing unit extracts pixel data of the first pixel region and pixel data of the second pixel region of the image data using the region information added to the image data received from the output unit. 
     In order to solve the aforementioned problems, the present invention provides an image sensor comprising: a pixel portion comprising a first pixel region and a second pixel region; and an output unit configured to output a result of adding region information indicating the first pixel region and the second pixel region to image data obtained from the pixel portion. 
     In order to solve the aforementioned problems, the present invention provides a control method of an image capturing apparatus in which a pixel portion has a first pixel region and a second pixel region, the method having: an output step of outputting a result of adding region information indicating the first pixel region and the second pixel region to image data obtained from the pixel portion; and a signal processing step of correcting pixel data of the first pixel region using pixel data of the second pixel region for image data read out from the pixel portion, wherein in the signal processing step, pixel data of the first pixel region and pixel data of the second pixel region of the image data is extracted using the region information added to the image data received in the output step. 
     According to the present invention, it becomes possible to reduce control information transmitted from a control unit to a circuit for signal processing. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a block diagram for showing a functional configuration example of a digital camera as an example of an image capturing apparatus according to embodiments of the present invention. 
         FIG. 2A  is a block diagram for showing a functional configuration example of an image sensor according to embodiments. 
         FIG. 2B  is a block diagram for showing an image output unit according to embodiments. 
         FIG. 3  is a block diagram for showing a functional configuration example of a DFE according to embodiments. 
         FIG. 4  is a flowchart for showing a series of operations of processing of an image capturing system according to embodiments. 
         FIG. 5  is a flowchart for showing a series of operations of packet generation processing according to a first embodiment. 
         FIG. 6  is a flowchart for describing image processing according to the first embodiment. 
         FIG. 7  is a view for illustrating an example of a packet format according to the first embodiment. 
         FIG. 8  is a view for illustrating an example configuration of pixel regions in a pixel portion according to the first embodiment. 
         FIG. 9  is a flowchart for showing a series of operations in image processing according to a second embodiment. 
         FIG. 10  is a view for illustrating an example configuration of pixel regions in a pixel portion according to the second embodiment. 
         FIG. 11A  is a block diagram for showing a functional configuration example of the image sensor according to a third embodiment. 
         FIG. 11B  is a block diagram for showing the image output unit according to the third embodiment. 
         FIG. 12  is a flowchart for showing a series of operations in image processing according to the third embodiment. 
         FIG. 13  is a view for illustrating an example of a packet format according to according to the third embodiment. 
         FIGS. 14A and 14B  are views for showing examples of an image sensor of a stacked structure in accordance with other embodiments. 
         FIG. 15  is a block diagram for showing a functional configuration example of a mobile telephone which is an example of the image capturing apparatus in accordance with other embodiments. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     First Embodiment 
     Exemplary embodiments of the present invention will be described hereinafter in detail, with reference to the accompanying drawings. Note that explanation is given below of examples in which the present invention is applied to a digital camera having an image sensor, a circuit for signal processing, and a control unit, which are connected to each other, as an example of an image capturing apparatus. However, the image capturing apparatus in the present invention is not limited to the digital camera, and can be applied to any electronic device having such a configuration of an image sensor, etc. The electronic device may include mobile telephones, game devices, tablet terminals, personal computers, clock-type or glasses-type information terminals, or the like, for example. 
     (Configuration of a Digital Camera  100 ) 
       FIG. 1  is a block diagram for showing a functional configuration example of a digital camera  100  which is an example of the image capturing apparatus of the present embodiment. Note that, one or more of the functional blocks shown in  FIG. 1  may be realized by hardware such as an ASIC, a programmable logic array (PLA), or the like, and may be realized by a programmable processor such as a CPU, an MPU, or the like, executing software. Also, these may be realized by a combination of software and hardware. Accordingly, in the following explanation, even in a case where different functional blocks are recited as the subject of operations, it is possible that this may be realized by the same hardware as the subject. 
     In signals output from pixels of an image sensor, generally, a dark current that occurs due to an influence of heat, or the like, is included even in a case of light-shielding. For this reason, in order to obtain a signal (a reference signal for black level) which is a signal level reference signal, the image sensor is provided with an optical black pixel region (an OB pixel region) that is light-shielded so not to react to light, and the image sensor performs computational processing for a signal of an effective pixel based on the reference signal for black level obtained from pixels of this OB pixel region. For example, an OB pixel region is arranged at an upper portion of an effective pixel region on the image sensor, and by calculating a correction value from the output of these OB pixels, it is possible to correct a shading in a horizontal direction due to an influence of a dark current for a signal output from a pixel of the effective pixel region. In embodiments, explanation will be given for an example in which correction processing corresponding to a dark current is performed as an example of image processing that the DSP performs. In other words, explanation is given for an example in which an image sensor outputs signals of both an effective pixel region and an OB pixel region and performs correction processing corresponding to a dark current on a signal that a DSP inputs. 
