JP2011087826A - Imaging apparatus and electronic endoscope apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus and an electronic endoscope apparatus, capable of surely executing dark current correction. <P>SOLUTION: The electronic endoscope apparatus 1 includes a video scope 5 provided with a flexible tube and a CCD image sensor 3 installed at the distal end part of the flexible tube, and a processor 4 which processes respective signals such as pixel signals read from the CCD image sensor 3 and in which a light source unit is integrally provided. When a freeze button 57 is pressurized, the still image of an observation part is displayed on a monitor 6. In this case, the entire pixel signals for one frame obtained by one exposure are read from the CCD image sensor 3. That is, the pixel signals before the correction of odd-numbered rows, the pixel signals before the correction of even-numbered rows, correction signals to be used when correcting (dark current correcting) the pixel signals of the odd-numbered rows and correction signals to be used when correcting the pixel signals of the even-numbered rows are successively read. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and an electronic endoscope apparatus.

  In an electronic endoscope apparatus including an imaging device, yellow (Ye), cyan (Cy), magenta (Mg), and green (G) color elements (colored portions) are checkered at the tip of the electronic endoscope. An interline type CCD image sensor (complementary color CCD image sensor) in which complementary color filters arranged side by side are provided on the imaging surface is provided. The CCD image sensor includes a plurality of photodiodes that constitute pixels on the imaging surface and are arranged in a matrix (aligned in the vertical direction and the horizontal direction), and the complementary color filter includes each color element, It arrange | positions corresponding to the photodiode.

  The reason why the complementary color CCD image sensor is used in the electronic endoscope apparatus is that the complementary color CCD image sensor can have higher sensitivity than a CCD image sensor (primary color CCD image sensor) in which a primary color filter is provided on the imaging surface. This is because the electronic endoscope apparatus has many advantages.

  In such an electronic endoscope apparatus, a moving image (electronic image of a moving image) of an observation site (subject) is displayed on a monitor, and a still image (an electronic image of a still image) for one frame by one exposure is displayed. It can also be displayed and stored (recorded).

  In the case of displaying a moving image, when reading out pixel signals from the complementary color CCD image sensor, pixel signals read out from two photodiodes adjacent in the vertical direction are added. That is, after exposure, a mixed signal of the pixel signal of the first row and the pixel signal of the second row, a mixed signal of the pixel signal of the third row and the pixel signal of the fourth row,... In the meantime, the next exposure is performed, and then the mixed signal of the pixel signal of the second row and the pixel signal of the third row, the pixel signal of the fourth row, and the pixel signal of the fifth row The mixed signal,... Is read out as the pixel signal of the second (even) field.

  On the other hand, when displaying and storing still images, the complementary color CCD image sensor outputs all pixel signals for one frame by one exposure. In this case, pixel signals for odd rows and pixel signals for even rows are output. Each is read out every field period (for example, 1/60 second period) (see, for example, Patent Document 1).

  That is, first, a pixel signal is obtained by exposure within a period of 1/60 seconds, pixel signals of odd-numbered rows are read out within the next period of 1/60 seconds, and further, the next 1/60 seconds. Pixel signals in even rows are read out during the period. However, in order to prevent exposure while reading out the pixel signals in the odd rows, the light emitted from the light source is blocked by the shutter until the start of reading out the pixel signals in the even rows after the exposure is completed.

  Note that the complementary color CCD image sensor cannot read out the pixel signals of each row in order like the pixel signal of the first row, the pixel signal of the second row, and the pixel signal of the third row due to its configuration.

  The obtained odd row pixel signals and even row pixel signals are subjected to predetermined signal processing, whereby one frame of video data (image data) is created. In this way, one frame of video data is created from the pixel signal obtained by one exposure within a period of 1/60 seconds, and the pixel signals obtained by transmitting two different color elements are mixed. Therefore, the image quality can be improved, and a high-resolution still image without blur can be obtained.

  However, in the conventional electronic endoscope apparatus, a noise component due to dark current corresponding to each pixel is detected to obtain a correction signal, and dark current correction using the correction signal has not been performed. This is because it is difficult to perform dark current correction corresponding to each pixel due to the configuration of the complementary color CCD image sensor to be used.

  Further, the pixel signal of the odd row includes a noise component due to the dark current for a period of about 1/60 seconds. While the pixel signal of the odd row is being read, Further, since noise components due to dark current are accumulated, the noise components due to dark current for a period of about 1/30 second, which is twice that of the pixel signals of odd rows, are included in the pixel signals of even rows. Will be included.

  As described above, in the conventional electronic endoscope apparatus, dark current correction is not performed, and furthermore, due to the noise component due to the dark current included in the pixel signal in the odd-numbered row and the dark current included in the pixel signal in the even-numbered row. Since it differs from the noise component by about twice, there is a problem that the quality of the still image, particularly, the color is deteriorated.

  The electronic endoscope apparatus is used by inserting the tip of the electronic endoscope into the body. However, the temperature inside the body is higher than the temperature outside the body, and the dark current is higher as the temperature is higher. Since it becomes large, the influence by the dark current is very large.

  It should be noted that the noise component due to dark current contained in the odd-numbered pixel signals and the noise component caused by dark current contained in the even-numbered pixel signals have twice different generation periods. It was difficult to remove (correct).

Japanese Patent No. 32988772

  An object of the present invention is to provide an imaging apparatus and an electronic endoscope apparatus that can reliably perform dark current correction.

Such an object is achieved by the present inventions (1) to (7) below.
(1) a solid-state imaging device having a plurality of photoelectric conversion elements that constitute pixels on the imaging surface arranged in the vertical direction and the horizontal direction;
When signals obtained by receiving light by two photoelectric conversion elements adjacent in the vertical direction are added and output, and signals obtained by receiving light by odd-numbered photoelectric conversion elements and by even-numbered photoelectric conversion elements A pixel signal generating means for selecting one of the signals obtained by receiving light and outputting the signal from the solid-state imaging device; and
Correction means for correcting a signal output from the solid-state imaging device;
Light shielding means for preventing light from entering the imaging surface of the solid-state imaging device,
When outputting all pixel signals obtained by one exposure from the solid-state imaging device, in the first period, the imaging surface of the solid-state imaging device is exposed,
In the second period having the same length as the first period after the first period, the pixel signal generation is performed in a state where light is not incident on the imaging surface of the solid-state imaging device by the operation of the light shielding unit. Means for reading out and obtaining a signal as a first pre-correction pixel signal from one of the photoelectric conversion elements in the odd-numbered rows and the photoelectric conversion elements in the even-numbered rows of the solid-state imaging device;
In the third period having the same length as the second period after the second period, the pixel signal generation is performed in a state where light is not incident on the imaging surface of the solid-state imaging device by the operation of the light shielding unit. Means for reading a signal from each photoelectric conversion element of the solid-state imaging device, adding the signals read from two photoelectric conversion elements adjacent in the vertical direction, and obtaining a second pre-correction pixel signal;
In the fourth period having the same length as the third period after the third period, the pixel signal generation is performed in a state where light is not incident on the imaging surface of the solid-state imaging device by the operation of the light shielding unit. By means of each of the photoelectric conversion elements in the odd-numbered rows of the solid-state imaging device and the photoelectric conversion elements in the even-numbered rows, from the photoelectric conversion elements in the same row as the reading source of the first pre-correction pixel signal. Reading out and acquiring the signal as the first correction signal;
After the fourth period, in the fifth period having the same length as the fourth period, the pixel signal generation unit reads a signal from each photoelectric conversion element of the solid-state imaging element, and the second period The signals read from the two photoelectric conversion elements adjacent in the vertical direction are added so that the photoelectric conversion elements from which the signals to be added are read are the same as when the pre-correction pixel signal is acquired. , Obtain a second correction signal,
The correction means corrects the first pre-correction pixel signal using the first correction signal, obtains one of an odd-numbered pixel signal and an even-numbered pixel signal, and outputs the second correction signal. The imaging apparatus is configured to correct the second pre-correction pixel signal to obtain the other of the odd row pixel signal and the even row pixel signal.

