JP6249909B2 - Imaging system and processing apparatus - Google Patents

Description

  The present invention relates to an imaging system including a light source that emits illumination light and an imaging device, and a processing device that performs signal processing of an electrical signal generated by the imaging device.

  Conventionally, in the medical field, an endoscope system is used for observing the inside of a subject. An endoscope system inserts a flexible insertion portion having an elongated shape into a subject such as a patient, illuminates illumination light from the distal end of the insertion portion, and captures reflected light of the illumination light at the distal end of the insertion portion. An in-vivo image is taken by receiving light with the element. The biological image captured in this way is displayed on the display of this endoscope system.

  As the image sensor, for example, a complementary metal oxide semiconductor (CMOS) image sensor is used. The CMOS image sensor generates an image pickup signal by a rolling shutter method in which reading is performed while shifting the timing for each horizontal line.

  In an endoscope system, for example, a subject moving with a vocal cord or the like may be observed using a rolling shutter system while irradiating intermittent illumination such as illumination with pulsed illumination light. As an endoscope system using such intermittent illumination, a technique for emitting pulsed illumination light (hereinafter referred to as pulsed light) in synchronization with the vibration frequency of the vocal cords is disclosed (for example, see Patent Document 1). ). In the technique disclosed in Patent Document 1, the brightness of the subject image is adjusted by adjusting the illumination period and the amount of illumination light by using the adjustment of the pulse width and pulse gain (pulse amplitude) of the pulsed light.

  By the way, when performing intermittent illumination, if the pulse gain (illumination light quantity) is increased in order to ensure the brightness of the image, it is necessary to apply a high voltage to the light source instantaneously or the amount of heat generated by the light source increases. There was a risk of problems such as Considering problems such as an increase in the amount of heat generated by the light source, it is preferable to adjust the brightness of the image of the subject by adjusting the pulse width.

JP 2001-104249 A

  However, if the pulse width (illumination period) is increased in order to ensure the brightness of the image, there is a possibility that an afterimage may occur in the image due to the movement (vibration) of the subject. In particular, when acquiring an image of a subject that vibrates at high speed, such as a vocal cord, an afterimage is likely to occur if the pulse width is increased. For this reason, it is necessary to set the pulse width so that both the brightness of the image and the suppression of the afterimage generation can be achieved and a high-quality image can be acquired.

  The present invention has been made in view of the above, and provides an imaging system and a processing apparatus capable of setting a pulse width capable of acquiring an image that achieves both image brightness and suppression of afterimage generation. With the goal.

  In order to solve the above-described problems and achieve the object, an imaging system according to the present invention includes an imaging unit that images an imaging target and outputs an imaging signal, a light source that generates pulsed light, and the imaging signal. A brightness evaluation unit that detects the brightness of the image and calculates a brightness evaluation value; evaluates the size of an afterimage in the image according to the imaging signal; and outputs the evaluation result as an afterimage evaluation value An afterimage evaluation unit, a pulse width calculation unit for calculating a pulse width of the pulsed light based on the brightness evaluation value and the afterimage evaluation value, and the pulse light with the pulse width calculated by the pulse width calculation unit. And a light source control unit that controls the light source so as to generate the light source.

  The imaging system according to the present invention is the imaging system according to the above invention, wherein the imaging unit is arranged in a matrix and has a plurality of pixels that photoelectrically convert received light to generate an electrical signal; and the light receiving unit A reading unit that sequentially reads out an electric signal for each pixel row, and the afterimage evaluation unit evaluates the size of the afterimage based on the electric signal read out by the reading unit. And

  The imaging system according to the present invention further includes a storage unit that stores setting information for the pulse width calculation unit to calculate a pulse width in the above-described invention, and the pulse width calculation unit is stored in the storage unit. The pulse width is calculated within a pulse width allowable range defined based on the set information.

  In the imaging system according to the present invention, in the above invention, an input unit that inputs change information for changing the setting information, and a control unit that changes the setting information based on the change information input by the input unit. The pulse width calculation unit calculates the pulse width based on the setting information changed by the control.

  In the imaging system according to the present invention, in the above invention, the setting information includes a minimum value of the brightness of the image and a reference level of the quality of the afterimage, and the pulse width calculation unit includes the brightness The pulse width is calculated based on the minimum value and the reference level.

  In the imaging system according to the present invention as set forth in the invention described above, the pulse width calculation unit uses a pulse width set based on a minimum value of the brightness of the image as a lower limit, and a pulse set based on the reference level. The pulse width allowable range is defined with the width as an upper limit value.

  In the imaging system according to the present invention as set forth in the invention described above, the input unit includes an operation unit capable of inputting the setting information by a rotation direction and a rotation amount with respect to a reference position.

  The processing device according to the present invention is connected to an imaging device having an imaging unit that images an imaging target and outputs an imaging signal, and a light source device having a light source that generates pulsed light based on a supplied pulse. A processing device capable of transmitting and receiving information between the imaging device and the light source device, and detecting brightness of an image corresponding to the imaging signal based on the imaging signal, and a brightness evaluation value A brightness evaluation unit that calculates the afterimage evaluation unit that evaluates the size of the afterimage in the image according to the imaging signal based on the imaging signal, and outputs the evaluation result as an afterimage evaluation value; Based on the brightness evaluation value and the afterimage evaluation value, a pulse width calculation unit for calculating a pulse width of the pulsed light, and the light source so as to generate the pulsed light with the pulse width calculated by the pulse width calculation unit Control light source Characterized by comprising a control unit, a.

  According to the present invention, there is an effect that it is possible to set a pulse width capable of acquiring an image that achieves both image brightness and suppression of afterimage generation.