     An image capturing unit  120  includes an image sensor  121  and a DFE (Digital Front End)  122 . The image sensor  121  includes a pixel portion  200 , an A/D converter  201 , an image output unit  202 , and a timing generator (TG)  203  as will be explained later in  FIG. 2A . The image sensor  121  generates image data from an optical image of an object formed by an optical system  102  and outputs it to the DFE  122 . 
     The DFE  122  is a processor for signal processing (a DSP) which performs image processing on image data that the image sensor  121  outputs, and the DFE  122  outputs image data to a control unit  101  after applying image processing to it. 
     The control unit  101  includes a CPU or an MPU, for example, and controls the digital camera  100  on the whole by loading a program stored in a non-volatile memory  105  into a work area of a volatile memory  103 , and executing the program. The control unit  101  controls units such as the image sensor  121 , the optical system  102 , and the DFE  122  in order to perform an image capturing operation in accordance with an image capturing condition set by a user. Also, as will be explained later, the control unit  101  instructs the image sensor  121  of a region of pixels for which to read out a signal from the pixel portion  200 . 
     The optical system  102  is connected electronically to the digital camera  100 ; the optical system  102  takes in external light, and includes a focusing lens, a zoom lens, an aperture, a shutter, or the like, for forming an image on an image capturing surface of the pixel portion  200 . 
     The volatile memory  103  is a main storage apparatus such as a RAM which stores temporary data that may disappear after a power supply of the digital camera  100  is cut. The volatile memory  103  is connected to the control unit  101 , and holds data provided from the control unit  101  in accordance with an instruction by the control unit  101 . 
     A power supply unit  104  supplies power to the digital camera  100 . A power supply destination is not limited to the control unit  101  shown in  FIG. 1 , and power may be supplied to each unit comprising in the digital camera  100 . 
     The non-volatile memory  105  is an auxiliary storage apparatus comprised of a semiconductor memory, a magnetic disk, or the like, and in addition to storing images and video that are captured, the non-volatile memory  105  stores information that must be held even after the power supply is cut, such as a Tv value, an Av value, or the like, set for the digital camera  100 . The non-volatile memory  105  is connected to the control unit  101 , and stores data provided from the control unit  101  in accordance with an instruction by the control unit  101 . 
     An accessory shoe  106  is arranged on the upper portion of the digital camera  100 , and is a set of metal connectors that can connect with a clip-on type flash. 
     A first shutter switch  107  is turned on and generates a first shutter switch signal SW 1  in the middle of an operation on a shutter release button arranged on the digital camera  100 , which is a so-called a half-press (a shooting preparation instruction). The control unit  101  starts an operation of AF (auto focus) processing, AE (auto exposure), AWB (auto white balance), or the like, upon the first shutter switch signal SW 1 . 
     A second shutter switch  108  is turned on and generates a second shutter switch signal SW 2  upon completion of an operation on the shutter release button, which is a so-called full-press (an image capturing instruction). The control unit  101  starts an operation of a series of image capturing processes, from when a signal is read from the image capturing unit  120  until when image data is written to the non-volatile memory  105 , upon the second shutter switch signal SW 2 . 
     An operation unit  109  has buttons, dials, a touch panel, or the like, for setting setting values such as the Av value or the Tv value which are set for the digital camera  100 . The operation unit  109  communicates operation content or setting values to the control unit  101  when a user operation is detected. Various settings values set by user operation are stored in the non-volatile memory  105  based on instructions of the control unit  101 , as described above. 
     A power supply switch  110  is a mechanical switch for switching a power supply state of the digital camera  100  on and off. When a on or off switching operation by a user is detected, a supply of power to units of the digital camera  100  from the power supply unit  104  is started or stopped. 
     (Configuration of the Image Sensor  121 ) 
     Next, explanation is given for a configuration of the image sensor  121  shown in  FIG. 1  with reference to  FIG. 2A . 
