JP6329062B2 - Endoscope system and operating method thereof - Google Patents

Description

  The present invention relates to an endoscope system and an operating method thereof.

  In the medical field, diagnosis using an endoscope system including a light source device, an endoscope, and a processor device is widely performed. As a light source device, in addition to a broadband light source such as a xenon lamp or a white LED (Light Emitting Diode), a monochromatic semiconductor light source such as a blue LED, a green LED, or a red LED is being used in combination. When a plurality of semiconductor light sources are used in this way, the light emitted from each semiconductor light source is combined and used as illumination light for illuminating the observation target in the body.

  When the illumination light is generated by combining light of a plurality of colors as described above, the color tone of the illumination light can be changed by independently adjusting the amount of light of each color. Accordingly, color balance processing such as white balance can be performed not only on the processor device side but also on the light source device side (see, for example, Patent Document 1).

JP 2002-122794 A

  An image obtained by imaging an in-vivo observation target such as the stomach and large intestine with an endoscope is entirely reddish. This is because the observation target is greatly influenced by the light absorption characteristics of hemoglobin, and the RGB image signal obtained by imaging the observation target has the signal level of the R image signal as the signal of the G image signal and the B image signal This is because it becomes larger than the level.

  Further, depending on the purpose of diagnosis, a dye such as a picotanine dye may be sprayed from the distal end portion of the endoscope to the observation target. When the pigment is sprayed in this way, each signal level of the RGB image signal is affected not only by the absorbance property of hemoglobin but also by the absorbance property of the pigment.

  For example, when a pioctane dye is dispersed on the observation object for the purpose of observing a pit pattern on the observation object, the green component of the illumination light is absorbed by the pioctanine dye. In this case, the signal level of the G image signal is lower than when only hemoglobin is present. The pit pattern is clarified by the dispersion of the picotanine dye, but the visibility of the observation target is reduced due to the brightness being reduced due to the decrease in the signal level of the G image signal. That is, it is required to improve the visibility of an observation target when a pigment is dispersed on the observation target.

  In addition, although application of the technique of patent document 1 is considered with respect to the said subject, in patent document 1, the light emission ratio of each color light after setting white balance is fixed. Therefore, even when the signal level of the image signal of a specific color is lowered due to the dispersion of a dye such as pioctane dye on the observation target in the body, the method of Patent Document 1 uses the reduced specific color. The signal level of the image signal cannot be improved.

  An object of this invention is to provide the endoscope system which can improve the visibility of an observation object, and its operating method, when a pigment | dye is spread | dispersed to the observation object.

  In order to achieve the above object, an endoscope system of the present invention includes an illuminating unit that irradiates an observation target with illumination light including red light, green light, and blue light, and a pigment distribution that scatters a pigment to the observation target. And an imaging device for imaging an observation target in which a pigment is dispersed, and includes a red pixel having sensitivity to red light, a green pixel having sensitivity to green light, and a blue pixel having sensitivity to blue light. An imaging device configured to change the exposure time for each color, and an imaging control unit that controls the imaging timing of the imaging device and sets the exposure time of the red pixel, the green pixel, and the blue pixel. Prepare.

  The imaging control unit controls the imaging device so that the exposure time of at least one color pixel of the red pixel, the green pixel, and the blue pixel is longer than the exposure time of the other two color pixels. Is preferred.

  It is preferable that the imaging control unit changes the exposure time ratio of the red pixel, the green pixel, and the blue pixel in accordance with the light absorption characteristics of the pigment sprayed by the pigment spraying unit.

  A light source control unit that controls the emission timing and intensity of red light, green light, and blue light is provided. The light source control unit terminates light emission of two colors of red light, green light, and blue light. Then, it is preferable to increase the emission intensity of the light of the other color.

  The imaging device is configured to be able to individually read out a red pixel, a green pixel, and a blue pixel, and the imaging control unit is time when emission of red light, green light, and blue light ends. It is preferable to read out the red pixel, the green pixel, and the blue pixel, respectively.

  When the dye is a picotanine dye, the imaging control unit preferably makes the exposure time of the green pixel longer than the exposure time of the red pixel and the exposure time of the blue pixel.

  When the dye is an iodine dye, the imaging control unit preferably makes the exposure time of the blue pixel longer than the exposure time of the green pixel, and makes the exposure time of the green pixel longer than the exposure time of the red pixel.

  When the dye is an indigo carmine dye, the imaging control unit preferably makes the exposure time of the red pixel longer than the exposure time of the green pixel and the exposure time of the blue pixel.

  The operation method of the endoscope system of the present invention includes an illumination unit that irradiates an observation target with illumination light including red light, green light, and blue light, a pigment spray unit that sprays pigment on the observation target, and a pigment An imaging device for imaging a scattered observation object, having a red pixel having sensitivity to red light, a green pixel having sensitivity to green light, and a blue pixel having sensitivity to blue light, for each color In an operation method of an endoscope system including an imaging device configured to be able to change an exposure time, the imaging device is controlled to control at least one pixel of a red pixel, a green pixel, and a blue pixel. The exposure time is set longer than the exposure times of the other two color pixels.

