WO2013146858A1 - Dispositif d'imagerie et dispositif d'endoscope équipant celui-ci - Google Patents

Dispositif d'imagerie et dispositif d'endoscope équipant celui-ci Download PDF

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Publication number
WO2013146858A1
WO2013146858A1 PCT/JP2013/058943 JP2013058943W WO2013146858A1 WO 2013146858 A1 WO2013146858 A1 WO 2013146858A1 JP 2013058943 W JP2013058943 W JP 2013058943W WO 2013146858 A1 WO2013146858 A1 WO 2013146858A1
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WIPO (PCT)
Prior art keywords
pulse
light source
light
amount
exposure time
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PCT/JP2013/058943
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English (en)
Japanese (ja)
Inventor
康宏 瀬戸
Original Assignee
富士フイルム株式会社
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Priority claimed from JP2013047904A external-priority patent/JP6006147B2/ja
Application filed by 富士フイルム株式会社 filed Critical 富士フイルム株式会社
Priority to CN201380010752.XA priority Critical patent/CN104135908B/zh
Publication of WO2013146858A1 publication Critical patent/WO2013146858A1/fr
Priority to US14/472,606 priority patent/US10194789B2/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/04—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
    • A61B1/045—Control thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/06—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
    • A61B1/0655—Control therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/06—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
    • A61B1/0661—Endoscope light sources
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • A61B1/06—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements
    • A61B1/07—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor with illuminating arrangements using light-conductive means, e.g. optical fibres
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
    • G02B23/2407—Optical details
    • G02B23/2461—Illumination
    • G02B23/2469—Illumination using optical fibres
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/50—Constructional details
    • H04N23/555—Constructional details for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/56—Cameras or camera modules comprising electronic image sensors; Control thereof provided with illuminating means
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • H04N23/73—Circuitry for compensating brightness variation in the scene by influencing the exposure time
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • H04N23/74—Circuitry for compensating brightness variation in the scene by influencing the scene brightness using illuminating means
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/50—Control of the SSIS exposure
    • H04N25/53—Control of the integration time

Definitions

  • the present invention relates to an imaging apparatus and an endoscope apparatus including the same.
  • a general endoscope apparatus emits white light from a white light source such as a xenon lamp as illumination light to a region to be observed in a body cavity through a light guide, and an image sensor reflects a reflected light image by the white light irradiation.
  • An observation image is generated by imaging.
  • the image sensor has an electronic shutter, and the amount of received light is adjusted by controlling the charge accumulation time to increase or decrease with the electronic shutter.
  • light amount information is extracted from an image signal output from an image sensor, and an exposure time (shutter speed) by an electronic shutter is controlled based on the light amount information. For example, if the extracted light quantity information is smaller than the reference value, the shutter speed is slowed down to increase the received light quantity.
  • the shutter speed is increased to reduce the received light quantity.
  • exposure according to the illumination light intensity and the observation target is performed, and the brightness of the captured image can be maintained well (see Patent Document 1).
  • CMOS Complementary Metal Oxide Semiconductor
  • CCD Charge Coupled Device
  • MOS type image sensors such as CMOS type image sensors are usually driven by a rolling shutter system.
  • the rolling shutter system is a MOS type image pickup device in which an exposure operation is sequentially performed for at least one or more scanning lines or pixels, that is, reset is sequentially performed for each scanning line or pixel, and charge accumulation is started and accumulated. This is a method of reading out the generated charges (also called a focal plane shutter method).
  • the rolling shutter type image sensor has a characteristic that the exposure start timing is shifted for each line according to the scanning timing of each line on the imaging surface.
  • the amount of emitted light is controlled by pulse modulation such as pulse width modulation (PWM), but the dimming dynamic range is insufficient when only the same modulation method is used. However, the dimming resolution may be insufficient in the low light quantity region.
  • PWM pulse width modulation
  • the exposure time by the shutter is fixed to the maximum exposure time, a fast-moving subject may be blurred.
  • the actual situation is that necessary and sufficient image quality and dimming performance cannot be obtained.
  • An object of the present invention is to provide an imaging apparatus capable of realizing both a wide light control dynamic range and a high light control resolution, and an endoscope apparatus including the same.