     The image sensor  121  receives an optical image of an object which is formed by the optical system  102  in a plurality of pixels arranged two-dimensionally, and the image sensor  121  photoelectrically converts each pixel and outputs an analog signal. The image sensor  121  may be an image sensor such as a CCD (Charge-Coupled Device) image sensor, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, or the like. The pixel portion  200  of the image sensor  121  outputs an analog signal in accordance with a timing signal supplied by the timing generator  203 . 
     The A/D converter  201  converts an analog signal output by the pixel portion  200  into a digital signal in accordance with operation timing generated by the timing generator  203 . 
     The image output unit  202  adds header information to the digital signal input from the A/D converter  201  based on control information obtained from the control unit  101 , and outputs image data including the header information. More specifically, the image output unit  202  obtains the control information, i.e. a later explained first and second vertical coordinate range, from the control unit  101 , and generates header information based on the vertical coordinate range. The image output unit  202  divides digitized pixel data by a predetermined data length when image data is output, and performs a packetization adding header information generated for this data. The image output unit  202  outputs the packetized data to the DFE  122  as image data. 
     The timing generator  203  supplies an operation timing to the pixel portion  200  and the A/D converter in accordance with operation timing information input from the control unit  101 . 
     (Configuration of an Image Output Unit  202 ) 
     Further detailed explanation is given for a configuration of the image output unit  202  shown in  FIG. 2A  with reference to  FIG. 2B . 
     A pixel data generation unit  250  inputs a digital signal that the A/D converter  201  outputs and converts the digital signal into pixel data. The pixel data generation unit  250  generates pixel data such that data is formed for each pixel in an RGB format in which the input digital signal is separated into R (red), G (green), and B (blue) color components, for example. 
     A row counter unit  251  inputs pixel data that the pixel data generation unit  250  outputs, counts a number of rows of pixels by counting a number of rows (a number of pixel lines) in units of a predetermined number of pixels, and outputs the counted value of the number of rows to a comparing unit  252 . 
     The comparing unit  252  inputs a value of the number of rows from the row counter unit  251 , and compares the value of the number of rows for a vertical coordinate range of a first pixel region (for example, an OB pixel region that is light-shielded) input from the control unit  101 , and a vertical coordinate range of a second pixel region (for example, an effective pixel region). The comparing unit  252  determines whether or not pixel data are included in the first pixel region or the second pixel region by this comparison, and generates data, as header information, that indicates whether or not pixel data is included in the first pixel region or the second pixel region in an image shown in  FIG. 8 . In embodiments, data indicating whether or not pixel data is included in the first pixel region or the second pixel region is referred to as first region information and second region information respectively. 
     A packet generation unit  253  generates packets based on pixel data output from the pixel data generation unit  250  and header information output from the comparing unit  252 . The packet generation unit  253  stores pixel data output from the pixel data generation unit  250  in a packet payload, and generates a packet further adding header information output from the comparing unit  252  to the payload. 
     A packet output unit  254  outputs packets generated by the packet generation unit  253  adapting to a transmission method corresponding to a transmission channel (not shown) that connects image sensor  121  and the DFE  122 . 
     (Configuration of the DFE  122 ) 
       FIG. 3  illustrates a detailed functional configuration example of the DFE  122 . 
     A packet separation unit  300  separates the header information and the payload data included in the input packet. 
     A pixel data extraction unit  301  extracts pixel data from payload data separated from a packet by the packet separation unit  300 . 
     A first region information extraction unit  302  extracts first region information based on the header information separated from the packet by the packet separation unit  300  and outputs it to a correction value calculation unit  303 . 
     The correction value calculation unit  303  determines whether or not pixel data inputted from the pixel data extraction unit  301  is included in the first pixel region based on the first region information that the first region information extraction unit  302  extracted. Then, when it is determined that the pixel data is included in the first pixel region, a correction value for correcting an influence of dark current is calculated based on an average value of pixel data. The correction value that is calculated is output to a pixel data processing unit  305 . Note that in embodiments various variations and changes can be made in accordance with objectives, and while explanation was given for an example in which the correction value for correcting the influence of dark current is calculated using an average value of pixel data, limitation is not made to calculating using an average value. 
     A second region information extraction unit  304  extracts second region information from header information separated from a packet by the packet separation unit  300 , and outputs it to the pixel data processing unit  305 . 
