KR101710627B1 - Photographing apparatus and photographing method - Google Patents

Abstract

The charge accumulated in the image pickup device is erased a plurality of times to obtain an image with good image quality. An image pickup apparatus includes an image pickup element having a plurality of pixels arranged in a matrix form and exposes the image pickup element to image an object. The image pickup apparatus includes a detection section for detecting an image pickup state of a subject, And a scan control section for controlling the exposure start scanning of the image pickup element by erasing the charges accumulated in the image pickup element prior to the travel of the film body, wherein the scan control section controls the image pickup element And erase the charge accumulated in the memory cell array a plurality of times.

Description

[0002] Photographing apparatus and photographing method [0003]

The present invention relates to an image pickup apparatus and an image pickup method, and more particularly to an image pickup apparatus and an image pickup method including an image pickup element having a plurality of pixels arranged in a matrix form.

(Front curtain) of the shutter operation is performed by an electronic shutter and a rear curtain is performed by a mechanical shutter in an image pickup apparatus equipped with a CMOS (Complementary Metal Oxide Semiconductor) type image pickup device For example, Patent Document 1). There is also disclosed a technique of preventing exposure unevenness caused by a difference in lens type, aperture value, and shutter speed by changing the timing at which charge accumulation is started for each area or line in a combination of an electronic shutter and a mechanical shutter For example, Patent Documents 2 and 3).

Patent Documents 2 and 3 aim to correct image quality problems caused by switching a conventional mechanical front film to an electronic reset function. Therefore, the operation timing of the electronic shutter that becomes the leading film is set to have substantially the same characteristics as the thick film of the mechanical shutter to be the thick film. In addition, the operation timing is set including the correction parameters for factors that change the characteristics of the shutter, such as the type of lens and the aperture value.

<Prior Art Literature>

Patent Document 1: JP-A-11-41523

Patent Document 2: Japanese Patent Application Laid-Open No. 2007-159061

Patent Document 3: Japanese Patent Application Laid-Open No. 2007-53742

The electronic shutter functions as a front curtain of the shutter that starts the exposure of the imaging element by erasing the electric charge accumulated in the imaging element. The time required for completely erasing the charges accumulated in the image pickup device is determined by the effective pulse width of the charge erase pulse as a specification of each device. It is necessary to narrow the pulse width of the charge erasing pulse in order to follow the exposure start speed of the electronic shutter to the running speed of the thick film of the mechanical shutter when the number of pixels increases and the number of lines in the vertical direction increases. However, if the pulse width is narrowed, the charge accumulated in the image pickup device can not be completely erased, and residual charge is generated, thereby increasing the residual image.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide an image pickup apparatus capable of obtaining an image with good image quality by erasing a charge accumulated in an image pickup element plural times in a configuration using an electronic shutter and a mechanical shutter together. And an improved imaging device and imaging method.

According to an aspect of the present invention, there is provided an imaging device including an imaging element having a plurality of pixels arranged in a matrix and for photographing a subject by exposing an imaging element, the imaging device comprising: And a scan control section for controlling the exposure start scanning of the image pickup element by erasing charges accumulated in the image pickup element prior to the travel of the film body, And the control unit erases the charge accumulated in the imaging element a plurality of times in accordance with the imaging state of the object.

According to the above arrangement, the imaging state of the subject is detected, and the number of times of erasing charges accumulated in the imaging element is adjusted in accordance with the imaging state to cause the film to shade the imaging element after exposure of the imaging element is started. As a result, an image with good image quality can be obtained by adjusting the number of times of erasing the charges accumulated in the image pickup element in accordance with the image pickup state.

In addition, the scan control section functions as a front curtain of the shutter for starting exposure of the imaging element by erasing the charges accumulated in the imaging element, and the operation control section functions as a shutter thick film as a film shielding the imaging element . Thereby, it is possible to prevent the afterimage phenomenon by accumulation of unnecessary electric charge by using the electronic shutter as the leading film and the mechanical shutter as the thick film, and controlling the number of times of running of the electronic shutter which becomes the leading film.

