JP2015119762A - Imaging system, and endoscope apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging system capable of acquiring a smooth moving image with high quality while preventing images due to a plurality of kinds of illumination light from being mixed in each frame image in the case of generating a moving image from a frame image picked up in a surface sequential system by using illumination light that lights intermittently, and to provide an endoscope apparatus.SOLUTION: An imaging system generates a moving image by a MOS type imaging element with a plurality of pixels two-dimensionally arranged. An illumination part is driven, having a radiation possible period and a radiation inhibition period of illumination light, and irradiates a plurality of kinds of illumination light switchingly every radiation possible period. An imaging part images a subject in each illumination light and surface sequentially outputs an image signal. An image processing part performs synthetic processing of a set of image signals picked-up under illumination light different from each other to generate one frame of a moving image. The imaging part simultaneously starts to expose respective pixel lines, exposes a period including the radiation possible period, and reads accumulated electric charge within the radiation inhibition period.

Description

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

  2. Description of the Related Art CCD (Charge Coupled Device) type image pickup devices are widely used in electronic devices and endoscope devices having an image pickup function such as digital cameras and video cameras. In recent years, MOS type image sensors such as CMOS (Complementary Metal Oxide Semiconductor) sensors that can be driven at a low voltage and are advantageous for downsizing have come to be used frequently instead of CCD type image sensors. For example, Patent Documents 1 and 2 disclose examples in which a MOS type image pickup device is mounted on an endoscope apparatus, and Patent Document 3 discloses an example in which a MOS type image pickup element is mounted on a digital camera.

JP 2011-206336 A JP 2009-136447 A JP 2007-318581 A

  In general, a MOS type image pickup device reads signal charges accumulated in each pixel by a method called rolling shutter (line exposure). In the rolling shutter system, the shutter is cut for each pixel line, and signal charges accumulated in each pixel are sequentially read for each pixel line. For this reason, a time difference of about one frame occurs in the charge accumulation period between the first pixel line read out first and the last pixel line read out last, and the captured image is captured when the subject moves quickly. Will be distorted. Therefore, in Patent Document 1, image distortion is eliminated by supplying a reset signal to all the pixel lines and matching the exposure periods of all the pixel lines. In Patent Document 2, image distortion is eliminated by performing signal charge reading of each pixel line during the light-out period of the light source unit. Japanese Patent Application Laid-Open No. 2004-228688 discloses a technique for eliminating the difference in exposure time between pixel lines by PWM driving illumination light to make the integrated light reception amount of each pixel line constant.

  By the way, when a moving image is generated from a frame image captured by the frame sequential method using illumination light that is intermittently lit, a plurality of types of illumination light are switched and emitted for each frame period. At that time, depending on the illumination light switching pattern, an image captured by the illumination light before switching and an image captured by the illumination light after switching may be mixed in one frame image. For example, when the illumination light is a light that switches between red light, green light, and blue light, a color-shifted image in which images of a plurality of colors are mixed in one frame image is deteriorated, and the quality of a color moving image captured in a frame sequential manner is degraded To do.

  Therefore, the present invention prevents a mixture of images from a plurality of types of illumination light in an image based on an image signal when generating a moving image from an image signal captured in a frame sequential manner using illumination light that is intermittently lit. It is another object of the present invention to provide an imaging system and an endoscope apparatus that can obtain a smooth and high-quality moving image.

(1) An imaging system that generates a moving image using a MOS type imaging device in which a plurality of pixels are two-dimensionally arranged.
An illumination unit that is driven to have a period in which illumination light can be emitted and a period in which emission is prohibited, and that illuminates a subject by switching a plurality of types of illumination light having different spectra for each of the above-described possible emission periods;
An imaging unit that images the subject with the imaging element for each illumination light to be switched and outputs an image signal in a surface sequential manner;
An image processing unit that synthesizes a set of image signals captured from different illumination lights output from the imaging unit and generates one frame of the moving image;
With
The imaging unit simultaneously starts exposure of the pixel lines arranged in the horizontal direction of the imaging device, exposes the plurality of pixels in a period including a period during which the illumination light can be emitted, and within the illumination light emission prohibited period. An imaging system that reads accumulated charges from the plurality of pixels.
(2) An endoscope apparatus including the imaging system.