  • the present invention has the following configuration. (1) a light source that emits light by pulse driving; A light source control unit for controlling the amount of light emitted from the light source by pulse modulation driving the light source; An image pickup unit having an image pickup device in which a plurality of pixels are arranged in a horizontal direction and a vertical direction, and driving the image pickup device by a rolling shutter system to pick up an image; The light source control unit controls the light source at a timing synchronized with a timing pulse signal having a period of 1 / p (p is an integer of 1 or more) of an exposure start timing interval when the image sensor is driven by a rolling shutter system. An imaging device that is pulse-driven. (2) An endoscope apparatus provided with the above imaging apparatus.
  • the present invention when imaging is performed under illumination light that is driven by pulsed light emission using a rolling shutter type image sensor, there is no variation in the amount of light received due to pulse illumination light in each line of the image sensor. A wide dimming dynamic range and high dimming resolution can be realized.
  • FIG. 1 It is a figure for describing an embodiment of the present invention, and is a block block diagram showing a schematic structure of an endoscope apparatus. It is an external view which shows one specific structural example of an endoscope apparatus. It is a control block diagram by an imaging signal processing part. It is explanatory drawing which shows the content of the light reception amount control table typically. It is typical explanatory drawing which shows the exposure timing of the image pick-up element by a rolling shutter system. It is explanatory drawing which shows the relationship between the exposure time in a 1st pulse width control area (PWM1) S1, and a pulse drive signal. It is explanatory drawing which shows the relationship between the exposure time of a rolling shutter in a shutter speed control area
  • PWM1 pulse width control area
  • FIG. 1 is a diagram for explaining an embodiment of the present invention, and is a block configuration diagram showing a schematic configuration of an endoscope apparatus
  • FIG. 2 is an external view showing a specific configuration example of the endoscope apparatus.
  • the endoscope apparatus 100 includes an endoscope scope (hereinafter referred to as an endoscope) 11, a control device 13 to which the endoscope 11 is connected, and a control device 13.
  • a display unit 15 such as a liquid crystal monitor to be connected and an input unit 17 such as a keyboard and a mouse for inputting information to the control device 13 are provided.
  • the control device 13 includes a light source device 19 that generates illumination light and a processor 21 that performs signal processing of a captured image.
  • the endoscope 11 includes a main body operation unit 23 and an insertion unit 25 connected to the main body operation unit 23 and inserted into a body cavity.
  • a universal cord 27 is connected to the main body operation unit 23.
  • the universal cord 27 has two ends.
  • the light guide connector 29A provided at one end is connected to the light source device 19, and the video connector 29B provided at the other end is connected to the processor 21.
  • An illumination window 31 and an observation window 33 are provided at the distal end of the insertion section 25 of the endoscope 11 opposite to the main body operation section 23.
  • the illumination window 31 emits illumination light guided through the light guide 35 toward the subject, and the observation window 33 provides an observation image to the image sensor 37.
  • the light source device 19 includes a light source 39 that emits light by pulse driving, and a light source control unit 41 that controls the amount of light emitted from the light source 39 by pulse emission driving. Light emitted from the light source 39 is introduced into the light guide 35.
  • the processor 21 includes an imaging signal processing unit 43, an endoscope control unit 45, an image processing unit 47, and a memory 49.
  • the endoscope 11 also includes an imaging control unit 51 for driving and controlling the imaging element 37.
  • the imaging control unit 51 controls driving of the imaging element 37 in accordance with an instruction from the endoscope control unit 45.
  • the image sensor 37 captures the reflected light from the subject by the illumination light emitted from the illumination window 31 through the observation window 33 and a lens (not shown) to generate a captured image.
  • the image sensor 37 generates a video of the generated observation image.
  • the signal is output to the processor 21.
  • the endoscope control unit 45 is connected to a memory 49 serving as a storage unit that stores observation images and various types of information to be described later.
  • the video signal output from the imaging signal processing unit 43 is subjected to appropriate image processing by the image processing unit 47. And displayed on the display unit 15.
  • the endoscope control unit 45 is connected to a network such as a LAN (not shown) and controls the entire endoscope apparatus 100 such as distributing information including image data.
  • the image sensor 37 is a CMOS image sensor driven by a so-called rolling shutter system.
  • the observation image formed and captured on the light receiving surface of the image sensor 37 is converted into an electric signal, input to the image signal processor 43 of the processor 21, and converted into a video signal.