  According to the present invention, a red pixel having sensitivity to red light, a green pixel having sensitivity to green light, and a blue pixel having sensitivity to blue light are configured such that the exposure time can be changed for each color. Since the exposure time of the red pixel, green pixel, and blue pixel is set by controlling the imaging timing of the image sensor, the visual recognition of the observation target is performed when the pigment is scattered on the observation target. Can be improved.

It is an external view of an endoscope system. It is a block diagram which shows the function of an endoscope system. It is a graph which shows the emission spectrum of purple light, blue light, green light, and red light. It is a figure which shows the structure of an image pick-up element. It is a figure which shows the color arrangement | sequence of a color filter. It is a figure which shows the spectral characteristic of a color filter. It is a figure which shows the structure of the pixel of an image pick-up element. It is a figure which shows the light emission and imaging timing of normal observation mode. It is a figure which shows light emission and imaging timing of special observation mode. It is a flowchart explaining the effect | action of an endoscope system. It is a figure which shows light emission and an imaging timing of the normal observation mode of a global shutter system. It is a figure which shows light emission and imaging timing of the special observation mode of a global shutter system. It is a timing diagram showing an example of increasing the emission intensity of green light after the emission of purple light, blue light, and red light is completed. It is a figure which shows the structure of the image pick-up element of 2nd Embodiment. It is a figure which shows the structure of the pixel of the image pick-up element of 2nd Embodiment. It is a figure which shows light emission and imaging timing of the special observation mode of 2nd Embodiment. It is a figure which shows light emission and imaging timing of the special observation mode in the case of spraying an iodine pigment. It is a figure which shows the correspondence table | surface which matched the kind of pigment | dye spread | dispersed, and exposure time ratio.

  In FIG. 1, the endoscope system 10 includes an endoscope 12, a light source device 14, a processor device 16, a monitor 18, and a console 19. The endoscope 12 is optically connected to the light source device 14 and electrically connected to the processor device 16 by the universal cord 25.

  The endoscope 12 includes an insertion portion 12a to be inserted into the subject, an operation portion 12b provided at the proximal end portion of the insertion portion 12a, a bending portion 12c provided at the distal end side of the insertion portion 12a, and a bending portion. And a tip portion 12d provided at the tip of the portion 12c. By operating the angle knob 12e of the operation portion 12b, the bending portion 12c is bent. With this bending operation, the tip 12d is directed in a desired direction.

  In addition to the angle knob 12e, the operation unit 12b is provided with a mode switching SW 13a and a zoom operation unit 13b. The mode switching SW 13a is used for switching operation between the normal observation mode and the special observation mode. The normal observation mode is a mode for displaying a normal observation image on the monitor 18 when the pioctane dye is not sprayed on the observation target. The special observation mode is a mode for displaying on the monitor 18 an observation image in which the pit pattern is clarified by dispersing the pioctane dye on the observation target.

  The processor device 16 is electrically connected to the monitor 18 and the console 19. The monitor 18 is a display unit that outputs and displays image information and the like. The console 19 functions as a user interface that receives input operations such as function settings. Note that an external recording unit (not shown) for recording image information or the like may be connected to the processor device 16.

  The endoscope 12 is provided with a forceps channel 20. The forceps channel 20 is inserted with a spray tube 22 for spraying the picotanine dye to the observation target. The spray tube 22 is inserted into the forceps channel 20 from a forceps inlet 20a provided in the operation unit 12b. At least the distal end 22a of the spray tube 22 is exposed from a forceps outlet 20b formed at the distal end portion 12d of the endoscope 12.

  A syringe 24 filled with a picotanine coloring agent is connected to the proximal end side of the spray tube 22. A user such as a doctor can spray the pioctanine dye in a mist toward the observation target from the tip 22a of the spray tube 22 by operating the syringe 24. As described above, when the user scatters the picotanine pigment on the observation target, the user selects the special observation mode as the observation mode by the mode switching SW 13a. The “pigment spraying portion” of the present invention corresponds to a configuration including the spray tube 22 and the syringe 24.

  In FIG. 2, the light source device 14 includes a light source unit 30, a light source control unit 31, and an optical path coupling unit 32. The light source unit 30 includes, as semiconductor light sources, a V-LED (Violet Light Emitting Diode) 30a, a B-LED (Blue Light Emitting Diode) 30b, a G-LED (Green Light Emitting Diode) 30c, and an R-LED (Red). Light Emitting Diode) 30d. The light source control unit 31 controls the light emission timing and light emission intensity of the light source unit 30. The optical path coupling unit 32 is configured by a dichroic mirror or the like, and couples the optical path of each light emitted from the light source unit 30.

  The light emitted from the optical path coupling unit 32 is irradiated to the observation target in the subject through the light guide 33 and the illumination lens 35 inserted into the insertion unit 12a. The “illumination unit” of the present invention corresponds to a configuration including the light source unit 30, the optical path coupling unit 32, the light guide 33, and the illumination lens 35.