The scan control unit generates an erase pulse for erasing the charge accumulated in the image pickup element so as to correspond to the running curve of the film, and generates an erase pulse a plurality of times according to the image pickup state of the object. This makes it possible to control the scanning start speed of the electron beam film by making the erase pulse correspond to the running curve of the film body, and at the same time, the number of erase times of the charges can be varied in accordance with the imaging state to prevent the afterimage phenomenon by accumulation of unnecessary charges.

It is also preferable that the scan control unit generate the erase pulse a plurality of times in units of lines of the image pickup device. This makes it possible to prevent the afterimage phenomenon by accumulation of unnecessary charges by generating the erase pulse a plurality of times in units of lines.

Further, the scan control unit may erase the charge accumulated in the image pickup element a plurality of times when the afterimage of the object remains in the image pickup state. The scan control unit may erase the charge accumulated in the image pickup device a plurality of times when the luminance of the subject is higher than a preset reference value. Further, the scan control unit may erase the charge accumulated in the image pickup device a plurality of times when the subject includes a high-intensity point light source.

Further, the scan control unit may erase the charge accumulated in the image pickup device a plurality of times when the motion vector of the subject is equal to or larger than a preset threshold value. Thereby, when the luminance of the subject is high, or when the subject includes a high-luminance point light source, or when the motion vector is not less than a preset threshold value and the afterimage of the subject remains, the charge accumulated in the imaging device is erased a plurality of times, An image can be obtained.

Further, the detection unit may detect the degree of camera shake at the time of image capture, and the scan control unit may erase the charge accumulated in the image pickup device a plurality of times when the degree of camera shake detected by the detection unit is equal to or greater than a predetermined value. This makes it possible to obtain an image with good image quality by erasing the charge accumulated in the image pickup device a plurality of times when there is a high possibility that the afterimage will remain due to the camera-shake.

According to another aspect of the present invention, there is provided an imaging method for imaging an object by exposing an imaging element having a plurality of pixels arranged in a matrix, comprising the steps of: detecting an imaging state of a subject; A step of erasing the charge accumulated in the imaging element a plurality of times in accordance with the imaging state to initiate exposure of the imaging element, and a step of operating the film body traveling to shield the imaging element after exposure of the imaging element starts An imaging method is provided.

As described above, according to the present invention, in the configuration using the electronic shutter and the mechanical shutter together, the charge accumulated in the image pickup element is erased a plurality of times, and an image with good image quality can be obtained.

Fig. 1 is an explanatory view for explaining the occurrence of a residual image.
Fig. 2 is an explanatory view for explaining the outline of an image pickup apparatus according to an embodiment of the present invention. Fig.
Fig. 3 is an explanatory diagram for explaining an outline of an image pickup apparatus according to another embodiment of the present invention. Fig.
4 is a block diagram showing a functional configuration of an image pickup apparatus according to an embodiment of the present invention.
5 is a block diagram showing a configuration of a CPU according to an embodiment of the present invention.
6 is an explanatory view for explaining the detection of an imaging scene according to an embodiment of the present invention.
7 is an explanatory view for explaining the detection of an imaging scene according to another embodiment of the present invention.
8 is a flowchart illustrating a specific operation of the imaging apparatus according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, elements having substantially the same functional configuration in the present specification and drawings are denoted by the same reference numerals, and redundant description will be omitted.

In addition, the "best mode for carrying out the invention" will be described according to the following procedure.

[1] Purpose of this embodiment

[2] Overview of imaging device

[3] Functional configuration of the image pickup apparatus

[4] Details of Operation of the Image Pickup Apparatus (Details)

[1] Purpose of this embodiment

First, the purpose of this embodiment will be described. Discloses an imaging device in which a CMOS (Complementary Metal Oxide Semiconductor) type image pickup device is mounted, a shutter operation line film is performed by an electronic shutter, and a thick film is performed by a mechanical shutter. Also disclosed is a technique for preventing exposure unevenness caused by the type of lens, the aperture value, and the shutter speed by changing the timing at which charge accumulation is started for each area or line in a combination of an electronic shutter and a mechanical shutter.

The above-described technique aims to correct image quality problems caused by switching a conventional mechanical front film to an electronic reset function. Therefore, the operation timing of the electronic shutter that becomes the leading film is set to have substantially the same characteristics as the thick film of the mechanical shutter to be the thick film. In addition, the operation timing is set by including correction parameters for factors that change the characteristics of the shutter, such as the type of lens and the aperture value.