  As a result, all pixel signals obtained by one exposure from a CCD image sensor (complementary color CCD image sensor) in which a complementary color filter is provided on the imaging surface or a solid-state image sensor that operates in the same manner as the complementary color CCD image sensor are obtained. When reading, dark current correction can be reliably performed for each of the odd-numbered pixel signals and the even-numbered pixel signals. Thus, in the case of a still image, noise components due to dark current can be reliably removed from each of the odd-numbered pixel signals and the even-numbered pixel signals, and a good still image can be obtained.

  In the case of a moving image, the sensitivity can be increased compared to the case of using a CCD image sensor (primary color CCD image sensor) in which a primary color filter is provided on the imaging surface, and a pixel signal is obtained from a solid-state imaging device. The reading time for reading can be shortened.

(2) having correction signal generation means for generating a correction signal for a moving image;
When outputting all the pixel signals obtained by one exposure from the solid-state imaging device, in the fifth period, the light shielding means is operated so that light does not enter the imaging surface of the solid-state imaging device,
After the fifth period, in the sixth period having the same length as the fifth period, the pixel signal generation means causes the photoelectric conversion elements in the odd-numbered rows of the solid-state imaging elements and the photoelectric conversion elements in the even-numbered rows to Among each photoelectric conversion element, a signal is read and acquired as a third correction signal from each photoelectric conversion element in a row different from the read source of the first pre-correction pixel signal,
The imaging apparatus according to (1), wherein the correction signal generation unit is configured to generate a correction signal for a moving image based on the first correction signal and the third correction signal.

  Accordingly, in the case of a moving image, dark current correction can be reliably performed on the pixel signal. That is, the noise component due to the dark current can be surely removed from the pixel signal, and a good moving image can be obtained.

(3) When outputting all pixel signals obtained by one exposure from the solid-state imaging device, the sixth period having the same length as the fifth period after the fifth period and the fifth period In this period, the light is not incident on the imaging surface of the solid-state imaging device by the operation of the light shielding means,
In one of the sixth period and the seventh period having the same length as the sixth period after the sixth period, each photoelectric conversion of the solid-state imaging device is performed by the pixel signal generation unit. Two photoelectric conversions adjacent in the vertical direction so that the signal from which the signal is read out and the second pre-correction pixel signal is acquired are the same as the photoelectric conversion element from which the signal is added. Adding the signals read from the elements to obtain a third correction signal;
In the other of the sixth period and the seventh period, the pixel signal generation unit reads out signals from the photoelectric conversion elements of the solid-state image sensor and acquires the second pre-correction pixel signal. The signals read from the two photoelectric conversion elements adjacent in the vertical direction are added so that the photoelectric conversion elements from which the signals to be added are shifted one row at a time, and a fourth correction signal is added. Get
The imaging apparatus according to (1), configured to use the third correction signal and the fourth correction signal as correction signals for moving images.

  Accordingly, in the case of a moving image, dark current correction can be reliably performed on the pixel signal. That is, the noise component due to the dark current can be surely removed from the pixel signal, and a good moving image can be obtained.

  (4) The correction of the first pre-correction pixel signal is to subtract the first correction signal from the first pre-correction pixel signal, and the correction of the second pre-correction pixel signal is The imaging apparatus according to any one of (1) to (3), wherein the second correction signal is subtracted from a second pre-correction pixel signal.

  Thereby, the noise component due to the dark current can be surely removed from each of the odd-numbered pixel signals and the even-numbered pixel signals, and a good still image can be obtained.

  (5) The solid-state imaging device includes a CCD image sensor in which a complementary color filter in which yellow color elements, cyan color elements, magenta color elements, and green color elements are arranged in a checkered pattern is provided on the imaging surface. The imaging device according to any one of (1) to (4) above.

  As a result, in the case of a moving image, the sensitivity can be increased as compared with the case where a primary color CCD image sensor is used, and the readout time when the pixel signal is read out from the complementary color CCD image sensor can be shortened.

  (6) Any of the above (1) to (5), wherein the light shielding means includes a light shielding member that blocks light incident on an imaging surface of the solid-state imaging device or a light shielding member that blocks light emitted from a light source. The imaging device described in 1.

  Thereby, it can block | prevent that light injects into the imaging surface of a solid-state image sensor with a simple structure.

(7) The imaging device according to any one of (1) to (6),
An electronic endoscope apparatus comprising: a light source that emits illumination light that illuminates a subject.

  Thus, it is possible to provide an electronic endoscope apparatus that can reliably remove a noise component due to dark current from each of an odd-numbered pixel signal and an even-numbered pixel signal and can obtain a good still image. it can.

  According to the present invention, a CCD image sensor (complementary color CCD image sensor) in which a complementary color filter is provided on the imaging surface or a solid-state imaging device that operates in the same manner as the complementary color CCD image sensor can be obtained by one exposure. When reading out pixel signals, dark current correction can be reliably performed for each of odd-numbered pixel signals and even-numbered pixel signals. Thereby, in the case of a still image, the noise component due to the dark current can be reliably removed from each of the odd-numbered pixel signals and the even-numbered pixel signals, and a good still image can be obtained.

  In the case of a moving image, the sensitivity can be increased compared to the case of using a CCD image sensor (primary color CCD image sensor) in which a primary color filter is provided on the imaging surface, and a pixel signal is obtained from a solid-state imaging device. The reading time for reading can be shortened.

It is a block diagram which shows the principal part in 1st Embodiment of the electronic endoscope apparatus of this invention. It is a top view of the rotary shutter of the electronic endoscope apparatus shown in FIG. It is a top view of the chopper of the electronic endoscope apparatus shown in FIG. It is a figure which shows typically the complementary color filter provided in the CCD image sensor of the electronic endoscope apparatus shown in FIG. It is a figure which shows typically the CCD image sensor of the electronic endoscope apparatus shown in FIG. It is a figure which shows typically the CCD image sensor for demonstrating reading of the signal from the CCD image sensor of the electronic endoscope apparatus shown in FIG. It is a figure which shows typically the CCD image sensor for demonstrating reading of the signal from the CCD image sensor of the electronic endoscope apparatus shown in FIG. It is a figure for demonstrating reading of the signal from the CCD image sensor of the electronic endoscope apparatus shown in FIG. It is a figure which shows typically the CCD image sensor for demonstrating reading of the signal from the CCD image sensor of the electronic endoscope apparatus shown in FIG. It is a figure for demonstrating reading of the signal from the CCD image sensor in 2nd Embodiment of the electronic endoscope apparatus of this invention. It is a figure which shows typically the CCD image sensor for demonstrating reading of the signal from the CCD image sensor in 2nd Embodiment of the electronic endoscope apparatus of this invention. It is a figure for demonstrating reading of the signal from the CCD image sensor in 3rd Embodiment of the electronic endoscope apparatus of this invention. It is a flowchart which shows the control action in 4th Embodiment of the electronic endoscope apparatus of this invention.

