JP6108854B2 - Imaging apparatus and control method thereof - Google Patents

Description

The present invention relates to an imaging apparatus and a control method thereof .

  In an image sensor such as a CCD image sensor or a CMOS image sensor that captures a still image or a moving image, generally, the dynamic range (ratio between the minimum luminance and the maximum luminance capable of distinguishing gradations) can be perceived by human eyes. It is known that it is narrow in comparison. Therefore, it is difficult to reproduce the gradation actually seen with eyes as a photograph. Therefore, a technique is known in which a plurality of images shot under different exposure conditions are overlapped to acquire an image having a wider dynamic range (hereinafter referred to as “HDR”) than normal shooting (see, for example, Patent Document 1).

  FIG. 14 is a diagram schematically illustrating an example of a photographing operation according to the related art that realizes HDR. After the start of photographing, a plurality of images (for example, three images of a dark underexposed L image, a properly exposed M image, and a bright overexposed H image) are taken under different exposure conditions. After that, by synthesizing the captured images, it is possible to realize HDR by the difference in exposure between the H image and the L image.

Japanese Patent Laid-Open No. 06-141229

  However, since Patent Document 1 only discloses that images with different exposure conditions are independently photographed, correction is required for each image, and correction parameters are created and corrected for each image. It is not possible to cope with the case where processing is necessary. As a result, there is a problem that a useless period occurs between frames, and there is a problem that the locus of the subject is interrupted with respect to a moving subject or the like. In addition, when the operation for obtaining HDR is performed during moving image shooting, the correction parameter creation area cannot be sufficiently taken into account due to the relationship with the frame rate at the time of reproduction, and thus sufficient correction accuracy is obtained. In other words, there is a problem that high image quality cannot be ensured.

  An object of the present invention is to provide an imaging apparatus capable of ensuring high image quality while reducing extra time generated between frames during an operation for obtaining HDR.

Imaging device according to the present invention, the imaging device having the complement Tadashiyo pixel you output a signal for correcting the signals output from the light receiving pixels and prior Symbol receiving pixel you output a signal corresponding to the amount of received light once used, an image obtaining means for obtaining two or more images by performing continuous shooting at different exposure settings, for each combination of the two or more images when obtaining the prior SL 2 or more images Any one of a first reading method of reading a signal from the correction pixel and a second reading method of reading a signal from the correction pixel every time each image is acquired when acquiring the two or more images. A reading means for reading a signal by the above method, and when the signal is read by the first reading method, the two sheets using a correction value generated from the signal read only once from the correction pixel. Correct the above image A correction means for correcting the image using the correction values generated using a signal read out for each image from the correction pixel when the signal is read by the second read method, characterized in that it comprises a synthesizing means for generating a corrected said two or more synthesized and the synthesized image pictures by said correcting means.

  According to the present invention, it is possible to ensure high image quality while reducing extra time that occurs between frames during the operation for obtaining HDR.

