JP2004304256A - Wide dynamic range image pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wide dynamic range image pickup device capable of reducing the capacity of a memory for temporarily storing image signals in signal processing including wide dynamic range processing. <P>SOLUTION: The wide dynamic range image pickup device 10 includes a master photosensitive section and a slave photosensitive section corresponding to each of pixels, and performs signal processing by a signal processor 30 for master photosensitive section data and slave photosensitive section data which can be respectively obtained. Also, a system control unit 16 determines whether each divided region of a photographic image screen is highlight or not by using a result of division photometry in a photometric circuit 82, and applies a result of determination of each divided region as highlight information of each pixel positioned on the divided region. By using the highlight information of each pixel for signal processing in the signal processing section 30, the slave photosensitive section data of a highlight pixel is stored in an image memory 70, and a non-highlight pixel is subjected to signal processing without being stored. Thus, only the effective information is temporarily stored to reduce the using capacity of the memory. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wide dynamic range imaging apparatus that enables a wide dynamic range process by arranging a main photosensitive portion and a secondary photosensitive portion in each pixel.
[0002]
[Prior art]
Usually, the imaging device is devised so that the main subject is exposed by adjusting the exposure with emphasis on the center of the object scene. For example, when a main subject is a person, it is preferable to design an automatic exposure (AE) so that the face of the person is exposed. However, in a wide dynamic range imaging device, it is possible to express details such as white clothes of the main subject (person) and white walls of the background even under exposure conditions that match the face of the person. That is, highlight details can be reproduced without changing the brightness of the main subject (without changing the main gradation).
[0003]
2. Description of the Related Art Conventionally, wide dynamic range imaging devices have achieved a wide dynamic range using a solid-state imaging device having a main photosensitive portion and a secondary photosensitive portion that have different sensitivities to incident light. At this time, the main photosensitive portion is a photosensitive portion having high sensitivity to incident light, and forms a sharp image. On the other hand, the secondary photosensitive unit is a photosensitive unit that is low in sensitivity to incident light, and accurately obtains information on an image area that is overexposed under normal exposure conditions or an image area in which the signal of the main photosensitive unit is saturated. To do. In the solid-state imaging device described in Patent Document 1, a wide dynamic range is realized by processing output signals from these two types of photosensitive units.
[0004]
For example, in FIG. 5, the photoelectric conversion characteristics when performing ideal imaging are shown. The incident light amount obtained by the solid-state imaging device is plotted on the horizontal axis, and the amount of signal charge generated according to this incident light amount is plotted on the vertical axis. Shown in At this time, in the conventional imaging device, when the amount of incident light reaches the highlight region, the amount of signal charge changes as indicated by a curve 502 that reaches a saturation level, and the amount of signal charge in the highlight region cannot be measured. On the other hand, in the solid-state imaging device described in Patent Document 1, since the wide photosensitive range processing is performed using the secondary photosensitive unit that can detect the incident light amount in the range of the secondary photosensitive unit information holding region, the incident light amount is in the highlight region. Even when the value reaches, the curve changes to a curve 504 that does not saturate, and the amount of signal charge can be measured with a wide dynamic range.
[0005]
[Patent Document 1]
Japanese Patent Application 2002-016835.
[0006]
[Problems to be solved by the invention]
In the solid-state imaging device described in Patent Document 1 described above, each pixel has a main photosensitive portion and a secondary photosensitive portion, and a wide dynamic range is realized by processing image signals from these photosensitive portions.
[0007]
Incidentally, in the signal processing of the solid-state imaging device, a memory or the like that temporarily stores an image signal is used, and the used capacity of the memory changes in proportion to the number of pixels. For example, in normal signal processing, each pixel has a unique photosensitive portion and outputs an image signal. Therefore, it is practically sufficient if the capacity of the memory is the number of pixels × 2 bytes.
[0008]
However, in the solid-state imaging device described in Patent Document 1, each pixel has two photosensitive parts, a main photosensitive part and a secondary photosensitive part, and outputs two types of image signals. Memory capacity is required.