  Hereinafter, an imaging device of the present invention and an electronic endoscope device of the present invention including the imaging device will be described in detail based on preferred embodiments shown in the accompanying drawings.

<First Embodiment>
FIG. 1 is a block diagram showing the main part of the electronic endoscope apparatus according to the first embodiment of the present invention, FIG. 2 is a plan view of a rotary shutter of the electronic endoscope apparatus shown in FIG. 1, and FIG. 1 is a plan view of a chopper of the electronic endoscope apparatus shown in FIG. 1, FIG. 4 is a diagram schematically showing a complementary color filter provided in the CCD image sensor of the electronic endoscope apparatus shown in FIG. 1, and FIG. 1 schematically shows a CCD image sensor of the electronic endoscope apparatus shown in FIG. 1, and FIGS. 6 and 7 are diagrams for explaining reading of signals from the CCD image sensor of the electronic endoscope apparatus shown in FIG. FIG. 8 is a diagram schematically showing a CCD image sensor, FIG. 8 is a diagram for explaining reading of signals from the CCD image sensor of the electronic endoscope apparatus shown in FIG. 1, and FIG. 9 is an electronic endoscope shown in FIG. Reading signals from the CCD image sensor of the mirror device The CCD image sensor to explain the issue is a diagram schematically illustrating.

  In the following, the vertical direction in FIGS. 4 and 5 is “vertical direction (vertical direction)”, the horizontal direction is “horizontal direction (horizontal direction)”, the upper side is “up”, the lower side is “lower”, and the left side Is described as “left” and the right side is “right”.

  6, FIG. 7, and FIG. 9 typically show photodiodes for one column and six rows (the same applies to FIG. 11).

  As shown in FIG. 1, an electronic endoscope apparatus 1 includes a videoscope (endoscope) 5 having a flexible tube and a CCD image sensor (solid-state imaging device) 3 installed at the distal end of the flexible tube. And a processor (light source device) 4 that processes each signal such as a pixel signal read from the CCD image sensor 3 and is provided with a light source unit integrally. The video scope 5 is detachably connected to the processor 4, and the processor 4 is detachably connected to a monitor (display means) 6 for displaying an image (electronic image) of an observation site (subject). It is comprised so that.

  The processor 4 includes a system control circuit (control means) 41, a processor-side signal processing circuit 42 having a frame memory (storage unit), a lamp control unit (light source control unit) 43, and illumination light that illuminates an observation site (subject). A lamp (light source) 44 that emits light), a rotary shutter 45, a condenser lens 46, a motor driver 47, a PWM drive circuit (drive unit control means) 48, a chopper 49, and the like. The PWM drive circuit 48 and the chopper 49 constitute a main part of light shielding means for preventing light from entering the imaging surface of the CCD image sensor 3.

  In addition to the CCD image sensor 3, the video scope 5 includes an initial signal including a light guide 51, a scope controller (control means) 52, a timing control circuit 53, a CCD driver 54, an amplification circuit 55, a frame memory (storage unit), and the like. A processing circuit 56 and a freeze button 57 are provided.

  In the electronic endoscope apparatus 1, when a lamp lighting switch (not shown) of the processor 4 is turned on, power (power) is supplied from the lamp control unit 43 to the lamp 44 and the lamp 44 is lit. The light emitted from the lamp 44 enters the incident end 51 </ b> A of the light guide 51 provided in the video scope 5 through the rotary shutter 45 and the condenser lens 46. The light guide 51 is an optical fiber bundle that transmits the light emitted from the lamp 44 to the distal end side of the video scope 5, and the light guided to the distal end side by the light guide 51 is emitted from the emission end 51B and is diffused by a diffusion lens. An observation site (subject) is irradiated through a certain light distribution lens (not shown).

  The light reflected at the observation site reaches the CCD image sensor 3 through an objective lens (not shown), and an image of the observation site is formed on the imaging surface (light receiving surface) of the CCD image sensor 3.

  In the present embodiment, the single plate simultaneous type is adopted as the color imaging method. As the CCD image sensor 3, an interline complementary color CCD image sensor is used. That is, on the imaging surface of the CCD image sensor 3, each color element (colored portion) of the yellow (Ye) filter region, cyan (Cy) filter region, magenta (Mg) filter region, and green (G) filter region shown in FIG. ) Are arranged in a checkered pattern. The complementary color filter 35 is arranged so that each color element corresponds to each pixel (photodiode 31) on the imaging surface of the CCD image sensor 3. In the CCD image sensor 3, each signal such as a pixel signal corresponding to the color and amount of light transmitted through the complementary color filter 35 is generated by photoelectric conversion.

  The configuration of the CCD image sensor 3 will be further described. As shown in FIG. 5, the CCD image sensor 3 constitutes pixels on the imaging surface, and is arranged in a matrix (a plurality of rows arranged in the vertical and horizontal directions). A photodiode (photoelectric conversion element) 31, a plurality of vertical transfer CCD registers (vertical transfer registers) 32, a horizontal transfer CCD register (horizontal transfer register) 33, and a charge / voltage conversion unit (output amplifier) 34 ing.

  Each vertical transfer CCD register 32 includes a plurality of vertical transfer CCDs (Charge Coupled Devices) 321 arranged in parallel along the vertical direction (column direction). The vertical transfer CCD registers 32 are arranged in parallel along the horizontal direction (row direction).

  The horizontal transfer CCD register 33 includes a plurality of horizontal transfer CCDs (not shown) arranged in parallel along the horizontal direction. The horizontal transfer CCD register 33 is disposed below each vertical transfer CCD register 32.

  The CCD image sensor 3, that is, the electronic shutter, the vertical transfer CCD registers 32, the horizontal transfer CCD registers 33, and the like are operated by drive signals output from the CCD driver 54. In addition, a signal obtained by receiving light received by two photodiodes 31 adjacent in the vertical direction is added and output, and a signal obtained by receiving light by odd-numbered photodiodes 31 and received by even-numbered photodiodes 31. The case where one of the signals obtained in this way is output is selected.

  At the time of imaging, incident light from the observation site is received by each photodiode 31 of the CCD image sensor 3 for a predetermined time and photoelectrically converted by the operation of the electronic shutter. Thereby, for example, a pixel signal (signal charge) is generated, and the pixel signal is transferred to the corresponding vertical transfer CCD register 32. The pixel signal is transferred from each vertical transfer CCD register 32 to the horizontal transfer CCD register 33 by the operation of each vertical transfer CCD register 32, and is passed through the charge / voltage converter 34 by the operation of the horizontal transfer CCD register 33. Output from the CCD image sensor 3. In the charge / voltage conversion unit 34, the pixel signal is converted from a charge (current) to a voltage, that is, from a charge (current) signal to a voltage signal. In the case of a moving image, the imaging operation, that is, the operation of the electronic shutter is continuously performed at a predetermined cycle, and addition reading described later is performed.