1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment of the present invention. It is a figure which shows schematic structure of the image pick-up element which the imaging part with which the imaging device of FIG. 1 is provided has. 2 is a timing chart of normal image acquisition by the imaging apparatus of FIG. 1. FIG. 3 is a diagram illustrating an OB clamp operation performed on an output signal from the image sensor of FIG. 2 and a diagram illustrating a configuration of an OB clamp circuit. It is a figure which shows typically the state in which the vertical stripe by the column offset component has generate | occur | produced in the output signal from the image pick-up element of FIG. It is a figure which shows the effect of the column offset correction with respect to the image of FIG. 3 is a timing chart according to the first embodiment for acquiring an HDR video using the imaging apparatus of FIG. 1. It is a figure which shows typically the lack of correction precision at the time of reading an OB pixel signal and a NULL pixel signal only once for every unit which produces | generates an HDR image. It is a timing chart which shows the operation | movement which reads an OB pixel signal and a NULL pixel signal for every acquisition of each image of L image and H image used by 2nd Embodiment. It is a flowchart which shows the acquisition method of the HDR image which concerns on 2nd Embodiment. 12 is a timing chart for acquiring an HDR image when the subject brightness becomes low according to the third embodiment. It is a flowchart which shows the specific correction method of H image based on 3rd Embodiment. It is a figure which shows schematic structure of the signal processing part with which an imaging device corrects H image according to the flowchart of FIG. It is a figure which shows typically an example of imaging | photography operation | movement which concerns on the prior art for acquiring the image of a dynamic range wider than normal imaging | photography.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a block diagram showing a schematic configuration of an imaging apparatus 100 according to the first embodiment of the present invention. In the present embodiment, specifically, the imaging device 100 is assumed to be a digital camera capable of still image shooting and moving image shooting. The imaging apparatus 100 includes a lens unit 101, a light amount adjustment unit 102, an imaging unit 103, a signal processing unit 104, an imaging control unit 105, an overall control unit 106, an operation unit 110, a recording unit 111, and a display unit 112. The overall control unit 106 includes a storage unit 107, a subject luminance detection unit 108, and an exposure calculation unit 109.

  The lens unit 101 includes a plurality of lens groups for forming an image of reflected light from a subject on the imaging unit 103, and includes a focal length changing unit, a light blocking unit that blocks incident light, and the like. The light amount adjustment unit 102 is disposed between the lens unit 101 and the imaging unit 103, and is a neutral density filter or the like that can reduce the amount of light transmitted through the lens unit 101 in, for example, three stages. However, the light amount adjustment unit 102 is not limited to this, and the setting value of the light reduction amount may be a value other than three steps, or the light amount adjustment unit 102 can be dimmed in multiple steps by using a diaphragm mechanism. Also good.

  The imaging unit 103 is an imaging device that converts light incident through the lens unit 101 and the light amount adjustment unit 102 into an analog electrical signal, and A / D conversion that converts an analog signal output from the imaging device into a digital signal (pixel signal). Including circuits. The signal processing unit 104 performs correction parameter generation and necessary image signal correction processing on the pixel signal input from the imaging unit 103. The imaging control unit 105, based on a command (input signal) from the overall control unit 106, a timing signal necessary for the imaging unit 103 and the signal processing unit 104, a gain setting signal for amplifying the video signal, and an exposure time A setting signal and other signals necessary for control are generated. The overall control unit 106 includes a CPU, a ROM, a RAM, and the like that store programs. The overall control unit 106 controls the overall operation of the imaging apparatus 100 by developing and executing programs read from the ROM in the RAM work area. Performs the necessary processing and calculations for control.

  A storage unit 107 included in the overall control unit 106 temporarily stores a signal from the signal processing unit 104 or the like. The subject brightness detection unit 108 detects the brightness value of the subject being shot based on the signal from the imaging unit 103. The exposure calculation unit 109 determines the exposure of the captured image based on the luminance value detected by the subject luminance detection unit 108. The overall control unit 106 adjusts the amount of light using the light amount adjustment unit 102 based on the calculation result of the exposure calculation unit 109, and adjusts the exposure time and the gain for amplifying the video signal using the imaging control unit 105. To do. In the present embodiment, the signal processing unit 104 is independent from the overall control unit 106, but the signal processing unit 104 may be included in the overall control unit 106 or included in the imaging unit 103. It may be. In addition, the imaging control unit 105 may be included in the imaging unit 103.

  The operation unit 110 is configured by a human IF such as various mechanical buttons and dials, and an icon capable of touch panel operation using the display unit 112. Information and commands input through the operation unit 110 are transmitted to the overall control unit 106, and the overall control unit 106 operates the imaging apparatus 100 based on the received information and commands. The recording unit 111 records image data generated by the overall control unit 106. The display unit 112 displays image data generated by the overall control unit 106 based on a signal from the signal processing unit 104, and displays an icon corresponding to the operation input from the operation unit 110.