[0009]
On the other hand, there are few high-contrast scenes in the normally photographed scene, and the secondary photosensitive portion data is often not used effectively. For example, most of the object scene can be ideally imaged by the amount of incident light in the vicinity of the range 512 shown in FIG. 5, so that an image can be generated using only the main photosensitive portion data. In a high-contrast scene, the highlight area is very small in the image frame, and there is a lot of unnecessary data in the sub-photosensitive portion data covering the entire image frame. Therefore, if the same amount of memory as that of the main photosensitive portion data is provided for the slave photosensitive portion data with less advantageous information, the waste is increased.
[0010]
The present invention eliminates the disadvantages of the prior art, and in signal processing including wide dynamic range processing, a memory capacity for temporarily storing image signals obtained from the main photosensitive portion and the secondary photosensitive portion arranged in each pixel. An object of the present invention is to provide a wide dynamic range imaging device capable of reducing the above.
[0011]
[Means for Solving the Problems]
According to the present invention, it includes a plurality of light receiving portions arranged in the row and column directions and corresponding to each pixel forming the imaging surface, and a signal processing means for performing signal processing on image signals obtained from the plurality of light receiving portions. The plurality of light receiving units include a first photosensitive unit that photoelectrically converts incident light, and a second photosensitive unit that has a lower sensitivity than the first photosensitive unit, and the signal processing unit includes the first photosensitive unit. A wide dynamic range imaging apparatus that performs signal processing on the first image signal obtained from the image capturing section and the second image signal obtained from the second photosensitive section, determines whether wide dynamic range processing is necessary, The signal processing means includes a first storage means for temporarily accumulating the first image signal and a second storage means for temporarily accumulating the second image signal. The second storage means is the determination means. Wherein the temporarily storing the second image signal in response to the constant results.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a wide dynamic range imaging device according to the present invention will be described in detail with reference to the accompanying drawings.
[0013]
As shown in FIG. 1, the wide dynamic range imaging apparatus 10 according to the embodiment includes an image captured by the imaging unit 24 via the optical system 12, a preprocessing unit 26, an analog / digital (A / D) converter 28, and This is a device that controls the respective units with the system control unit 16, the optical system drive unit 18, the timing generator 20, and the imaging drive unit 22 by operating the operation unit 14 so that the signal processing unit 30 performs signal processing. The image processed in this way is displayed on the display unit 32 or recorded on the recording unit 34. Note that portions not directly related to understanding the present invention are not shown and redundant description is avoided.
[0014]
Further, in the photometry in the present apparatus 10, a TTL (Through The Lens) photometry method for measuring incident light passing through the optical system 12 is applied, and this incident light is taken into the imaging unit 24, and the amount of light is controlled by the system. Measured at section 16.
[0015]
The optical system 12 includes a lens, a diaphragm adjustment mechanism, a shutter mechanism, a zoom mechanism, and an automatic focus adjustment mechanism, although a specific configuration is not illustrated. This lens is an optical lens disposed almost in front of a lens barrel (not shown), and a plurality of lenses may be used in combination. The aperture adjustment mechanism adjusts the amount of light incident on the imaging unit 24 by changing the diameter of the opening, and the shutter mechanism is a mechanical shutter that blocks the optical path by closing the opening. The zoom mechanism adjusts the position of the lens for zooming, and the automatic focus adjustment mechanism adjusts the focus according to the distance between the object scene and the imaging device 10.
[0016]
The optical system 12 is controlled by a drive signal 114 and is driven by an aperture adjustment mechanism, a shutter mechanism, a zoom mechanism, and an automatic focus adjustment mechanism to capture a desired object scene image and enter the imaging surface of the imaging unit 24. This is a light incident mechanism. Further, since the width that can be measured at a time is limited at the time of photometry, for example, the aperture or electronic shutter may be driven to obtain photometric data in several steps. In the following description, each signal is specified by the reference number of the connecting line in which it appears.
[0017]
The operation unit 14 is a manual operation device that inputs an instruction from the operator, and has a function of generating an operation signal 104 according to the manual operation state of the operator and supplying the operation signal 104 to the system control unit 16. For example, the operation signal 104 is supplied to the system control unit 16 in response to a stroke operation of a release button (not shown).