     The pixel data processing unit  305  determines whether pixel data input from the pixel data extraction unit  301  is included in the second pixel region based on the second region information that the second region information extraction unit  304  extracted. Then, subtraction processing of the correction value that the correction value calculation unit  303  calculates is performed on the pixel data determined to be included in the second pixel region, and the influence of dark current included in the pixel data is corrected. The pixel data processing unit  305  outputs the post-correction image data to the control unit  101  when the correction processing completes. 
     (Series of Operations for Image Capturing Processing) 
     Next, with reference to  FIG. 4 , explanation is given for a series of operations for image capturing processing by the image capturing unit  120 . This processing is started when an image capturing instruction from a user on the second shutter switch  108  of the digital camera  100 , for example, is detected. Note that each step corresponding to this processing is executed in accordance with an instruction of the control unit  101 , and is realized by the control unit  101  loading a program stored in the non-volatile memory  105  in a work area of the volatile memory  103 , and executing the program. 
     In step S 1 , the image capturing unit  120  performs image capturing. The control unit  101  performs control for driving of an aperture, control of an exposure time, and the like for the optical system  102 , for example, and causes the pixel portion  200  to be exposed by an appropriate exposure amount. An analog signal read out from the pixel portion  200 , as described above, is converted into a digital signal, and thereby pixel data is generated. 
     In step S 2 , the image output unit  202  generates a packet into which image data is divided.  FIG. 7  illustrates a format of the packet that the image output unit  202  generates. The packet comprises a header and a payload. In one row of pixel data stored in the payload, pixel data output from pixels of the OB pixel region or pixel data output from pixels of the effective pixel region is stored. In the header information, information indicating whether the pixel data stored in the payload is pixel data output from pixels of the first pixel region or the second pixel region is added. The image output unit  202  divides the image data into rows of pixel data, and in addition to storing a row of pixel data in the payload, the image output unit  202  adds header information, thereby generating a packet. Packet generation processing will be explained later separately with reference to a flowchart shown in  FIG. 5 . The image output unit  202  outputs the generated packet to the DFE  122  via a transmission channel (not shown). 
     In step S 3 , the DFE  122  performs image processing on the image data input from the image sensor  121 . The DFE  122  separates the inputted packet data into the payload storing the pixel data and the header storing first region information and second region information, and performs image processing on the pixel data, i.e. the DFE  122  performs correction for removing the influence of dark current. Details of image processing will be explained later with reference to a flowchart shown in  FIG. 6 . When the DFE  122  outputs the post-correction image data to the control unit  101 , the control unit  101  completes the series of operations for this processing. 
     (Series of Operations for Packet Generation Processing) 
     With reference to the flowchart shown in  FIG. 5  explanation will be given for a series of operations for the packet generation processing shown as step S 2  in  FIG. 4 . 
     In step S 21 , the pixel data generation unit  250  inputs a digital signal output by the A/D converter, generates pixel data in an RGB format as described above, for example, and outputs sequentially each pixel as data. For the generated pixel data, a number of rows is counted by the row counter unit  251  where one row is made to be a predetermined number of pixels. 
     In step S 22 , the comparing unit  252  compares the number of rows that the row counter unit  251  generates (i.e. a vertical coordinate of the pixel data) and a vertical coordinate range of the first pixel region input from the control unit  101 , and determines if the vertical coordinate of the pixel data is included in the first pixel region. The comparing unit  252  updates the first region information if it is determined that pixel data to be processed (i.e. the number of rows input) is included in the vertical coordinate range of the first pixel region. The first region information is a binary identifier for which an initial value is set to be 0, for example, and the first the region information is set to 1 if the pixel data is included in the vertical coordinate range of the first pixel region, and set to 0 if the pixel data is not included in the range. 
     In step S 23 , the comparing unit  252  compares the number of rows that the row counter unit  251  generated and the vertical coordinate range of the second pixel region input from the control unit  101 , and determines whether a vertical coordinate of the pixel data is included in the second pixel region. The comparing unit  252  updates the second region information if it is determined that the pixel data to be processed is included in the vertical coordinate range of the second pixel region. The second region information is set similarly to the above described first region information. 
     In step S 24 , the comparing unit  252  generates header information comprising the first region information and the second region information. 
     In step S 25 , the packet generation unit  253  generates a packet based on payload data including pixel data and the header information generated by the comparing unit  252 . 
     In step S 26 , the packet output unit  254  outputs the packet generated in step S 25  to the DFE  122 . The packet output unit  254  repeatedly transmits a packet for each row, and when the transmission of the packets completes for all of the image data, the series of operations for this processing completes. 