  The CCD driver 54, the timing control circuit 53, and the scope controller 52 constitute the main part of the pixel signal generation means.

  In the present embodiment, for example, the NTSC system is adopted as the color television system. When a moving image is displayed on the monitor 6, when a pixel signal is output from the CCD image sensor 3, field readout (normal readout) is performed. Is done. That is, in accordance with the drive signal sent from the CCD driver 54, pixel signals obtained by receiving light by two photodiodes 31 adjacent in the vertical direction are added every 1/60 second period (one field period). The odd-field pixel signal (ODD) and the even-field pixel signal (EVEN) are sequentially read out and sent to the amplifier circuit 55. The case where a still image is displayed and stored will be described in detail later. Further, the one field period differs depending on the apparatus, and is not limited to 1/60 seconds, but may be, for example, 1/30 seconds, 1/20 seconds, 1/15 seconds, or the like.

  Specifically, first, as shown in FIG. 6, the imaging surface of the CCD image sensor 3 is exposed within a period of 1/60 seconds, and pixel signals a, b, c, d, e, and f are obtained. In the next 1/60 second period, the pixel signal a + b obtained by adding the pixel signal a of the first row and the pixel signal b of the second row, and the pixel signal c of the third row and the fourth row A pixel signal c + d obtained by adding the pixel signal d of the eye and a pixel signal e + f obtained by adding the pixel signal e of the fifth row and the pixel signal f of the sixth row are pixel signals of the odd field. Is read as

  Further, as shown in FIG. 7, the next exposure is performed while the pixel signal of the odd field is being read, and the pixel signals a, b, c, d, e, and f are obtained. / Pixel signal b + c obtained by adding the pixel signal b of the second row and the pixel signal c of the third row within a period of / 60 seconds, the pixel signal d of the fourth row, and the pixel signal e of the fifth row Is read out as a pixel signal in an even field. The pixel signal a in the first row in the even field is not used. As described above, in reading out the pixel signals in the even field, the photodiodes 31 from which the pixel signals to be added are read out one row at a time with respect to reading out the pixel signals in the odd field.

  Here, the pixel signals for one column and six rows have been described here as a representative, but the same applies to other pixel signals. This also applies to FIGS. 9 and 11.

  The pixel signal output from the CCD image sensor 3 is subjected to amplification processing or the like by the amplification circuit 55, subjected to predetermined signal processing by the initial signal processing circuit 56, and sent to the processor side signal processing circuit 42 of the processor 4. The

  The processor-side signal processing circuit 42 performs various signal processing such as white balance adjustment and gamma correction on the pixel signal output from the initial signal processing circuit 56, and displays video data (image data) for displaying an electronic image. Is created. This video data is output to the monitor 6 and displayed on the monitor 6 as a moving image of the observation site.

  When the freeze button 57 is pressed, a still image of the observation site is displayed on the monitor 6. In this case, all the pixel signals for one frame obtained by one exposure are read from the CCD image sensor 3 by the operation described later. At the time of reading, as described later, when correcting pixel signals before correction of odd rows (pre-correction pixel signals), pixel signals before correction of even rows, and pixel signals of odd rows (dark current correction). The correction signal to be used and the correction signal to be used when correcting the pixel signals in the even rows are sequentially read out and sent to the amplifier circuit 55.

  Each signal output from the CCD image sensor 3 is subjected to amplification processing and the like by the amplification circuit 55, subjected to predetermined signal processing by the initial signal processing circuit 56, and sent to the processor side signal processing circuit 42 of the processor 4. Is done.

  The processor-side signal processing circuit 42 corrects the pixel signals before correction of the odd rows and the pixel signals before correction of the even rows output from the initial signal processing circuit 56 using the corresponding correction signals, respectively. Various signal processing such as white balance adjustment and gamma correction are performed. Thereby, video data (image data) for displaying a still image is created. This video data is output to the monitor 6 and displayed on the monitor 6 as a still image of the observation site.

  The dark current correction is not limited to the processor-side signal processing circuit 42, and may be performed by the initial signal processing circuit 56, for example.

  Further, the video data of the still image can be stored (recorded) in a storage medium (recording medium) by a storage unit (not shown) that is detachably connected to the processor 4, for example.

  The processor side signal processing circuit 41 and the system control circuit 42 constitute the main parts of the correction means and the image data creation means.

  The system control circuit 41 includes a CPU, a microcomputer, and the like, and sends control signals to predetermined circuits such as the processor-side signal processing circuit 42, the lamp control unit 43, the motor driver 47, and the PWM drive circuit 48 of the processor 4. Output and control the overall operation (drive) of the processor 4. In a timing control circuit (not shown) on the processor 4 side, a clock pulse signal for adjusting the processing timing of the signal is output to each predetermined circuit in the processor 4, and the synchronization associated with the video data (video signal). The signal is sent to the processor side signal processing circuit 42.

  The scope controller 52 includes a CPU, a microcomputer, etc., and outputs a control signal to each predetermined circuit (each unit) of the video scope 5 such as a timing control circuit 53, an amplification circuit 55, and an initial signal processing circuit 56. The overall operation (drive) of the video scope 5 is controlled.

  The timing control circuit 53 outputs a drive signal to the CCD driver 54 based on the control signal sent from the scope controller 52, and reads out signals such as pixel signals from the CCD image sensor 3 via the CCD driver 54. Control processing. When the video scope 5 is connected to the processor 4, signals (data) can be transmitted and received between the scope controller 52 and the system control circuit 41.

  The rotary shutter 45 is attached to a rotation shaft of a motor (not shown), and rotates at a constant speed based on a drive signal sent from the motor driver 47. A light shielding chopper 49 is provided between the rotary shutter 45 and the condenser lens 46. The chopper 49 operates based on a series of pulse signals sent from the PWM drive circuit 48.

  As shown in FIG. 2, in the rotary shutter 45, the semicircular portion 45P corresponds to one field period (one field readout period) (1/60 seconds in the NTSC system). Each semicircular portion 45P includes an opening 45A that transmits illumination light and a light shielding portion 45B that blocks illumination light.

  The rotary shutter 45 makes one rotation in one frame period (one frame readout period) (1/30 seconds in the NTSC system), and the rotation of the rotary shutter 45 causes an opening 45A on the optical path of the illumination light emitted from the lamp 44. , The light shielding part 45B passes in order. As a result, the light blocking state for blocking the illumination light and the non-light blocking state for allowing the illumination light to pass are repeated twice in one frame period. That is, an exposure period and a light shielding period can be provided in one field period, and thereby the brightness of the image of the observation region can be adjusted in the same manner as the electronic shutter.