[0018]
In this embodiment, the release button is a push button having a two-step push function. When the release button is not pressed, it is a standby state, which is an initial state. The operation unit 14 supplies the system control unit 16 with an operation signal 104 for instructing photometry in the first-stage half-pressed state, and in the second-stage fully pressed state.
[0019]
The system control unit 16 is a control function unit that controls and controls the overall operation of the apparatus in response to the operation signal 104 supplied from the operation unit 14. For example, the system control unit 16 in this embodiment generates control signals 106, 108, 110, and 112 according to the operation signal 104, and the optical system driving unit 18, the timing generator 20, the signal processing unit 30, and the recording, respectively. It supplies to the part 34 and is controlled.
[0020]
In this embodiment, the system control unit 16 includes a read only memory (ROM) 80, a photometry circuit 82, and a central processing unit (CPU) 84, as shown in FIG. For example, the ROM 80 may be written with the operation procedure of the apparatus 10. The system control unit 16 uses the control signals 106, 108, 110, and 112 that control the operation of each unit using information supplied from the operation unit 14 in accordance with the user's operation, that is, the operation signal 104 and information stored in the ROM 80. Is generated.
[0021]
The photometric circuit 82 is a circuit that is controlled by the CPU 84 and obtains the luminance value of the object scene from the photometric signal 136 supplied from the A / D converter 28. In the present embodiment, a split photometry method or the like in which the image represented by the photometry signal 136 is divided into a plurality of divided areas with a predetermined number of divisions is advantageously applied. The predetermined number of divisions is 1 or more and the number of pixels or less, and may be settable.
[0022]
Particularly in the present invention, the system control unit 16 has a function of determining whether or not wide dynamic range processing is necessary. For example, in each of the plurality of divided areas, it is determined that a wide dynamic range process is necessary in an area where the photometric result is a highlight, and that the process is not necessary in an area that is not a highlight. In this determination, the photometric value of the divided area may be compared with a predetermined threshold value, and this threshold value may be settable. In this embodiment, the determination result of each divided region is applied as the determination result of each pixel located in the divided region. The system control unit 16 supplies the control signal 110 to the signal processing unit 30 to supply the determination result of each pixel, that is, highlight information indicating whether or not each pixel is highlighted. The highlight information may indicate whether each of the divided areas is a highlight.
[0023]
For example, as shown in FIG. 3, the photometric circuit 82 divides the entire area of the image frame 300 into 64 × 8 × 8, and performs divided photometry so that 64 field luminance integrated values can be obtained. At this time, as shown in FIG. 4, the system control unit 16 determines that 14 areas represented by hatched areas 302 and 304 are highlighted, and determines that the other areas are not highlighted. Highlighted information is obtained.
[0024]
The optical system drive unit 18 has a function of generating a drive signal 114 for controlling the drive of the optical system 12. In this embodiment, the optical system drive unit 18 generates the drive signal 114 according to the control signal 106 from the system control unit 16.
[0025]
The timing generator 20 includes a transmitter that generates a basic clock (system clock) for operating the imaging apparatus 10, and supplies the basic clock 116 to the system control unit 16, for example. Although not shown in FIG. 1, the timing generator 20 supplies a basic clock to almost all the blocks, and also divides the basic clock to generate various timing signals.
[0026]
In this embodiment, the timing generator 20 generates a timing signal based on the control signal 108 supplied from the system control unit 16. For example, a timing signal 118 including a vertical synchronization signal, a horizontal synchronization signal, and an electronic shutter pulse is generated and supplied to the imaging drive unit 22. The preprocessing unit 26 is supplied with a timing signal 120 including a sampling pulse for a correlated double sampling circuit, and the A / D converter 28 is supplied with a timing signal 122 such as a conversion clock.
[0027]
The image pickup drive unit 22 has a function of generating a drive signal 124 that controls the drive of the image pickup unit 24. In this embodiment, the image pickup drive unit 22 generates a horizontal drive signal and a vertical drive signal in accordance with the timing signal 118 from the timing generator 20. And a drive signal 124 including an overflow drain.
