WO2019221306A1

WO2019221306A1 - Endoscope system

Info

Publication number: WO2019221306A1
Application number: PCT/JP2019/019986
Authority: WO
Inventors: 智樹岩崎; 橋本　進; 祐一綿谷; 洋彦松澤
Original assignee: オリンパス株式会社
Priority date: 2018-05-18
Filing date: 2019-05-20
Publication date: 2019-11-21
Also published as: JPWO2019221306A1; JP6937902B2

Abstract

An endoscope system of the present invention is provided with: an illumination unit for irradiating a subject with a plurality of illuminating lights having mutually different wavelength bands while successively switching the illuminating lights; an endoscope provided with an imaging unit that includes a plurality of pixels generating image signals by subjecting return light from the subject to photoelectric conversion, and that reads, in synchronization with the timing of irradiation by the illumination unit, the image signals generated by the pixels; an image processing unit which performs a synchronization process using a plurality of image signals generated on the basis of the return light of each illuminating light; an imaging condition switch unit which, on the basis of identification information of the endoscope, switches the mode of the imaging unit to a conventional mode or a high-speed mode having an imaging frame rate higher than that of the conventional mode; and a binning control unit which, when set in the high-speed mode, causes the imaging unit to perform a read process with the number of pixels as a unit of reading increased from that in the conventional mode.

Description

Endoscope system

The present invention relates to an endoscope system including an endoscope.

Conventionally, in the medical field, an endoscope system is used for observation inside a subject. In general, an endoscope inserts a flexible insertion portion having an elongated shape into a subject such as a patient, illuminates illumination light supplied by a light source device from the distal end of the insertion portion, and reflects the illumination light. An in-vivo image is picked up by receiving light at the image pick-up part at the tip of the insertion part. The in-vivo image captured by the imaging unit of the endoscope is displayed on the display of the endoscope system after being subjected to predetermined image processing in the processing device of the endoscope system. A user such as a doctor observes the organ of the subject based on the in-vivo image displayed on the display.

A frame sequential method is known as one of methods for acquiring a color image (see, for example, Patent Documents 1 and 2). In the frame sequential method, illumination light in a plurality of different wavelength bands is sequentially switched to irradiate the subject, and a color image is acquired by capturing the subject in synchronization with illumination light illumination.

By the way, when acquiring an image of a subject by the frame sequential method, when the subject is moving at high speed, a color shift occurs due to a shift in the position of the subject every time illumination light is irradiated. In

Patent Documents

1 and 2, color misregistration is prevented by increasing the imaging frame rate. For example, in Patent Document 2, switching between a light emission mode that emits illumination light at a 1/60 second period and a light emission mode that emits illumination light at a 1/120 second period, depending on the observation site. ing.

JP 2016-46780 A JP 2007-29746 A

However, when the imaging frame rate is increased, there is a problem that the brightness of the image decreases.

The present invention has been made in view of the above, and an object of the present invention is to provide an endoscope system that can acquire an image in which a decrease in brightness is suppressed even when the imaging frame rate is increased.

In order to solve the above-described problems and achieve the object, an endoscope system according to the present invention includes an illumination unit that sequentially switches a plurality of illumination lights including different wavelength bands to irradiate a subject, An endoscope having a plurality of pixels that photoelectrically convert return light to generate an image signal, and an imaging unit that reads out the image signal generated by the pixels in synchronization with an irradiation timing of the illumination unit; An image processing unit that performs a synchronization process on the image signal read by the imaging unit using a plurality of the image signals generated based on return lights of illumination light having different wavelength bands; and the endoscope Based on the identification information, the imaging unit is configured to take any one of a normal mode for imaging at a preset imaging frame rate and a high-speed mode in which the imaging frame rate is higher than the normal mode. An imaging condition switching unit that switches to a mode, and a binning control unit that, when set to the high-speed mode, causes the imaging unit to execute a readout process with a larger number of pixels as a readout unit than the normal mode, It is characterized by providing.