FIG. 1 is a diagram illustrating a schematic configuration of an endoscope system according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a schematic configuration of the endoscope system according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the first embodiment of the present invention. FIG. 4 is a diagram for explaining an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment of the present invention, and schematically showing an open state of the vocal cords. FIG. 5 is a diagram illustrating an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment of the present invention. FIG. 6 is a diagram illustrating an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment of the present invention. FIG. 7 is a diagram for explaining afterimage evaluation processing performed by the afterimage evaluation unit of the endoscope system according to the first embodiment of the present invention. FIG. 8 is a diagram for explaining an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment of the present invention, and the position on the horizontal line when the emission width is short, and the position at the position It is a graph which shows the relationship with brightness. FIG. 9 is a diagram for explaining an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment of the present invention, and the position on the horizontal line when the emission width is long, and the position at the position It is a graph which shows the relationship with brightness. FIG. 10 is a block diagram illustrating a schematic configuration of the endoscope system according to the modification of the first embodiment of the present invention. FIG. 11 is a block diagram illustrating a schematic configuration of the endoscope system according to the second embodiment of the present invention. FIG. 12 is a diagram schematically illustrating the configuration of the foot switch of the endoscope system according to the second embodiment of the present invention. FIG. 13 is a diagram for explaining a pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the second embodiment of the present invention, and is a graph when there is no optimum point. FIG. 14 is a diagram for explaining a pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the second embodiment of the present invention, and is a graph when the minimum value of brightness is adjusted. FIG. 15 is a diagram for explaining the pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the second embodiment of the present invention, and is a graph when the quality of the afterimage is adjusted. FIG. 16 is a diagram for explaining a pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the second embodiment of the present invention, and is a graph when the gain adjustment value is adjusted. FIG. 17 is a timing chart illustrating frame output in the observation mode in the endoscope system according to the third embodiment of the present invention.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described. In the embodiment, as an example of an imaging system according to the present invention, a medical endoscope system that captures and displays an image of a body cavity of a subject such as a patient will be described. Moreover, this invention is not limited by this embodiment. Furthermore, in the description of the drawings, the same portions will be described with the same reference numerals.

(Embodiment 1)
FIG. 1 is a schematic diagram illustrating a schematic configuration of the endoscope system according to the first embodiment of the present invention. As shown in FIG. 1, an endoscope system 1 according to the first embodiment is introduced into a subject, and an endoscope 2 (images in the subject are generated by imaging the inside of the subject) ( A scope), a voice input device 3 to which voice is input, a processing device 4 that performs predetermined image processing on an imaging signal picked up by the endoscope 2 and controls each part of the endoscope system 1; A light source device 5 (light source unit) that generates pulsed light as illumination light (observation light) of the endoscope 2, and a display device 6 that displays an image corresponding to an image signal generated by the processing device 4 performing image processing; .

  The endoscope 2 includes an insertion part 21 to be inserted into a subject, an operation part 22 on the proximal end side of the insertion part 21 and held by an operator, and a flexible universal extending from the operation part 22. A code 23.

  The insertion portion 21 is realized using an illumination fiber (light guide cable) and an electric cable. The insertion unit 21 includes a distal end portion 211 having an imaging unit that incorporates an imaging element for imaging the inside of the subject, a bendable bending portion 212 configured by a plurality of bending pieces, and a proximal end portion side of the bending portion 212. And a flexible tube portion 213 having flexibility. The distal end portion 211 includes an illumination unit that illuminates the inside of the subject via an illumination lens, an observation unit that images the inside of the subject, an opening that communicates with the processing tool channel, and an air / water supply nozzle (not shown). Is provided.

  The operation unit 22 includes a bending knob 221 that bends the bending unit 212 in the vertical direction and the left-right direction, a treatment tool insertion unit 222 in which a treatment tool such as a bioforceps or a laser knife is inserted into the body cavity of the subject, and the processing device 4. And a plurality of switch units 223 for operating peripheral devices such as the light source device 5, the air supply device, the water supply device, and the gas supply device. The treatment instrument inserted from the treatment instrument insertion portion 222 is exposed from the opening at the distal end of the insertion portion 21 via a treatment instrument channel provided inside.

  The universal cord 23 is configured using an illumination fiber and an electric cable. The universal cord 23 branches at the proximal end, and the end of one branched cord 231 is a connector 232, and the other proximal end is a connector 233. The connector 232 is detachable from the processing device 4, and the connector 233 is detachable from the light source device 5. The universal cord 23 propagates the illumination light emitted from the light source device 5 to the distal end portion 211 via the connector 232, the operation unit 22, and the flexible tube unit 213. The universal code 23 transmits an imaging signal captured by the imaging unit provided at the distal end portion 211 to the processing device 4.

  The insertion portion 21 and the universal cord 23 are provided with an illumination fiber 214 (see FIG. 2) that guides illumination light from the light source device 5. One end of the illumination fiber 214 is located on the distal end surface of the insertion portion 21, and the other end is located on the connection surface of the universal cord 23 with the light source device 5.

  When the subject is a vocal cord, the voice input device 3 receives a voice emitted from the vocal cord. The distal end of the cord 31 is connected to the audio input device 3, and the proximal connector 311 is detachable from the processing device 4. The voice input device 3 outputs the input voice to the processing device 4 via the cord 31 and the connector 311.

  The processing device 4 performs predetermined image processing on the imaging signal in the subject imaged by the imaging unit at the distal end portion 211 of the endoscope 2 input via the universal code 23. The processing device 4 controls each unit of the endoscope system 1 based on various instruction signals transmitted from the switch unit 223 in the operation unit 22 of the endoscope 2 via the universal code 23.

  The light source device 5 includes a light source that emits pulsed white light as illumination light (hereinafter referred to as pulsed light), a condenser lens, and the like. The light source device 5 receives the dimming signal from the processing device 4 and, based on the dimming signal, the drive timing (light emission period) for driving the light source is PWM (Pulse Width Modulation) controlled. For this reason, the illumination unit 31 emits pulsed light by pulse driving under the control of the illumination control unit 32. The light source device 5 illuminates (intermittent illumination) the pulsed light from the light source toward the subject, which is the subject, to the endoscope 2 connected via the connector 232 and the universal cord 23 (illumination fiber). Supplied as illumination light.

  The display device 6 is configured using a display using liquid crystal or organic EL (Electro Luminescence). The display device 6 displays various information including an image corresponding to the display image signal generated by the processing device 4 via the video cable 61. Thereby, the surgeon can observe and characterize a desired position in the subject by operating the endoscope 2 while viewing the image (in-vivo image) displayed on the display device 6.

  Next, the configuration of the endoscope 2, the voice input device 3, the processing device 4, and the light source device 5 described in FIG. 1 will be described. FIG. 2 is a block diagram schematically showing the configuration of the endoscope system 1.

  The endoscope 2 has an imaging unit 24 at the distal end portion 211. The imaging unit 24 is provided at an image forming position of the optical system 241 such as an objective lens disposed on the light receiving surface side of the light receiving unit 242a, which will be described later, and receives light collected by the optical system 241. An image sensor 242 that performs photoelectric conversion to an electrical signal.

  The image sensor 242 is realized using a complementary metal oxide semiconductor (CMOS) image sensor. The imaging element 242 includes a light receiving unit 242a and a reading unit 242b.