  As shown in FIG. 3, the V-LED 30 a generates violet light LV having a center wavelength of about 405 nm and a wavelength range of about 380 to 420 nm. The B-LED 30b generates blue light LB having a center wavelength of about 460 nm and a wavelength range of about 420 to 500 nm. The G-LED 30c generates green light LG having a wavelength range of about 480 to 600 nm. The R-LED 30d generates red light LR having a center wavelength of about 620 to 630 nm and a wavelength range of about 600 to 650 nm.

  The light source control unit 31 drives and controls the light source unit 30 with each light emission intensity of the violet light LV, the blue light LB, the green light LG, and the red light LR as a predetermined ratio (light emission ratio). The light source controller 31 simultaneously emits purple light LV, blue light LB, green light LG, and red light LR. The purple light LV, the blue light LB, the green light LG, and the red light LR are combined by the optical path coupling unit 32 to become white illumination light, and this illumination light is supplied to the light guide 33. Note that the violet light LV may not be emitted, and the light of the three colors of the blue light LB, the green light LG, and the red light LR may be combined to provide illumination light.

  The light guide 33 is incorporated in the endoscope 12 and the universal cord 25, and propagates the illumination light supplied from the optical path coupling unit 32 to the distal end portion 12d of the endoscope 12. As the light guide 33, a multimode fiber can be used. As an example, a thin fiber cable having a core diameter of about 105 μm, a cladding diameter of about 125 μm, and a diameter including an outer skin (protective layer) of φ0.3 to 0.5 mm can be used.

  The distal end portion 12d of the endoscope 12 is provided with an illumination optical system 34a and an imaging optical system 34b. The illumination optical system 34 a has an illumination lens 35. The illumination light emitted from the light guide 33 is applied to the observation target via the illumination lens 35. The imaging optical system 34 b includes an objective lens 36, a zoom lens 37, and an imaging element 38. The return light from the observation target of the illumination light enters the image sensor 38 through the objective lens 36 and the zoom lens 37. An optical image to be observed is formed on the image sensor 38.

  The zoom lens 37 moves between the tele end and the wide end in accordance with the operation of the zoom operation unit 13b. When magnification observation is not performed (during non-magnification observation), the zoom lens 37 is disposed at the wide end. When performing magnified observation, the zoom lens 37 moves from the wide end to the tele end according to the operation of the zoom operation unit 13b.

  The image sensor 38 is a simultaneous color sensor, and receives the return light from the observation target irradiated with the illumination light and outputs an image signal. The image sensor 38 can receive light for each of blue (B), green (G), and red (R) colors, and can change the exposure time for each color. As the image sensor 38, a complementary metal-oxide semiconductor (CMOS) type image sensor is used. The image sensor 38 outputs an RGB image signal composed of a B pixel signal, a G pixel signal, and an R pixel signal as an image signal.

  The processor device 16 includes an imaging control unit 40, a reception unit 41, a DSP (Digital Signal Processor) 42, a noise removal unit 43, an observation image generation unit 44, and a video signal generation unit 45.

  The imaging control unit 40 controls the imaging timing of the observation target by the imaging element 38. Further, the imaging control unit 40 changes the imaging timing of the imaging element 38 according to the observation mode selected by the mode switching SW 13a.

  The receiving unit 41 receives a digital RGB image signal output from the imaging device 38 of the endoscope 12. The DSP 42 performs various signal processing such as defect correction processing, offset processing, gain correction processing, linear matrix processing, gamma conversion processing, and demosaicing processing on the received RGB image signal.

  In the defect correction process, the signal of the defective pixel of the image sensor 38 is corrected. In the offset process, the dark current component is removed from the RGB image signal subjected to the defect correction process, and an accurate zero level is set. In the gain correction process, the signal level is adjusted by multiplying the RGB image signal after the offset process by a specific gain value. The RGB image signal after the gain correction process is subjected to a linear matrix process for improving color reproducibility. After that, brightness and saturation are adjusted by gamma conversion processing. The RGB image signal after the linear matrix processing is subjected to demosaic processing (also referred to as isotropic processing or synchronization processing), and signals of RGB colors are generated for each pixel.

  The noise removal unit 43 removes noise by performing noise removal processing (processing by a moving average method, a median filter method, or the like) on the RGB image signal subjected to demosaic processing or the like by the DSP 42. The RGB image signal from which noise has been removed is input to the observation image generation unit 44.

  The observation image generation unit 44 generates an observation image by performing color conversion processing, color enhancement processing, and structure enhancement processing on the RGB image signal input from the noise removal unit 43. In color conversion processing, color conversion processing is performed on RGB image signals by 3 × 3 matrix processing, gradation conversion processing, three-dimensional LUT (look-up table) processing, and the like. The color enhancement process is performed on the RGB image signal that has been subjected to the color conversion process. The structure enhancement process is a process for enhancing the structure of the observation target such as a surface blood vessel or a pit pattern, and is performed on the RGB image signal after the color enhancement process.

  The observation image generated by the observation image generation unit 44 is input to the video signal generation unit 45. The video signal generation unit 45 converts the observation image into a video signal for display on the monitor 18. The monitor 18 displays an image based on the video signal input from the video signal generation unit 45.