In the endoscope system according to the present invention, in the above invention, the illuminating unit includes a red semiconductor light emitting element that emits red illumination light in a red wavelength band and a green light that emits green illumination light in a green wavelength band. From the semiconductor light emitting element, the blue semiconductor light emitting element that emits blue illumination light in the blue wavelength band, and the red semiconductor light emitting element, the green semiconductor light emitting element, and the blue semiconductor light emitting element according to the setting of the imaging frame rate An illumination control unit that switches the emission of the illumination light, and when the illumination control unit is set to the high-speed mode, the lighting order of the illumination light is changed to the red illumination light, the green illumination light, The blue illumination light and the green illumination light are used.

The endoscope system according to the present invention further includes an enlargement processing unit that performs electronic enlargement processing on the image signal in the above-described invention, and the enlargement processing unit includes the binning control unit in the imaging unit. The electron enlargement ratio is switched according to the number of pixels used as the readout unit.

In the endoscope system according to the present invention as set forth in the invention described above, the imaging condition switching unit switches the imaging frame rate and / or the number of pixels as the readout unit based on a parameter relating to the image signal. It is characterized by.

According to the present invention, it is possible to obtain an image in which a decrease in brightness is suppressed even when the imaging frame rate is increased.

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 timing chart illustrating imaging processing in the normal mode performed by the endoscope system according to the first embodiment of the present invention. FIG. 4 is a timing chart illustrating high-speed mode imaging processing performed by the endoscope system according to the first embodiment of the present invention. FIG. 5 is a diagram schematically illustrating an example of an image acquired by the endoscope system according to the first embodiment of the present invention by high-speed mode imaging processing and displayed on the display device. FIG. 6 is a diagram schematically illustrating an example of an image acquired by the endoscope system according to the first embodiment of the present invention through imaging processing in the normal mode and displayed on the display device. FIG. 7 is a timing chart illustrating high-speed mode imaging processing performed by the endoscope system according to the modification of the first embodiment of the present invention. FIG. 8 is a block diagram illustrating a schematic configuration of the endoscope system according to the second embodiment of the present invention.

Hereinafter, modes for carrying out the present invention (hereinafter referred to as “embodiments”) will be described. In the embodiment, a medical endoscope system that captures and displays an image in a subject such as a patient will be described as an example of the endoscope system according to the present invention. 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 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.

An endoscope system 1 shown in FIGS. 1 and 2 includes an endoscope 2 that captures an image in a subject by inserting a distal end portion into the subject, and illumination light emitted from the distal end of the endoscope 2. And a processing device 3 that performs predetermined signal processing on the image signal captured by the endoscope 2 and comprehensively controls the operation of the entire endoscope system 1, and the processing device 3. And a display device 4 for displaying the in-vivo image generated by the signal processing.

The endoscope 2 includes an insertion portion 21 having an elongated shape having flexibility, an operation portion 22 that is connected to a proximal end side of the insertion portion 21 and receives input of various operation signals, and an insertion portion from the operation portion 22. And a universal cord 23 that includes various cables that extend in a direction different from the direction in which 21 extends and that are connected to the processing device 3 (including the illumination unit 3a).

The insertion unit 21 is a bendable portion formed of a distal end portion 24 including an image pickup device 244 in which pixels that generate light by receiving light and performing photoelectric conversion are arranged in a two-dimensional manner, and a plurality of bending pieces. It has a bending portion 25 and a long flexible tube portion 26 that is connected to the proximal end side of the bending portion 25 and has flexibility. The insertion unit 21 uses the image sensor 244 to image a subject such as a living tissue that is inserted into the body cavity of the subject and is not reachable by external light.

The tip portion 24 is configured by using a glass fiber or the like, and forms a light guide path for light emitted from the illumination portion 3a, an illumination lens 242 provided at the tip of the light guide 241, and condensing optics. A system 243, an imaging element 244 (imaging unit) that is provided at an imaging position of the optical system 243, receives light collected by the optical system 243, photoelectrically converts the light into an electrical signal, and performs predetermined signal processing; H.245.

The optical system 243 is configured by using one or a plurality of lenses, and has an optical zoom function for changing the angle of view and a focus function for changing the focus.