  • the imaging signal processing unit 43 also functions as a light quantity detection unit that detects the light quantity of the subject image based on the imaging signal output from the imaging element 37.
  • the light source 39 includes one or more laser light sources that are semiconductor light emitting elements.
  • the light source 39 may irradiate a specific wavelength light alone or simultaneously with a plurality of wavelength lights, in addition to the one that generates white light.
  • the light source that generates white light includes a laser light source that outputs blue laser light having a central wavelength of 445 nm, and a plurality of types of phosphors that absorb part of the blue laser light and emit green to yellow light (for example, YAG fluorescence).
  • this laser light source for example, a broad area type InGaN laser diode can be used.
  • the blue laser light from the laser light source and the green to yellow excitation light obtained by wavelength-converting the blue laser light are combined to generate white light.
  • the intensity of light emitted from the light source 39 is arbitrarily adjusted by pulse modulation driving.
  • a wavelength conversion member (not shown) is disposed in the light source 39, and white light extracted through the wavelength conversion member passes through a light guide 35 formed of a fiber bundle made up of a number of fiber bundles, and the distal end of the endoscope insertion portion 25. The light is guided to the illumination window 31 arranged in the window.
  • the light source 39 includes, for example, a laser light source that outputs laser light having a central wavelength of 405 nm in addition to the white light laser light source, and generates illumination light suitable for observing capillaries and fine patterns on the surface of living tissue. Can be made. In that case, illumination light for endoscopic observation is obtained by irradiating the light source 39 with laser light having a central wavelength of 405 nm and white light by laser light having a central wavelength of 445 nm simultaneously emitted at an arbitrary ratio of intensity. It is good to use as composition.
  • the wavelength conversion member is disposed in the immediate vicinity of the illumination window 31 .
  • one or several single-mode optical fibers can be laid along the endoscope insertion portion 25 so that the light emission end emits light toward the wavelength conversion member. Diameter reduction is achieved.
  • the light source 39 may be configured by a light emitting diode instead of the laser light source, and may be configured to obtain light having a desired wavelength by combining white light and a color filter that selectively extracts light having a specific wavelength. .
  • the imaging signal processing unit 43 provided in the processor 21 illustrated in FIG. 1 receives RAW data output from the imaging element 37 of the endoscope 11 connected to the processor 21.
  • the imaging signal processing unit 43 captures a control signal for controlling the amount of light emitted from the light source 39 in the light source control unit 41 so as to obtain an optimal amount of received light (a luminance value detected by the imaging device) according to the RAW data.
  • a control signal for controlling the element 37 to the optimum shutter speed is output from the endoscope control unit 45 to the imaging control unit 51.
  • FIG. 3 shows a control block diagram of the imaging signal processing unit 43.
  • Raw data (raw image information) output from the image sensor 37 is input to the histogram creation unit 55.
  • the histogram creation unit 55 creates a light intensity histogram corresponding to the RAW data and outputs the histogram to the photometric value calculation unit 57.
  • the photometric value calculation unit 57 calculates a photometric value based on the created histogram and brightness detection values obtained by various photometric modes (peak value, average value, etc.). Then, the target light amount calculation unit 59 obtains the target received light amount of the next frame according to the calculated photometric value.
  • the target light reception amount is a control parameter that is expressed by, for example, 12-bit gradation (0 to 4096), and is set to a value higher than the current target light amount value when the photometric value is higher than the reference value.
  • the endoscope apparatus 100 selects various control patterns to be described later according to a control parameter expressed as a target light reception amount.
  • the endoscope control unit 45 shown in FIG. 1 refers to the received light amount control table stored in the memory 49 and based on the target received light amount output from the imaging signal processing unit 43, the light source control unit 41 and the imaging control Each control signal to be output to the unit 51 is determined.
  • the endoscope control unit 45 functions as a received light amount control unit that drives the light source 39 and the image sensor 37 based on the determined control signals and controls the received light amount of the image sensor. For example, if the brightness detected by the image sensor decreases depending on the state of the subject, the received light amount that is larger than the received light amount corresponding to the current combination of the emitted light amount and the exposure time is changed to the target received light amount, and the detected luminance is Control to achieve brightness.