  The light receiving unit 242a receives light from the subject illuminated with pulsed light from the light source device 5 on the light receiving surface, and photoelectrically converts the received light to generate an electrical signal. Specifically, in the light receiving unit 242a, a plurality of pixels each having a photodiode that accumulates charges according to the amount of light, a capacitor that converts charges transferred from the photodiodes to voltage levels, and the like are arranged in a matrix, Each pixel photoelectrically converts light from the optical system 241 to generate an electrical signal. In the light receiving unit 242a, a plurality of pixel rows (horizontal lines) in which two or more pixels are arranged in the horizontal direction are arranged in the vertical direction.

  The readout unit 242b sequentially reads out electrical signals generated by pixels arbitrarily set as readout targets among the plurality of pixels of the light receiving unit 242a, and outputs them as imaging signals. The reading unit 242b performs exposure of a plurality of pixels in the light receiving unit 242a and reading of electric signals from the plurality of pixels. The reading unit 242b sequentially reads out electrical signals generated by a plurality of pixels arranged in a matrix for each horizontal line (pixel row). The readout unit 242b executes an imaging operation for performing exposure and readout from the top horizontal line, shifts the timing for each horizontal line, performs charge reset (capacitor reset), and an imaging signal by a rolling shutter system that performs exposure and readout. Generate.

  Therefore, in the imaging unit 24, the exposure timing and the readout timing are different for each horizontal line even in one imaging period (frame). The reading unit 242b outputs an electrical signal (imaging signal) read from the plurality of pixels of the light receiving unit 242a to the processing device 4 via a cable (not shown) and the connector 232.

  Next, the processing device 4 will be described. The processing device 4 includes an AGC (Auto Gain Control) 401, a strobe processing unit 402, an image processing unit 403, a memory 404, a display control unit 405, an input unit 406, a vibration frequency detection unit 407, and a light source control. Unit 408, brightness evaluation unit 409, afterimage evaluation unit 410, and control unit 411. In the present embodiment, description will be made assuming that the processing device 4, the endoscope 2, and the light source device 5 operate based on a clock signal generated by a clock generator (not shown) provided in the processing device 4.

  The AGC 401 adjusts the amplification factor (gain) of the electrical signal and maintains a constant output level.

  The strobe processing unit 402 acquires a PWM signal for controlling intermittent illumination using pulsed light from the light source device 5, and outputs an imaging signal input from the AGC 401 in association with the PWM signal to the image processing unit 403.

  The image processing unit 403 performs predetermined signal processing on the electrical signals (imaging signals) of a plurality of pixels read by the reading unit 242b of the imaging unit 24 to generate an image signal. For example, the image processing unit 403 performs at least an optical black subtraction process, a white balance (WB) adjustment process, a synchronization process, a color matrix calculation process, and a gamma correction process when the image pickup device is a Bayer array. Image processing including color reproduction processing and edge enhancement processing is performed.

  The memory 404 is realized using a volatile memory or a nonvolatile memory, and stores various programs for operating the processing device 4 and the light source device 5. The memory 404 temporarily records information being processed by the processing device 4. The memory 404 stores the imaging signal read by the reading unit 242b in units of frames in association with the matrix arrangement of the plurality of pixels in the light receiving unit 242a. The memory 404 stores the image signal generated by the image processing unit 403 in units of frames. The memory 404 may be configured using a memory card or the like mounted from the outside of the processing device 4.

  The display control unit 405 selects a display image signal from the image signals of a plurality of frames generated by the image processing unit 403 in accordance with the display cycle of the display device 6, and displays the selected image signal on the display device 6. To output as an image signal. Alternatively, the display control unit 405 generates a display image signal by combining the image signals of a plurality of frames generated by the image processing unit 403 for each display cycle of the display device 6, and outputs the display image signal to the display device 6. The display control unit 405 converts the display image signal from a digital signal to an analog signal, changes the converted analog image signal to a format such as a high-definition method, and outputs the converted signal to the display device 6.

  The input unit 406 is realized using an operation device such as a mouse, a keyboard, and a touch panel, and receives input of various instruction information (instruction signals) of the endoscope system 1. Specifically, the input unit 406 inputs subject information (for example, ID, date of birth, name, etc.), identification information (for example, ID or examination corresponding item) of the endoscope 2, and various instruction information such as examination contents. Accept.

  The vibration frequency detection unit 407 detects the frequency of the voice (voice band frequency) input to the voice input device 3 and input to the processing device 4 via the cord 31 and the connector 311. In the first embodiment, this sound is emitted from a vocal cord that is a subject. The vibration frequency detection unit 407 outputs the detected audio frequency to the control unit 411.

  The light source control unit 408 controls the operation of the light source device 5. Specifically, the light source control unit 408 controls the illumination timing and illumination period of the pulsed light from the light source 51 in synchronization with the audio frequency detected by the vibration frequency detection unit 407.

  In addition, the light source control unit 408 includes a pulse width calculation unit 408a. Based on the evaluation results from the brightness evaluation unit 409 and the afterimage evaluation unit 410, the pulse width calculation unit 408a calculates a pulse width (or duty ratio) that is an illumination period of the pulsed light from the light source 51. The duty is a ratio obtained by dividing the pulse width by the pulse period.

  The brightness evaluation unit 409 detects the brightness level corresponding to each pixel from the imaging signal input from the strobe processing unit 402 and outputs the detected brightness level to the light source control unit 408. Specifically, the brightness evaluation unit 409 detects the pixel values of the pixels constituting the image, calculates the average of the pixel values (luminance), and controls the light source as a brightness evaluation value for evaluating the brightness. Output to the unit 408.

  The afterimage evaluation unit 410 acquires pixel values of pixels arranged in a direction orthogonal to the horizontal lines of the pixels of the light receiving unit 242a from the imaging signal input from the strobe processing unit 402, and whether there is continuity of the pixel values Alternatively, the size of the afterimage is evaluated by evaluating (detecting) the degree of discontinuity. The size of the afterimage here is a numerical value of the degree of presence of the afterimage when the afterimage has occurred. The afterimage evaluation unit 410 outputs the evaluation result to the light source control unit 408.

  The control unit 411 is realized using a CPU or the like. The control unit 411 controls the processing operation of each unit of the processing device 4. The control unit 411 controls the operation of the processing device 4 by transferring instruction information and data to each component of the processing device 4. The control unit 411 is connected to the imaging unit 24 and the light source device 5 via each cable. Note that the control unit 411 also controls the operation of the imaging unit 24. In this embodiment, the image sensor 242 and the light source 51 are described as being driven in synchronization with the imaging timing and the illumination timing under the control of the control unit 411.