The image sensor 244 photoelectrically converts light from the optical system 243 to generate an electrical signal (image signal). Specifically, in the imaging element 244, a plurality of pixels each having a photodiode that accumulates electric charge according to the amount of light, a capacitor that converts electric charge transferred from the photodiode into a voltage level, and the like are arranged in a matrix, A light receiving unit 244a in which each pixel photoelectrically converts light from the optical system 243 to generate an electric signal, and an electric signal generated by a pixel arbitrarily set as a reading target among a plurality of pixels of the light receiving unit 244a is sequentially read out The readout unit 244b outputs as an image signal, and the binning control unit 244c controls the pixel unit read out by the readout unit 244b according to the imaging conditions. The image sensor 244 is realized using, for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor.

The memory 245 stores an execution program and a control program for the image sensor 244 to execute various operations, and data including identification information of the endoscope 2. The identification information includes unique information (ID) of the endoscope 2, year model, specification information, transmission method, and the like. The memory 245 may temporarily store image data generated by the image sensor 244 and the like. The memory 245 includes a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, and the like.

The operation unit 22 includes a bending knob 221 that bends the bending unit 25 in the vertical direction and the left-right direction, and a treatment tool insertion unit 222 that inserts a treatment tool such as a biopsy forceps, an electric knife, and an inspection probe into the body cavity of the subject. In addition to the processing device 3, it has a plurality of switches 223 which are operation input units for inputting operation instruction signals of peripheral devices such as air supply means, water supply means, and screen display control. The treatment tool inserted from the treatment tool insertion portion 222 is exposed from the opening (not shown) via the treatment tool channel (not shown) of the distal end portion 24.

The universal cord 23 includes at least a light guide 241 and a collective cable 246 in which one or a plurality of signal lines are collected. The collective cable 246 includes information including a signal line for transmitting an image signal, a signal line for transmitting a drive signal for driving the image sensor 244, unique information regarding the endoscope 2 (image sensor 244), and the like. Including a signal line for transmitting and receiving. In the present embodiment, the description will be made assuming that an electrical signal is transmitted using a signal line. However, an optical signal may be transmitted, or the endoscope 2 and the processing device 3 may be connected by wireless communication. A signal may be transmitted between them.

Next, the configuration of the processing device 3 will be described. The processing device 3 includes an illumination unit 3a, an image processing unit 31, a frame memory 32, a communication unit 33, an imaging condition switching unit 34, a synchronization signal generation unit 35, an input unit 36, a storage unit 38, And a control unit 37.

First, the configuration of the illumination unit 3a will be described. The illumination unit 3a includes a light source unit 310 and an illumination control unit 320.

The light source unit 310 is configured using a plurality of light sources that emit a plurality of illumination lights having different wavelength bands, a plurality of lenses, and the like, and emits illumination light including light of a predetermined wavelength band by driving each light source. To do. Specifically, the light source unit 310 emits a light source driver 311, a first light source 312 </ b> V that emits light in a wavelength band of 360 to 400 nm (violet light), and light (blue light) in a wavelength band of 400 to 495 nm. A second light source 312B, a third light source 312G that emits light (green light) in a wavelength band of 495 to 570 nm, a fourth light source 312A that emits light (amber light) in a wavelength band of 590 to 620 nm, and 620 to A fifth light source 312R that emits light (red light) in a wavelength band of 750 nm, a lens 313V that collects violet light emitted from the first light source 312V, and a lens that collects blue light emitted from the second light source 312B. 313B, a lens 313G that condenses the green light emitted from the third light source 312G, and a lens 313 that condenses the amber light emitted from the fourth light source 312A. A lens 313R that collects red light emitted from the fifth light source 312R, a dichroic mirror 314V that bends light in the wavelength band emitted from the first light source 312V, and transmits light in other wavelength bands, and a second The light of the wavelength band emitted from the light source 312B is bent, the dichroic mirror 314B that transmits light of the other wavelength band, and the light of wavelength band emitted from the third light source 312G are bent and the light of the other wavelength band is transmitted. The dichroic mirror 314G to be bent and the light in the wavelength band emitted from the fourth light source 312A are bent, the dichroic mirror 314A to transmit the light in the other wavelength band, and the light in the wavelength band emitted from the fifth light source 312R are bent. The dichroic mirror 314R that transmits light in other wavelength bands and each light source And a lens 315 for guiding the wavelength to the light guide 241. Each light source is realized using an LED light source, a laser light source, or the like. The dichroic mirrors 314V, 314B, 314G, 314A, and 314R bend the light from the light source and travel on the same optical axis.
In the first embodiment, it is only necessary to emit illumination light of each color of red, blue, and green, and at least the second light source 312B, the third light source 312G, and the fifth light source 312R may be provided. A lens and a dichroic mirror are provided according to the light source arrange | positioned.