  Here, when a still image is displayed and stored, all pixel signals for one frame (obtained by one exposure) obtained from the illumination light that has passed through one opening 45A are read from the CCD image sensor 3. However, the rotary shutter 45 makes a half turn in one field period (1/60 seconds in the NTSC system). Therefore, when the other opening 45A moves on the optical path of the illumination light, or when the one opening 45A moves on the optical path of the illumination light, the opening 45A is blocked to block the illumination light. There is a need to. The chopper 49 is a mechanism that opens and closes the opening 45 </ b> A, that is, a light shielding unit that prevents light from entering the imaging surface of the CCD image sensor 3. The chopper 49 has a light blocking member 49B that blocks the illumination light emitted from the lamp 44. When blocking the illumination light, the chopper 49 operates so as to cover the opening 45A by the light blocking member 49B. In FIG. 3, the light shielding member 49 </ b> B is shown by a solid line when it is located at the retracted position where the illumination light is retracted (allows the illumination light to pass) and covers the opening 45 </ b> A (the illumination light is blocked). The light shielding member 49B when it is located at is indicated by a two-dot chain line.

  The chopper 49 is a pivot type DC solenoid that includes a DC solenoid (drive unit) 49A, and a plate-shaped light shielding member 49B that is a movable unit rotates about a shaft 49C. When the chopper 49 operates to block light, the opening of the rotary shutter 45 is covered with the tip 49D of the light blocking member 49B. The PWM drive circuit 48 is a drive circuit that drives a DC solenoid 49A (chopper 49), and outputs a pulse signal to the DC solenoid 49A. The PWM drive circuit 48 is a full-bridge driver, and outputs a series of two types of pulse signals to intermittently rotate (intermittently reciprocate) the light shielding member 49B in both forward and reverse directions.

  That is, when one pulse signal is sent from the PWM drive circuit 48 to the DC solenoid 49A, the operation of the DC solenoid 49A causes the light shielding member 49B to move to the light shielding position and be held at the light shielding position. Thereby, even if the opening 45A is located on the optical path of the illumination light, the opening 45A is covered by the light shielding member 49B and the illumination light is blocked.

  When the other pulse signal is sent from the PWM drive circuit 48 to the DC solenoid 49A, the operation of the DC solenoid 49A causes the light shielding member 49B to move to the retracted position and be held at the retracted position. Thereby, when the opening 45A is positioned on the optical path of the illumination light, the illumination light is irradiated to the observation site without being blocked.

Next, a case where a still image is displayed and stored will be described.
In the electronic endoscope apparatus 1, for example, when the freeze button 57 is pressed while a moving image is displayed on the monitor 6, all the frames for one frame obtained by one exposure from the CCD image sensor 3 are displayed. A pixel signal is output.

  At this time, as shown in FIG. 8, first, in the period (first period) A during which the pixel signal of the last odd field in the moving image is read, the imaging surface of the CCD image sensor 3 is scanned. Then, exposure is performed, and a pixel signal (signal) is generated in each photodiode 31 of the CCD image sensor 3. Note that the period A and the periods B, C, D, and E described later are all the same period, that is, one field period.

  Subsequently, all pixel signals for one frame obtained by the one-time exposure are read from the CCD image sensor 3 (all pixel reading is performed). That is, as described below, the first pre-correction pixel signal, the second pre-correction pixel signal, the first correction signal, and the second correction signal are sequentially read from the CCD image sensor 3.

  First, in a period (second period) B, the illumination light is blocked by the operation of the chopper 49 (a state where no light is incident on the imaging surface of the CCD image sensor 3). In other words, the signals from the photodiodes 31 in the odd-numbered rows and the photodiodes 31 in the even-numbered rows of the CCD image sensor 3 (in this embodiment, the photodiodes 31 in the odd-numbered rows) before the first correction. It reads out as a pixel signal (DATA_a), and obtains the first pre-correction pixel signal.

  Specifically, as shown in FIG. 9, among the pixel signals a, b, c, d, e, and f obtained by exposure, the pixel signal a in the first row a, the pixel signals c, 5 in the third row, The pixel signal e in the row is read as the first pre-correction pixel signal.

  This first pre-correction pixel signal is composed of the odd-numbered pixel signals accumulated in the period A and the noise component due to the odd-numbered dark current accumulated in the period A.

  Next, in the period (third period) C, a reading process similar to that of the above-described moving image is performed in a light-shielded state. That is, a signal is read from each photodiode 31 of the CCD image sensor 3, and signals read from two photodiodes 31 adjacent in the vertical direction are added to obtain a second pre-correction pixel signal (DATA_b).

  Specifically, as shown in FIG. 6, the pixel signal a + b obtained by adding the pixel signal a in the first row and the pixel signal b in the second row, the pixel signal c in the third row, and the fourth row A pixel signal c + d obtained by adding the pixel signal d of the second pixel, and a pixel signal e + f obtained by adding the pixel signal e of the fifth row and the pixel signal f of the sixth row is a second uncorrected pixel. Read out as a signal.

  Here, the odd-numbered pixel signals accumulated in the period A and the noise components due to the dark currents accumulated in the period A have already been read out in the period B. Therefore, the second pre-correction pixel signal includes the even-row pixel signal accumulated in the period A, the noise component due to the dark current accumulated in the period A, and all the pixels accumulated in the period B. It consists of noise components due to dark current.

  In the signal reading process in the period C, as shown in FIG. 7, the pixel signal b + c obtained by adding the pixel signal b in the second row and the pixel signal c in the third row, and the fourth row A pixel signal d + e obtained by adding the pixel signal d and the pixel signal e in the fifth row may be read out as the second pre-correction pixel signal.

  Next, in the period (fourth period) D, the first pre-correction pixel signal of the odd-numbered photodiodes 31 and the even-numbered photodiodes 31 of the CCD image sensor 3 is shielded in the light-shielded state. A signal is read as a first correction signal (DATA_c) from each photodiode 31 in the same row as the reading source (in this embodiment, an odd row), and the first correction signal is acquired.

  Specifically, as shown in FIG. 9, the pixel signal a in the first row, the pixel signal c in the third row, and the pixel signal e in the fifth row are read out as the first correction signal.

  This first correction signal is constituted by a noise component due to the dark current in the odd-numbered rows accumulated in the period C. Since the magnitude of the noise component due to the dark current depends on time and temperature, the noise component due to the dark current in the odd-numbered rows accumulated in this period C accumulates in the period A included in the first pre-correction pixel signal. It is equal to the noise component caused by the dark current in the odd-numbered rows.

  Next, in a period (fifth period) E, the illumination light is not blocked by the operation of the chopper 49 (a state in which light is incident on the imaging surface of the CCD image sensor 3). In other words, a signal is read out from each photodiode 31 of the CCD image sensor 3 so that the readout source photodiode 31 of the signal to be added is the same as the case where the second pre-correction pixel signal is acquired. Then, the signals read from the two photodiodes 31 adjacent in the vertical direction are added to obtain a second correction signal (DATA_d).

  Specifically, as shown in FIG. 6, the pixel signal a + b obtained by adding the pixel signal a in the first row and the pixel signal b in the second row, the pixel signal c in the third row, and the fourth row A pixel signal c + d obtained by adding the pixel signal d of the second row, and a pixel signal e + f obtained by adding the pixel signal e of the fifth row and the pixel signal f of the sixth row as the second correction signal. Read out.