  Next, the light source device 5 will be described. The light source device 5 includes a light source 51, a light source driver 52, and a pulse generation unit 53.

  The light source 51 includes a light source such as a white LED that emits pulsed white light (pulse light) and an optical system such as a condenser lens. The light source 51 generates illumination light to be supplied to the endoscope 2 and guides the illumination light to the endoscope 2 through an illumination fiber or the like.

  The light source driver 52 supplies predetermined power to the light source 51 based on the PWM signal generated by the pulse generation unit 53. Thereby, the light (pulse light) emitted from the light source 51 is illuminated on the subject from the distal end portion 211 of the insertion portion 21 via the connector 233 and the universal cord 23.

  The pulse generator 53 generates a pulse for driving the light source 51 based on the sound frequency detected by the vibration frequency detector 407 and the value (pulse width or duty ratio) calculated by the pulse width calculator 408a. Then, a PWM signal for light source control including the pulse is generated and output to the light source driver 52. Further, the pulse generation unit 53 outputs the generated PWM signal to the strobe processing unit 402.

  Next, a pulse width calculation process in the endoscope system 1 will be described with reference to FIG. FIG. 3 is a diagram illustrating a pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the first embodiment. The graph shown in FIG. 3 shows the relationship between the pulse width and the pulse width with respect to the afterimage quality and image brightness. In the graph shown in FIG. 3, the time width of the pulse is, for example, a duty ratio. In the following description, it is assumed that the quality of the afterimage and the setting value of the minimum brightness value (Min value) are set in advance and stored in the memory 404 or the like. The quality of the afterimage indicates the degree of presence of the afterimage. The smaller the presence of the afterimage in the image, the better the quality of the image, and the greater the presence of the afterimage in the image, the worse the quality of the image. . For example, when the reciprocal of the degree of presence of the afterimage is used as the quality of the afterimage, the higher the afterimage quality value, the higher the quality of the image. In the first embodiment, a set value (reference level) is set as an allowable level of afterimage quality corresponding to the value output from the afterimage evaluation unit 410.

  The pulse width calculation unit 408a generates a curve S1 for the brightness of the image based on the brightness detection value calculated by the brightness evaluation unit 409, the frequency detected by the vibration frequency detection unit 407, and the like. Specifically, the pulse width calculation unit 408a includes a pixel value (or average value), a duty ratio (pulse width) when the pixel value (or average value) is acquired (during imaging), and a vibration frequency detection unit. Based on the frequency detected by 407, the curve S1 is generated (updated). Since the brightness of the image changes according to the distance between the distal end portion 211 and the subject, the pulse width calculation unit 408a generates the curve S1 every time the brightness evaluation value is input from the brightness evaluation unit 409.

In addition, the pulse width calculation unit 408a calculates a curve S2 for the quality of the afterimage based on the evaluation result of the afterimage by the afterimage evaluation unit 410 and the frequency of the voice (voice band frequency) detected by the vibration frequency detection unit 407. Specifically, the pulse width calculation unit 408a generates (updates) the curve S2 every time the pulse width is calculated based on the acquired vocal cord frequency. The quality of afterimage (occurrence of afterimage) changes monotonously (with linearity) according to the vocal cord frequency (pulse width). Since the quality of the residual image will vary depending on the vocal cords frequency, pulse width calculating unit 408a, each time the evaluation result is inputted from the residual image evaluation unit 410, it generates the curve S 2.

  The pulse width calculation unit 408a generates a graph (see FIG. 3) indicating the relationship between the brightness of the image and the light emission pulse width (curve S1) and the relationship between the quality of the afterimage and the light emission pulse width (curve S2). Referring to the set values stored in the memory 404 or the like, the intersection S11 between the curve S1 and the minimum brightness necessary for observation, and the quality (allowable level) of the afterimage allowed in the curve S2 and observation. The intersection S21 is obtained, and the interval between the intersections S11 and S21 is defined as a pulse width allowable range (hatched portion in FIG. 3). The pulse width calculation unit 408a adjusts the duty ratio (optimum point) within a prescribed pulse width allowable range. The pulse width calculation unit 408 a calculates the pulse width based on the adjusted duty ratio and the frequency (pulse period) detected by the vibration frequency detection unit 407 and outputs the pulse width to the pulse generation unit 53.

  When the pulse generation unit 53 acquires the pulse width from the pulse width calculation unit 408a, the pulse generation unit 53 generates a pulse corresponding to the pulse width, the vocal cord frequency detected by the vibration frequency detection unit 407, and the acquired pulse width.

  In this way, the light source 51 drives the light source 51 according to the pulse generated by the pulse generation unit 53 under the control of the light source driver 52 to emit pulsed light.

  Next, afterimage evaluation performed by the afterimage evaluation unit 410 will be described with reference to the drawings. FIG. 4 is a diagram for explaining an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment and schematically showing an open state of the vocal cords. The vocal cords emit sound by causing the air discharged from the lungs to pass through a gap between a pair of left and right pleats that change their open state by approaching or separating from each other, causing vibrations. At this time, the gap between the folds of the vocal cords changes at a high speed due to vibration. For example, the vocal cords are shown in FIG. 4C from the open state (interval d1) of the vocal cord V1 shown in FIG. 4A to the open state (interval d2) of the vocal cord V2 shown in FIG. After the open state of V3 (interval d3), the change is repeated such that the vocal cord V2 returns to the state of the vocal cord V1 through the open state of the vocal cord V2. In general, in a vocal cord image, the folds are white and the trachea visible behind the folds appears dark. For this reason, in the vocal cord image, the contrast between the folds and the trachea is large.

  FIG. 5 is a diagram for explaining the afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment, and is a timing chart showing the timing of the readout process and the exposure process (FIG. 5A). ), And a diagram (FIG. 5B) schematically showing an image showing a vocal cord open state corresponding to a pseudo frame obtained by one light emission. In addition, V1-V3 in Fig.5 (a) has shown the open state of the vocal cords in the time. As shown in FIG. 5A, the image sensor 242 reads out the electrical signals of the first to nth lines (for one frame) at different timings for the exposure processing of the light receiving unit 242a and for each horizontal line. The imaging process including the in-vivo image of the subject is acquired by alternately repeating the reading process by the unit 242b. Further, the intermittent illumination by the pulsed light from the light source device 5 is performed in synchronization with the movement (voice band frequency) of the vocal cords V1 to V3 described above (for example, light emission T1 to T3 in FIG. 5A).