[0028]
Although the specific configuration is not illustrated, the imaging unit 24 includes an imaging surface and a horizontal transfer path that form one screen of a captured image, and the imaging surface includes a light receiving unit and a vertical transfer path corresponding to a plurality of pixels. I have. The imaging unit 24 has a function of photoelectrically converting an object scene image formed on the imaging surface into an electric signal 126. In this embodiment, for example, a charge coupled device (CCD) or a metal oxide is used. Any image sensor such as a film type semiconductor (Metal Oxide Semiconductor: MOS) may be used.
[0029]
In this imaging surface, it is preferable to use a honeycomb arrangement in which the plurality of light receiving portions are arranged with the positions shifted every other in the row direction and the column direction, and every other position is shifted in the row direction and the column direction. May be arranged. Particularly in this embodiment, each of these light receiving portions includes a main photosensitive portion which is a high sensitivity light receiving element and a secondary photosensitive portion which is a low sensitivity light receiving element. The main photosensitive portion and the secondary photosensitive portion are optical sensors that photoelectrically convert light into an electrical signal corresponding to the amount of received light when receiving incident light. For example, a photodiode is used.
[0030]
The image pickup unit 24 of this embodiment is controlled by the drive signal 124 to read the signal charge obtained by photoelectric conversion in each photosensitive unit to the vertical transfer path, and shift this signal charge in the vertical direction and supply it to the horizontal transfer path. To do. Further, the signal charge in the horizontal transfer path is converted to an analog electric signal 126 and output to the preprocessing unit 26 in an output circuit (not shown). Further, when the drive signal 124 includes a photometry instruction, the imaging unit 24 may read out only the signal charge of the main photosensitive unit.
[0031]
The preprocessing unit 26 is controlled by the timing signal 120 and has a function of performing analog signal processing on the analog electric signal 126 indicating an image. The preprocessing unit 26 includes a correlated double sampling circuit (Correlated Double Sampling: CDS) and a gain control amplifier (Gain Controlled Amplifier: GCA), and the analog image signal 128 processed by these circuits or the like is converted into an A / A signal. This is supplied to the D converter 28.
[0032]
In response to the timing signal 122 from the timing generator 20, the A / D converter 28 quantizes the signal level of the analog image signal 128 supplied from the preprocessing unit 26 with a predetermined quantization level to obtain a digital image signal. Convert. At this time, when the timing signal 122 indicates photometry, the converted digital image signal is supplied to the system control unit 16 as the photometry signal 136. On the other hand, when the timing signal 122 instructs photographing, the converted digital image signal 130 is supplied to the signal processing unit 30.
[0033]
The signal processing unit 30 has a function of performing digital signal processing, which will be described later, on the input digital image signal 130. In this embodiment, the digital image signal 130 including the main photosensitive portion data and the secondary photosensitive portion data is A. / D converter 28 inputs. The digital image signals 132 and 134 that have been subjected to the digital signal processing are supplied to the display unit 32 and the recording unit 34, respectively.
[0034]
In the present embodiment, the signal processing unit 30 is configured as shown in FIG. 2 and performs digital signal processing in accordance with the control signal 110 supplied from the system control unit 16. The signal processing unit 30 includes image memories 50 and 70 and has a function of temporarily storing a main image signal and a sub image signal, respectively. In addition, it has a white balance (WB) gain unit 52 and a gamma (γ) conversion unit 54 that process the main image signal, and a WB gain unit 72 and a γ conversion unit 74 that process the sub image signal. Further, an image adding unit 56 that combines the main image signal and the sub-image signal is provided. In addition, the synchronization processing unit 58, the various correction units 60, the compression / expansion unit 62, and the enlargement / reduction unit 64 perform synthesis. Process the main image signal. Note that the processing by the WB gain unit 52 and the gamma conversion unit 54 may be performed after the main image signal and the sub image signal are combined by the image addition unit 56.
[0035]
The image memory 50 stores main photosensitive portion data as a main image signal, while the image memory 70 stores sub photosensitive portion data as a sub image signal. In this embodiment, the image memory 50 stores the main photosensitive portion data of all the pixels, and the image memory 70 stores the secondary photosensitive portion data only for the pixels that are the highlight in accordance with the highlight information included in the control signal 110. It may be accumulated. For example, as shown in FIG. 4, when the pixels located in the hatched areas 302 and 304 are highlighted, the main photosensitive part data is accumulated for all areas of the image frame 300, but the secondary photosensitive part data. Are accumulated for these regions 302 and 304 only. Further, the image memory 70 may be designed to have a smaller storage capacity than the image memory 50.