  In FIG. 4, the image sensor 38 includes a pixel array unit 50, a readout scanning circuit 51, a reset scanning circuit 52, a column ADC (Analog-to-digital converter) circuit 53, a line memory 54, and a column scanning circuit 55. And a timing generator (TG) 56. The TG 56 generates a timing signal based on the imaging control signal input from the imaging control unit 40 of the processor device 16 and controls each unit.

  The pixel array unit 50 includes a plurality of pixels 50 a two-dimensionally arranged in a matrix in the row direction (X direction) and the column direction (Y direction), and is provided on the imaging surface of the imaging element 38. In the pixel array unit 50, a first row selection line LS1, a second row selection line LS2, and a row reset line LR are arranged along the row direction, and a column signal line LV is arranged along the column direction. ing.

  The first row selection line LS1, the second row selection line LS2, and the row reset line LR are provided for each pixel row. The column signal line LV is provided for each pixel column. Here, the pixel row refers to one row of pixels 50a arranged in the row direction. The pixel column refers to one column of pixels 50a arranged in the column direction.

  As shown in FIG. 5, a color filter array 60 is provided on the light incident side of the pixel array unit 50. The color filter array 60 includes a green (G) filter 60a, a blue (B) filter 60b, and a red (R) filter 60c. Any one of these filters is arranged on each pixel 50a. The color arrangement of the color filter array 60 is a Bayer arrangement, in which G filters 60a are arranged every other pixel in a checkered pattern, and the B filter 60b and the R filter 60c are each in a square lattice pattern on the remaining pixels. Is arranged.

  The color filter array 60 has the spectral characteristics shown in FIG. The G filter 60a has a high transmittance with respect to a wavelength region of about 450 to 630 nm. The B filter 60b has a high transmittance with respect to a wavelength range of about 380 to 560 nm. The R filter 60c has a high transmittance with respect to a wavelength range of about 580 to 760 nm.

  Hereinafter, the pixel 50a in which the G filter 60a is disposed is referred to as a G pixel, the pixel 50a in which the B filter 60b is disposed is referred to as a B pixel, and the pixel 50a in which the R filter 60c is disposed is referred to as an R pixel. The G pixel has sensitivity to the green light LG. The R pixel has sensitivity to the red light LR. The B pixel has sensitivity to the blue light LB and the purple light LV. B pixels and G pixels are alternately arranged in each pixel row of even numbers (0, 2, 4,..., N−1). G pixels and R pixels are alternately arranged in each odd (1, 3, 5,..., N) pixel row.

  Each pixel 50a in one pixel row is commonly connected to the row reset line LR. In addition, among the pixels 50a in one pixel row, the G pixel is commonly connected to the first row selection line LS1, and the B pixel and the R pixel are each commonly connected to the second row selection line LS2.

  As shown in FIG. 7, each pixel 50a includes a photodiode D1, an amplifier transistor M1, a pixel selection transistor M2, and a reset transistor M3. The photodiode D1 photoelectrically converts incident light to generate signal charges corresponding to the amount of incident light, and accumulates the signal charges. The amplifier transistor M1 converts the signal charge accumulated in the photodiode D1 into a voltage value (pixel signal). The pixel selection transistor M2 is controlled by the first row selection line LS1 or the second row selection line LS2, and outputs the pixel signal generated by the amplifier transistor M1 to the column signal line LV. The reset transistor M3 is controlled by the row reset line LR, and discards (resets) the signal charge accumulated in the photodiode D1 to the power supply line.

  The read scanning circuit 51 generates a row selection signal based on the timing signal input from the TG 56. The read scanning circuit 51 provides a row selection signal to the first row selection line LS1 or the second row selection line LS2 during a signal read operation, thereby providing the first row selection line LS1 or the second row to which the row selection signal is applied. The pixel signal of the pixel 50a connected to the selection line LS2 is output to the column signal line LV.

  The reset scanning circuit 52 generates a reset signal based on the timing signal input from the TG 56. During the reset operation, the reset scanning circuit 52 applies a reset signal to the row reset line LR, thereby resetting the pixels 50a connected to the row reset line LR to which the reset signal is applied.

  The column ADC circuit 53 receives the pixel signal output to the column signal line LV during the signal read operation. The column ADC circuit 53 includes an ADC connected to each column signal line LV, and compares the pixel signal input from each column signal line LV with a reference signal (ramp wave) that changes stepwise with time. , Converted into a digital signal and output to the line memory 54.

  The line memory 54 holds pixel signals for one row digitized by the column ADC circuit 53. The column scanning circuit 55 sequentially outputs pixel signals from the output terminal Vout by scanning the line memory 54 based on the timing signal input from the TG 56. The pixel signal for one frame output from the output terminal Vout is the aforementioned RGB image signal.

  The image sensor 38 can execute a “sequential readout method” and a “partial readout method” as signal readout methods. In the sequential readout method, the readout scanning circuit 51 selects the first and second row selection lines LS1 and LS2 of each pixel row in order, and selects the first and second row selection lines LS1 and LS2. At the same time, a row selection signal is given. As a result, for all the pixels 50a in the pixel array unit 50, signal reading is sequentially performed for each pixel row from the first pixel row “0” to the last pixel row “N”.