  • the endoscope control unit 45 gives the light source control unit 41 a drive pulse generation function based on the received light amount control table so that the endoscope control unit 45 changes the light source control unit 41 to A configuration may be adopted in which a light emission intensity signal of the light source 39 is output.
  • the received light amount control table 49a defines the relationship between the luminance according to the reflectance and distance of the subject image, the amount of light emitted from the light source 39, and the shutter speed of the electronic shutter of the image sensor 37, and determines the received light amount of the image sensor 37. Stipulate.
  • the received light amount control table 49a is set with a control pattern that optimizes the light source drive signal and the shutter speed as control variables with respect to the target received light amount, based on experimental / analytical methods and empirical rules. 49.
  • FIG. 4 schematically shows the contents of the received light amount control table in this configuration example.
  • the received light amount control table 49a is a table in which the amount of light emitted from the light source 39 and the combination of the exposure time of the image sensor 37 are associated with the amount of light received by the image sensor 37.
  • a shutter speed control pattern of the image sensor 37 is composed of a control signal and a control parameter of each part for obtaining a target value of the emitted light quantity with respect to the target light reception amount, a target value of the shutter speed of the image sensor, and the like.
  • the received light amount control table 49a has a constant exposure time of the image sensor, a first pulse width control region (PWM1) S1 for increasing or decreasing the pulse width of the pulse drive signal output to the light source 39, and the pulse of the pulse drive signal of the light source 39.
  • the shutter speed control region S2 for increasing and decreasing the exposure time of the image sensor 37 with a constant width and the exposure time of the pulse drive signal in a state where the exposure time is fixed to an integral multiple of n times the horizontal scanning period (n is an integer of 2 or more).
  • PWM2 pulse width control region
  • the control pattern in each control region is the first pulse width control region S1 when the target light reception amount is maximum, and when the target light reception amount decreases, the first pulse width control region S1 and the shutter speed control region S2 are the target. Switching is based on the amount of received light Ra. When further lowered, the shutter speed control region S2 and the pulse number control region S3 are switched at the target light reception amount Rb, and the pulse number control region S3 and the second pulse width control region S4 are switched at the target light reception amount Rc.
  • the light source 39 is pulse-driven at a timing synchronized with a timing pulse signal whose period is 1 / p (p is an integer of 1 or more) of the exposure start timing interval of the image sensor.
  • FIG. 5 is a schematic explanatory view showing the exposure timing of the image pickup element by the rolling shutter system.
  • the horizontal pixel lines L1, L2,... Aligned in the horizontal direction H in the pixel area of the image sensor in which pixels composed of a large number of photoelectric conversion elements are arranged in the horizontal direction H and the vertical direction V are used. Is sequentially scanned in the vertical direction V from the upper end line to the lower end line, the exposure start timing of each horizontal pixel line L1, L2,... Is sequentially shifted from the upper end line on one end side in the vertical direction for the horizontal scanning period t.
  • the setting is made by shifting in the delay direction.
  • the horizontal scanning period t is a requirement per line required for a command on a logic circuit such as a reset and readout of a stored charge line for one line of one horizontal pixel line (hereinafter also referred to simply as a line). This is a time, and is expressed as a difference in exposure start time between the line L1 and the line L2 shown in FIG.
  • the exposure time T for each line L1, L2,..., Ln of the line block LB is set to a length divisible by a block period tn obtained by multiplying the horizontal scanning period t by n.
  • the total number of lines L for one frame is an integer multiple of n.
  • the difference in exposure start timing between one line block LB and the subsequent line block LB having the same number of lines is a block period tn.
  • the exposure time T of each line L1, L2,..., Ln becomes an integral multiple of the block period tn.
  • FIG. 6 is an explanatory diagram showing the relationship between the exposure time and the pulse drive signal in the first pulse width control region (PWM1) S1.
  • the endoscope control unit 45 sets the exposure time of the rolling shutter for all lines in one frame defined by the vertical synchronization signal VD as the TV signal when the target light reception amount is an area between the maximum value and Ra. The same maximum exposure time Tmax is set.
  • FIG. 6 shows only one line block LB among all the lines in one frame.
  • the endoscope control unit 45 sets the pulse drive signal for driving the light source 39 to the maximum pulse width Wmax when the target light reception amount is the maximum value, and causes the light source 39 to be in a continuously lit state.