The light source driver 311 causes the light sources to emit light by supplying current to each light source under the control of the illumination control unit 320.
In the light source unit 310, light is emitted to the first light source 312V and the second light source 312B to make blue illumination light, and light is emitted to the third light source 312G to make green illumination light, and the fourth light source 312A and the fifth light source 312A are used. Light is emitted to the light source 312R, and illumination light of each color is emitted as red illumination light.
Hereinafter, red (R) illumination light, green (G) illumination light, and blue (B) illumination light are simply referred to as R illumination light, G illumination light, and B illumination light, respectively.

The illumination control unit 320 controls the amount of power supplied to each light source based on a control signal (dimming signal) from the control unit 37 and also controls the drive timing of each light source.

The image processing unit 31 receives the image data of the illumination light of each color captured by the image sensor 244 from the endoscope 2. When analog image data is received from the endoscope 2, the image processing unit 31 performs A / D conversion to generate a digital imaging signal. Further, when image data is received as an optical signal from the endoscope 2, the image processing unit 31 performs photoelectric conversion to generate digital image data.

The image processing unit 31 performs predetermined image processing on the image data received from the endoscope 2, generates an image, and outputs the image to the display device 4. Here, the predetermined image processing includes synchronization processing, gradation correction processing, color correction processing, and the like. The synchronization processing includes R image data based on image data generated by the image sensor 244 when the light source 310 is irradiated with the R illumination light, and G based on image data generated by the image sensor 244 when the light source 310 is irradiated with the G illumination light. This is a process of synchronizing each of the image data and the B image data based on the image data generated by the image sensor 244 when the light source unit 310 is irradiated with the B illumination light. The gradation correction process is a process for correcting gradation for image data. The color correction process is a process for performing color tone correction on image data. The image processing unit 31 generates a processed imaging signal (hereinafter also simply referred to as an imaging signal) including the in-vivo image generated by the above-described image processing. The image processing unit 31 may adjust the gain according to the brightness of the image. The image processing unit 31 includes a general-purpose processor such as a CPU (Central Processing Unit) and a dedicated processor such as various arithmetic circuits that execute specific functions such as an ASIC (Application Specific Integrated Circuit).

The image processing unit 31 includes a frame memory 32 that holds R image data, G image data, and B image data.

The communication unit 33 acquires unique information stored in the memory 245 of the endoscope 2 when the endoscope 2 is connected. The communication unit 33 is configured using a general-purpose processor such as a CPU or a dedicated processor such as various arithmetic circuits that execute specific functions such as an ASIC.

The imaging condition switching unit 34 refers to the information stored in the storage unit 38 and switches the imaging condition based on the unique information of the endoscope 2 acquired by the communication unit 33. Specifically, the imaging condition switching unit 34 is an endoscope in which the connected endoscope 2 is compatible with a frame sequential method (hereinafter also simply referred to as high-speed frame sequential) in which the imaging frame rate is increased. If it is possible to cope with the high-speed frame sequential, the high-speed mode is switched to the high-speed mode. In contrast, the imaging condition switching unit 34 switches to the normal mode in which the imaging frame rate is lower than that in the high-speed mode if the connected endoscope 2 is not compatible with high-speed frame sequential. In the first embodiment, an example in which the imaging frame rate in the high speed mode is 120 fps (1 frame: 1/120 second) and the normal mode is 60 fps (1 frame: 1/60 second) will be described. In the high-speed mode, the binning number as a pixel readout unit is set to 4 pixels, and in the normal mode, the binning number is set to 1 pixel. The imaging conditions for the normal mode and the high speed mode are preset and stored in the storage unit 38.