  According to the present invention, when a moving image is generated from an image signal picked up in a frame sequential manner using illumination light that is intermittently lit, it is possible to prevent images from a plurality of types of illumination light from being mixed in the image based on the image signal. However, a smooth and high-quality moving image can be obtained.

It is a figure for demonstrating embodiment of this invention, and is a block block diagram of an endoscope apparatus. It is an external view as an example of the endoscope apparatus shown in FIG. It is an expansion perspective view of an endoscope front-end | tip part. (A), (B) is a block diagram which shows the specific structural example of a light source part. It is a timing chart which shows the 1st example of a drive of an imaging system. 12 is a timing chart illustrating a second driving example of the imaging system. It is a timing chart which shows the 3rd example of a drive of an imaging system. 12 is a timing chart illustrating a fourth driving example of the imaging system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, an imaging system mounted on an endoscope apparatus will be described as an example.
<Configuration of endoscope apparatus>
FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a block configuration diagram of an endoscope apparatus. FIG. 2 is an external view as an example of the endoscope apparatus shown in FIG.
First, the configuration of the endoscope apparatus 100 will be described with reference to FIGS. The endoscope apparatus 100 includes an endoscope scope 11, a control device 13, a display unit 15, and an input unit 17 such as a keyboard and a mouse for inputting information to the control device 13. The control device 13 includes a light source device 19 that outputs illumination light and a processor 21 that performs signal processing of an observation image.

<Endoscope>
As shown in FIG. 2, the endoscope scope 11 includes a main body operation unit 23, an endoscope insertion unit 25 connected to the main body operation unit 23 and inserted into a body cavity, and the main body operation unit 23 as a control device. 13 and a universal cord 27 for connecting to the mobile phone. A light guide (LG) connector 29 </ b> A connected to the light source device 19 and a video connector 29 </ b> B connected to the processor 21 are provided at the end of the universal cord 27 opposite to the main body operation unit 23.

  The main body operation unit 23 of the endoscope scope 11 includes a button for performing suction, air supply, and water supply at the distal end side of the endoscope insertion unit 25, a shutter button at the time of imaging, and an observation mode (normal observation that emits white light). A variety of operation input units 31 including a mode switching button for switching the operation mode of the imaging unit 51, which will be described in detail later, and a pair of angle knobs 33. ing.

  The insertion portion 25 is composed of a flexible portion 35, a bending portion 37, and a distal end portion (endoscope distal end portion) 39 in order from the main body operation portion 23 side. The distal end portion 39 has an imaging unit 51 (see FIG. 1) which will be described later. The bending portion 37 is remotely bent by turning the angle knob 33 of the main body operation portion 23. Thereby, the endoscope front end 39 can be directed in a desired direction.

  FIG. 3 shows an enlarged perspective view of the distal end portion of the endoscope. An observation window 41 and illumination windows 43A and 43B are arranged at the endoscope distal end 39. Each of the illumination windows 43A and 43B emits illumination light toward the subject. Reflected light from the subject is detected (imaged) by the imaging unit 51 through the observation window 41.

  As shown in FIG. 1, an emission end 45 a of a light guide 45 that guides illumination light emitted from the light source device 19 is disposed inside the illumination windows 43 </ b> A and 43 </ b> B. An optical member such as a lens or a light diffusing member may be disposed between the emission end 45a of the light guide 45 and the illumination windows 43A and 43B. In some cases, the phosphor may be disposed at the emission end 45a. The illumination windows 43A and 43B, the light guide 45, and the light source device 19 function as an illumination unit that generates illumination light.