The electronic shutter functions as a front curtain of the shutter that starts the exposure of the imaging element by erasing the electric charge accumulated in the imaging element. The time required for completely erasing the charges accumulated in the image pickup device is determined by the effective pulse width of the charge erase pulse as a specification of each device. It is necessary to narrow the pulse width of the charge erase pulse in order to follow the exposure start speed of the electronic shutter to the running speed of the thick film of the mechanical shutter when the number of pixels increases and the number of lines in the vertical direction increases. However, if the pulse width is narrowed, the charges accumulated in the image pickup device can not be completely erased, and residual charges are generated, thereby increasing the residual image.

Therefore, an imaging apparatus according to an embodiment of the present invention has been created with the above circumstances as one point of view. According to the image pickup apparatus 10 of the present embodiment, in the configuration using the electronic shutter and the mechanical shutter together, the charge accumulated in the image pickup element is erased a plurality of times, and an image with good image quality can be obtained.

[2] Overview of imaging device

Next, the outline of the imaging apparatus 10 according to the present embodiment will be described with reference to Figs. 1 to 3. Fig. First, the occurrence of a residual image will be described with reference to FIG. The residual image phenomenon is a phenomenon in which a signal remains for a few frames even if the light of the subject is lost, and is a phenomenon that the tail is attracted to a moving subject as shown in the image example 302 of FIG. This is because the charges accumulated in the image pickup element can not be completely erased when the exposure of the image pickup element is started, so that the charges remaining in the image pickup element are read little by little after the next frame.

As the number of pixels increases and the number of lines in the vertical direction increases as described above, unless the pulse width of the charge elimination pulse is narrowed, the exposure start speed of the electronic shutter can not follow the running speed of the thick film of the mechanical shutter. However, if the pulse width is narrowed, the charges accumulated in the image pickup device can not be completely erased, and residual charge is generated, resulting in the afterimage phenomenon as shown in the image example 302 of FIG.

On the other hand, in the image example 301 of Fig. 1, the charge accumulated in the image pickup element was completely erased, and the image was free from afterimage. It is also conceivable to perform a telephone reset to temporarily erase the charge of the telephone so as not to cause the afterimage phenomenon as in the picture example 302 of Fig. For example, as shown in Fig. 2, the telephone is reset before the exposure of the electronic front curtain shutter is started, and the charges accumulated in the imaging element are erased. However, when a subject is normally photographed using an imaging device such as a digital camera, the shutter is pressed in the live view mode. The live view mode is a state in which the shutter is open and light is always irradiated onto the image pickup element.

As shown in FIG. 2, when the telephone reset is performed in the live view mode, the display screen of the imaging element once becomes very dark, or a time lag occurs from when the shutter is pressed to when the exposure starts. Therefore, a still image can not be continuously captured in the live view mode, which hinders smooth image capture.

Thus, in the imaging apparatus 10 according to the present embodiment, the charge accumulated in the image pickup device in the live view mode is once erased by the exposure start scan by operating the shutter of the electron beam shutter a plurality of times, and the exposure start The scan is started to start the exposure. When the charge accumulated in the imaging element is erased by the telephone reset, not only a time for resetting the telephone is required but also the amount of residual charge is different between the upper and lower portions of the screen, resulting in image unevenness. However, by operating the shutter of the multiple-electron shutter, it is possible to reduce the amount of residual charge in the upper and lower portions of the screen and reduce image unevenness.

For example, in Fig. 3, the electron beam shutter is operated twice. As shown in Fig. 3, the exposure start scanning run curves of the first and second electron beam film shutters are the same as the running curves of the thick film of the mechanical shutter. The traveling curves of the electronic front curtain shutter and the mechanical shutter are made to have the same running curves, so that the amount of residual electric charge is made equal between the upper and lower portions of the screen, thereby obtaining an image with less unevenness.

As shown in Fig. 3, the exposure start scan of the electron beam shutter is started by the generation of the charge erase pulse. More specifically, the charge is erased by the charge erase pointer (Pointer) to designate the line address. When the charge elimination pulse becomes &quot; H &quot; (H = High), the image pickup element of the line designated by the charge erase pointer is connected to the ground (GND) and the charge accumulated in the pixel is erased. It is also referred to as erasing the charge accumulated in the image pickup device and then resetting the charge.