  For example, in the light emission T2, different open vocal cords V1 to V3 are illuminated during the light emission period, and an image obtained by the light receiving unit 242a receiving light from the illumination is output as an imaging signal. For example, the vocal cord image P1 (see FIG. 5B) obtained by the light emission T2 is an image of a pseudo frame in which electrical signals to be read out as the frame 1 and the frame 2 are mixed, and is a vocal cord image indicating the open state of the vocal cords. is there. The pseudo frame can be generated by the strobe processing unit 402 based on the electrical signal associated with the PWM signal. The vocal cord image P1 is divided along a horizontal line of pixels, and a first region R1 in which an image is generated by the frames 1 and 2, a second region R2 in which an image is generated by the frame 1, And a third region R3 in which an image is generated by the frame 2. Since the exposure time for each open state of the vocal cords V1 to V3 is different at the boundary between the regions, there is a difference in the pixel value of the obtained image (luminance in adjacent pixels).

  FIG. 6 is a diagram for explaining an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment, and shows an open state of a vocal cord according to a pseudo frame obtained by one light emission. A diagram schematically showing the image (FIG. 6A), and a position along a straight line L1 (a straight line parallel to a direction (vertical direction of the pixel) perpendicular to the horizontal line of the pixel) in the image, It is a graph (Drawing 6 (b)) showing relation with an output value (pixel value). The output value (pixel value) corresponding to the position on the straight line L1 (see FIG. 6A) provided in the vocal cord image P1 continuously changes in each of the first region R1 to the third region R3. However, the output values of adjacent pixels (pixels located at each boundary) at the boundary position are different and change discontinuously at the boundary of each region.

  FIG. 7 is a diagram for explaining an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment, and schematically shows an open state of the vocal cords (FIG. 7A). 8 is a timing chart (FIG. 7B) showing timings of reading processing and exposure processing in one frame. FIG. 8 is a diagram for explaining an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment, where the horizontal line (H direction) when the light emission width (the illumination period by the light emission Tn) is short. ) Is a graph showing the relationship between the upper position and the brightness (pixel value) at the position. FIG. 9 is a diagram for explaining an afterimage evaluation process performed by the afterimage evaluation unit of the endoscope system according to the first embodiment, and is a horizontal line (H direction) when the light emission width (the illumination period by the light emission Tn) is long. ) Is a graph showing the relationship between the upper position and the brightness (pixel value) at the position.

  In the frame N (see FIG. 7B) obtained by the light emission Tn, for example, when the pixel value (brightness) is viewed along a predetermined horizontal line (straight line L2), as shown in FIG. 8, the light emission width (light emission Tn) is obtained. When the illumination period is short, the brightness (edge) between the folds and the gap (trachea) in the vocal cords changes abruptly. That is, the number of pixels when the brightness changes from the maximum value to the minimum value is relatively small. In this case, the obtained vocal cord image is an image having a high contrast between the folds and the gap, for example, an image of the vocal cord V2. The light emission Tn in this case, for example, illuminates only the state of the vocal cord V2, not including the state of the vocal cords V1, V3.

  On the other hand, as shown in FIG. 9, when the light emission width (illumination period by the light emission Tn) is long, the brightness (edge) between the folds and the gap in the vocal cords gradually changes along the H direction. That is, the number of pixels when the brightness changes from the maximum value to the minimum value is relatively large. In this case, the obtained vocal cord image is an image with low contrast between the folds and the gap. The light emission Tn in this case includes, for example, the states of vocal cords V1 to V3. In this case, the obtained vocal cord image is an image in which open states shown in vocal cords V1 to V3 are mixed.

  The afterimage evaluation unit 410 has presence / absence of continuity of pixel values (luminance) in a direction orthogonal to the horizontal line of the pixels obtained based on the imaging signal input from the strobe processing unit 402 (for locations having discontinuity). Afterimage is evaluated based on (detection) and a change in pixel value (luminance) (edge detection) along the horizontal line (H direction) of the pixel. Specifically, the afterimage evaluation unit 410 has discontinuity when the difference between the pixel values of adjacent pixels at each boundary of the first region R1 to the third region R3 in the vertical direction of the pixel is greater than a predetermined value. While detecting as a thing, the magnitude | size of an afterimage is determined based on the magnitude | size of the difference. In addition, the afterimage evaluation unit 410 sets a presence level for each predetermined number of pixels, and determines the size of the afterimage based on the number of pixels included in the detected edge range. The afterimage evaluation unit 410 digitizes the degree of presence of the afterimage based on the size of each afterimage in the horizontal and vertical directions, and outputs it as an afterimage evaluation result. For example, when the afterimage evaluation unit 410 calculates the reciprocal of the product of the size of each afterimage as the quality of the afterimage, the higher the afterimage quality (closer to 1), the better the afterimage quality.

  Based on the evaluation results from the brightness evaluation unit 409 and the afterimage evaluation unit 410, the light source control unit 408 causes the pulse width calculation unit 408a to calculate the pulse width that is the illumination period of the pulsed light from the light source 51. Specifically, the light source control unit 408 calculates the pulse width to the pulse width calculation unit 408a based on the evaluation value of the brightness acquired from the brightness evaluation unit 409 and the afterimage level from the afterimage evaluation unit 410. Let

  According to the first embodiment described above, based on the evaluation results from the brightness evaluation unit 409 and the afterimage evaluation unit 410, the light source control unit 408 causes the pulse width calculation unit 408a to calculate the pulse width, and the calculated pulse width Since the pulse generation unit 53 generates a pulse based on the above and controls the light emission by the light source 51, it is possible to set a pulse width capable of acquiring an image that achieves both the brightness of the image and the suppression of the afterimage generation. it can.

(Modification of Embodiment 1)
Next, a modification of the first embodiment of the present invention will be described. FIG. 10 is a block diagram illustrating a schematic configuration of an endoscope system according to a modification of the first embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the structure same as the structure mentioned above. An endoscope system 1a according to this modification includes the endoscope 2, the voice input device 3, the light source device 5, the display device 6, and the processing device 4a described above. In the processing device 4a, in addition to the configuration of the processing device 4 of the first embodiment described above, the light source control unit 408 includes a gain value calculation unit 408b.