  The imaging unit 51 illustrated in FIG. 1 includes a pixel unit 53, an ADC unit 55, a memory unit 57, a communication unit 59, and a drive control unit 61. The pixel portion 53 is formed by arranging a large number of pixels (light receiving elements: photodiodes (PD)) in a two-dimensional array on a MOS type semiconductor. The pixel portion 53 is driven by a rolling shutter system in which a plurality of pixel lines including pixel groups arranged in the row direction are arranged in the column direction, and signal reading is performed for each pixel line. The rolling shutter system is a system in which an exposure operation is sequentially performed for at least one scanning line or pixel, that is, a reset is sequentially performed for each scanning line or pixel, charge accumulation is started, and the accumulated signal charge is read. It is.

  The pixel unit 53 of this configuration is a single-color light receiving element group that captures an image in which R, G, and B illumination lights are sequentially irradiated from a light source unit described later.

  The ADC unit 55 includes a correlated double sampling (CDS) circuit, an amplifier unit, and an A / D converter. The CDS circuit performs correlated double sampling processing on the imaging signal output from each pixel of the pixel unit 53 and removes reset noise and amplifier noise generated in the pixel unit 53.

  The amplifier unit amplifies the imaging signal from which noise has been removed by the CDS circuit with a designated gain (amplification factor). The A / D converter converts the imaging signal amplified by the amplifier unit into a digital signal having a predetermined number of bits and outputs the digital signal.

  The memory unit 57 includes a FIFO memory that is a buffer memory advantageous for high-speed access. The FIFO memory temporarily stores digital data output from the ADC unit, and the stored digital data is output to the communication unit 59 as a frame image signal.

  The communication unit 59 includes an LVDS (Low voltage differential signaling) conversion circuit, sequentially reads image information of frame image signals stored in the memory unit 57, converts the read image information into a low voltage differential signal, and converts the image information into a processor. Forward to 21.

  The drive control unit 61 has a drive circuit including a TG (timing generator), and drives and controls each unit. The drive circuit generates various drive pulses based on a drive signal from a drive signal communication unit 71 of the processor 21 described later. The drive pulse includes a drive pulse (vertical / horizontal scanning pulse, reset pulse, etc.) of the pixel unit 53, a synchronization pulse for the ADC unit 55, a drive pulse of the memory unit 57, and the like. The pixel unit 53 is driven by the drive pulse input from the drive control unit 61, photoelectrically converts the formed optical image, and outputs it as an imaging signal.

  The pixel unit 53, the ADC unit 55, the memory unit 57, the communication unit 59, and the like may not be formed on one chip, but may be formed on separate chips and interconnected to form an imaging unit. . Further, the memory unit 57 and the communication unit 59 may be arranged at a position away from the pixel unit 53 as long as it is within the endoscope scope 11.

<Processor>
The processor 21 supplies power to the endoscope scope 11 via a signal line inserted into the universal cord 27 shown in FIG. 1 and controls the driving of the imaging unit 51. In addition, the imaging signal transmitted from the imaging unit 51 via the signal line is received, and the received imaging signal is subjected to various signal processing to be converted into image data.

  The image data converted by the processor 21 is displayed as an observation image on a display unit 15 such as a liquid crystal monitor connected to the processor 21 by a cable. The processor 21 controls the operation of the entire endoscope apparatus 100 including the light source device 19. The display unit 15 is not limited to a display device provided outside the processor 21, and may have various forms such as a unit integrated with the processor 21 or the endoscope scope 11.

  The processor 21 includes a control unit 63, an image reception unit 65, an image processing unit (DSP) 67, a display signal generation unit 69, and a drive signal communication unit 71.

  The control unit 63 controls each unit in the processor 21 and outputs a drive signal to the imaging unit 51 of the endoscope scope 11 and the light source device 19 described later to control the entire endoscope device 100. The control unit 63 includes a RAM and a ROM in which various programs for controlling the operation of the processor 21 and various data such as control data are stored.

  Specifically, the control unit 63 has a function of controlling the light source control unit 73 of the light source device 19 and a function of controlling the imaging unit 51 to generate a frame image, and emission of illumination light by the light source device 19. The operation, the exposure of the image sensor, and the signal readout operation are synchronized with each other to drive the light source control unit 73 and the imaging unit 51 of the illumination unit.