[0036]
Each of the WB gain units 52 and 72 has a function of adjusting the white balance of the main image signal and the sub image signal. For example, these image signals are multiplied by a white balance gain, and an image signal with a white balance is output. .
[0037]
The γ conversion units 54 and 74 each have a function of correcting the main image signal and the sub image signal, for example, in accordance with the gradation characteristics of the imaging unit 24, and output corrected image signals.
[0038]
The image adder 56 has a function of combining the main image signal stored in the image memory 50 and the sub image signal stored in the image memory 70, and outputs the combined main image signal to the image memory 50. Accumulate. In the present embodiment, the image adding unit 56 performs composition processing on pixels in which the highlight information is highlighted, and does not perform composition processing on pixels that are not highlights, in accordance with highlight information included in the control signal 110. The original main image signal is output as it is and stored in the image memory 50. Alternatively, the slave image signal corresponding to each pixel may be acquired from the image memory 70, and the synthesis process may be performed on the pixel having the slave image signal, and the synthesis process may not be performed on the pixel having no slave image signal.
[0039]
The synchronization processing unit 58 has a function of synchronizing the combined main image signal, and the various correction units 60 have a function of processing the main image signal such as shading correction and black and white correction.
[0040]
The compression / decompression unit 62 compresses the main image signal in accordance with, for example, JPEG (Joint Photographic Experts Group) standard using orthogonal transformation, and a circuit that decompresses the compressed image to the original data again. Have The compression / decompression unit 62 is controlled to record images by the control signal 112 of the system control unit 16 and records the compressed image data 132 on the information recording medium 92 via the card I / F 90.
[0041]
The enlargement / reduction unit 64 has a function of performing enlargement or reduction processing on the main image signal, and outputs the image signal 130 to the display unit 32.
[0042]
The display unit 32 has a function of displaying an image based on the digital image signal 132 supplied from the signal processing unit 30. For example, a liquid crystal display (LCD) panel or the like is used. In this embodiment, as shown in FIG. 2, a digital image signal 132 is supplied from the enlargement / reduction unit 64.
[0043]
The recording unit 34 has a function of reading and recording the digital image signal 134 from the signal processing unit 30. In this embodiment, as shown in FIG. 2, a card interface (I / F) 90 and an information recording medium 92 are provided, and a digital image signal 134 supplied from the compression / decompression unit 62 is transmitted via the card I / F 90. Write to the information recording medium 92. The information recording medium 92 may be detachable using a package containing a rotating recording body such as a memory card on which a semiconductor memory is mounted or a magneto-optical disk.
[0044]
Next, the operation of the wide dynamic range imaging apparatus 10 in this embodiment will be described with reference to the state transition diagram of FIG. When the imaging device 10 is in the standby state (step 600), if the operator operates the release button of the operation unit 14, the process proceeds to step 602, where it is determined whether this button is half-pressed. If this button is pressed halfway or more, the process proceeds to divided photometry data evaluation (step 604). If not pressed, the process returns to standby (step 600). When the button is half-pressed, an operation signal 104 for instructing photometry is supplied from the operation unit 14 to the system control unit 16.
[0045]
In divided photometric data evaluation (step 604), divided photometry and the evaluation of each photometric value in each divided area are performed. At this time, the system control unit 16 generates control signals 106 and 108 including photometry instructions and supplies them to the optical system driving unit 18 and the timing generator 20, respectively. In the optical system drive unit 18, a drive signal 114 including a photometry instruction is generated according to the control signal 106 and supplied to the optical system 12. In the timing generator 20, timing signals 118, 120, and 122 including photometry instructions are generated according to the control signal 108 and supplied to the imaging drive unit 22, the preprocessing unit 26, and the A / D converter 28, respectively. In the imaging drive unit 22, a drive signal 124 including a photometry instruction is generated according to the timing signal 118 and supplied to the imaging unit 24.