     (Series of Operations for Image Processing) 
     Next, with reference to the flowchart shown in  FIG. 6 , explanation will be given for image processing shown as step S 3  in  FIG. 4 . 
     When, in step S 300 , the DFE  122  inputs a packet transferred from the image sensor  121 , the packet separation unit  300  of the DFE  122 , in step S 301 , separates the header information and the payload data. 
     In step S 302 , the pixel data extraction unit  301  extracts pixel data included in the payload. 
     In step S 303 , the first region information extraction unit  302  extracts first region information included in the header information separated in step S 301 , and outputs to the correction value calculation unit  303 . 
     In step S 304 , the correction value calculation unit  303 , based on the extracted first region information, determines if a vertical coordinate of the pixel data extracted from the payload in step S 302  is included in the first vertical region. The correction value calculation unit  303  determines that the pixel data is included in the first vertical region and advances the processing to step S 305  when the first region information indicates 1, and the correction value calculation unit  303  determines that the pixel data is not included in the first vertical region and advances the processing to step S 307  when the first region information indicates 0. 
     In step S 305 , the correction value calculation unit  303  compares a horizontal coordinate of pixel data obtained by counting pixel data of the payload with a first horizontal coordinate range input from the control unit  101 , and determines if a horizontal coordinate of the pixel data is included in the first horizontal coordinate range. When a horizontal coordinate of the pixel data is determined to be included in the first horizontal coordinate range, the processing proceeds to step S 306 , and when it is determined that the horizontal coordinate is not included in the range, the processing advances to step S 307 . 
     In step S 306 , the correction value calculation unit  303  calculates an average value of all of the pixel data of the first pixel region included in the first horizontal coordinate range, and generates a correction value for the image. 
     In step S 307 , the second region information extraction unit  304  extracts second region information included in the header information. 
     In step S 308 , the pixel data processing unit  305  determines, similarly to in step S 304 , whether a vertical coordinate of pixel data is included in the second vertical region from the extracted second region information, and when it is determined that the pixel data is included in the second vertical region, the processing advances to step S 309 . 
     In step S 309 , the pixel data processing unit  305  compares horizontal coordinate information that the correction value calculation unit  303  indicates with the second horizontal coordinate range input from the control unit  101 . When it is determined that a horizontal coordinate of the pixel data is included in the horizontal coordinate range that is input, the processing advances to step S 310 . 
     In step S 310 , the pixel data processing unit  305  performs subtraction processing of the correction value calculated in step S 306  on a pixel specified in the second region information. If the pixel data processing unit  305  completes correction processing on a pixel specified by the second region information, the series of operations for the image processing completes. 
     Note that in embodiments, configuration is such that pixel data is stored in a packet for each row, and such that the control unit  101  transmits a vertical coordinate range to the image output unit  202 , but configuration may be taken such that pixel data is stored in a packet for each column, and such that a horizontal coordinate range is transmitted from the control unit  101 . In such a case, the row counter unit  251  may count pixel data items for each column, and the comparing unit  252  may determine whether the counter value is included in the horizontal coordinate range. 
     Also, an example of correction processing is described in present embodiments in which processing for subtracting a correction value from pixel data included in the second pixel region was performed, but the correction processing is not limited to subtraction processing, and various variations and changes can be made in accordance with objectives. 
     As explained above, in embodiments, configuration is taken such that the image sensor  121  inputs vertical coordinate information of pixel data, and the image sensor  121  supplies the vertical coordinate information of the pixel data in addition to the pixel data in a centralized fashion. With such a configuration, it is possible for the DFE  122 , which is a circuit for signal processing, to perform image processing without receiving information relating to a vertical coordinate from the control unit  101 . Accordingly, it is possible to reduce control information transmitted from the control unit to the circuit for signal processing. 
     Second Embodiment 
     Next, explanation will be given for a second embodiment. In embodiments, explanation is given for processing for correcting shading in a vertical direction due to an influence of dark current as an example of image processing that the DFE  122  performs. For the digital camera  100  of the present embodiment, a configuration of pixels of an image sensor, and image processing that is applied differs from the first embodiment; other than this the configuration is the same as in the first embodiment. For these reasons, the same reference numerals are given to the same elements, and overlapping explanation is omitted, and predominantly explanation is given for differences. 