  The gain value calculation unit 408b calculates a gain adjustment value for gain adjustment performed by the AGC 401 based on the evaluation result by the brightness detection unit 410, and outputs the calculated gain adjustment value to the AGC 401. Specifically, the gain value calculation unit 408b determines the electrical signal based on the brightness evaluation value (luminance) acquired from the brightness evaluation unit 409 and the minimum brightness value stored in the memory 404. An amplification factor is calculated, and the amplification factor is output to the AGC 401 as a gain adjustment value.

  According to the modified example described above, as in the first embodiment described above, the pulse light is controlled by the light source 51 and the electric power obtained based on the brightness evaluation result acquired from the brightness evaluation unit 409 is obtained. Since the gain of the signal is calculated and the AGC 401 adjusts the gain based on the calculated gain, a high-quality image is obtained that ensures the brightness of the image and suppresses the occurrence of afterimages. can do.

  Note that, as in this modification, the gain adjustment by the AGC 401 may be controlled, and the light source control unit 408 outputs the light source 51 based on the gain adjustment value obtained by the gain value calculation unit 408b. The light source driver 52 may be controlled so as to adjust the above.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. FIG. 11 is a block diagram illustrating a schematic configuration of the endoscope system according to the second embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the structure same as the structure mentioned above. In the first embodiment described above, the reference level of the afterimage quality and the minimum value (Min value) of the brightness are stored in the memory 404 and the like, and the pulse width calculation unit 408a refers to the reference level and the minimum value of the brightness. In the second embodiment, the pulse width calculation unit 408a sets the afterimage quality (reference level) or the minimum brightness value changed according to the input from the outside. The pulse width is calculated based on the value.

  The endoscope system 1b according to the second embodiment includes the endoscope 2, the voice input device 3, the processing device 4, the light source device 5, the display device 6, and the foot switch 7 (input means) described above. . In the second embodiment, the endoscope 2 is provided with a switch 223a that inputs an instruction signal to the pulse width calculation unit 408a as one of the plurality of switch units 223. Specifically, the switch 223 a inputs, to the control unit 411, an instruction signal that gives priority to gain adjustment by the AGC 401 over control of pulsed light (pulse width) by the light source 51.

  FIG. 12 is a diagram schematically illustrating the configuration of the foot switch of the endoscope system according to the second embodiment. A foot switch 7 shown in FIG. 12 has a base 70 and a pedal 71 (operation means). The base 70 has a substantially flat plate shape, and outputs an instruction signal to the processing device 4 (control unit 411) via a signal line (not shown). The pedal 71 has a substantially plate shape, one end is connected to the base 70, and is movable in a direction (first direction (arrow Q 1)) orthogonal to the main surface of the base 70. It is possible to move in a direction parallel to the main surface (second direction (arrow Q2)). In other words, the pedal 71 can change the angle formed by the main surface of the pedal 71 and the main surface of the base portion 70 (arrow Q1) and rotates around an axis orthogonal to the main surface of the pedal 71. Possible (arrow Q2). The foot switch 7 continues to output the instruction signal periodically while the pedal 71 is operated, and stops outputting the instruction signal when the pedal 71 returns to the reference position. The reference position in the second embodiment is a position that is set in advance and returns when the pedal 71 is not applied with a load other than gravity and its own weight, and the pedal is at a predetermined angle with respect to the base 70. It is a position that rises and becomes the center of the movement range in the second direction. In the second embodiment, the pedal is described as the operating means, but a lever that can be operated by the operator manually may be used.

  The foot switch 7 is operated according to the operation of the surgeon's pedal 71, for example, when the pedal 71 is depressed (moving in the direction of the arrow Q1) or rotated (moving in the direction of the arrow Q2) by the surgeon's foot. Input the signal. Specifically, the foot switch 7 outputs an instruction signal to adjust the emission frequency when the pedal 71 is pressed, that is, when the pedal 71 moves in the direction of the arrow Q1. For example, when the pedal 71 is pressed in the downward direction of the arrow Q1 in FIG. 12, the foot switch 7 inputs an instruction signal for increasing the frequency according to the pressed amount to the control unit 411. By adjusting the light emission frequency, the frequency difference between the light emission frequency and the vocal cord frequency is adjusted. For example, if the frequency difference becomes zero, the same open vocal cord image is picked up, and as the frequency difference increases, a different open vocal cord image is picked up.

  Further, when the pedal 71 rotates, that is, when the pedal 71 moves in the direction of the arrow Q2, the foot switch 7 outputs an instruction signal for adjusting the reference level of the afterimage quality or the minimum value of brightness. For example, when the pedal 71 rotates to the right of the arrow Q2 in FIG. 12, the foot switch 7 outputs an instruction signal to the control unit 411 to decrease the minimum brightness value (Min value) according to the rotation amount. To do. When the pedal 71 rotates in the left direction of the arrow Q2 in FIG. 12, the foot switch 7 outputs an instruction signal to the control unit 411 to lower the reference level of the afterimage quality according to the amount of rotation.

  Here, in Embodiment 1 described above, the pulse width calculation unit 408a generates a graph (see FIG. 3), and then refers to the setting value stored in the memory 404 or the like, and is necessary for the curve S1 and observation. The intersection S11 with the minimum brightness value and the intersection S21 between the curve S2 and the quality of the afterimage (reference level) allowed in observation are obtained, and between the intersections S11 and S21 (within the allowable pulse width). Adjust the pulse width.

  FIG. 13 is a graph for explaining a pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the second embodiment, and is a graph when there is no optimum point. The graph shown in FIG. 13 shows a curve S3 indicating the relationship between the pulse width (duty ratio) and the brightness of the image, and a curve S4 indicating the relationship between the duty ratio and the quality of the afterimage. Depending on the size and volume of the vocal cords and the amplitude of the vocal cord vibration, there may be no optimum point. Here, the optimum point is determined based on whether or not the obtained pulse width is larger than a predetermined value. If the pulse width is smaller than the predetermined value, it is determined that there is no optimum point. If there is no optimum point, the pulse width calculation unit 408a cannot calculate the pulse width.

  In this case, the surgeon adjusts the setting value of the quality of the afterimage or the minimum value of brightness, and the curve S3 and the minimum value of brightness required for observation (set minimum value: setting value) and The foot switch 7 is operated so that the optimum point exists by changing the position of the intersection S31 between the intersection S31 or the curve S4 and the quality of the afterimage allowed for observation (set reference level: set value). To do.