  The image receiving unit 65 receives the frame image signal transmitted from the endoscope scope 11 and outputs it to the image processing unit 67.

  Based on the control of the control unit 63, the image processing unit 67 performs color interpolation, color separation, color balance adjustment, white balance correction, gamma correction, image enhancement processing, and the like on the imaging signal received by the image receiving unit 65. Generate a frame image. In addition, the frame images sequentially captured under a plurality of illumination lights are combined to generate a combined image signal of a moving image.

  The display signal generation unit 69 converts the image data input from the image processing unit 67 into a signal format corresponding to the display unit 15 and displays the converted signal on the screen of the display unit 15.

  The input unit 17 receives various instruction inputs from the user, and also receives an instruction input for selecting or switching the above-described observation mode and the operation mode of the imaging unit 51 described later in detail.

<Light source device>
The light source device 19 includes a light source control unit 73 and a light source unit 75, and functions as an illumination device in combination with the light guide 45 and the illumination windows 43A and 43B described above. The light source unit 75 sequentially emits a plurality of illumination lights having different spectra at a predetermined timing. A specific configuration example of the light source unit 75 is shown in FIGS. 4A includes a red light emitting laser light source 77R, a green light emitting laser light source 77G, a blue light emitting laser light source 77B, and a half mirror 79R that changes the optical paths of the red laser light and the green laser light. 79G. In addition, it may replace with a half mirror and the structure using combiners, such as a combiner, may be sufficient.

  Each of the laser light sources 77R, 77G, and 77B is individually turned on at different timings on the time axis by being subjected to pulse modulation control such as pulse width modulation (PWM) by the light source control unit 73 (FIG. 1). Laser light from each of the laser light sources 77R, 77G, and 77B is sequentially introduced into the light guide 45 and provided as surface-sequential illumination light.

  The light source unit 75A may be configured to use other semiconductor light sources such as LEDs instead of the laser light sources 77R, 77G, and 77B.

  Furthermore, the light source part 75 can also be comprised using a white light source besides said laser light source. The light source unit 75B shown in FIG. 4B is a white light source 79 such as a xenon lamp, a halogen lamp, or a metal halide lamp, and a shutter that is disposed in the path of the emitted light from the white light source, and controls the on / off control and light amount control of the emitted light. 81 and a rotary filter 85 having a plurality of spectral filters 83A, 83B,... Having different wavelength bands of transmitted light.

  The spectral filter of the rotary filter 85 includes a spectral filter that transmits only R light, a spectral filter that transmits only G light, a spectral filter that transmits only B light, a combination of R, G, B and white W, A combination of three colors of complementary colors C, M, and Y, or a combination of four colors of C, M, Y, and G may be used. In addition, a configuration equipped with a spectral filter that emits light of two narrow-band wavelengths (390 to 445 nm / 530 to 550 nm) that is easily absorbed by hemoglobin in blood for the special light observation mode of the endoscope apparatus It is good.

  In the light source unit 75B, the rotary filter 85 is driven to rotate by the motor M, and the emission timing is controlled by the shutter 81, so that the white light emitted from the white light source 79 is illuminated for each color of R, G, B light. The light is emitted sequentially.

  When observing the inside of a body cavity with the endoscope apparatus 100 having the above-described configuration, the insertion portion 25 of the endoscope scope 11 is inserted into the body cavity, and imaging is performed while illuminating the inside of the body cavity with pulse illumination light from the light source device 19. The image in the body cavity imaged by the unit 51 is observed on the display unit 15.

Next, driving examples of the imaging system provided in the endoscope apparatus 100 will be sequentially described. The imaging system of the endoscope apparatus 100 performs driving of illumination light and driving of an imaging element, which will be described below, by an operation input from the operation input unit 31 of the endoscope scope 11 or the input unit 17 connected to the processor 21. Switch. Further, it may be switched automatically in synchronization with the observation mode switching timing.
<First driving example>
FIG. 5 is a timing chart illustrating a first driving example of the imaging system. The endoscope apparatus 100 having this configuration is configured to perform imaging and image display at a frame rate of 60 frames / second. Therefore, in the following description, the frame rate is described as 60 frames / second, but the present invention is not limited to this.