As described above, the image capturing using the image capturing apparatus 10 is used for still image capturing from the live view mode. Therefore, the charges accumulated in the live view mode are erased while the charge erasing pulse is &quot; H &quot;. In FIG. 3, a pulse is generated by sequentially specifying Line [0] to Line [N], and then a second pulse is generated by designating Line [0] to Line [N].

The imaging device 10 detects an imaging scene (imaging state) of a subject based on the photometry value for each area or each line of the screen. Then, a charge elimination pulse train as an electron beam shutter is output a plurality of times according to the detected imaging scene.

The imaging apparatus 10 outputs the charge erase pulse train a plurality of times when the detected imaging scene is an imaging scene in which a residual image is likely to remain. The imaging scene having a high possibility of remaining afterimage is, for example, a case where a large amount of high luminance part is included in the screen, a case where there is a dark scene such as a night view, and a point light source of high luminance is also included. In addition, even when the vector amount of the motion vector in the image is a predetermined value or more and the luminance is high, there is a high possibility that the afterimage remains. Further, in the case of detecting the shaking motion, the charge erasing pulse train may be outputted a plurality of times in order to alleviate the influence of the shaking motion. In this manner, the charge accumulated in the imaging element is erased a plurality of times when the imaging scene is likely to remain, and when the camera shake occurs, the deterioration of the image quality due to the afterimage can be reduced.

[3] Functional configuration of the image pickup apparatus

The outline of the imaging device 10 has been described. Next, the functional configuration of the image sensing apparatus 10 will be described with reference to FIG. Fig. 4 is a block diagram showing a functional configuration of the image capturing apparatus 10. Fig. 4, the image sensing apparatus 10 includes a CMOS 102, shutters 104a and 104b (hereinafter also referred to as a shutter unit 104), an AFE (analog front end) 106, A TG (Timing Generator) 108, an imaging signal processing unit 110, a memory controller 112, a memory 114, a memory card controller 116, an AE / AF / AWB 120, a CPU 122 An LCD / Image Output (LCD / IO) 124, an LCD 126, a RAM table 130, a shutter driver 132, a lens unit 15, and the like.

The CMOS 102 is an example of an image pickup device having a plurality of pixels arranged in the matrix form of the present invention and is an element for converting light incident from the lens unit 15 into an electric signal. Specifically, the CMOS 102 converts the optical image of the object imaged by the lens unit 15 into an analog electric signal (image) of each color component of R (red), G (green), and B Signal) and outputs it as an image signal of each of R, G, and B colors. In the present embodiment, a reset signal is applied to each pixel of the CMOS 102 at a predetermined timing to start the exposure operation of the CMOS 102 to perform a function as an electron beam shutter.

The shutter unit 104 functions as a thick film that has a shutter that moves in the vertical direction of a predetermined pixel line of the CMOS 102 and performs a shutoff operation of the light exposed to the CMOS 102. The operation of the shutter unit 104 is controlled by the shutter driver 132. [

The AFE 106 is an analog front stage circuit that provides an analog electrical signal output from the CMOS 102 to the imaging signal processing section 110. [ The TG (Timing Generator) 108 has a function of inputting timing signals to the CMOS 102 and the AFE 106. The shutter speed is determined by the timing signal from the TG 108. [ That is, the driving of the CMOS 102 is controlled by the timing signal from the TG 108 and the video light from the subject is incident within the driving time of the CMOS 102, thereby generating an electric signal as the basis of the image data.

The imaging signal processing unit 110 has a function of generating RAW data of an image obtained by converting an analog electric signal output from the AFE 106 into a digital signal. Further, the image pickup signal processing section 110 adjusts the gain correction and the white balance of the light amount with respect to the RAW data of the image obtained from the CMOS 102. The memory controller 112 has a function of temporarily storing the photographed image in the memory 114 or reading the stored image. The memory 114 has a storage capacity enough to store a plurality of images. As the memory 114, for example, SDRAM (Synchronous Dynamic Random Access Memory) may be used.

The memory card controller 116 has a function of storing a photographed image or a synthesized image on the memory card 118. [ The memory card 118 is a card-type storage device that stores data in a flash memory.