  In the partial readout method, it is possible to selectively read out pixels of a specific color from the pixel array unit 50. For example, when only G pixels are read out from the pixel array unit 50, the read scanning circuit 51 performs odd (1, 3, 5,..., N) and even (0, 2, 4,..., N The row selection signal is given to the selected first row selection line LS1, while only the first row selection line LS1 of each pixel row of -1) is selected in order. As a result, signal readout is performed sequentially for each pixel row for only the G pixel of all the pixels 50a.

  In this case, the line memory 54 stores only the pixel signal (G pixel signal) read from the G pixel. The column scanning circuit 55 scans the line memory 54 every time a pixel signal (G pixel signal) for one pixel row is stored in the line memory 54.

  Further, when only the R pixel is read from the pixel array unit 50, only the second row selection line LS2 of each odd (1, 3, 5,... While being selected, a row selection signal is applied to the selected second row selection line LS2. As a result, signal readout is performed in order for each pixel row for only the R pixel of all the pixels 50a.

  In this case, the line memory 54 stores only the pixel signal (R pixel signal) read from the R pixel. The column scanning circuit 55 scans the line memory 54 every time pixel signals (R pixel signals) from odd rows to one pixel row are stored in the line memory 54.

  In the partial readout method, it is possible to selectively read out pixels of two specific colors from the pixel array unit 50. For example, when reading out the B pixel and the R pixel from the pixel array unit 50, the read scanning circuit 51 performs odd (1, 3, 5,..., N) and even (0, 2, 4,. , N−1), the row selection signal is given to the selected second row selection line LS2 while only the second row selection line LS2 of each pixel row is selected in order. As a result, signal readout is sequentially performed for each pixel row for the B pixel and the R pixel of all the pixels 50a.

  In this case, the pixel signal read from the B pixel (B pixel signal) is stored in the line memory 54 when the even-numbered pixel row is read, and is read from the R pixel when the odd-numbered pixel row is read. Only the pixel signal (R pixel signal) is stored. The column scanning circuit 55 scans the line memory 54 every time a pixel signal for one pixel row is stored in the line memory 54 from even rows or odd rows.

  The image sensor 38 can execute a “sequential reset method” and a “batch reset method” as a reset method. In the sequential reset method, the reset signal is given to the selected row reset line LR while the row reset line LR is sequentially selected by the reset scanning circuit 52. As a result, in the sequential reset method, the reset is performed sequentially for each pixel row from the first pixel row “0” to the last pixel row “N”.

  In the collective reset method, all the row reset lines LR are selected by the reset scanning circuit 52, and a reset signal is collectively applied to all the row reset lines LR. Thereby, all the pixel rows of the pixel array unit 50 are simultaneously reset at the same time.

  Although not shown in FIG. 4, the imaging device 38 is appropriately provided with a correlated double sampling (CDS) circuit and an automatic gain control (AGC) circuit. The CDS circuit performs correlated double sampling processing on the pixel signal output from the pixel 50a to each column signal line LV. The AGC circuit performs gain adjustment on the pixel signal on which the correlated double sampling processing has been performed.

  The light source control unit 31 and the imaging control unit 40 are electrically connected to each other. The imaging control unit 40 controls the imaging timing of the imaging device 38 in accordance with the emission timing of the illumination light of the light source device 14 controlled by the light source control unit 31.

Next, the light emission timing and the imaging timing controlled by the light source control unit 31 and the imaging control unit 40 will be described. FIG. 8 shows the light emission timing and imaging timing in the normal observation mode. The light source control unit 31 causes the light source unit 30 to start emitting purple light LV, blue light LB, green light LG, and red light LR. At this time, the light source control unit 31, the emission intensity _{I V} of violet light LV, the emission intensity _{I B} of the blue light LB, the emission intensity _{I G} of the green light LG, the emission intensity _{I R} of the red light LR, the predetermined ratio To do.

  Each light emitted from the light source unit 30 is combined by the optical path coupling unit 32 and supplied to the light guide 33 as white illumination light. This illumination light is emitted from the distal end portion 12d of the endoscope 12 and illuminates the observation target.

  In a state where the observation target is illuminated by the illumination light, the imaging control unit 40 controls the imaging element 38 to sequentially perform the reset operation by the reset method from time t0. As a result, all the pixel rows are sequentially reset one pixel row at a time. Each pixel row is sequentially placed in a charge accumulation state (exposure state) when unnecessary charges of the pixel 50a are discarded by resetting.

Then, the imaging control unit 40, after a lapse of the exposure time T _E from the time t0, and controls the image sensor 38, by sequentially reading method, B pixel, G pixel, to perform all of the read operation of the R pixel. Accordingly, the digitized B pixel signal, G pixel signal, and R pixel signal are output from the image sensor 38. In this normal observation mode, the imaging operation by the imaging device 38 is repeated while the violet light LV, the blue light LB, the green light LG, and the red light LR are always emitted.