  FIG. 2 is a diagram illustrating a schematic configuration of an image sensor provided in the imaging unit 103. In the present embodiment, the imaging element is a CMOS image sensor. The image sensor includes a light receiving pixel 201 that receives light from the lens unit 101 and outputs an electric signal corresponding to the amount of light received through photoelectric conversion. The light receiving pixel 201 includes a photodiode 202, a transfer transistor 203, a signal amplification amplifier 204, and a reset transistor 205 as one unit. The transfer transistor 203 and the reset transistor 205 are operated by signals from the horizontal drive circuit 206. The horizontal drive circuit 206 includes a shift register for driving each pixel of the light receiving pixel 201, a signal generation circuit such as the transfer transistor 203, and the like. The transfer transistor 203 and the reset transistor 205 are controlled by the timing signal generated by the horizontal driving circuit 206, whereby the charge / reset of the photodiode charge of each pixel is performed, and the exposure time is controlled.

  The imaging element includes a light-shielding pixel 207 (hereinafter referred to as “OB pixel 207”), a dummy pixel 208 (hereinafter referred to as “NULL pixel 208”), and a vertical drive circuit 209. The OB pixel 207 and the NULL pixel 208 are correction pixels that output an electric signal for correcting the electric signal output from the light receiving pixel 201.

  Unlike the light receiving pixel 201, the surface of the OB pixel 207 is shielded from light by a light shielding film. The signal output from the OB pixel 207 is used when determining the black reference of the image in the subsequent image processing. Unlike the light receiving pixel 201 and the OB pixel 207, the NULL pixel 208 does not have a photoelectric conversion function. A signal output from the NULL pixel 208 is used when detecting an offset component of the horizontal drive circuit 206 that operates each pixel. Note that the NULL pixel 208 is equivalent to a configuration in which the photodiode 202 is omitted from the light receiving pixel 201.

  The vertical drive circuit 209 includes a shift register, a column amplifier circuit and A / D conversion circuit 210, a signal output selection switch 211, an output circuit (not shown) to the outside, and the like. By changing the settings of the column amplifier circuit and the A / D conversion circuit 210 according to the signal from the imaging control unit 105, the signal read from each pixel can be amplified.

  FIG. 3 is a timing chart of normal image acquisition by the imaging apparatus 100. Exposure to the image capturing unit 103 and signal readout from the image capturing unit 103 are performed by a vertical synchronization signal generated by the overall control unit 106 or the image capturing control unit 105. In the present embodiment, the signals of the light receiving pixel 201, the OB pixel 207, and the NULL pixel 208 are read in a predetermined order under the conditions set by the imaging control unit 105.

  As described above, the CMOS image sensor is used in the present embodiment. Therefore, it is possible to select which row of the transfer transistors 203 is driven in what order by setting the shift register of the horizontal driving circuit 206, and it is also possible to repeatedly select the same row and read a signal. Further, by setting the shift register of the vertical drive circuit 209, it is possible to select which column signal is output from the same row signal depending on which column signal output selection switch 211 is operated. In this way, it is possible to specify in what order the signal is read from which pixel in the screen. The signal read from the light receiving pixel 201 is corrected by using the correction value generated from the signal read from the OB pixel 207 and the NULL pixel 208 in the signal processing unit 104. Thereafter, the overall control unit 106 creates a final image.

  Next, a signal read from the light receiving pixel 201 (hereinafter referred to as “light receiving”) using a signal read from the OB pixel 207 (hereinafter referred to as “OB pixel signal”) and a signal read from the NULL pixel 208 (hereinafter referred to as “NULL pixel signal”). A method for correcting “pixel signal” will be described.

  As an example of the correction method of the light receiving pixel signal using the OB pixel signal, there is an OB clamping operation for subtracting the dark current component generated with the temperature rise of the image sensor from the light receiving pixel signal. That is, the output signal value of the OB pixel 207 is subtracted from the output signal value of the light receiving pixel 201. FIG. 4A is a diagram showing this OB clamping operation. The dark current component generated in the OB pixel 207 is at the same level as the dark current component generated in the light receiving pixel 201. Therefore, by performing the OB clamping operation, it is possible to remove the influence of the dark current component on the image quality even if the temperature of the image sensor rises during shooting.