[0046]
In the optical system 12, incident light 102 from the object scene enters the image pickup unit 24, and an object scene image is formed on the image pickup surface. In the imaging unit 24, the signal charge used for photometry on the imaging surface is read by the drive signal 124, and the analog electric signal 126 generated thereby is supplied to the preprocessing unit 26. In the pre-processing unit 26, the analog electric signal 126 is subjected to analog signal processing by the timing signal 120, and an analog image signal 128 generated thereby is supplied to the A / D converter 28. In the A / D converter 28, the analog image signal 128 is converted into a digital image signal by the timing signal 122, and this digital image signal is supplied to the system control unit 16 as the photometric signal 136 because the timing signal 122 also instructs photometry. Is done.
[0047]
The photometric signal 136 is divided into a predetermined number of divisions in the photometric circuit 82 of the system control unit 16, and the photometric result of each divided area is obtained. Further, the system control unit 16 determines whether or not the photometric value is a highlight for each divided region, and the determination result is held in the system control unit 16 as highlight information.
[0048]
Next, the routine proceeds to step 606, where it is determined whether or not the operation of the release button is a full press. If the release button is fully pressed, the process proceeds to main photosensitive portion data reading (step 608). If not, the process returns to standby (600). When the button is fully pressed, an operation signal 104 for instructing photographing is supplied from the operation unit 14 to the system control unit 16.
[0049]
In main photosensitive portion data reading (608), data is read from all main photosensitive portions on the imaging surface of the imaging unit 24. At this time, the system control unit 16 generates control signals 106, 108, and 110 including photographing instructions and supplies them to the optical system driving unit 18, the timing generator 20, and the signal processing unit 30, respectively. In the optical system drive unit 18, a drive signal 114 including a photographing instruction is generated according to the control signal 106 and supplied to the optical system 12. In the timing generator 20, timing signals 118, 120, and 122 including shooting instructions are generated according to the control signal 108 and supplied to the imaging drive unit 22, the preprocessing unit 26, and the A / D converter 28, respectively. In the imaging drive unit 22, a drive signal 124 including a shooting instruction is generated according to the timing signal 118 and supplied to the imaging unit 24.
[0050]
In the optical system 12, incident light 102 from the object scene enters the image pickup unit 24, and an object scene image is formed on the image pickup surface. In the imaging unit 24, the signal charge of the main photosensitive unit on the imaging surface is read by the drive signal 124, and the analog electric signal 126 generated thereby is supplied to the preprocessing unit 26. In the preprocessing unit 26, the analog electric signal 126 is subjected to analog signal processing by the timing signal 120, and an analog image signal 128 generated thereby is supplied to the A / D converter 28. In the A / D converter 28, the analog image signal 128 is converted into the digital image signal 130 by the timing signal 122, and the digital image signal 130 is supplied to the signal processing unit 30 because the timing signal 122 also instructs photographing.
[0051]
Next, the process proceeds to main photosensitive portion data writing (step 610), where main photosensitive portion data is written. At this time, the digital image signal 130 is written into the image memory 50 by the signal processing unit 30.
[0052]
Next, the process proceeds to subordinate photosensitive unit data reading (step 612), and data is read from all the subordinate photosensitive units on the imaging surface of the imaging unit 24. At this time, the same processing as the main photosensitive portion data reading (step 608) is performed. However, in the imaging unit 24, the signal charge of the slave photosensitive unit is read out.
[0053]
Next, in step 614, it is determined whether each pixel is highlighted. At this time, in the system control unit 16, highlight information indicating whether or not each pixel is highlighted is supplied to the signal processing unit 30 by the control signal 110. The signal processing unit 30 determines the highlight information for each pixel, and if it is the highlight, the process proceeds to the secondary photosensitive unit data writing (step 616), and the digital image signal 130 is written to the image memory 70. On the other hand, if it is not a highlight, the process proceeds to sub-photosensitive portion data writing Off (step 618), and the digital image signal 130 is not written to the image memory 70. Such determination is made for all the pixels, and when completed, the process proceeds from step 620 to step 622.
[0054]
In the next step 622, as in step 614, it is determined whether each pixel is highlighted. In step 622, when the highlight is selected, the process proceeds to a wide dynamic range process (step 624), and the signal processor 30 performs the wide dynamic range signal process. On the other hand, if it is not a highlight, the signal processing unit 30 performs normal processing (step 626). Such a determination is performed for all the pixels, and when the determination is completed, the process proceeds from step 628 to step 630.