  The control unit 63 outputs to the light source control unit 73 an illumination drive signal for sequentially emitting a plurality of colors of illumination light from the light source device 19 to the light source control unit 73, and an imaging drive signal for sequentially capturing the subject images illuminated for each color. Is output to the drive control unit 61.

  A period in which an image signal of one captured image is generated by one imaging of the pixel unit 53 by the drive control unit 61 is defined as one frame period, and signal charges are accumulated by photoelectric conversion in each pixel within this one frame period. An exposure period for reading out and a readout period for reading out the accumulated charge from each pixel.

  The light source unit 75 is driven intermittently by the light source control unit 73. Within one frame period, an illumination light can be emitted (shown as enable) and an emission prohibited period (shown as disable). Driven with.

  The control unit 63 exposes each pixel in a period including the illumination light irradiable period, and reads the accumulated charge from each pixel within the illumination light emission prohibition period. That is, the light source device 19 and the imaging unit 51 are controlled so that the illumination light can be emitted and the signal charge readout period overlap to prevent color mixing.

  That is, the period from the signal charge read start timing of the last line in the pixel unit 53 to the signal charge read start timing of the first line of the next frame is defined as a period in which illumination light can be emitted. The exposure period of each pixel line is different for driving by the rolling shutter system, but illumination light may be emitted during this emission possible period.

  The imaging unit 51 has an electronic shutter function, and the drive control unit 61 sets the exposure period start timing by global reset of each pixel line by the electronic shutter. Specifically, the control unit 63 simultaneously outputs reset signals to the pixel lines of the pixel unit 53 in each frame period, so that each pixel line starts exposure simultaneously. Thus, by setting the exposure start timing with the electronic shutter, the exposure amount of each pixel can be arbitrarily set, and the optimal exposure amount adapted to the brightness of the illumination light and the intensity of the reflected light from the subject can be set.

  The exposure start timing may be set before the illumination light emission start timing. In this case, the illumination light emission start timing can be set to the exposure start timing without using an electronic shutter.

  As shown in the figure, the control unit 63 emits the illumination light as red light in the first frame, green light in the second frame, and blue light in the third frame during each emission possible period. In the fourth frame, the control unit 63 emits red light, and the image processing unit 67 performs synthesis processing using the R, G, and B image signals of the first, second, and third frames as a set, and one color image. A composite image signal is generated.

  In the fifth frame, the control unit 63 emits green light, and the image processing unit 67 replaces the R image signal generated in the fourth frame with the image signal of the first frame set as described above. The second frame G image signal, the third frame B image signal, and the fourth frame R image signal are updated to a set, and the updated set of image signals is combined into a single color image. A composite image signal is generated. In the same manner, a synthesized image signal of a color image is generated for each frame, and a moving image is generated using this as a frame signal.

  According to this driving method, a moving image of 60 frames / second is obtained in a pseudo manner. In addition, it is possible to prevent color shift of the generated moving image without mixing images with different illumination lights in each frame image. As a result, a high-quality moving image that is smooth and has no color shift can be displayed on the display unit 15. For example, even in a system where the signal transmission rate cannot be increased, such as an endoscope device in which the imaging unit and image processing unit are connected by a long cable, a moving image with high image continuity is generated. Can be performed and the accuracy of diagnostic imaging is not reduced.

  In addition, the order of emission of each of the above illumination lights (red light, green light, blue light) is an example, and other orders may be used.

<Second driving example>
FIG. 6 is a timing chart illustrating a second driving example of the imaging system. In the first driving example, R, G, B, R, G, B,... And illumination light are sequentially emitted sequentially for each frame, but in the second driving example, a specific type of illumination light is emitted. The illumination light is emitted at a higher emission frequency than any other type of illumination light.

  The control unit 63 emits the illumination light as red light in the first frame, green light in the second frame, and blue light in the third frame during each emission possible period. In the fourth frame, the control unit 63 emits green illumination light, and the image processing unit 67 performs synthesis processing using the R, G, B image signals of the first, second, and third frames as a set. A composite image signal to be a color image is generated.