  The second correction signal is composed of a noise component due to the even-numbered dark current accumulated in the period C and a noise component due to the dark current accumulated in all the pixels (odd and even-numbered rows) accumulated in the period D. . The noise component due to the dark current in the even-numbered row accumulated in the period C is equal to the noise component due to the dark current in the even-numbered row accumulated in the period A included in the second pre-correction pixel signal. The accumulated noise component due to the dark current of all pixels is equal to the noise component due to the dark current of all pixels accumulated in the period B included in the second pre-correction pixel signal.

  Note that when the signal reading process in the period C is performed as shown in FIG. 7, the signal reading process in the period C is similarly performed as shown in FIG.

  In the period E, the imaging surface of the CCD image sensor 3 is exposed to display subsequent moving images, and after displaying a still image, switching to moving image display is performed automatically or manually.

  As described above, the first pre-correction pixel signal, the second pre-correction pixel signal, the first correction signal, and the second correction signal are passed through the amplifier circuit 55 and the initial signal processing circuit 56, and then the processor side signal. It is sent to the processing circuit 42.

  The processor-side signal processing circuit 42 performs correction (dark current correction) on the first pre-correction pixel signal output from the initial signal processing circuit 56 using the first correction signal. Thereby, pixel signals in odd rows are obtained. Further, the second pre-correction pixel signal is corrected using the second correction signal. As a result, even row pixel signals are obtained.

  That is, in the correction of the first pre-correction pixel signal, the pixel signal in the odd-numbered row is obtained by subtracting the first correction signal from the first pre-correction pixel signal. Further, in the correction of the second pre-correction pixel signal, the pixel signal of even rows is obtained by subtracting the second correction signal from the second pre-correction pixel signal. In this way, the noise component due to the dark current contained in each of the odd row pixel signals and the even row pixel signals is removed.

  Note that the first correction signal and the second correction signal are not limited to the current still image, and the first correction pixel signal and the second correction pixel signal are corrected in each still image after the next time. It can also be used for correction. Thereby, it is possible to shorten the reading period of all the pixel signals for one frame obtained by one exposure in each still image after the next time, that is, the period of the light shielding state. In this case, the first pre-correction pixel signal (DATA_a) is read out in the period B shown in FIG. 8, the second pre-correction pixel signal (DATA_b) is read out in the period C, and the first pre-correction pixels in the subsequent periods D and E are read. Reading of the correction signal and the second correction signal is omitted. However, in the period C, the light is not blocked.

  As described above, according to the electronic endoscope apparatus 1, when all the pixel signals for one frame obtained by one exposure are read out from the CCD image sensor 3 which is a complementary color CCD image sensor, the pixels in odd rows are read out. The dark current correction can be reliably performed for each of the signal and the pixel signal in the even-numbered row. As a result, when displaying and storing a still image of the observation site, noise components due to dark current can be reliably removed from each of the odd-numbered pixel signal and the even-numbered pixel signal, thereby obtaining a good still image. Can do.

  Further, when displaying a moving image of an observation site, sensitivity can be increased as compared with the case where a so-called primary color CCD image sensor is used, and the readout time when reading out a pixel signal from the CCD image sensor 3 can be shortened. Can do.

Second Embodiment
FIG. 10 is a diagram for explaining reading of signals from the CCD image sensor in the second embodiment of the electronic endoscope apparatus of the present invention, and FIG. 11 is a second embodiment of the electronic endoscope apparatus of the present invention. It is a figure which shows typically the CCD image sensor for demonstrating reading of the signal from the CCD image sensor.

  Hereinafter, the second embodiment will be described with a focus on the differences from the first embodiment described above, and the description of the same matters will be omitted.

  In the electronic endoscope apparatus 1 according to the second embodiment, the period up to the period (fourth period) D is the same as in the first embodiment. In the period (fifth period) E, the second correction signal (DATA_d) is acquired in the same manner as when the second pre-correction pixel signal is acquired in a light-shielded state.

  Then, in the period (sixth period) F, in the non-light-shielding state, the odd-numbered photodiodes 31 and the even-numbered photodiodes 31 of the CCD image sensor 3 before the first correction. A signal is read out as a third correction signal (DATA_c) from each photodiode 31 in a row different from the pixel signal (first correction signal) from which the pixel signal (first correction signal) is read out, and the third correction signal is obtained. get. The period F is the same period as each of the periods A, B, C, D and E, that is, one field period.

  Specifically, as shown in FIG. 11, the pixel signal b on the second row, the pixel signal d on the fourth row, and the pixel signal f on the sixth row are read out as the third correction signal.

  This third correction signal is composed of noise components due to the dark current in the even-numbered rows accumulated in the period E.

  As described above, the first pre-correction pixel signal, the second pre-correction pixel signal, the first correction signal, the second correction signal, and the third correction signal are supplied to the amplifier circuit 55 and the initial signal processing circuit 56, respectively. Then, it is sent to the signal processing circuit 42 on the processor side.

  In the processor side signal processing circuit 42, a correction signal for a moving image is created based on the first correction signal and the third correction signal output from the initial signal processing circuit 56. Therefore, the processor-side signal processing circuit 42 constitutes a main part of correction signal generation means for generating a correction signal for moving images.

  The moving image correction signal (odd field correction signal) used when correcting the pixel signal in the odd field adds the noise component due to the dark current in the first row and the noise component due to the dark current in the second row. Addition of adding noise component due to dark current in line 3 and noise component due to dark current in line 4 and adding noise component due to dark current in line 5 and noise component due to dark current in line 6 It is created by processing the following lines.

  The correction signal for moving image (correction signal for even field) used when correcting the pixel signal in the even field includes a noise component due to the dark current in the second row and a noise component due to the dark current in the third row. Add the noise component due to the dark current in the fourth row and the noise component due to the dark current in the fifth row, and add the noise component due to the dark current in the sixth row and the noise component due to the dark current in the seventh row. Such addition processing is also performed for the following lines.

  Then, the processor-side signal processing circuit 42 performs dark current correction on the pixel signal before correction of the odd field output from the initial signal processing circuit 56 using the correction signal for the odd field, so that the odd field is corrected. A pixel signal is generated. Similarly, the processor-side signal processing circuit 42 performs dark current correction on the pixel signal before the even-field correction using the even-field correction signal, thereby generating an even-field pixel signal.

  That is, in the correction of the pixel signal before correction of the odd field, the pixel signal of the odd field is obtained by subtracting the correction signal for the odd field from the pixel signal. In the correction of the pixel signal before correction of the even field, the pixel signal of the even field is obtained by subtracting the correction signal for the even field from the pixel signal. In this way, noise components due to dark current contained in each of the odd-field pixel signal and the even-field pixel signal are removed.

  As in the first embodiment, the first correction signal and the second correction signal are respectively used for correcting the first pre-correction pixel signal and the second pre-correction pixel signal in each still image. Is done. Further, the correction signal for the odd field and the correction signal for the even field are used for correcting the pixel signal before correction of the odd field and the correction of the pixel signal before correction of the even field, respectively, in each moving image.

According to the electronic endoscope apparatus 1, the same effects as those of the first embodiment described above can be obtained.
In the electronic endoscope apparatus 1, when a moving image of an observation site is displayed, noise components due to dark current can be reliably removed from each of the odd-field pixel signal and the even-field pixel signal. Can be obtained.