  Next, FIG. 9 shows the light emission timing and imaging timing in the special observation mode performed by spraying the pioctanine pigment on the observation target. The light source control unit 31 causes the light source unit 30 to simultaneously start emission of purple light LV, blue light LB, green light LG, and red light LR from time t0. At this time, the light source control unit 31 sets the emission intensity of each light to a predetermined ratio as in the normal observation mode.

  As in the normal observation mode, each light emitted from the light source unit 30 is combined by the optical path coupling unit 32 and supplied to the light guide 33 as white illumination light. This illumination light is emitted from the distal end portion 12d of the endoscope 12 and illuminates the observation target.

The imaging control unit 40 controls the imaging element 38 to sequentially perform a reset operation using a reset method from time t0. As a result, all the pixel rows are sequentially reset one pixel row at a time. Each pixel row is sequentially placed in a charge accumulation state (exposure state) when unnecessary charges of the pixel 50a are discarded by resetting. Then, after the first exposure time _TE1 has elapsed from the time t0, the imaging control unit 40 controls the imaging element 38 to perform the readout operation for only the B pixel and the R pixel by the partial readout method. As a result, digitized B pixel signals and R pixel signals are output from the image sensor 38.

Thereafter, after the second exposure time _TE2 has elapsed from time t0, the imaging control unit 40 controls the imaging element 38 so that only the G pixel is read out by the partial readout method. As a result, a digitized G pixel signal is output from the image sensor 38. Even in this special observation mode, the imaging operation by the imaging device 38 is repeated while the violet light LV, the blue light LB, the green light LG, and the red light LR are always emitted.

  Next, a series of flows in the present embodiment will be described along the flowchart shown in FIG. First, a user such as a doctor performs screening in a distant view using the normal observation mode, with the inside of the stomach, esophagus, or the like as an observation target. In the normal observation mode, the endoscope system 10 is driven according to the light emission timing and the imaging timing shown in FIG. 8, and the observation image generated by the observation image generation unit 44 is displayed on the monitor 18. This observation image is reddish. This is because hemoglobin in the observation target absorbs shortwave light.

  When the user detects a possible lesion (such as a possible lesion) such as a brownish area or redness during screening, the user operates the zoom operation unit 13b to enlarge the observation target including the likely lesion. Perform magnified observation. Further, the user operates the mode switching SW 13a to switch to the special observation mode. Further, the user, after confirming the distal end 22a of the spray tube 22 in the observation image, operates the syringe 24 filled with the picotanine dye agent, thereby spraying the picotanine dye on the observation target.

In the special observation mode, the endoscope system 10 is driven according to the light emission timing and the imaging timing shown in FIG. 9, and the observation image generated by the observation image generation unit 44 is displayed on the monitor 18. Although the pit pattern on the observation object is clarified by the pioctanine dye dispersed on the observation object, the brightness is reduced by the absorption of the green light LG component of the illumination light by the pioctanine dye. In the present embodiment, in the special observation mode, the second exposure time T _E2 that is the G pixel exposure time of the image sensor 38 is longer than the first exposure time T _E1 that is the exposure time of the B pixel and the R pixel. Therefore, a decrease in the level of the G image signal (a decrease in brightness) is prevented, and the visibility of the observation target is improved.

  In the above embodiment, as shown in FIGS. 8 and 9, the reset method is sequentially used as the reset method, and the image pickup device 38 is driven by a so-called rolling shutter method. The image sensor 38 may be driven by a so-called global shutter method using a reset method. In this case, the reading operation is performed after the light of the color corresponding to the pixel signal to be read is turned off.

In this case, in the normal observation mode, as illustrated in FIG. 11, the imaging control unit 40 controls the imaging device 38 in a state where the observation target is illuminated with illumination light, and the imaging device 38 is controlled by the batch reset method from time t0. Reset all pixel rows. The light source control unit 31, the light emitting operation of the light source unit 30 is stopped at time t1 at which the exposure time T _E has elapsed from the time t0. Then, the imaging control unit 40 controls the imaging element 38 in the dark state where the illumination light is extinguished, and performs all readout operations of the B pixel, the G pixel, and the R pixel by the sequential readout method.

In the special observation mode, as shown in FIG. 12, the imaging control unit 40 controls the imaging device 38 in a state where the observation target is illuminated with illumination light, and the imaging device 38 is controlled by the batch reset method from time t0. Reset all pixel rows. The light source control unit 31, the time t1 from time t0 the first exposure time _{T E1} has elapsed, V-LED30a, B-LED30b , stops the light emission operation of the R-LED30d, violet light LV, the blue light LB, red The light emission of the light LR is terminated. Then, the imaging control unit 40 controls the imaging element 38 so that only the B pixel and the R pixel are read by the partial reading method.

Thereafter, the light source control unit 31, a time t2 from the time t0 has passed the second exposure time _{T E2} is to stop the light emission operation of the G-LED 30c, to terminate the emission of green light LG. Then, the imaging control unit 40 controls the imaging element 38 to perform a readout operation for only the G pixel by a partial readout method.

  In this way, by using the global shutter system, the light receiving period for each color of all the pixel rows becomes the same (so-called synchronism is obtained). In addition, the global shutter system has the advantage that the exposure time is longer and the exposure amount is increased than the rolling shutter system.