     As is shown in  FIG. 10 , the pixel portion  200  according to embodiments comprises an OB pixel region which is adjacent to an effective pixel region in a horizontal direction. Pixels of the OB pixel region arranged in a horizontal direction from the effective pixel region are input into the DFE  122 , and the DFE  122  in addition to calculating a correction value using an output of the pixels of the OB pixel region performs correction processing on the effective pixel region. With such a configuration, shading in a vertical direction due to an influence of dark current is corrected. 
     The OB pixel region (a first pixel region) and the effective pixel region (a second pixel region) are arranged so as to be adjacent in a horizontal direction. Pixels included in the first pixel region are specified by a vertical coordinate range of the first pixel region and a horizontal coordinate range of the first pixel region which indicate a vertical direction coordinate range and a horizontal direction coordinate range. Similarly, pixels included in the second pixel region are specified by a vertical coordinate range in the second pixel region and a horizontal coordinate range in the second pixel region. 
     A series of operations for image processing according to embodiments will be explained with reference to a flowchart shown in  FIG. 9 . Note that in  FIG. 9  processing that is the same as in  FIG. 6  is given the same step number. 
     The DFE  122  performs each process from step S 300 -step S 305  as explained in  FIG. 6 . 
     Next, in step S 901 , the correction value calculation unit  303  calculates an average value for pixel data of each row when it is determined that a horizontal coordinate of pixel data is included in the first horizontal coordinate range. The correction value calculation unit  303  outputs to the pixel data processing unit  305  an average value for each calculated row as a correction value for correcting vertical direction shading due to an influence of dark current. 
     After this, each process from step S 307 -step S 309  as explained in  FIG. 6  is performed. 
     Also, in step S 902 , the pixel data processing unit  305  performs correction processing on pixel data of a row to be processed from the pixel data of the second pixel region using the correction values for each row calculated in step S 901 . The pixel data processing unit  305  corrects the shading in the vertical direction due to the influence of dark current on the image data by subtraction processing of a correction value from the pixel data of the second pixel region, for example. 
     As explained above, in embodiments, the DFE  122  is configured to calculate a correction value using pixels specified from out of the same row, and to perform correction processing therewith for pixel data of each row determined based on header information. With such a configuration, even in a case where the image sensor has an OB pixel region adjacent to the effective pixel region in a horizontal direction, the DFE  122 , which is a circuit for signal processing, is able to perform image processing without receiving information relating to a vertical coordinate from the control unit  101 . Accordingly, it is possible to reduce control information transmitted from the control unit to the circuit for signal processing. 
     Third Embodiment 
     Next, explanation will be given for a third embodiment. In the third embodiment, a horizontal coordinate range for the first and second pixel region is further input from the control unit  101  into the image sensor  121 , and on this point the third embodiment differs from the embodiments described above. For this reason a configuration for generating header information of a packet, and a configuration for receiving the packet and calculating a correction value from the header information are different. Because other elements are the same as in the embodiments described above, the same reference numerals will be given to the same elements, overlapping explanation will be omitted, and predominantly explanation will be given for differences. Note that the image sensor in this embodiment is configured to have first and second pixel regions as shown in  FIG. 10  in the second embodiment, and the DFE  122  performs processing for correcting shading in a vertical direction due to an influence of dark current similarly to the second embodiment. 
       FIG. 11A  illustrates a functional configuration example of the image sensor  121  in the present embodiment. In the above described embodiments, the image output unit  202  shown in  FIG. 3  generates first region information from a first vertical coordinate range and a number of rows. In contrast to this, an image output unit  1101  according to the present embodiment inputs first and second horizontal coordinate ranges in addition to first and second vertical coordinate ranges from the control unit  101 .  FIG. 11B  illustrates a functional configuration example of the image output unit  1101  according to embodiments. The image output unit  1101  generates first region information from a first vertical coordinate range, a first horizontal coordinate range, a number of rows and a number of columns of pixel data to be processed. Note that in the present embodiment, explanation is given for an example in which pixel data for one pixel is stored as a payload as shown in  FIG. 13 . However, configuration may be taken such that pixel data for one row is stored in the payload similarly to the above described embodiment, and a header indicating region information for each pixel stored in the payload is added. 