  FIG. 14 is a diagram for explaining a pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the second embodiment, and is a graph when the minimum value of brightness is adjusted. When the pedal 71 is rotated in the right direction of the arrow Q2 by the operator's operation, the foot switch 7 inputs an instruction signal for decreasing the minimum value of brightness according to the rotation amount to the control unit 411. The control unit 411 adjusts the setting value by lowering the minimum brightness value (setting value) in accordance with the input instruction signal, and causes the pulse width calculation unit 408a to adjust the adjusted minimum brightness value (adjustment value). ) Instruct to calculate the pulse width.

  Based on the instruction from the control unit 411, the pulse width calculation unit 408a obtains an intersection S32 between the curve S3 and the adjusted minimum brightness value (adjustment value), and allows a pulse width between the intersection S32 and the intersection S41. It is defined as a range (hatched portion in FIG. 14). The pulse width calculation unit 408a adjusts the pulse width within a prescribed pulse width allowable range. Thereby, although the brightness is slightly deteriorated, an image with little afterimage (maintaining the quality of the afterimage) can be acquired.

  FIG. 15 is a graph for explaining the pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the second embodiment, and is a graph when the quality of the afterimage is adjusted. When the pedal 71 is rotated in the left direction of the arrow Q2 by the operator's operation, the foot switch 7 sends an instruction signal to the control unit 411 to lower the reference level (setting value) of the afterimage quality according to the rotation amount. input. The control unit 411 adjusts the set value by lowering the reference level (set value) according to the input instruction signal, and calculates the pulse width at the adjusted reference level (adjusted value) for the pulse width calculating unit 408a. To instruct

  Based on an instruction from the control unit 411, the pulse width calculation unit 408a obtains an intersection S42 between the curve S4 and the adjusted reference level (adjustment value), and a pulse width allowable range (see FIG. 15) between the intersection S31 and the intersection S42. (Hatched part in the middle) The pulse width calculation unit 408a adjusts the pulse width within a prescribed pulse width allowable range. Thereby, although the afterimage increases slightly, it is possible to obtain an image maintaining the brightness.

  As described above, in the second embodiment, the pulse width calculation unit 408a uses the pulse width set based on the minimum value of the image brightness as the lower limit value and the pulse width set based on the reference level as the upper limit value. A width allowable range is defined, and the pulse width is calculated within the defined pulse width allowable range.

  Further, the surgeon changes the noise adjustment value by rotating the pedal 71 in the arrow Q2 direction while pressing the switch 223a. FIG. 16 is a diagram for explaining a pulse width calculation process performed by the pulse width calculation unit of the endoscope system according to the second embodiment, and is a graph when the gain adjustment value is adjusted. For example, when the switch 223a is pressed by the operator's operation and an instruction signal is input to the control unit 411, and the pedal 71 is rotated in the right direction of the arrow Q2 and the instruction signal is input, the foot switch 7 is An instruction signal for adjusting the gain adjustment value according to the rotation amount, specifically, increasing the amplification factor of the electric signal, is input to the control unit 411.

  When the instruction signal is input from the switch 223a and the foot switch 7, the control unit 411 instructs the AGC 401 to adjust the gain adjustment value (the amplification factor of the electric signal) according to the rotation amount. The pulse width calculation unit 408a corrects the slope of the curve S3 according to the changed amplification factor, and newly generates a curve S3a indicating the relationship between the pulse width (duty ratio) and the brightness of the image. The pulse width calculation unit 408a obtains an intersection S33 between the generated curve S3a and the adjusted minimum brightness value (set value), and adjusts the pulse width between the intersection S33 and the intersection S41.

  The AGC 401 increases the amplification factor of the electric signal based on an instruction from the control unit 411 and adjusts the gain of the electric signal input from the imaging unit 24. Thereby, although the noise generation rate is slightly increased, it is possible to acquire an image that maintains brightness and has little afterimage (maintains the quality of the afterimage).

  According to the second embodiment described above, the pulse width calculation unit 408a calculates the pulse width by changing the set value according to the input from the outside, and the pulse generation unit 53 generates the pulse based on the calculated pulse width. Since the light emission by the light source 51 is generated and controlled, even if there is no optimal point in the graph for calculating the pulse width, the brightness of the image and the high image quality that suppresses the occurrence of afterimages. Of these, at least one can be maintained and the other finely tuned image can be acquired.

(Embodiment 3)
Next, a third embodiment of the present invention will be described. In the third embodiment, the two observation modes of the normal observation mode and the super slow mode can be switched in the configuration of the first embodiment described above, and the observation mode is switched according to the input instruction signal. An imaging process and an image display process are performed.

  For example, when an instruction signal for switching the observation mode is input via the input unit 406, the control unit 411 instructs the imaging unit 24 to perform imaging processing in the observation mode corresponding to the instruction signal. When the observation mode is the normal observation mode, the imaging unit 24 reads out the electrical signals of all the pixels in the effective pixel region in the light receiving unit 242a and outputs them to the AGC 401.

  On the other hand, when the observation mode is the super slow mode, the readout unit 242b reads out an electrical signal partially by thinning out some of the pixels in the effective pixel region in the light receiving unit 242a and outputs the electrical signal to the AGC 401. For example, the reading unit 242b reads every other line in each line. Note that the drive frequency of the imaging unit 24 may be increased by reducing the number of output bits from the imaging unit 24 or increasing the transmission speed of the cable. In the super slow mode, it is preferable to improve sensitivity by adding adjacent pixels.

  Specifically, in the normal observation mode, the imaging unit 24, the processing device 4, and the display device 6 are driven at a driving frequency of 60 Hz, for example. On the other hand, in the super slow mode, for example, the imaging unit 24 and the processing device 4 are driven at a driving frequency of 480 Hz, and the display device 6 is driven at a driving frequency of 60 Hz.

  FIG. 17 is a timing chart for explaining the frame output in the observation mode in the endoscope system according to the third embodiment. FIG. 17A shows a timing chart in the normal observation mode, and FIG. Shows a timing chart in the super slow mode. In the normal observation mode, since the driving frequency of the imaging process is the same as the driving frequency for the display device 6 to perform display, the display device 6 displays an image of each frame at a speed equivalent to the frame rate. For this reason, the display device 6 reproduces a moving image in which the movement of the subject has an operation speed equivalent to the actual movement speed.

  On the other hand, in the super slow mode, since the driving frequency of the imaging process is higher than the driving frequency for the display device 6 to perform display, the display device 6 displays an image of each frame at a speed slower than the frame rate. For this reason, the display device 6 reproduces a moving image in which the movement of the subject is slower than the actual operation speed.