Furthermore, in the special observation mode, as shown in FIG. 13, violet light LV, the blue light LB, after time t1 ended the emission of red light LR, it may increase the emission intensity I _G of the green light LG. Incidentally, after the time t1, the larger the light emission intensity I _G of the green light LG, including increasing the emission intensity I _G of the green light LG on the time t1. In this case, the desired that amount of the green light LG is obtained in a short time, as compared with the case of not changing the luminous intensity I _G of the green light LG as shown in FIG. 12, a second exposure time T _E2 Can be shortened.

[Second Embodiment]
In the first embodiment, by configuring the image sensor 38 to be able to perform partial readout for each color, it is possible to set the exposure time for each color by the imaging control unit 40, but instead, In the second embodiment, by configuring the image sensor to be able to perform partial reset for each color, it is possible to set the exposure time for each color by the image capture control unit 40.

  In the second embodiment, an image sensor 70 shown in FIGS. 14 and 15 is used instead of the image sensor 38 of the first embodiment. The image sensor 70 has a single row selection line LS, and each pixel 50a in one pixel row is commonly connected to the row selection line LS. The image sensor 70 includes a first row reset line LR1 and a second row reset line LR2, and the G pixel is commonly connected to the first row reset line LR1, and the B pixel and the R pixel are respectively connected to the second row reset line LR1. Commonly connected to the row reset line LR2.

  The read scanning circuit 51 sequentially applies row selection signals to the row selection lines LS during signal readout operation, and performs “sequential readout” in which pixel signals are sequentially read out one pixel row at a time. During the reset operation, the reset scanning circuit 52 gives a reset signal to the first row reset line LR1 or the second row reset line LR2, thereby providing the first row reset line LR1 or the second row reset line LR2 to which the reset signal is given. The pixel 50a connected to is reset. Other configurations of the image sensor 70 are the same as those of the image sensor 38 of the first embodiment.

  The image sensor 70 can reset only the G pixel at once by giving a reset signal to all the first row reset lines LR1 at the same time. In addition, the image sensor 70 can simultaneously reset the B pixel and the R pixel by supplying reset signals to all the second row reset lines LR2 at the same time.

  The image sensor 70 can simultaneously reset only the B pixels by simultaneously applying a reset signal to the second row reset line LR2 of the even-numbered pixel rows, and the second-row reset of the odd-numbered pixel rows. By simultaneously applying a reset signal to the line LR2, it is possible to reset only the R pixels at once. Furthermore, the image sensor 70 can simultaneously reset all the pixel rows simultaneously by giving a reset signal to all the first row reset lines LR1 and the second row reset lines LR2.

  In the special observation mode of the second embodiment, as shown in FIG. 16, the imaging control unit 40 controls the imaging element 70 in a state where the observation target is illuminated with illumination light, and performs imaging by the collective reset method from time t0. All pixel rows of the element 70 are reset. Then, at time t1 after the lapse of a predetermined time, a reset signal is simultaneously applied to all the second row reset lines LR2, thereby resetting only the B pixel and the R pixel simultaneously (partial reset).

Then, the light source control unit 31 stops the light emission operation of the light source unit 30 at time t2 when the first exposure time _TE1 has elapsed from time t1. Then, the imaging control unit 40 controls the imaging element 70 in the dark state where the illumination light is turned off, and performs all readout operations of the B pixel, the G pixel, and the R pixel by the sequential readout method. In the present embodiment, the time from time t0 to time t2, a second exposure time for the green light LG T _E2.

  In the first embodiment, an image sensor 38 configured to be able to read out R pixel, G pixel, and B pixel for each color individually, and in the second embodiment, R pixel and G pixel are used. , The image pickup device 70 configured to be able to reset the B pixel individually for each color is used. Instead of the image pickup devices 38 and 70, the R pixel, the G pixel, and the B pixel are used. You may use the image pick-up element comprised so that reading and reset could be performed for every color separately. In this case, the start and end timing of the exposure period can be freely set for each color.

  In each of the above embodiments, in the special observation mode, the exposure time of the B pixel and the R pixel is the same, and the exposure time of the G pixel is longer than the exposure time of the B pixel and the R pixel. This is because a pioctanine dye having a light absorption characteristic that absorbs almost only the green light LG of the illumination light is used as the dye to be dispersed on the observation target.

  The present invention is not limited to the picotanine dye, but other dyes can also be used as the dye to be dispersed on the observation target by the pigment dispersion unit. For example, when an iodine dye is used as the dye, the iodine dye absorbs the blue light LB of the illumination light and also slightly absorbs the green light LG. Therefore, in the special observation mode, as shown in FIG. , G pixel, and B pixel may be partially read out, and the exposure times of the R pixel, G pixel, and B pixel may be different.

Specifically, in FIG. 17, when the R pixel exposure time is R exposure time T _ER , the G pixel exposure time is G exposure time T _EG , and the B pixel exposure time is B exposure time T _EB , The relationship is T _ER <T _EG <T _EB . FIG. 17 shows an example in which the image sensor 38 is driven by the rolling shutter system, but it goes without saying that the global shutter system or the image sensor 70 can be used instead.