  FIG. 4B is a diagram showing a schematic configuration of the OB clamp circuit. Before reading a signal from the light receiving pixel 201, the signal of the OB pixel 207 is read and input to the signal processing unit 104. The signal processing unit 104 includes a correction value generation circuit 401, and the correction value generation circuit 401 calculates a dark current component from the input OB pixel signal. Thereafter, a signal is read from the light receiving pixel 201, and a dark current component is subtracted from the read light receiving pixel signal. Thereby, the influence of the dark current component on the image quality can be reduced.

  On the other hand, as an example of a method for correcting a light receiving pixel signal using a NULL pixel signal, an offset component (hereinafter referred to as “column offset component”) that is superposed due to transistor variations in a column amplifier circuit or a column A / D conversion circuit. Column offset correction operation of subtracting “)” from the light receiving pixel signal.

  FIG. 5 is a diagram schematically illustrating a state in which vertical stripes are generated due to the column offset component. FIG. 6 is a diagram showing the effect of column offset correction on the image of FIG. 5, and FIG. 5 shows before and after the column offset correction operation (FIG. 6 (a): before correction, FIG. 6 (b): after correction). It is a figure which shows the output between A-A 'and between B-B'.

  As shown in FIGS. 5 and 6A, the light receiving pixel 201 has an output in which a column offset component is superimposed in addition to a dark current and a signal due to light incident from the lens unit 101 between A and A ′. Yes. On the other hand, the NULL pixel 208 has no portion for photoelectric conversion between B and B ′, and thus is hardly affected by the dark current and can detect the column offset component satisfactorily. Therefore, as shown in FIG. 6B, an output signal from which the column offset component is removed can be obtained by subtracting the output signal value of the NULL pixel 208 for each column from the output signal value of the light receiving pixel 201. . It should be noted that obtaining the column offset correction value shown in FIG. 6B is realized by using the same circuit as the circuit used in the OB clamp circuit for the same signal by the number of columns for each column. be able to.

  The correction values of the OB clamp operation and the column offset correction operation described above are performed by averaging signal values of a plurality of pixels or performing operations such as a cyclic filter in order to improve the correction accuracy by reducing the influence of random noise. Calculated. Therefore, the correction accuracy depends on the number of pixels for calculating the correction value.

  A method for acquiring a moving image having a wider dynamic range than normal shooting (hereinafter referred to as “HDR moving image”) by the imaging apparatus 100 will be described below.

  FIG. 7 is a timing chart according to the first embodiment for acquiring an HDR video using the imaging apparatus 100. For example, the overall control unit 106 generates a vertical synchronization signal every 1/60 s, and thereby performs imaging at an imaging cycle of 60 fps. Here, it is assumed that the exposure operation of the dark underexposed L image and the bright overexposed H image are alternately performed under the conditions set by the imaging control unit 105. The captured L image and H image are temporarily stored in the storage unit 107, and when the L image and the H image are aligned, the overall control unit 106 combines the two images and is a combined image having a wide dynamic range. Create an HDR image. An HDR video is composed of a plurality of HDR images.

  Here, the OB pixel signal and the NULL pixel signal are read out for generating a correction value only once for each combination of the L image and the H image for generating the HDR image. The read OB pixel signal and NULL pixel signal are input to the signal processing unit 104, and the signal processing unit 104 generates a correction value. Thereafter, the signal processing unit 104 performs a correction operation using the same correction value generated for each of the read L image and H image. Thereby, the interval for reading out the L image and the H image can be narrowed, and a good HDR image can be acquired even for a moving subject or the like. In addition, signals having a larger number of pixels than the number of OB pixels 207 or NULL pixels 208 that have been read for each image can be read at a time, and the influence of random noise on the generated correction value can be reduced. it can.