  • the pulse drive signal is a pulse signal having the same pattern with a block period tn that is n times the horizontal scanning period t as one period, and the endoscope control unit 45 uses this pulse drive signal as the first line in the line block LB. Is output in synchronization with the exposure start timing. Further, it is repeatedly output while at least one of all the lines of the image sensor is set to the exposure time.
  • the endoscope control unit 45 fixes the exposure time of the rolling shutter at the maximum exposure time Tmax in the region where the target light reception amount is from the maximum value to Ra, and pulses each pulse of the pulse drive signal with respect to the target light reception amount. Perform width modulation.
  • the pulse width Wa at the target received light amount Ra is 20% of the maximum pulse width Wmax.
  • the number of pulses of the pulse drive signal at this time is n in the block period tn. That is, the horizontal scanning period t has a pulse width corresponding to 100% of one pulse.
  • the endoscope control unit 45 performs pulse driving until the target light reception amount reaches Ra1 without controlling the shutter speed control region S2 described below.
  • the exposure time of the image sensor is fixed to the same exposure time as the exposure time in the first pulse width control region S1, and the pulse drive signal of the light source 39 is kept constant with the pulse width of the pulse drive signal of the light source 39 constant.
  • a second pulse number control region is provided in which the amount of light received when the number of pulses is increased or decreased is associated.
  • the amount of light received in the second pulse number control region is between the amount of light received in the first pulse width control region S1 and the amount of light received in the shutter speed control region S2. Then, the received light amount control unit 45 increases or decreases the exposure time in the shutter speed control region S2 in block cycle units.
  • the pulse drive signal is not an equidistant pulse as shown in the two-dot chain line in FIG. 6, but is repeatedly output in units of the block period tn which is n times the horizontal scanning period t.
  • the integrated received light amount by the pulsed light is always kept constant.
  • the endoscope control unit 45 performs the first pulse width control until the target light reception amount Ra, and performs the shutter speed control for the region where the target light reception amount is not less than Rb and less than Ra. As described above, when the pulse number control is performed in the region less than the target light receiving amount Ra and Ra1 or more, the shutter speed control is performed.
  • FIG. 7 is an explanatory diagram showing the relationship between the exposure time of the rolling shutter and the pulse drive signal in the shutter speed control region S2.
  • the endoscope control unit 45 fixes the pulse drive signal at the target light receiving amount Ra in the region where the target light receiving amount is from Ra to Rb. Then, the exposure time of each line is changed in units of the horizontal scanning cycle t, and the target light reception amount Rb is set to the minimum exposure time Tmin that is equal to the block cycle tn that is n times the horizontal scanning cycle t. The increase / decrease of the exposure time at this time is performed by the back end based on the end timing of the exposure time.
  • the pulse of the pulse drive signal is controlled so as not to overlap within the transition period of shutter opening / closing.
  • the integrated amount of light received by light is always kept constant.
  • the endoscope control unit 45 increases or decreases the shutter speed change in units of a block period tn that is n times the horizontal scanning period t. In this case, the shutter speed control is performed in consideration of the pulse number modulation performed between Ra and Ra1.
  • the endoscope control unit 45 performs shutter speed control up to the target light reception amount Rb, and performs pulse number control for a region where the target light reception amount is greater than or equal to Rc and less than Rb.
  • FIG. 8 is an explanatory diagram showing the relationship between the exposure time of the rolling shutter and the pulse drive signal in the pulse number control region (PNM) S3 and the second pulse width control region (PWM2) S4.
  • the endoscope control unit 45 fixes the exposure time of each line to the minimum exposure time Tmin equal to the block period tn in the region where the target light reception amount is from Rb to Rc. Then, pulse number control is performed to reduce the pulse number from the state of the target light reception amount Rb, and the target light reception amount is decreased to one pulse within the block period tn when the target light reception amount is Rc.
  • the endoscope control unit 45 thins out the pulse drive signal of the light source 39 while fixing the exposure time of each line to the minimum exposure time Tmin equal to the block period tn. In the state, the second pulse width control for reducing the pulse width of the pulse drive signal is performed.
  • the pulse width modulation by the endoscope control unit 45 it is preferable to output the pulse of the pulse drive signal at a timing that does not overlap within the transition period of the shutter opening / closing of the image sensor 37.