  Then, in the fifth frame, the control unit 63 emits blue illumination light, and the image processing unit 67 generates the G image signal generated in the fourth frame, and the G image signal of the second frame set as described above. Are updated to a set of the R image signal of the first frame, the B image signal of the third frame, and the G image signal of the fourth frame. The updated set of image signals is combined to generate a combined image signal that becomes one color image. In the same manner, a synthesized image signal of a color image is generated for each frame to generate a moving image.

  According to this driving method, R, G, B, G, B, R, G, B, G, B,... And illumination light are periodically emitted sequentially for each frame, and green and blue illumination light is emitted. Can be emitted more frequently than red illumination light. As a result, the emission frequency on the time axis of the frame image captured with illumination light of a specific color (G, B in the above example) is captured with illumination light of a color different from the specific color (R in the above example). It can be set higher than the appearance frequency of the frame image.

  By changing the illumination light that contains a lot of specific information to the illumination light of a specific color that has a high emission frequency, the frequency of updating the frame image of the specific color that contains a lot of specific information can be increased, and the changes in the specific information can be detailed. A moving image to be reproduced can be generated.

  For example, in an endoscopic observation image, a large amount of information on capillaries and fine structure patterns of living tissue is included in a B frame image captured under blue illumination light, and G image captured under green illumination light. The frame image also includes a lot of blood vessel information in the deep tissue layer. When the update frequency of the B and G frame images captured under the blue and green illumination light increases, the image blur of the blood vessel image is less likely to occur, and a moving image suitable for clearer endoscopic diagnosis can be obtained.

  In addition, the G frame image captured under green illumination light includes a lot of luminance information when generating a color image. Therefore, by increasing the update frequency of the G frame image, it is possible to obtain an effect of making color misregistration and image blur less noticeable due to human visual characteristics.

  Note that the combination of specific colors and the emission frequency may be changed as appropriate. Moreover, you may irradiate the illumination light of the same color continuously.

<Third driving example>
FIG. 7 is a timing chart illustrating a second driving example of the imaging system. In this driving example, image information data obtained by A / D converting the signal charges of the pixel unit 53 by the ADC unit 55 is transferred to the memory unit 57 of the imaging unit 51 (FIG. 1). The image information is transferred to the processor 21 at a data transfer speed slower than the reading speed (data transfer speed for transferring data from the pixel portion 53 to the memory portion 57).

  That is, the data of the R frame image captured under red illumination light is transferred to the memory unit 57 at high speed within a short period excluding the exposure period within one frame period. In general, the communication unit 59 transfers the frame image signal stored in the memory unit 57 to the processor 21 at the same speed in synchronization with the transfer from the pixel unit 53. The data is transferred from the memory unit 57 to the processor 21 at a frame rate of 60 frames / second. That is, the communication unit 59 transfers the frame image signal to the processor 21 without depending on the transfer rate from the pixel unit 53 to the memory unit 57.

  According to this driving example, it is not necessary to increase the operating frequency of the LVDS conversion circuit of the communication unit 59 while ensuring a long illumination light emission time. Further, power consumption can be suppressed.

<Fourth driving example>
FIG. 8 is a timing chart illustrating a third driving example of the imaging system. In this driving example, a plurality of types of illumination light are switched and irradiated within a cycle for generating one frame of a moving image, and a subject is imaged in a surface sequential manner for each illumination light. , Referred to as a sub-frame image). At this time, the period for generating one frame of the moving image is fixed, and the illumination light irradiation time for each of the sub-frame images is changed. That is, a plurality of colors of illumination light are sequentially emitted for each color within one frame period, and a plurality of subframe images captured under the illumination light of each color are obtained.

In the illustrated example, the R sub-frame image exposed in the exposure period t _R by irradiating the red illumination light, a G sub-frame image exposed with radiation to the exposure period t _G the green illumination light, blue illumination light 2 shows a control example in which a B sub-frame image that is exposed in the exposure period t _B and is exposed in one frame period of a desired frame rate (60 frames / second) is shown.