  In this embodiment, a 30 fps movie is created using two images continuously shot at 60 fps. However, the same operation as in this embodiment can be applied even at a different frame rate. An effect can be obtained. Further, regarding the acquisition order of the L image and the H image, the L image is acquired first in the present embodiment, but may be acquired before the H image. Furthermore, the number of images used for generating the HDR image may be two or more (for example, three), and the same effect can be obtained by performing the same operation as in the present embodiment.

  The correction value generated from the OB pixel signal and the NULL pixel signal may be newly generated for each unit for generating the HDR image, or may be generated across a plurality of past frames. Furthermore, as shown in FIG. 2, in this embodiment, the imaging device has a NULL pixel 208 inside, but this embodiment uses an operation that does not read a signal from the light receiving pixel 201 (empty transfer). The same effect can be obtained by performing the same operation as.

Second Embodiment
In the first embodiment, an OB pixel signal and a NULL pixel signal are read out only once for each unit for generating an HDR image (first reading method). In this case, since the exposure conditions such as gain and shutter speed differ between the specific L image and the H image for generating the HDR image, the OB pixel signal and the NULL pixel signal are read only once for each unit for generating the HDR image. In such a case, there is a risk that the correction accuracy may be insufficient. FIG. 8 is a diagram schematically illustrating a lack of correction accuracy when an OB pixel signal and a NULL pixel signal are read only once for each unit for generating an HDR image. As described above, when attention is paid to the correction accuracy, the conventional operation in which the operation of reading the OB pixel signal and the NULL pixel signal (second reading method) is performed every time the images of the L image and the H image are acquired is preferable. .

  The imaging device, the image correction method, the HDR image generation method, and the like in the second embodiment are the same as those in the first embodiment, but in the second embodiment, when generating an HDR image, The operation (first reading method) and the above-described conventional operation (second reading method) are switched.

  FIG. 9 is a timing chart showing an operation of reading out the OB pixel signal and the NULL pixel signal (the above-described conventional operation) every time the L image and the H image are acquired. The overall control unit 106 generates a vertical synchronization signal every 1/60 s, thereby performing shooting at a shooting period of 60 fps. Under the conditions set by the imaging control unit 105, the exposure operation of the L image and the H image is performed. It shall be performed alternately. The captured L image and H image are temporarily stored in the storage unit 107, and when the L image and the H image are aligned, the overall control unit 106 combines both images to create an HDR image.

  At this time, an operation of reading out the OB pixel signal and the NULL pixel signal is performed every time the L image and the H image are acquired. The read OB pixel signal and NULL pixel signal are input to the signal processing unit 104, and the signal processing unit 104 generates a correction value. Thereafter, the signal processing unit 104 performs a correction operation using correction values generated for each of the read L image and H image. In the present embodiment, the HDR image synthesis based on the timing chart shown in FIG. 7 and the HDR image synthesis based on the timing chart shown in FIG. 9 are switched in a timely manner.

  FIG. 10 is a flowchart illustrating an HDR image acquisition method according to the second embodiment. The overall control unit 106 controls the imaging control unit 105 to acquire an image for setting exposure (step S1001). Then, the subject brightness detection unit 108 of the overall control unit 106 calculates the subject brightness Bv from the image acquired in step S1001 (step S1002). Subsequently, the exposure calculation unit 109 of the overall control unit 106 determines an exposure setting EvL for acquiring an L image and an exposure setting EvH for acquiring an H image from the subject luminance Bv calculated in step S1002 (step S1003). Here, the exposure setting method includes exposure time, gain setting for amplifying the video signal, presence / absence of insertion of a neutral density filter, and the like.