  • FIG. 9 is an explanatory diagram schematically showing variations in shutter closing operation and shutter opening operation.
  • the behavior of the shutter operation at the exposure end timing and the exposure start timing of each line is not constant for all lines, and has variations inherent to each line of an end error ⁇ t1 and a start error ⁇ t2. Therefore, the endoscope control unit 45 performs control so that the pulse of the pulse drive signal does not enter during the period tc having the variation.
  • the endoscope control unit 45 sets the pulse width of each pulse of the pulse drive signal by back-aligning at least the exposure end timing of any line. Increase or decrease. That is, the falling timing of the pulse 61 of the pulse drive signal is synchronized with the shutter closing timing of the rolling shutter.
  • the number of received light pulses of the pulse drive signal in the exposure time of each line is 4 pulses in any line in this case, and the received light amount is equalized.
  • the endoscope control unit 45 controls the pulse of the pulse drive signal so as not to output the pulse of the pulse drive signal basically within the shutter opening / closing transition period as described above.
  • the first pulse width control is performed.
  • an error with respect to the integrated light reception amount is slight. Therefore, if the pulse output timing is controlled so that the pulses do not overlap within the above shutter opening / closing transition period in at least the pulse number control region S3 and the second pulse width control region S4, exposure is substantially achieved. The accuracy of the quantity is not reduced.
  • the endoscope control unit 45 When the target light reception amount is increased from Rb, the endoscope control unit 45 does not shift to the shutter speed control of S2 during the period from the target light reception amount Rb to Rb1, for example, and pulses the pulse drive signal.
  • the width may be controlled.
  • the pulse modulation control rather than switching the pulse modulation control to the shutter speed control, by extending the pulse modulation control as it is, there is no switching of the control target, and smoother light control can be performed. That is, when changing the received light amount across the control areas of the received light amount control table shown in FIG. 4, when changing from the larger target light received amount side to the smaller side and when changing from the smaller side to the larger side.
  • hysteresis control for performing different received light amount control may be performed.
  • a plurality of received light amount control tables having different received light amount values at the change points of the respective control areas are prepared, and the received light amount control table is switched and referred to according to the change direction of the received light amount, and the target value of the emitted light amount from the light source A target value for the exposure time of the image sensor is determined. In this way, control is performed by a combination of different emitted light quantity and exposure time.
  • the received light amount control table has an additional area for obtaining the same received light quantity, and uses the additional area for only one direction of change of the received light quantity, and a combination of different emitted light quantity and exposure time. Control by.
  • the received light amount control unit has a timing pulse with a period of 1 / p of the exposure start timing interval when driving the imaging device by the rolling shutter method.
  • the light source is pulse-driven at a timing synchronized with the signal.
  • this one block period is defined as one period.
  • the light source and the image sensor are controlled so as to output a pulse signal of the same pattern as a pulse drive signal of the light source. Therefore, even with a rolling shutter type image sensor in which the exposure timing is not simultaneous for all pixels, a wide light control dynamic range can be achieved without causing a failure of light amount control. Then, it is possible to control the received light amount with a wide settable received light amount width.
  • the endoscope control unit controls the received light amount by combining the shutter speed control in addition to the pulse driving of the light source, the light control resolution can be improved compared to the case where the light control is performed only by the pulse lighting control of the light source. it can.
  • the received light amount of a wide light control dynamic range equivalent to or greater than this Control can be realized, and an endoscopic image with high image quality can always be acquired.
  • endoscopic images must be diagnosed from subtle shadow images, and images with a wide dimming dynamic range and higher dimming resolution than ordinary photographs are required for accurate medical diagnosis. Is done. According to the endoscope apparatus having this configuration, it is possible to provide high-quality observation image information that can cope with such severe image quality.
  • FIG. 11 is a block configuration diagram illustrating a schematic configuration of the endoscope apparatus 200.
  • the endoscope apparatus 200 includes a chopper circuit 65 that is connected to the light source control unit 41 and generates a drive signal for the light source 39 in order to continuously light the light source 39 with a chopping pulse signal. 100.
  • FIG. 12 shows the waveform of the drive signal from the chopper circuit with respect to the set light amount.
  • the drive signal has a pulsation in which a bias component and a chopping pulse component are superimposed, as shown in the case where the light amount is 20% or 60% in the figure.