<Third Embodiment>
FIG. 12 is a view for explaining reading of signals from the CCD image sensor in the third embodiment of the electronic endoscope apparatus of the present invention.

  Hereinafter, the third embodiment will be described with a focus on the differences from the first embodiment described above, and description of similar matters will be omitted.

  In the electronic endoscope apparatus 1 of the third embodiment, the period up to the period (fourth period) D is the same as that of the first embodiment. In the period (fifth period) E, the second correction signal (DATA_d) is acquired in the same manner as when the second pre-correction pixel signal is acquired in a light-shielded state.

  Then, in a period (sixth period) F, a signal that is added to a case where a signal is read from each photodiode 31 of the CCD image sensor 3 in a light-shielded state and the second pre-correction pixel signal is acquired. The signals read from the two photodiodes 31 adjacent in the vertical direction are added to obtain the third correction signal (DATA_e). A period F and a period G described later are the same period as each of the periods A, B, C, D, and E, that is, one field period.

  Specifically, as shown in FIG. 6, the pixel signal a + b obtained by adding the pixel signal a in the first row and the pixel signal b in the second row, the pixel signal c in the third row, and the fourth row A pixel signal c + d obtained by adding the pixel signal d of the second pixel, and a pixel signal e + f obtained by adding the pixel signal e of the fifth row and the pixel signal f of the sixth row as a third correction signal. Read out.

  The third correction signal is composed of a noise component due to dark current accumulated in the period E corresponding to the pixel signal in the odd field.

  Next, in a period (seventh period) G, a signal is read from each photodiode 31 of the CCD image sensor 3 in a non-light-shielding state, and the second pre-correction pixel signal (third correction signal) is acquired. The signals read from the two adjacent photodiodes 31 in the vertical direction are added so that the readout source photodiodes 31 of the signals to be added are shifted one row at a time, and a fourth correction signal (DATA_f) is added. To get.

  Specifically, as shown in FIG. 7, the pixel signal b + c obtained by adding the pixel signal b in the second row and the pixel signal c in the third row, the pixel signal d in the fourth row, and the fifth row. A pixel signal d + e obtained by adding the pixel signal e is read out as a fourth correction signal.

  The fourth correction signal is composed of a noise component due to dark current accumulated in the period F corresponding to the pixel signal in the even field.

  As described above, the first pre-correction pixel signal, the second pre-correction pixel signal, the first correction signal, the second correction signal, the third correction signal, and the fourth correction signal are the amplification circuit 55 and The signal is sent to the processor side signal processing circuit 42 via the initial signal processing circuit 56.

  In the processor-side signal processing circuit 42, the third correction signal and the fourth correction signal output from the initial signal processing circuit 56 are used as correction signals for moving images. The third correction signal is used when correcting pixel signals in the odd field, and the fourth correction signal is used when correcting pixel signals in the even field.

  That is, the processor-side signal processing circuit 42 performs correction (dark current correction) on the pixel signal before correction of the odd field output from the initial signal processing circuit 56 by using the third correction signal, and the odd field. The pixel signal is obtained. Further, the pixel signal before correction of the even field is corrected using the fourth correction signal, and the pixel signal of the even field is obtained.

  More specifically, in the correction of the pixel signal before correction of the odd field, the pixel signal of the odd field is obtained by subtracting the third correction signal from the pixel signal. In the correction of the pixel signal before correction of the even field, the pixel signal of the even field is obtained by subtracting the fourth correction signal from the pixel signal. In this way, the noise component due to the dark current contained in each of the odd-field pixel signal and the even-field pixel signal is removed.

  As in the first embodiment, the first correction signal and the second correction signal are used for correcting the first pre-correction pixel signal and the second pre-correction pixel signal in each still image, respectively. Is done. The third correction signal and the fourth correction signal are used for correcting the pixel signal before correction of the odd field and the correction of the pixel signal before correction of the even field in each moving image, respectively.

According to the electronic endoscope apparatus 1, the same effects as those of the first embodiment described above can be obtained.
In the electronic endoscope apparatus 1, when a moving image of an observation site is displayed, noise components due to dark current can be reliably removed from each of the odd-field pixel signal and the even-field pixel signal. Can be obtained.

  In the present invention, in the period F, the fourth correction signal ((4) is set so that the photodiodes 31 from which the signals to be added are shifted one row at a time with respect to the case where the second pre-correction pixel signal is acquired. DATA_f), and then in the period G, the third correction signal (in the period G is set so that the readout source photodiode 31 of the signal to be added is the same as in the case of acquiring the second pre-correction pixel signal. DATA_e) may be acquired.

<Fourth embodiment>
FIG. 13 is a flowchart showing a control operation in the fourth embodiment of the electronic endoscope apparatus of the present invention.

  Hereinafter, the fourth embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.

  In the electronic endoscope device 1 according to the fourth embodiment, when the freeze button 57 is pressed, a process for estimating (discriminating) whether or not to perform appropriate dark current correction is performed, and appropriate dark current correction is performed. Only when it is possible to perform dark current correction.

  The reason is as follows. That is, when all the pixels are read out by blocking the illumination light outside the body without inserting the distal end portion (CCD image sensor 3) of the video scope 5 into the body, the external light (indoor illumination etc.) is emitted from the CCD image sensor. This is because the light enters the image pickup surface 3 and is not completely shielded from light.

  In view of this, in the electronic endoscope apparatus 1, with the illumination light blocked, the imaging surface of the CCD image sensor 3 is exposed, a pixel signal is obtained from the CCD image sensor 3, and the magnitude of the pixel signal is obtained. Based on this, it is determined whether or not an appropriate correction signal can be obtained.

Next, the operation of the electronic endoscope apparatus 1 will be described based on FIG.
When the freeze button 57 is pressed, the program shown in FIG. 13 is executed. First, the pixel signal is discharged from the CCD image sensor 3, and the chopper 49 is operated to turn off the illumination light (step S101).

  Next, when the same time as the exposure time elapses, the first correction signal (DATA_c) is read from the CCD image sensor 3 and acquired (step S102). In step S102, the second correction signal (DATA_d) may be read and acquired.

  Next, it is determined whether or not the data value carried by the first correction signal (DATA_c) is equal to or less than a predetermined threshold value α (step S103). The threshold value α is preferably set to a maximum value that can be considered as a dark current level, for example, a value within a range of about 95 to 105% of the signal level, and a value within a range of about 99 to 101%. It is more preferable to set to. The value of the dark current can be known as the performance unique to the sensor.

  When the data value carried by the first correction signal (DATA_c) is equal to or less than the threshold value α, dark current correction is performed (step S104).

  On the other hand, when the data value carried by the first correction signal (DATA_c) exceeds the threshold value α, dark current correction is not performed (step S105).

According to the electronic endoscope apparatus 1, the same effects as those of the first embodiment described above can be obtained.
And in this electronic endoscope apparatus 1, it can prevent degrading the quality of an image by performing dark current amendment using an improper amendment signal.

  The fourth embodiment can also be applied to the second and third embodiments.