  The overall control unit 106 sets the light amount adjustment unit 102 and the imaging unit 103 through the imaging control unit 105 according to each exposure condition determined in step S1003 (step S1004). Next, the overall control unit 106 performs the operation of FIG. 7 using the L image acquisition gain setting value (Sv_L) and the H image acquisition gain setting value (Sv_H), which are gain setting values in the exposure settings EvH and EvL, respectively. And switching between the operations shown in FIG. 9 (step S1005). In step S1005, here, the determination criterion is whether or not the relational expression “Sv_H = Sv_L” is satisfied.

  When “Sv_H = Sv_L” (YES in S1005), the overall control unit 106 performs the operation of FIG. 7 (step S1006). On the other hand, if “Sv_H ≠ Sv_L” (NO in S1005), the overall control unit 106 performs the operation of FIG. 9 (step S1007). After steps S1006 and 1007, the overall control unit 106 determines whether or not the photographing is finished (step S1008). If shooting has not ended (NO in step S1008), the overall control unit 106 returns the process to step S1001. On the other hand, when the shooting is completed (YES in S1008), the overall control unit 106 ends the shooting.

  By performing the above operations, high-quality HDR images can be acquired even when exposure conditions such as gain and shutter speed are different. In the present embodiment, switching between the operation of FIG. 7 (operation of the first embodiment) and the operation of FIG. 9 (conventional operation) is performed based on the gain setting value. The power consumption period may be switched according to increase / decrease or other conditions.

<Third Embodiment>
In the second embodiment, when generating an HDR image, the operation of FIG. 7 (operation of the first embodiment) and the operation of FIG. 9 (conventional operation) are switched. On the other hand, in the third embodiment, when the correction accuracy is insufficient, the correction accuracy is improved by an operation different from the conventional operation. Note that the imaging apparatus, the image correction method, the HDR image generation method, and the like in the third embodiment are the same as those in the first embodiment.

  FIG. 11 is a timing chart for acquiring an HDR image when the subject brightness becomes low. For each unit for generating an HDR image, the OB pixel signal and the NULL pixel signal are read when the L image as the head image is acquired, and the OB pixel signal and the NULL pixel signal are also read when the next H image is acquired. At this time, the number of pixels of the OB pixel signal and the NULL pixel signal read when acquiring the H image is made smaller than the number of pixels of the OB pixel signal and the NULL pixel signal read when acquiring the L image. And about L image, the correction | amendment similar to 1st Embodiment is performed using the OB pixel signal and NULL pixel signal read at the time of L image acquisition. For the H image, correction is performed using the OB pixel signal and the NULL pixel signal read out at the time of acquiring the H image in addition to the OB pixel signal and the NULL pixel signal at the time of acquiring the L image.

  FIG. 12 is a flowchart showing a specific method for correcting the H image. FIG. 13 is a diagram illustrating a schematic configuration of the signal processing unit 104 that corrects the H image according to the flowchart of FIG. 12. Note that the signal processing unit 104 in FIG. 13 also corrects the L image.

  The overall control unit 106 calculates a correction value OFF_L for L image correction from the OB pixel signal and the NULL pixel signal input to the signal processing unit 104 (step S1201). Subsequently, the overall control unit 106 multiplies the correction value OFF_L by a predetermined gain value G in order to generate a correction value for H image correction (step S1202). The predetermined gain value G is a gain value for each of the L image and the H image when the exposure difference between the L image and the H image is realized by a gain adjusting unit that adjusts the gain for amplifying the video signal. It is a difference. A predetermined gain value G multiplied by the correction value OFF_L is input from the imaging control unit 105 and is multiplied by the correction value generation circuit 1301.

The overall control unit 106 sets the result calculated in step S1202 the (OFF_L × G) to an initial value OFF_H ₀ (step S1203). Then, the remaining error is finely adjusted using the pixel signal read out when the H image is acquired. Specifically, a desired correction value is calculated by passing through a recursive filter each time the number of pixels read out at the time of H image acquisition is read as M (M: natural number) (steps S1204 to S1208).