The synchronization signal generation unit 35 generates a clock signal (synchronization signal) that serves as a reference for the operation of the processing device 3, and uses the generated synchronization signal for the illumination unit 3 a, the image processing unit 31, the control unit 37, and the endoscope 2. Output to. Here, the synchronization signal generated by the synchronization signal generator 35 includes a horizontal synchronization signal and a vertical synchronization signal.
For this reason, the illumination unit 3a, the image processing unit 31, the control unit 37, and the endoscope 2 operate in synchronization with each other by the generated synchronization signal.

The input unit 36 is realized by using a keyboard, a mouse, a switch, and a touch panel, and receives input of various signals such as an operation instruction signal for instructing an operation of the endoscope system 1. The input unit 36 may include a portable terminal such as a switch provided in the operation unit 22 or an external tablet computer.

The storage unit 38 stores various programs for operating the endoscope system 1 and data including various parameters necessary for the operation of the endoscope system 1. Further, the storage unit 38 stores identification information of the processing device 3. Here, the identification information includes unique information (ID) of the processing device 3, model year, specification information, and the like. In addition, the storage unit 38 includes an imaging information storage unit 381 that stores information related to imaging conditions for performing imaging by controlling the endoscope 2 and the illumination unit 3a. In the imaging information storage unit 381, for example, for each imaging condition (mode), the readout timing of the imaging device 244 and the setting of the number of pixels (binning number) as a readout unit and the emission timing of illumination light of the illumination unit 3a are set. It is remembered.

Further, the storage unit 38 stores various programs including an image acquisition processing program for executing the image acquisition processing method of the processing device 3. Various programs can be recorded on a computer-readable recording medium such as a hard disk, a flash memory, a CD-ROM, a DVD-ROM, or a flexible disk and widely distributed. The various programs described above can also be obtained by downloading via a communication network. The communication network here is realized by, for example, an existing public line network, LAN (Local Area Network), WAN (Wide Area Network), etc., and may be wired or wireless.

The storage unit 38 having the above configuration is realized by using a ROM (Read Only Memory) in which various programs and the like are installed in advance, and a RAM, a hard disk, and the like that store calculation parameters and data of each process.

The control unit 37 performs drive control of each component including the imaging device 244 and the illumination unit 3a, and input / output control of information with respect to each component. The control unit 37 refers to control information data (for example, readout timing) for image capturing control stored in the storage unit 38 and captures an image as a drive signal via a predetermined signal line included in the aggregate cable 246. Transmit to element 244. The control unit 37 is configured using a general-purpose processor such as a CPU or a dedicated processor such as various arithmetic circuits that execute specific functions such as an ASIC.

The display device 4 displays a display image corresponding to the image signal received from the processing device 3 (image processing unit 31) via the video cable. The display device 4 is configured using a monitor such as a liquid crystal or an organic EL (Electro Luminescence).

Subsequently, image acquisition processing performed by the endoscope system 1 will be described. FIG. 3 is a timing chart illustrating imaging processing in the normal mode performed by the endoscope system according to the first embodiment of the present invention. FIG. 4 is a timing chart illustrating high-speed mode imaging processing performed by the endoscope system according to the first embodiment of the present invention.

3 and 4, from the top, (a) shows the frame counter, (b) shows the illumination timing and imaging timing of the illumination light, and (c) to (e) show each color held by the frame memory 32. (F) to (h) show the timing of the image data of each color output by the image processing unit 31. In FIG. 3, the control unit 37 causes the image sensor 244 to image at 60 fps, and the illumination control unit 320 applies R illumination light, G illumination light, and light to the light source unit 310 at 60 fps in synchronization with the imaging frame rate of the image sensor 244. B illumination light is sequentially switched and irradiated. On the other hand, in FIG. 4, the imaging device 244 is imaged at 120 fps in the high-speed mode, and the illumination control unit 320 applies R illumination light, G illumination light, and B to the light source unit 310 at 120 fps in synchronization with the imaging frame rate of the imaging device 244. Illumination light is switched in order and irradiated. Even in the high-speed mode, the frame rate at which the display device 4 switches images is set to 60 fps as in the normal mode.