  As described above, the imaging apparatus and the electronic endoscope apparatus according to the present invention have been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each unit is an arbitrary function having the same function. It can be replaced with that of the configuration. In addition, any other component may be added to the present invention.

  Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments.

  In the above-described embodiment, a mechanism having a light blocking member that blocks light emitted from the light source is used as the light blocking unit. However, the present invention is not limited to this, and, for example, enters the imaging surface of the solid-state image sensor. A mechanism having a light blocking member that blocks light may be used.

  In the embodiment, the case where the complementary color CCD image sensor is used as the solid-state image sensor has been described. However, the present invention is not limited to this, and other solid-state image sensors that operate in the same manner as the complementary color CCD image sensor are used. Also good.

  In the above-described embodiment, the case where the imaging apparatus of the present invention is applied to an electronic endoscope apparatus has been described. However, the use of the imaging apparatus of the present invention is not particularly limited. The present invention can be applied to various devices including a solid-state imaging device such as a video camera, a digital camera, and a mobile phone.

1 Electronic Endoscope 3 CCD Image Sensor 31 Photodiode 32 Vertical Transfer CCD Register 321 CCD
33 Horizontal transfer CCD register 34 Charge / voltage conversion unit 35 Complementary color filter 4 Processor 41 System control circuit 42 Processor side signal processing circuit 43 Lamp control unit 44 Lamp 45 Rotary shutter 45A Aperture 45B Light shielding unit 45P Semicircular unit 46 Condensing lens 47 motor driver 48 PWM drive circuit 49 chopper 49A DC solenoid 49B light shielding member 49C shaft 49D tip 5 video scope 51A incident end 51B emission end 51 light guide 52 scope controller 53 timing control circuit 54 CCD driver 55 amplification circuit 56 initial signal processing circuit 57 Freeze Button 6 Monitor S101-S105 Step

Claims (7)

A solid-state imaging device having a plurality of photoelectric conversion elements that constitute pixels on the imaging surface aligned in the vertical direction and the horizontal direction;
When signals obtained by receiving light by two photoelectric conversion elements adjacent in the vertical direction are added and output, and signals obtained by receiving light by odd-numbered photoelectric conversion elements and by even-numbered photoelectric conversion elements A pixel signal generating means for selecting one of the signals obtained by receiving light and outputting the signal from the solid-state imaging device; and
Correction means for correcting a signal output from the solid-state imaging device;
Light shielding means for preventing light from entering the imaging surface of the solid-state imaging device,
When outputting all pixel signals obtained by one exposure from the solid-state imaging device, in the first period, the imaging surface of the solid-state imaging device is exposed,
In the second period having the same length as the first period after the first period, the pixel signal generation is performed in a state where light is not incident on the imaging surface of the solid-state imaging device by the operation of the light shielding unit. Means for reading out and obtaining a signal as a first pre-correction pixel signal from one of the photoelectric conversion elements in the odd-numbered rows and the photoelectric conversion elements in the even-numbered rows of the solid-state imaging device;
In the third period having the same length as the second period after the second period, the pixel signal generation is performed in a state where light is not incident on the imaging surface of the solid-state imaging device by the operation of the light shielding unit. Means for reading a signal from each photoelectric conversion element of the solid-state imaging device, adding the signals read from two photoelectric conversion elements adjacent in the vertical direction, and obtaining a second pre-correction pixel signal;
In the fourth period having the same length as the third period after the third period, the pixel signal generation is performed in a state where light is not incident on the imaging surface of the solid-state imaging device by the operation of the light shielding unit. By means of each of the photoelectric conversion elements in the odd-numbered rows and the photoelectric conversion elements in the even-numbered rows of the solid-state imaging device, the photoelectric conversion elements in the same row as the reading source of the first pre-correction pixel signal Reading out and acquiring the signal as the first correction signal;
After the fourth period, in the fifth period having the same length as the fourth period, the pixel signal generation unit reads a signal from each photoelectric conversion element of the solid-state imaging element, and the second period The signal read from the two photoelectric conversion elements adjacent in the vertical direction is added so that the photoelectric conversion element from which the signal to be added is read is the same as when the pre-correction pixel signal is acquired. , Obtain a second correction signal,
The correction means corrects the first pre-correction pixel signal using the first correction signal, obtains one of an odd-numbered pixel signal and an even-numbered pixel signal, and outputs the second correction signal. The imaging apparatus is configured to correct the second pre-correction pixel signal to obtain the other of the odd row pixel signal and the even row pixel signal. A correction signal creating means for creating a correction signal for a moving image;
When outputting all the pixel signals obtained by one exposure from the solid-state imaging device, in the fifth period, the light shielding means is operated so that light does not enter the imaging surface of the solid-state imaging device,
After the fifth period, in the sixth period having the same length as the fifth period, the pixel signal generation means causes the photoelectric conversion elements in the odd-numbered rows of the solid-state imaging elements and the photoelectric conversion elements in the even-numbered rows to Among each photoelectric conversion element, a signal is read and acquired as a third correction signal from each photoelectric conversion element in a row different from the read source of the first pre-correction pixel signal,
The imaging apparatus according to claim 1, wherein the correction signal generating unit is configured to generate a correction signal for a moving image based on the first correction signal and the third correction signal. When outputting all pixel signals obtained by one exposure from the solid-state imaging device, in the sixth period having the same length as the fifth period after the fifth period and the fifth period. Is in a state in which light does not enter the imaging surface of the solid-state imaging device by the operation of the light shielding means,
In one of the sixth period and the seventh period having the same length as the sixth period after the sixth period, each photoelectric conversion of the solid-state imaging device is performed by the pixel signal generation unit. Two photoelectric conversions adjacent in the vertical direction so that the signal from which the signal is read out and the second pre-correction pixel signal is acquired are the same as the photoelectric conversion element from which the signal is added. Adding the signals read from the elements to obtain a third correction signal;
In the other of the sixth period and the seventh period, the pixel signal generation unit reads out signals from the photoelectric conversion elements of the solid-state image sensor and acquires the second pre-correction pixel signal. The signals read from the two photoelectric conversion elements adjacent in the vertical direction are added so that the photoelectric conversion elements from which the signals to be added are shifted one row at a time, and a fourth correction signal is added. Get
The imaging apparatus according to claim 1, wherein the third correction signal and the fourth correction signal are used as a correction signal for a moving image.   The correction of the first pre-correction pixel signal is to subtract the first correction signal from the first pre-correction pixel signal, and the correction of the second pre-correction pixel signal is the second correction The imaging apparatus according to claim 1, wherein the second correction signal is subtracted from a pre-correction pixel signal.   The solid-state imaging device is a CCD image sensor in which a complementary color filter in which a yellow color element, a cyan color element, a magenta color element, and a green color element are arranged in a checkered pattern is provided on the imaging surface. Item 5. The imaging device according to any one of Items 1 to 4.   The imaging apparatus according to claim 1, wherein the light shielding unit includes a light shielding member that blocks light incident on an imaging surface of the solid-state imaging device or a light shielding member that blocks light emitted from a light source. An imaging device according to any one of claims 1 to 6;
An electronic endoscope apparatus comprising: a light source that emits illumination light that illuminates a subject.

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