The AE / AF / AWB 120 has a function of detecting an ambient light amount (brightness), a focal distance, an aperture value (focus), a color temperature and the like at the time of imaging and providing the detection result to the CPU 122. The CPU 122 executes a command of the signal system for the CMOS 102, the TG 108, or the like or executes an instruction of the operation system for the operation unit 150. [ In this embodiment, a command of the sign system and a command of the operation system are executed by one CPU 122, but the present invention is not limited to this example, and two CPUs may be used. The control of the thick film by the front curtain and the mechanical shutter by the electronic shutter by the CPU 122 will be described later in detail.

The LCD 126 has a function of displaying a live view before the shooting operation, various setting screens of the imaging device 10, and a captured image. The TV 128 also has a function of displaying a captured image or the like on the screen of the television receiver. The display on the LCD 126 or the TV 128 such as image data is displayed through the LCD / IO (Image Output)

The RAM table 130 is a table storing the scan table of the present invention. The RAM table 130 may store a plurality of scan patterns in advance and select a scan pattern according to the imaging scene. In addition, the scan pattern to be a reference may be stored in the RAM table 130, and the scan pattern may be changed in accordance with the difference between the value of the ambient light amount in the image capturing scene and the reference value. The scanning pattern is a timing for outputting a reset timing (exposure start timing) by an electron beam shutter. In this embodiment, the scan curve of the reset scan of the electron beam shutter is formed to have substantially the same shape as the running curve of the mechanical thick-film shutter.

In addition, the RAM table 130 may store the number of times of erasing charges in accordance with the imaging scene such as the brightness of the sensed image. It is also possible to store the number of times of erasing the charge of the electronic shutter according to the degree of camera shake. For example, the charge of the electronic shutter may be erased a plurality of times when the luminance value is equal to or greater than a predetermined value or when the degree of shaking is equal to or greater than a predetermined value.

In addition, a function generating circuit (not shown) may be mounted instead of the RAM table 130 for storing a scan pattern. In this case, the function can be expressed simply as a quadratic function or as a linear function. The loading circuit can be made smaller by outputting the scanning timing by the function generating circuit.

The operation unit 150 is provided with members for operating the imaging device 10 or performing various settings at the time of imaging. The member disposed on the operation portion 150 may include a power button, a cross key and a selection button for selecting a photographing mode or a photographing drive mode and setting an effect parameter, a shutter button for starting a photographing operation of the subject, and the like.

Next, the control of the front curtain and the thick curtain by the CPU 122 will be described with reference to Fig. Fig. 4 is a block diagram showing the configuration of the CPU 122. Fig. 4, the CPU 122 includes a detection unit 202, a scan control unit 204, an operation control unit 206, a gain adjustment unit 208, and the like.

The detection unit 202 has a function of detecting an imaging state of a subject. More specifically, the detection unit 202 detects the imaging state (imaging scene) from the ambient light amount (brightness), focal length, aperture value, color temperature, etc., detected by various sensors 120 such as AE / AF / It is detected whether or not the scene satisfies the range of an appropriate dynamic range when the image is reproduced. For example, it is detected whether there is an image that can not be reproduced due to overexposure of white due to overexposure or black overexposure due to underexposure.

Hereinafter, the detection of the imaging scene by the detection unit 202 will be described with reference to Figs. 6 and 7. Fig. Figs. 6 and 7 are explanatory diagrams for explaining detection of an imaging scene by the detection unit 202. Fig. 6 is an image in which the upper part of the image is blown away by so-called white spots and the blue sky can not be reproduced. The detection unit 202 obtains an area where white spots have occurred in the screen 71. For example, as shown in the explanatory diagram (72), the screen 71 may be divided into predetermined areas so as to obtain white spots. In this case, it is detected that the upper four areas of the screen 71 are the white dust areas, that is, the areas exceeding the upper limit of the dynamic range.

The white spots in the screen may be obtained by the histogram 73 shown in Fig. In the histogram 73, a large mountain appears on the right. In other words, it can be seen that there is an area where white spots are particularly generated in a part of the screen. When there are many white spots in the screen, that is, when a large amount of high luminance parts are included in the screen, there is a high possibility that a residual image phenomenon occurs because the charges accumulated in the image pickup element are not erased. In the image pickup apparatus 10, when the occurrence of the afterimage phenomenon is high, the scan control unit 204, which will be described later, adjusts the number of times of exposure scanning of the image pickup element, thereby obtaining an image with good image quality.