[0055]
In the wide dynamic range process (step 624), the main photosensitive portion data included in the image memory 50 is subjected to wide dynamic range signal processing using the slave photosensitive portion data included in the image memory 70. First, the main photosensitive portion data is processed by the WB gain portion 52 and the γ converting portion 54, and the secondary photosensitive portion data is processed by the WB gain portion 72 and the γ converting portion 74. Next, the main photosensitive portion data is combined with the secondary photosensitive portion data in the image adding portion 56, and the combined main photosensitive portion data is stored in the image memory 50. Further, the combined main photosensitive portion data is processed by the synchronization processing portion 58 and various correction portions 60 and stored in the image memory 50.
[0056]
On the other hand, in the normal processing (step 626), only the main photosensitive portion data included in the image memory 50 is normally subjected to signal processing. First, the main photosensitive portion data is processed by the WB gain portion 52 and the γ conversion portion 54. Next, since there is no corresponding secondary photosensitive portion data, the main photosensitive portion data is not processed by the image adding portion 56, processed by the synchronization processing portion 58 and various correction portions 60, and stored in the image memory 50. The
[0057]
Next, in the image storage (step 630), the image signal that has been subjected to the signal processing is subjected to compression processing by the compression / expansion unit 62. The recording image signal 132 processed in this way is recorded on the information recording medium 92 via the card I / F 90. In this embodiment, the process returns to standby (600) next, but for example, processing in the enlargement / reduction unit 64 may be performed and displayed on the display unit 32.
[0058]
As another example, the wide dynamic range imaging apparatus 10 can determine whether or not the wide dynamic range process is necessary in the system control unit 16 by a method different from the above example. At this time, the system control unit 16 compares the photometric results with each other, and in the descending order of the photometric value, the wide dynamic range by a predetermined number of areas or pixels, for example, one third of all areas or all pixels. Do processing. In this embodiment, since the number of pixels to be subjected to the wide dynamic range process is reduced, the storage capacity of the image memory 70 may be smaller than that of the image memory 50.
[0059]
As another example, the wide dynamic range imaging apparatus 10 does not evaluate the photometric value for each divided area in the divided photometric data evaluation in step 604, and reads each main photosensitive part data in step 608. The photometric value can be evaluated from the main photosensitive portion data of the pixel. At this time, the signal processing unit 30 can determine whether or not dynamic range processing is necessary for each pixel, and the slave photosensitive unit data is stored in the image memory 70 according to the determination result. The photometric circuit 82 may perform normal photometry instead of split photometry.
[0060]
【The invention's effect】
As described above, according to the present invention, the wide dynamic range imaging apparatus can reduce the use capacity of the memory by accumulating only the secondary photosensitive portion image data that needs the wide dynamic range processing.
[0061]
Further, during signal processing, wide dynamic range processing is performed using the main photosensitive portion image data and the secondary photosensitive portion image data in the area where the necessary secondary photosensitive portion image data is accumulated, and in the other areas, the main photosensitive portion image data is processed. By performing normal signal processing using only the photosensitive part image data, wide dynamic range processing can be performed using only effective information.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of a wide dynamic range imaging apparatus according to the present invention.
2 is a block diagram illustrating in detail a signal processing unit included in the wide dynamic range imaging apparatus according to the embodiment illustrated in FIG. 1;
3 is a schematic diagram illustrating a state of a divided image in the wide dynamic range imaging apparatus of the embodiment illustrated in FIG. 1. FIG.
4 is a schematic diagram showing whether each divided area of a divided image is a highlight in the wide dynamic range imaging apparatus of the embodiment shown in FIG. 1;
FIG. 5 is a diagram illustrating photoelectric conversion efficiency when a wide dynamic range process is performed and when a wide dynamic range process is not performed in a conventional solid-state imaging device.
6 is a flowchart showing an operation example of the wide dynamic range imaging apparatus of the embodiment shown in FIG.