     A counter unit  1102  of the image output unit  1101  counts rows and columns for each pixel inputted for the pixel data inputted from the pixel data generation unit  250 , and outputs the number of rows and columns of pixels to be processed to a comparing unit  1103 . The comparing unit  1103  compares the counter value for the rows and columns input from the counter unit  1102  with coordinate ranges of the first and second pixel regions input from the control unit  101 , and thereby generates header information. The comparing unit  1103  determines whether a counter value for the input rows is included in the first vertical coordinate range, and further determines if a counter value for the number of columns included in the first horizontal coordinate range. The comparing unit  1103  updates a value corresponding to the first region information when the column counter value is included in the first vertical coordinate range. Also, when the row counter value is included in the first horizontal coordinate range, the first region information is similarly updated. The first region information is a two digit binary identifier for which an initial value is set to 00, for example, and when each of the vertical coordinate and the horizontal coordinate in that order are included in the respective coordinate range a 1 is set. Accordingly, when the row counter value and the column counter value are included in the first pixel region, the first region information becomes 11. The comparing unit  1103  further generates second region information by determining whether the pixel data is included in the second pixel region. At this time, the comparing unit  1103  performs the generation of the second region information similarly to the generation of the first region information. 
     Next, for a series of operations for image processing in embodiments, explanation will be given with reference to  FIG. 12 . Note that in  FIG. 12  processing that is the same as in  FIG. 6  or  FIG. 9  is given the same step number. 
     The DFE  122  performs each process from step S 300 -step S 304  as explained in  FIG. 6 . 
     Next, in step S 1201 , the correction value calculation unit  303  of the DFE  122  references the first region information, determines whether or not a horizontal coordinate of the pixel data is included in the first horizontal region, and when it is determined that the horizontal coordinate of the pixel data is included in the first horizontal region, advances the processing to step S 901 . More specifically, when, in the above described first region information, the value of the digit corresponding to the horizontal coordinate in the 2 digit identifier is 1, the correction value calculation unit  303  determines that the pixel data is included in the first horizontal region. 
     After this, step S 901  explained in  FIG. 9 , performs the processes of step S 307 -step S 308  explained in  FIG. 6 . 
     Next, in step S 1203 , the correction value calculation unit  303  references the second region information, and determines whether a horizontal coordinate of the pixel data is included in the second horizontal region, and if the coordinate is determined to be included in the second horizontal region, the processing of step S 902  explained in  FIG. 9  is performed. 
     As explained above, in the present embodiment, vertical coordinate information and horizontal coordinate information of the pixel data is input into the image sensor  121 , and the image sensor  121  supplies in a centralized fashion the vertical coordinate information and the horizontal coordinate information of the pixel data in addition to the pixel data. With such a configuration, the DFE  122 , which is a circuit for signal processing, is able to perform image processing without receiving information relating to the vertical coordinate and the horizontal coordinate from the control unit  101 , and thus it is possible to reduce control information for transmitting the circuit for signal processing from the control unit. 
     Other Embodiments 
     Also, the present invention can be applied to other embodiments shown below. For example, the present invention can be applied to an image sensor  1400  which is of a stacked structure as shown in  FIG. 14A . As shown in  FIG. 14A , in the image sensor  1400  of the present embodiment a first semiconductor chip  1401  and a second semiconductor chip  1402  are stacked at a chip level.  FIG. 14A  is an oblique projection view, and  FIG. 14B  illustrates a top view of each chip. A region including a pixel portion  1405  is included in the first semiconductor chip  1401 , and a portion  1403  capable of high speed processing including digital data such as a column AD conversion circuit or a horizontal scanning circuit is included in the second semiconductor chip  1402  which is for high speed logic process. In the configuration of  FIG. 1  described above, for example, the pixel portion  200  that the image sensor  121  comprises corresponds to the pixel portion  1405  of the first semiconductor chip  1401 . Also, configuration may be taken such that circuits other than the pixel portion  200  and the image output unit  202  and the A/D converter  201  included in the image sensor  121  are arranged on the second semiconductor chip  1402 . 