  • the waveform of the pulsation is smoothed as the set light amount increases, and is almost flat at the maximum light amount.
  • FIG. 13 shows the relationship between the timing of the exposure period of each line by the rolling shutter and the drive signal.
  • the light source control unit 41 drives the light source 39 to emit light at all timings of the timing pulse signal.
  • the light source 39 is driven at a timing synchronized with a timing pulse signal (drive signal) having a period of 1 / p of the exposure start timing interval of the image sensor.
  • the drive signal within the exposure time for each line (Ln, Ln + 1,...) Of the image sensor includes an equal number of pulsations. Therefore, the integrated intensity of the drive signal is the same for each line, and the amount of received light does not vary. Therefore, both a wide dimming dynamic range and high dimming resolution can be realized.
  • the present invention is not limited to the above-described embodiments, and the configurations of the embodiments may be combined with each other, or modified or applied by those skilled in the art based on the description of the specification and well-known techniques.
  • the invention is intended and is within the scope of seeking protection.
  • the endoscope apparatus is illustrated in the above example, the present invention is not limited to this.
  • the imaging device including at least the light source device 19, the processor 21, the imaging device 37, and the imaging control unit 51 illustrated in FIG. 1, high-quality imaging with high dimming resolution in a wide dimming dynamic range. An image can be obtained.
  • a light source that emits light by pulse driving
  • a light source control unit for controlling the amount of light emitted from the light source by pulse modulation driving the light source
  • An image pickup unit having an image pickup device in which a plurality of pixels are arranged in a horizontal direction and a vertical direction, and driving the image pickup device by a rolling shutter system to pick up an image
  • the light source control unit controls the light source at a timing synchronized with a timing pulse signal having a period of 1 / p (p is an integer of 1 or more) of an exposure start timing interval when the image sensor is driven by a rolling shutter system.
  • An imaging device that is pulse-driven.
  • the imaging unit sequentially scans and drives a horizontal pixel line in which the pixels are arranged in the horizontal direction from one end to the other end in the vertical direction of the horizontal pixel line, and sets the exposure start timing of each horizontal pixel line to one horizontal pixel line. Are shifted by the horizontal scanning period, which is the scanning period, Furthermore, it has a received light amount control table in which a combination of the amount of light emitted from the light source and the exposure time of the image sensor and the received light amount assumed to be received by the image sensor in that case are included.
  • the target value of the emitted light quantity and the target value of the exposure time of the imaging device are determined with reference to the received light amount control table, and based on the determined target value of the emitted light quantity and the target value of the exposure time,
  • a light source control unit and a received light amount control unit for controlling the imaging unit In the light source control unit, a line block composed of n lines (n is an integer of 2 or more) obtained by equally dividing the number L of all horizontal pixel lines of the image sensor by m (m is an integer of 2 or more) is the vertical block.
  • An image pickup apparatus that pulse-drives the light source by a pulse drive signal having the same pattern with a block period that is an exposure start timing interval of blocks arranged in a direction as one period.
  • the received light amount control table is at least A first pulse width control region that associates the received light amount when the exposure time of the image sensor is constant and the pulse width of the pulse drive signal of the light source is increased or decreased; A shutter speed control region in which the pulse width of the pulse drive signal of the light source is constant and the amount of received light when the exposure time of the image sensor is increased or decreased, In the state in which the exposure time of the image sensor is fixed to an integral multiple of the block period obtained by multiplying the horizontal scanning period by n, the first received light amount associated with increasing or decreasing the number of pulses of the pulse drive signal of the light source A pulse number control region of The exposure time of the image sensor is fixed to an integral multiple of the block period, and the received light amount when the pulse width of the pulse drive signal is increased or decreased with the pulse drive signal of the light source being thinned is associated And a second pulse width control region.
  • the imaging device is: The first pulse width control region; The shutter speed control region, The first pulse number control region, The imaging device which becomes smaller in order of the second pulse width control region.
  • the imaging device (4), The imaging device that outputs the pulse driving signal in the first pulse number control region and the second pulse width control region at a timing that does not overlap within a shutter opening / closing operation period of the imaging device.
  • the imaging apparatus has a pulse width of the pulse drive signal in the first pulse width control region and the second pulse width control region as a reference based on an exposure end timing of at least one of the horizontal pixel lines. An imaging device that outputs by increasing / decreasing the size.