The generation periods T _R , T _G , and T _B of the R, G, and B sub-frame images can be divided at an arbitrary ratio, whereby the exposure periods t _R , t _G , and t _B of each illumination light are arbitrarily set. Can be set to a ratio. In addition, each exposure time can be adjusted by increasing / decreasing the signal charge readout time.

  According to this driving example, since all image signals are updated to the latest image in a cycle of one frame of the moving image, a smoother and higher quality moving image can be obtained. Note that the sub-frame image captured under the illumination light of each color within one frame period is not limited to the three-color sub-frame images of R, G, and B, and may be any two colors, and sub-colors of other colors. A frame image may be added.

For example, in the special light observation mode of the endoscope apparatus, when the illumination light to be used is two colors of green light and blue light, the exposure time ratio t _G : t _B of green light and blue light can be arbitrarily changed. When the ratio t _G : t _B is changed, the obtained blood vessel information becomes an image in which the capillaries and fine structure patterns on the surface of the biological tissue are emphasized as the blue light component increases, and the blood vessels in the deeper biological tissue as the green light component increases. The information is emphasized.

As described above, the present invention is not limited to the above-described embodiments, and those skilled in the art can change or apply them based on combinations of the configurations of the embodiments, descriptions in the specification, and well-known techniques. Is also within the scope of the present invention, which is intended to be protected.
For example, the endoscope apparatus having the above configuration is configured to include the control unit 63 and the image processing unit 67 on the control device 13 side, but may be configured to be mounted on the endoscope scope 11 side.

As described above, the following items are disclosed in this specification.
(1) An imaging system that generates a moving image using a MOS type imaging device in which a plurality of pixels are two-dimensionally arranged.
An illumination unit that is driven to have a period in which illumination light can be emitted and a period in which emission is prohibited, and that illuminates a subject by switching a plurality of types of illumination light having different spectra for each of the above-described possible emission periods;
An imaging unit that images the subject with the imaging element for each illumination light to be switched and outputs an image signal in a surface sequential manner;
An image processing unit that synthesizes a set of image signals captured from different illumination lights output from the imaging unit and generates one frame of the moving image;
With
The imaging unit simultaneously starts exposure of the pixel lines arranged in the horizontal direction of the imaging device, exposes the plurality of pixels in a period including a period during which the illumination light can be emitted, and within the illumination light emission prohibited period. An imaging system that reads accumulated charges from the plurality of pixels.
(2) The imaging system according to (1),
The imaging system in which the imaging unit reads the accumulated charges from the pixel lines at different timings.
(3) The imaging system according to (1) or (2),
The imaging system including the plurality of types of illumination light including at least blue light, green light, and red light.
(4) The imaging system according to (3),
Each time the image signal is newly output from the imaging unit, the image processing unit is under the same illumination light as the illumination light used for imaging the newly output image signal in the set of image signals. An imaging system that updates the set of image signals by replacing the image signal captured in step 1 with the newly generated image signal, and performs the combining process using the updated set of image signals.
(5) The imaging system according to any one of (1) to (4),
The said illumination part is an imaging system which radiate | emits a specific kind of illumination light among the said multiple types of illumination light with the radiation | emission frequency raised rather than any other kind of illumination light.
(6) The imaging system according to any one of (1) to (5),
A buffer memory for storing charge signals of accumulated charges read from the plurality of pixels;
A communication unit that outputs the charge signal from the buffer memory at a data transfer rate slower than a data transfer rate when the charge signal is input from the pixel to the buffer memory;
An imaging system comprising:
(7) The imaging system according to any one of (1) to (6),
Within the period for generating one frame of the above moving image,
The illumination unit switches and emits multiple types of illumination light,
The imaging unit is configured to output each image signal captured under different types of illumination light in a frame sequential manner.
(8) The imaging system according to (7),
The said illumination part is an imaging system which makes irradiation time of the said multiple types of illumination light differ, respectively.
(9) The imaging system according to any one of (1) to (8),
The said illumination part is provided with the multiple types of semiconductor light source from which the spectrum of an emitted light mutually differs, The imaging system which radiate | emits the said multiple types of illumination light from the said multiple types of semiconductor light source.
(10) The imaging system according to any one of (1) to (8),
The illumination unit includes a white light source, and a rotary filter disposed in the middle of the optical path of the emitted light of the white light source,
The rotary filter includes a plurality of spectral filters each having a different wavelength band of transmitted light, and transmits the light emitted from the white light source to any one of the spectral filters to generate the illumination light.
(11) An endoscope apparatus including the imaging system according to any one of (1) to (10).