     Furthermore, the present invention can be applied to a mobile telephone  1500  shown in  FIG. 15  which is an example of the image capturing apparatus.  FIG. 15  is a block diagram for showing a functional configuration of the mobile telephone  1500 . The mobile telephone  1500  comprises in addition to an audio call function, an electronic mail function, an Internet connection function, an image capturing and reproduction function, or the like. A communication unit  1010  communicates audio data, image data, or the like, with another telephone device by a communication scheme according to a communication carrier with which a user has made a contract. Upon an audio call, an audio processing unit  1020  converts audio data from a microphone  1030  into a format suited to transmission and sends the result to the communication unit  1010 . Also, the audio processing unit  1020  decodes audio data from a call partner sent from the communication unit  1010  and sends the result to a speaker  1040 . An image capturing unit  1050  captures an image of an object, and outputs pixel data. The image capturing unit  1050  includes the image sensor  121  described above in embodiments. Here, the image sensor  121  may be an image sensor of a stacked structure as described above. Also, the above described packet is transmitted between the image capturing unit  1050  and an image processing unit  1060 . The image processing unit  1060  includes the DFE  122  described above in embodiments, and the image processing unit  1060  processes pixel data captured by the image capturing unit  1050  upon capturing of an image, converts the result into a format suitable for recording, and outputs the result. Also, the image processing unit  1060  processes a reproduced image upon reproduction of a recorded image, and sends the result to a display unit  1070 . The display unit  1070  comprises a liquid crystal display panel of several inches, and displays various screens in accordance with instructions from a control unit  1090 . A non-volatile memory  1080  stores address book information, electronic mail data, or the like, or data such as image data captured by the image capturing unit  1050 . 
     The control unit  1090  has a CPU, a memory, or the like, controls each unit of the mobile telephone  1500  in accordance with a control program stored in a memory (not shown). An operation unit  1100  comprises various operation keys for the user to input data in addition to a power button, and number keys. A memory IF  1110  performs a recording reproduction of various data in a recording medium  1120 , which may be a memory card, or the like. An external IF  1130  transmits data stored in the non-volatile memory  1080  and the recording medium  1120  to an external device, and receives data transmitted from an external device. The external IF  1130  performs communication by a wired connection communication scheme such as USB, or a publicly known communication scheme such as one for wireless communication. 
     Next, explanation is given of an audio call function in the mobile telephone  1500 . When a call partner is called, a user inputs a number of the call partner by operating number keys of the operation unit  1100 , or an address book stored in the non-volatile memory  1080  is displayed on the display unit  1070 , a call partner is selected, and transmission is instructed. When the transmission is instructed, the control unit  1090  transmits to a call partner via the communication unit  1010 . Upon an incoming call from a call partner, the communication unit  1010  outputs audio data of a partner to the audio processing unit  1020 , and also transmits audio data of a user to the partner. 
     Also, when transmitting an electronic mail, a user instructs the generation of the mail using the operation unit  1100 . When the generation of a mail is instructed, the control unit  1090  displays a screen for generating a mail on the display unit  1070 . The user inputs a transmission destination address, a body, or the like, using the operation unit  1100 , and instructs transmission. When a mail transmission is instructed, the control unit  1090  sends address information and mail body data to the communication unit  1010 . The communication unit  1010  converts data of the mail into a format suitable for communication, and transmits the result to the transmission destination. Also, when the communication unit  1010  receives an electronic mail, the communication unit  1010  converts the received mail data into a format that is suited to display, and displays the result on the display unit  1070 . 
     Next, explanation is given of a capturing function in the mobile telephone  1500 . When capturing of a still image or a moving image is instructed, after a user sets an image capturing mode by operating the operation unit  1100 , the image capturing unit  1050  captures still image data or moving image data, and sends it to the image processing unit  1060 . The image processing unit  1060  processes the still image data or the moving image data that was captured, and stores the result in the non-volatile memory  1080 . Also, the image processing unit  1060  sends the captured still image data, moving image data, or the like, to the memory IF  1110 . The memory IF  1110  stores the still image data, or moving image data in the recording medium  1120 . 
     Also, the mobile telephone  1500  is able to transmit a file including the captured still image, moving image data, or the like, as an electronic mail attachment file. Specifically, when an electronic mail is transmitted, an image file stored in the non-volatile memory  1080 , the recording medium  1120 , or the like, is selected, and transmission as an attachment file is instructed. 
     The mobile telephone  1500  can transmit files including captured still image or moving image data to an external device such as a PC, another telephone device, or the like, by the external IF  1130 . The user selects an image file stored in the non-volatile memory  1080  or the recording medium  1120  and instructs transmission by operating the operation unit  1100 . The control unit  1090  reads out the selected image file from the non-volatile memory  1080  or the recording medium  1120 , and controls the external IF  1130  so as to transmit to the external device. 
     Embodiment(s) of the present invention 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 (e.g., central processing unit (CPU), micro processing unit (MPU)) 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)™), a flash memory device, a memory card, and the like. 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. 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 Japanese Patent Application No. 2014-178508, filed Sep. 2, 2014, and Japanese Patent Application No. 2015-159137, filed Aug. 11, 2015, which are hereby incorporated by reference herein in their entirety.