  • the imaging apparatus according to any one of (3) to (6), An imaging apparatus in which an exposure time of the imaging element in the first pulse width control region of the received light amount control table is a maximum exposure time of one frame.
  • the imaging apparatus according to any one of (3) to (7), The imaging apparatus, wherein the light source control unit outputs a maximum width of each pulse of the pulse drive signal in the first pulse width control region as the horizontal scanning period.
  • the imaging apparatus according to any one of (3) to (8), The image pickup apparatus, wherein the light source control unit outputs the number of pulses of the pulse drive signal within the exposure time of the horizontal pixel line as the same number of pulses for any of the horizontal pixel lines.
  • the imaging apparatus according to any one of (3) to (9), The imaging device that increases or decreases the exposure time in the shutter speed control region in units of the horizontal scanning period.
  • the imaging apparatus according to any one of (4) to (10), The received light amount control table further fixes the exposure time of the image sensor to the same exposure time as the exposure time in the first pulse width control region, and keeps the pulse width of the pulse drive signal of the light source constant.
  • a second pulse number control region that associates the received light amount when the number of pulses of the pulse drive signal of the light source is increased or decreased, and the received light amount in the second pulse number control region is Between the received light amount in one pulse width control region and the received light amount in the shutter speed control region,
  • the light receiving amount control unit is an imaging device that increases or decreases the exposure time in the shutter speed control region in units of the block period.
  • An imaging apparatus for determining a target value of the amount of light emitted from the light source and a target value of an exposure time of the imaging element.
  • the imaging apparatus according to (1), The light source control unit drives the light source to emit light at all timings of the timing pulse signal.
  • An endoscope apparatus comprising the imaging device according to any one of (1) to (14).

Abstract

La présente invention concerne un dispositif d'imagerie permettant d'obtenir une large plage dynamique de commande de lumière et une résolution élevée de commande de lumière sans générer de fluctuations dans la quantité de lumière reçue en raison d'impulsions de lumière d'éclairage dans chaque ligne d'un élément d'imagerie. Le dispositif d'imagerie selon l'invention est pourvu d'une source de lumière qui est excitée par impulsions pour émettre de la lumière, d'une unité de commande de source de lumière qui excite la source de lumière au moyen d'une modulation par impulsions pour commander la quantité de lumière émise, et d'un imageur équipé d'un élément d'imagerie comprenant une pluralité de pixels disposés en réseau dans la direction horizontale et dans la direction verticale, et qui met en œuvre la formation d'image par excitation de l'élément d'imagerie à l'aide d'un procédé obturateur roulant. L'unité de commande de source de lumière excite la source de lumière au moyen d'impulsions selon une temporisation synchronisée avec un signal d'impulsion de temporisation, et la période dudit signal d'impulsion de temporisation est fixé à 1/p (p étant un nombre entier supérieur ou égal à 1) de l'intervalle de temporisation de début d'exposition lorsque l'élément d'imagerie est excité par le biais du procédé obturateur roulant.
PCT/JP2013/058943 2012-03-28 2013-03-27 Dispositif d'imagerie et dispositif d'endoscope équipant celui-ci WO2013146858A1 (fr)

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CN201380010752.XA CN104135908B (zh) 2012-03-28 2013-03-27 摄像装置以及具备其的内窥镜装置
US14/472,606 US10194789B2 (en) 2012-03-28 2014-08-29 Rolling shutter imaging device and endoscope apparatus including the same

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JP2012-074245 2012-03-28
JP2012074245 2012-03-28
JPPCT/JP2013/054975 2013-02-26
JP2013054975 2013-02-26
JP2013-047904 2013-03-11
JP2013047904A JP6006147B2 (ja) 2012-03-28 2013-03-11 撮像装置、及びこれを備える内視鏡装置

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EP3146713A4 (fr) * 2014-05-19 2018-01-03 Redbeard Ventures LLC Source de lumière synchronisée pour imageurs du type à "volet roulant"

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EP3146713A4 (fr) * 2014-05-19 2018-01-03 Redbeard Ventures LLC Source de lumière synchronisée pour imageurs du type à "volet roulant"
CN105473052A (zh) * 2014-06-23 2016-04-06 奥林巴斯株式会社 摄像装置以及内窥镜装置

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