The detection unit 202 may detect the degree of camera shake when the user presses the shutter button of the imaging device 10. [ For example, the detection unit 202 detects the degree of camera shake using the angular velocity detected by the gyro sensor when the gyro sensor is provided in the imaging device 10. [

Returning to Fig. 5, the description of the configuration of the CPU 122 will be continued. The exposure of the CMOS 102 is started by erasing the charges accumulated in the CMOS 102 prior to the travel of the film by the operation control unit 206, which will be described later. The scan control unit 204 adjusts the number of times of erasing to erase the charge accumulated in the imaging element in accordance with the imaging state of the subject detected by the detection unit 202. [ The scan control unit 204 erases the charges accumulated in the CMOS 102 based on the scan pattern stored in the scan pattern storage unit (RAM table)

When the scan pattern storage unit 130 stores the number of times of charge erase corresponding to the luminance value or the degree of camera shake, the pulse string of the charge erase pulse is output a plurality of times based on the number of times of erase.

As shown in Fig. 3, the exposure start scan of the electron beam shutter is started by the generation of the charge erase pulse. Specifically, a line address to which charges are erased by a charge erasing pointer (Pointer) is designated. When the charge elimination pulse becomes &quot; H &quot; (H = High), the image pickup element of the line designated by the charge erase pointer is connected to the ground (GND) and the charge accumulated in the pixel is erased.

For example, when the scan control unit 204 erases the charge accumulated in the image pickup element twice, the front-film start signal 1 and the front-film start signal 2 are output in advance of the thick film start signal of the mechanical shutter. When the leading film start signal 1 is outputted, the line address from Line [0] to Line [N] is designated and the pulse string of the first charge erase pulse is outputted. After the leading film start signal 1 is outputted, the leading film start signal 2 is outputted and the pulse string of the electric charge eliminating pulse is outputted as the first. As shown in FIG. 3, the first and second charge elimination pulses are sequentially output in a line unit so as to have the same scan pattern as the scan pattern of the mechanical shutter.

Returning to Fig. 4, the operation control unit 206 has a function of controlling the operation of the film body that travels to shield the CMOS 102. The operation control unit 206 controls the operation of the film body through the shutter driver 132. The operation control unit 206 starts the exposure operation to the CMOS 102 under the control of the scan control unit 204 and then performs the mechanical shading by driving the film body after the lapse of the set exposure time, .

When a plurality of shutter curtains are operated by the scan control unit 204 as described above, the film is driven after the final operation of the main shutter of the electron beam shutter is performed. As described above, the scan control unit 204 functions as a front curtain of the shutter for starting the exposure of the CMOS 102 by giving the reset signal to the pixels 102 based on the scan pattern.

Then, the operation control unit 206 makes the film that shields the CMOS 102 function as a thick film of the shutter. In addition, the scan control unit 204 outputs the pulse of the reset signal a plurality of times in accordance with the imaging scene or the camera shake. In this manner, the scan control unit 204 adjusts the number of times of outputting the reset signal in accordance with the imaging scene or the camera shake, and the operation control unit 206 controls the mechanical thick-film shutter so as to alleviate the deterioration of image quality due to afterimage.

The gain adjustment unit 208 is a circuit for causing the scan control unit 204 to synchronize with the reading of the pixels in the horizontal direction of the CMOS 102 when the reading operation of each pixel of the CMOS 102 is controlled by the scan control unit 204. [ And adjusts the gain for each predetermined area. The gain adjusting unit 208 adjusts the gain on a pixel-by-pixel basis of the CMOS 102 and adjusts the gain based on a predetermined function indicating the variation width of the gain in synchronization with the reading position of the pixel in the horizontal direction of the CMOS 102. [

For example, in the case where a plurality of regions or pixel-by-pixel readout circuits are mounted in the horizontal direction in the CMOS 102, and each of them has a gain adjustment amplifier, the gain adjustment section 208 sets the gain of the amplifier Adjust by area. Alternatively, the gain of the gain adjustment circuit in the AFE 106 may be changed in synchronization with horizontal pixel reading.