  Further, the memory 404 stores data according to the driving frequency at the time of image capturing processing. For this reason, even when an image (moving image) is displayed on the display device 6 with reference to the memory 404, moving image reproduction according to the observation mode at the time of imaging can be performed.

  According to the third embodiment described above, since the imaging processing speed and the image display speed are changed according to the observation mode, vibration of the subject that is difficult to synchronize with light emission, for example, abnormal vocal cord vibration (voice vocal vibration is irregular) Even when the object is asymmetrical or non-periodic), a moving subject such as a vocal cord can be observed. Moreover, since observation can be performed only by changing the mode, it can be realized at low cost.

  In the first and second embodiments described above, a plurality of light beams that are arranged on the optical path of white light (illumination light) emitted from the light source 51 and transmit only light in a predetermined wavelength band among the white light by rotating. You may provide the rotation filter which has these filters. By providing the rotary filter, light having the wavelength bands of red light (R), green light (G), and blue light (B) is sequentially transmitted and emitted. Of the white light (W illumination) emitted from the light source 51, by rotating the rotation filter in accordance with the emission timing of the pulsed light, the narrow band red light (R illumination), green light (G illumination), and blue light Any light (B illumination) can be sequentially emitted to the endoscope 2 (plane sequential method). In addition to the rotary filter, a light source (for example, an LED light source) that emits light in each wavelength band may be used.

  In the first and second embodiments described above, the image sensor 242 is described as operating under the control of the control unit 411. However, the timing detection unit 47 and the illumination timing setting unit 48 are arranged on the endoscope 2 side. It may be provided to control the polarizing element 53 on the endoscope 2 side. In addition, although it has been described that the image sensor 242 operates based on the clock signal generated by the processing device 4, the endoscope 2 is provided with a clock generation unit, and the clock signal generated by the clock generation unit (endoscope 2). May be operated based on a clock signal generated by an external clock generator, or may be operated based on a clock signal generated by an external clock generator.

  In the first and second embodiments described above, the AGC 401 is described as being provided in the processing device 4, but may be provided in the endoscope 2 (for example, the imaging unit 24). Further, the pulse width calculation unit 408a and the gain value calculation unit 408b have been described as being provided in the light source control unit 408. However, the pulse width calculation unit 408a and the gain value calculation unit 408b are provided independently of the light source control unit 408. An evaluation value may be acquired from the unit 410.

  In the first and second embodiments described above, the subject has been described as a vocal cord. However, in addition to the vocal cord, any subject that vibrates at high speed and can detect the frequency by the vibration frequency detection unit 407 is applicable. .

  As described above, the imaging system and the processing apparatus according to the present invention are useful for setting a pulse width capable of acquiring an image that achieves both image brightness and suppression of afterimage generation.

1, 1a, 1b Endoscope system 2 Endoscope 3 Audio input device 4 Processing device 5 Light source device 6 Display device 7 Foot switch 21 Insertion unit 22 Operation unit 23 Universal code 24 Imaging unit 401 AGC
402 Strobe processing unit 403 Image processing unit 404 Memory 405 Display control unit 406 Input unit 407 Vibration frequency detection unit 408 Light source control unit 408a Pulse width calculation unit 408b Gain value calculation unit 409 Brightness evaluation unit 410 Afterimage evaluation unit 411 Control unit 51 Light source 52 Light Source Driver 53 Pulse Generation Section 211 Tip Section 212 Bending Section 213 Flexible Tube Section 231 Branch Code 232, 233 Connector 242 Image Sensor 242a Light Receiving Section 242b Reading Section

Claims (8)

An imaging unit for imaging an imaging target and outputting an imaging signal;
A light source that generates pulsed light;
A brightness evaluation unit that detects brightness of an image according to the imaging signal and calculates a brightness evaluation value;
An afterimage evaluation unit that evaluates the size of an afterimage in the image according to the imaging signal and outputs the evaluation result as an afterimage evaluation value;
Based on the brightness evaluation value and the afterimage evaluation value, a pulse width calculation unit that calculates a pulse width of the pulsed light,
A light source controller that controls the light source to generate the pulsed light with the pulse width calculated by the pulse width calculator;
An imaging system comprising: The imaging unit
A light receiving section that is arranged in a matrix and has a plurality of pixels that photoelectrically convert received light to generate an electrical signal;
A readout unit that sequentially reads out an electrical signal for each pixel row of the light receiving unit;
Have
The imaging system according to claim 1, wherein the afterimage evaluation unit evaluates the size of the afterimage based on the electrical signal read by the reading unit. The pulse width calculation unit further includes a storage unit that stores setting information for calculating a pulse width,
The imaging system according to claim 1, wherein the pulse width calculation unit calculates the pulse width within a pulse width allowable range defined based on the setting information stored in the storage unit. Input means for inputting change information for changing the setting information;
A control unit for changing the setting information based on the change information input by the input means;
Further comprising
The imaging system according to claim 3 , wherein the pulse width calculation unit calculates the pulse width based on setting information changed by the control unit . The setting information includes a minimum value of the brightness of the image and a reference level of the quality of the afterimage,
The imaging system according to claim 3 or 4, wherein the pulse width calculation unit calculates a pulse width based on the minimum value of the brightness and the reference level. The pulse width calculation unit defines the pulse width allowable range with a pulse width set based on a minimum value of the brightness of the image as a lower limit value and a pulse width set based on the reference level as an upper limit value. The imaging system according to claim 5 .   The imaging system according to claim 4, wherein the input unit includes an operation unit that can input the setting information according to a rotation direction and a rotation amount with respect to a reference position. An imaging device having an imaging unit that images an imaging target and outputs an imaging signal, and a light source device that has a light source that generates pulsed light based on a supplied pulse are connected to the imaging device and the light source device, respectively. A processing device capable of transmitting and receiving information between,
A brightness evaluation unit that detects brightness of an image according to the imaging signal based on the imaging signal and calculates a brightness evaluation value;
An afterimage evaluation unit that evaluates the size of an afterimage in an image corresponding to the image pickup signal based on the image pickup signal, and outputs the evaluation result as an afterimage evaluation value;
Based on the brightness evaluation value and the afterimage evaluation value, a pulse width calculation unit that calculates a pulse width of the pulsed light,
A light source controller that controls the light source to generate the pulsed light with the pulse width calculated by the pulse width calculator;
A processing apparatus comprising:

Images