DESCRIPTION OF SYMBOLS 11 Endoscope 13 Control apparatus 19 Light source apparatus 21 Processor 51 Imaging part 53 Pixel part 55 ADC part 57 Memory part 59 Communication part 61 Drive control part 63 Control part 65 Image reception part 67 Image processing part 71 Drive signal communication part 73 Light source Control unit 75, 75A, 75B Light source unit 77R, 77G, 77B Laser light source 85 Rotary filter 100 Endoscope device

Claims (11)

An imaging system that generates a moving image using a MOS type imaging device in which a plurality of pixels are two-dimensionally arranged,
An illumination unit that is driven to have a period in which illumination light can be emitted and a period in which emission is prohibited, and that illuminates a subject by switching a plurality of types of illumination light having different spectra for each of the emission possible periods;
An imaging unit that images the subject with the imaging element for each illumination light to be switched and outputs an image signal in a surface sequential manner;
An image processing unit that synthesizes a set of image signals captured from different illumination lights output from the imaging unit, and generates one frame of the moving image;
With
The imaging unit simultaneously starts exposure of the pixel lines arranged in the horizontal direction of the imaging device, exposes the plurality of pixels in a period including a period during which the illumination light can be emitted, and within the illumination light emission prohibition period. An imaging system that reads accumulated charges from the plurality of pixels. The imaging system according to claim 1,
The imaging system in which the imaging unit reads the accumulated charges from the pixel lines at different timings. The imaging system according to claim 1 or 2,
The imaging system including the plurality of types of illumination light including at least blue light, green light, and red light. The imaging system according to claim 3,
Each time the image signal is newly output from the imaging unit, the image processing unit is under the same illumination light as the illumination light used for imaging the newly output image signal in the set of image signals. An imaging system that updates the set of image signals by replacing the image signal captured in step 1 with the newly generated image signal, and performs the combining process using the updated set of image signals. The imaging system according to any one of claims 1 to 4,
The said illumination part is an imaging system which radiate | emits a specific kind of illumination light among the said multiple types of illumination light with the frequency | count of emission higher than any other kind of illumination light. An imaging system according to any one of claims 1 to 5,
A buffer memory for storing a charge signal of accumulated charges read from the plurality of pixels;
A communication unit that outputs the charge signal from the buffer memory at a data transfer rate slower than a data transfer rate when the charge signal is input from the pixel to the buffer memory;
An imaging system comprising: The imaging system according to any one of claims 1 to 6,
Within a cycle for generating one frame of the moving image,
The illumination unit switches and emits multiple types of illumination light,
The imaging unit is an imaging system that sequentially outputs each image signal captured under different types of illumination light. The imaging system according to claim 7,
The said illumination part is an imaging system which makes irradiation time of the said multiple types of illumination light differ, respectively. The imaging system according to any one of claims 1 to 8,
The said illumination part is an imaging system provided with the multiple types of semiconductor light source from which the spectrum of an emitted light mutually differs, and radiate | emits the said multiple types of illumination light from the said multiple types of semiconductor light source. The imaging system according to any one of claims 1 to 8,
The illumination unit includes a white light source, and a rotary filter disposed in the optical path of the emitted light of the white light source,
The rotation system includes a plurality of spectral filters having different wavelength bands of transmitted light, and transmits the light emitted from the white light source to any one of the spectral filters to generate the illumination light.   An endoscope apparatus comprising the imaging system according to any one of claims 1 to 10.

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