In this case, the circuit for presenting the gain in accordance with the horizontal position may be provided inside the AFE 106 or may be provided to the external image pickup signal processing unit 110 or the TG 108. The gain adjustment unit 208 may change the gain of the gain adjustment circuit in the imaging signal processing unit 110 in synchronization with horizontal pixel reading. In this case, a circuit for providing a change amount of the gain due to the position in the horizontal direction is given to the image pickup signal processing section 110.

In the present embodiment, the gain is adjusted by the gain adjusting unit 208 for each predetermined area or pixel, but the present invention is not limited to this example, and the gamma curve may be changed on a region-by-area basis. The gamma curve is a characteristic curve showing the ratio between the signal level of the input image and the brightness of the output image. The CPU 122 may adjust the exposure of the screen by adjusting this gamma curve.

[4] Detailed Operation of the Image Pickup Apparatus

The functional configuration of the image sensing apparatus 10 has been described above. Next, the operation of the image sensing apparatus 10 will be described in detail with reference to FIG. Fig. 8 is a flowchart showing a specific operation of the image capturing apparatus 10. Fig. As shown in Fig. 8, the detection unit 202 first starts photometry in the screen (S102).

Then, a histogram is calculated based on the photometric data acquired in step S102 (S104). The histogram calculated in step S104 may be, for example, the graph shown in Fig. Then, the luminance distribution and the contrast in the screen are analyzed from the histogram calculated in step S104 (S106).

Then, the imaging state of the subject (scene) is recognized based on the analysis of the luminance distribution and the contrast in the screen performed in step S106 (S108). In step S108, not only AE information but also AF / AWB information or motion vector information may be used.

The aperture value and the shutter speed are determined according to the set mode (S110). Then, a profile (characteristic curve) of the electron beam film is set based on the aperture value determined in step S110, the shutter speed, the scan pattern of the mechanical thick film shutter, and the like (S112).

Next, it is judged whether or not the imaging scene is a scene in which a residual image is generated based on the luminance value or the like detected in steps S106 to S110 (S114). A scene in which a residual image occurs in step S114 includes, for example, a case where a high luminance part in the screen exceeds a reference value, a case where a point light source of high luminance is included in a dark scene, a case where a motion vector amount exceeds a reference value .

The case where the high luminance part in the screen exceeds the reference value is, for example, a case where there are many white spots. The case where a high-intensity point light source is included in a dark scene is, for example, a case where a night view is photographed. The motion vector amount is a value obtained by detecting a speed at which an object is moving compared with an image of a previous frame. When a moving object is imaged, the vector amount exceeds a reference value. In the above case, it is determined that there is a possibility that the afterimage remains.

If it is determined in step S114 that the imaging scene is not the scene in which the afterimage occurs, the normal exposure starts (S116). That is, the electron beam film is operated only once. If it is determined in step S114 that the imaging scene is a scene in which a residual image occurs, the electronic front curtain is operated a plurality of times. In Fig. 8, the electron beam film is operated twice. Initially, exposure of the first electron beam film is started (S120), and then exposure of the second electron beam film is started (S122).

In step S120 and step S122, the exposure start of the electron beam film is performed by sequentially generating charge erase pulses for each line of the image pickup device and erasing the charges accumulated in the image pickup device. As shown in Fig. 3, the charge elimination pulses of the image pickup element are outputted at the timing at which the characteristics are the same as those of the thick film of the mechanical shutter which becomes the thick film.

Returning to Fig. 8, it is judged whether or not an unintentional hand movement occurs after the start of exposure in step S116 (S118). The shaking in step S118 occurs when the output value of the gyro sensor is larger than a predetermined reference value. If it is determined in step S118 that an unintentional hand movement has occurred, the processes of step S120 and step S122 are executed. If it is determined in step S118 that no camera-shake has occurred, the process is terminated.

Whether or not an unintentional hand movement occurs in step S118 is determined when the shutter of the image capturing apparatus is depressed. Therefore, in step S114, the number of erase times of the electric charges is adjusted in accordance with the luminance in the screen or the motion of the subject. Even if it is determined in step S114 that it is not necessary to scan the electron beam film a plurality of times, the electronic-ray film is scanned a plurality of times in the case where the camera-shake is detected in step S116.