The calculation formula of the recursive filter in this embodiment is given by “OFF_H _{n + 1} = OFF_H _n−1 × (n−1) / n + OFF_H _n × (1 / n)”. First "n = 0 (n: integer)" is set (step S1204), then, OFF_H _n is determined to get a NULL pixel signals for H image (step S1205). Then, the H image correction value OFF_H _{n + 1} is calculated by the above formula (step S1206), and then n is incremented (step S1207), and it is determined whether or not n has reached M (step S1208). If n has not reached M (NO in S1208), the process returns to step S1205. If n has reached M (YES in S1208), the H image is corrected with the H image correction value OFF_H _{n + 1} .

  With the above method, even if the exposure conditions such as the gain and the shutter speed are different between the L image and the H image, sufficient correction accuracy can be ensured for each image. In this embodiment, the L image is acquired first with respect to the acquisition order of the L image and the H image shown in FIG. 11, but may be acquired first. Also, three or more images may be used for the image used for generating the HDR image, and the same effect can be obtained by performing the same operation as in the present embodiment. In this case, how many pixels of the OB pixel signal and the NULL pixel signal are read out may be changed between at least one image and the other two or more images, and the OB pixel signal and the NULL pixel signal may be changed for each image. It may be changed whether to read out pixels. Further, the number of OB pixel signals and NULL pixel signals to be read when acquiring the L image and the H image may be changed in accordance with a change in exposure conditions during moving image shooting.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. Furthermore, each embodiment mentioned above shows only one embodiment of this invention, and it is also possible to combine each embodiment suitably. The present invention is not limited to a digital camera, and can be applied to various electronic devices such as a digital video camera and a mobile phone or a portable game machine having a photographing function using an imaging device.

DESCRIPTION OF SYMBOLS 100 Imaging device 101 Lens part 102 Light quantity adjustment part 103 Imaging part (imaging element)
105 Imaging Control Unit 106 Overall Control Unit 108 Subject Brightness Detection Unit 109 Exposure Calculation Unit

Claims (4)

Using the imaging device having the complement Tadashiyo pixel you output a signal for correcting a signal output a signal corresponding to the amount of light received from you that the light receiving pixels and prior Symbol receiving pixel output, sequentially with different exposure settings Image acquisition means for taking a picture and acquiring two or more images ;
When acquiring a first reading method of reading a signal from only the correction pixel once for each combination of the two or more images when obtaining the prior SL 2 or more images, an image of the two or more Reading means for reading out signals by any one of the second reading methods for reading out signals from the correction pixels each time each image is acquired ;
When a signal is read by the first reading method, the two or more images are corrected using a correction value generated from the signal read only once from the correction pixel, and the second Correction means for correcting each image using each correction value generated using a signal read for each image from the correction pixel when the signal is read by the reading method ,
Imaging apparatus characterized by comprising a synthesizing means for generating a composite image by combining the two or more images corrected by said correction means. 2. The imaging according to claim 1, wherein when the signal is read by the first reading method, the reading unit does not read the signal from the correction pixel while the two or more images are acquired. apparatus. The imaging apparatus according to claim 1, further comprising a moving image generation unit configured to generate a moving image using a plurality of the composite images. Using an image sensor having a light receiving pixel that outputs a signal corresponding to the amount of received light and a correction pixel that outputs a signal for correcting the signal output from the light receiving pixel, continuous shooting is performed with different exposure settings. An image acquisition step of acquiring two or more images,
A first reading method of reading a signal from the correction pixel only once for each combination of the two or more images when acquiring the two or more images; and each of the two or more images when acquiring the two or more images A signal reading step of reading a signal by any one of the second reading methods of reading a signal from the correction pixel every time an image is acquired;
When the signal is read by the first reading method, the two or more images are corrected using a correction value generated from the signal read only once from the correction pixel, and the second reading is performed. A correction step of correcting each image using each correction value generated using the signal read for each image from the correction pixel when the signal is read by the method;
And a combining step of generating a combined image by combining the two or more images corrected in the correcting step.