[Explanation of symbols]
10 Wide dynamic range imaging device
12 Optical system
14 Operation unit
16 System controller
18 Optical system drive
20 Timing generator
22 Imaging drive unit
24 Imaging unit
26 Pre-processing section
28 Analog / digital converter
30 Signal processor
32 Display section
34 Recording section

Claims (15)

A plurality of light receiving portions arranged in a row and column direction and corresponding to each pixel forming an imaging surface;
Signal processing means for performing signal processing on image signals obtained from the plurality of light receiving sections, wherein the plurality of light receiving sections have a first photosensitive section for photoelectrically converting incident light, and a sensitivity lower than that of the first photosensitive section. A second photosensitive part having
The signal processing means is a wide dynamic range imaging device that performs signal processing on a first image signal obtained from a first photosensitive portion and a second image signal obtained from a second photosensitive portion.
A determination means for determining whether or not wide dynamic range processing is necessary, and obtaining a determination result for each pixel;
The signal processing means includes first storage means for temporarily storing a first image signal and second storage means for temporarily storing a second image signal,
The wide storage range imaging apparatus characterized in that the second storage means temporarily stores the second image signal in accordance with the determination result of the determination means. 2. The wide dynamic range imaging apparatus according to claim 1, wherein the signal processing means includes synthesis processing means for synthesizing the first image signal and the second image signal. The wide dynamic range imaging apparatus according to claim 2, wherein the synthesis processing unit includes the first image signal and the first image signal for pixels determined to require wide dynamic range processing according to a determination result of the determination unit. A wide dynamic range image pickup apparatus characterized in that a third image signal is output by combining the two image signals, and the first image signal is output as it is at a pixel determined not to require wide dynamic range processing. . In the wide dynamic range imaging device according to any one of claims 1 to 3, the second storage unit is configured to perform only the pixels determined to require the wide dynamic range process according to the determination result of the determination unit. A wide dynamic range imaging apparatus characterized by temporarily storing a second image signal. 5. The wide dynamic range imaging apparatus according to claim 4, wherein the synthesis processing unit synthesizes the first image signal and the second image signal in a pixel in which the second image signal is temporarily stored in the second storage unit. Then, the third image signal is output, and the first image signal is output as it is for a pixel that is not temporarily stored. 6. The wide dynamic range imaging device according to claim 1, wherein the device divides the imaging surface into a plurality of divided regions by a predetermined number of divisions, and changes the amount of incident light from an object scene. A wide dynamic range imaging apparatus comprising: a divided photometric unit that performs photometry in each of the divided regions, wherein the divided photometric unit obtains a photometric result for each of the plurality of divided regions. The wide dynamic range imaging apparatus according to claim 6, wherein the apparatus sets the predetermined number of sections. 8. The wide dynamic range imaging apparatus according to claim 6, wherein the divided photometry unit obtains the photometry result from a first image signal. 9. The wide dynamic range imaging apparatus according to claim 6, wherein the determination unit determines whether or not wide dynamic range processing is necessary in each of the plurality of divided regions, A wide dynamic range imaging device obtained as a determination result of each pixel located in The wide dynamic range imaging apparatus according to claim 9, wherein the determination unit makes a determination according to the photometric result. The wide dynamic range imaging apparatus according to claim 10, wherein the determination unit determines whether or not the photometric result is a highlight, and the divided region that is a highlight needs a wide dynamic range process. A wide dynamic range imaging apparatus characterized by determining that a wide dynamic range process is not necessary for a divided area that is not light. The wide dynamic range imaging apparatus according to claim 11, wherein the determination unit determines whether or not a highlight is obtained by comparing the photometric result with a predetermined threshold value. . The wide dynamic range imaging apparatus according to claim 12, wherein the apparatus sets the predetermined threshold value. 11. The wide dynamic range imaging apparatus according to claim 10, wherein the determination unit needs to perform wide dynamic range processing for a predetermined number of regions in descending order of the photometric value of the photometric result among the plurality of divided regions. And a wide dynamic range imaging device. The wide dynamic range imaging apparatus according to claim 10, wherein the determination unit has a wide dynamic range of the plurality of divided regions by a number of one third of the entire region in descending order of the photometric value of the photometric result. A wide dynamic range imaging apparatus characterized by determining that processing is necessary.

Images