As a result, not only the brightness of the screen and the movement of the subject but also the afterimage phenomenon caused by the camera shake can be prevented, and an image with good image quality can be obtained.

Details of the operation of the imaging apparatus 10 have been described. According to the imaging device 10, after the imaging state of the object is detected and the number of times of erasing charges accumulated in the imaging element is adjusted in accordance with the imaging state, the exposure of the imaging element is started, and the film is driven to shade the imaging element. This makes it possible to reduce the afterimage phenomenon by scanning the shutter of the electron beam film a plurality of times when capturing an image which is likely to cause a residual image phenomenon.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited thereto. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents, . &Lt; / RTI &gt;

In the above description, the electron beam film is scanned a plurality of times in order to reduce the afterimage phenomenon in accordance with the luminance in the screen or the motion of the subject. However, the present embodiment is not limited to the above example. For example, when performing imaging in which a residual image is left intentionally, the number of times of scanning of the electron beam film may be adjusted so as to leave a desired residual image.

For example, each step in the processing of the imaging apparatus 10 in the present specification does not necessarily have to be processed in a time series in accordance with the procedure described in the flowchart. That is, each step in the processing of the imaging apparatus 10 may be executed in parallel with other processing.

It is also possible to create a computer program for causing hardware such as a CPU, ROM, and RAM to be incorporated in the image capturing apparatus 10 or the like to perform functions equivalent to the above-described respective configurations of the image capturing apparatus 10. A storage medium storing the computer program is also provided.

10 Imaging device
102 Image sensor (CMOS)
104a, 104b Shutter
202 detector
204,
206 Operation Control Unit
208 gain adjustment section

Claims (10)

An imaging device that includes an imaging element having a plurality of pixels arranged in a matrix form and exposes the imaging element to image a subject,
A detecting unit for detecting an imaging state of a subject;
An operation control section for controlling an operation of a film body which travels to shield the imaging element from light; And
And a scan control section for controlling the exposure start scanning of the imaging element by erasing the charge accumulated in the imaging element prior to the running of the film body,
Wherein the scan control unit erases the charge accumulated in the imaging element a plurality of times according to the luminance information of the subject or the number of times of charge erase corresponding to the degree of camera shake at the time of imaging. The method according to claim 1,
The scan control unit includes:
Wherein the exposure start scanning of the imaging element functions as a front curtain of the shutter to start the exposure of the imaging element by erasing the charges accumulated in the imaging element,
Wherein the operation control section causes the film body that shields the imaging element to function as a rear curtain of the shutter. The method according to claim 1,
The scan control unit includes:
Generating an erase pulse for erasing the charge accumulated in the imaging element so as to correspond to the traveling curve of the film body,
And the erasing pulse is generated a plurality of times according to an imaging state of the subject. The method of claim 3,
The scan control unit includes:
Wherein the erasing pulse is generated a plurality of times in units of lines of the imaging element. The method according to claim 1,
The scan control unit includes:
And erases the charge accumulated in the image pickup device a plurality of times when the after-image of the subject remains in an imaging state. The method according to claim 1,
The scan control unit includes:
And erases the charge accumulated in the imaging element a plurality of times when the luminance of the subject is higher than a preset reference value. The method according to claim 1,
The scan control unit includes:
And the charge accumulated in the imaging element is erased a plurality of times when the subject includes a high-intensity point light source. The method according to claim 1,
The scan control unit includes:
And erases the charge accumulated in the imaging element a plurality of times when the motion vector of the subject is equal to or larger than a preset threshold value. The method according to claim 1,
The detection unit detects the degree of camera shake at the time of image capture,
Wherein the scan control unit erases the charge accumulated in the imaging element a plurality of times when the degree of camera shake detected by the detection unit is equal to or greater than a preset value. An imaging method for imaging an object by exposing an imaging element having a plurality of pixels arranged in a matrix form,
Detecting an imaging state of a subject;
Starting the exposure of the imaging element by erasing the charge accumulated in the imaging element a plurality of times according to the luminance information of the object or the number of charges canceled corresponding to the degree of camera shake at the time of imaging; And
And operating the film body to travel so as to shield the imaging element after the start of exposure of the imaging element.

Images