Further, when an indigo carmine dye is used as the dye, the indigo carmine dye absorbs the red light LR and the green light LG of the illumination light, and therefore, in the special observation mode, the R exposure time _TER and the G exposure time T _EG are set. The B exposure time T _EB may be longer, and the R exposure time _TER and the G exposure time T _EG may be the same.

As described above, in the special observation mode, it is preferable that the exposure time for each color of the imaging elements 38 and 70 can be changed in accordance with the light absorption characteristics of the dispersed pigment. For this purpose, for example, as shown in FIG. 18, the imaging control unit 40 has a type (absorption characteristic) of the dye to be dispersed and a ratio (exposure time ratio) between the exposure times T _ER , T _EG , and T _EB. Is stored, the exposure time ratio is selected from the correspondence table 80 based on the type of the selected dye, and the image sensors 38 and 70 are controlled. The type of pigment to be dispersed may be selected from the endoscope 12 operation unit 12b, the console 19, or the like. It is also preferable that the correspondence table 80 can be edited by operating the console 19 such as changing the exposure time ratio for each type of dye or adding a new dye type.

  The user may connect the syringe 24 filled with the dye corresponding to the dye selected from the correspondence table 80 to the spray tube 22 and spray it from the tip 22a of the spray tube 22 onto the observation target.

  Moreover, in each said embodiment, although the light source part 30 which consists of V-LED30a, B-LED30b, G-LED30c, and R-LED30d is used, since V-LED30a is not essential, it replaces with the light source part 30, You may use the light source part which consists of B-LED, G-LED, and R-LED. In addition, it is also possible to use other semiconductor light sources such as LD (Laser Diode) instead of LEDs as a semiconductor light source constituting the light source unit.

  In each of the above embodiments, the light source device 14 and the processor device 16 are configured separately, but the light source device and the processor device may be configured as a single device.

DESCRIPTION OF SYMBOLS 10 Endoscope system 12 Endoscope 14 Light source apparatus 16 Processor apparatus 20 Forceps channel 22 Spreading tube 22a Tip 24 Syringe 30 Light source part 50 Pixel array part 50a Pixel 70 Imaging element

Claims (9)

An illumination unit that irradiates the observation target with illumination light including red light, green light, and blue light in a state where the red light, the green light, and the blue light overlap in time ,
A pigment spraying section for spraying pigment on the observation object;
An imaging device for imaging the observation object in which the pigment is dispersed, wherein the red pixel is sensitive to the red light, the green pixel is sensitive to the green light, and the blue pixel is sensitive to the blue light; An image sensor configured to be able to change the exposure time for each color, and
An imaging control unit that controls an imaging timing of the imaging element and sets an exposure time of the red pixel, the green pixel, and the blue pixel;
An endoscope system comprising:   The imaging control unit controls the imaging device to set an exposure time of at least one color pixel among the red pixel, the green pixel, and the blue pixel, and an exposure time of the other two color pixels. The endoscope system according to claim 1, wherein the endoscope system is longer.   The said imaging control part changes the exposure time ratio of the said red pixel, the said green pixel, and the said blue pixel according to the light absorption characteristic of the pigment | dye spread | dispersed by the said pigment | dye distribution part. Endoscopic system. A light source controller that controls the emission timing and emission intensity of the red light, the green light, and the blue light;
The light source control unit increases the light emission intensity of the other one color light after terminating the light emission of two colors of the red light, the green light, and the blue light. Or the endoscope system of 3. The image sensor is configured to be able to individually read out the red pixel, the green pixel, and the blue pixel,
The imaging control unit causes the red pixel, the green pixel, and the blue pixel to be read out in accordance with a time when light emission of the red light, the green light, and the blue light ends. Item 5. The endoscope system according to Item 4.   The said pigment | dye is a picotanine pigment | dye, The said imaging control part makes the exposure time of the said green pixel longer than the exposure time of the said red pixel, and the exposure time of the said blue pixel. The endoscope system described.   The dye is an iodine dye, and the imaging control unit makes the exposure time of the blue pixel longer than the exposure time of the green pixel, and makes the exposure time of the green pixel longer than the exposure time of the red pixel. The endoscope system according to any one of 1 to 5.   The said pigment | dye is an indigo carmine pigment | dye, and the said imaging control part makes the exposure time of the said red pixel longer than the exposure time of the said green pixel, and the exposure time of the said blue pixel. The endoscope system described in 1. An illumination unit that irradiates an observation target with illumination light including red light, green light, and blue light in a state where the red light, the green light, and the blue light overlap in time, and the observation target A pigment spraying unit that sprays a pigment; an imaging device that captures the observation target in which the pigment is sprayed; a red pixel having sensitivity to the red light; a green pixel having sensitivity to the green light; In an operating method of an endoscope system including a blue pixel having sensitivity to blue light and an imaging element configured to be able to change an exposure time for each color,
An internal view that controls the image pickup device so that the exposure time of at least one of the red pixel, the green pixel, and the blue pixel is longer than the exposure time of the other two color pixels. How to operate the mirror system.

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