(Normal mode: Fig. 3)
First, the illumination control unit 320 irradiates the light source unit 310 with R ₀ illumination light at the timing of frame counter (FC) = 0. In this case, the control unit 37 causes the image sensor 244 to capture the return light from the R ₀ illumination light and causes the image processing unit 31 to output image data. The image processing unit 31 stores digital R ₀ image data in a corresponding channel (frame memory R) of the frame memory 32 and performs various image processing. In the normal mode, one frame is processed for 1/60 second.

Subsequently, the control unit 37 causes the image processing unit 31 to output the R ₀ image data in the frame memory 32 to the display device 4 at the timing of FC = 1. In this case, the illumination control unit 320 causes the light source unit 310 to emit _G0 illumination light. At this time, the control unit 37 causes the image sensor 244 to image the return light by the G ₀ illumination light and causes the image processing unit 31 to output the image data. The image processing unit 31 stores digital G ₀ image data in a corresponding channel (frame memory G) of the frame memory 32 and performs various image processing.

Thereafter, the control unit 37 causes the image processing unit 31 to output the _G0 image data in the frame memory 32 to the display device 4 at the timing of FC = 2. In this case, the illumination control unit 320 causes the light source unit 310 to emit B ₀ illumination light. At this time, the control unit 37 causes the image sensor 244 to image the return light from the B ₀ illumination light, and causes the image processing unit 31 to output image data. The image processing unit 31 stores digital B ₀ image data in a corresponding channel (frame memory B) of the frame memory 32 and performs various image processing.

Subsequently, the control unit 37 causes the image processing unit 31 to output the B ₀ image data in the frame memory 32 to the display device 4 at the timing of FC = 3.

In the normal mode described above, the illumination controller 320 sequentially repeats the cycle of R illumination light → G illumination light → B illumination light as one cycle until the end of photographing. In the normal mode, since the number of binning is set to one pixel, the reading unit 244b sequentially reads pixel values using one pixel as a reading unit.

(High-speed mode: Fig. 4)
In the high speed mode, the illumination control unit 320 and the control unit 37 irradiate the light source unit 310 with illumination light and cause the image sensor 244 to return light by illumination light in the same manner as in the normal mode except that the imaging frame rate is set to 120 fps. And image data is output to the image processing unit 31. In the high speed mode, the number of binning is further set as the imaging condition. As the binning number, 4 pixels, 9 pixels, and 16 pixels are set depending on the characteristics of the endoscope 2 and the like. For example, when the number of binning is four pixels, reading is performed with four pixels forming a shape similar to one pixel as one pixel. In the high-speed mode, one frame is processed for 1/120 seconds.

In the high-speed mode described above, the illumination control unit 320 sequentially repeats the cycle of R illumination light → G illumination light → B illumination light as one cycle until the end of photographing. In the high-speed mode, since the number of binning is set to 4 pixels, the readout unit 244b sequentially reads out pixel values obtained by collecting 4 pixels as one readout unit. For this reason, the pixel value can be increased as compared with the case where the readout unit is one pixel.

FIG. 5 is a diagram schematically illustrating an example of an image acquired by the endoscope system according to the first embodiment of the present invention by high-speed mode imaging processing and displayed on the display device. FIG. 6 is a diagram schematically illustrating an example of an image acquired by the endoscope system according to the first embodiment of the present invention through imaging processing in the normal mode and displayed on the display device. 5 and 6, from the top, (R1) and (R2) indicate scenes, captured images, and display images captured with R illumination light, and (G1) and (G2) are captured with G illumination light. A scene, a captured image, and a display image are shown, and (B1) and (B2) indicate a scene, a captured image, and a display image that are captured by the B illumination light.

As can be seen from FIGS. 5 and 6, the display image with a higher imaging frame rate has a smaller color shift feeling than the display image with a lower imaging frame rate. Specifically, the shift of the image of each color in the display image area Q is smaller in the display image with a higher imaging frame rate than in the display image with a lower imaging frame rate.

In the first embodiment described above, when the endoscope 2 supports high-speed frame sequential, the control unit 37 sets the high-speed mode and performs illumination / imaging control at 120 fps. Further, in the high speed mode, the reading process is performed with the binning number set larger than that in the normal mode. According to the first embodiment, it is possible to suppress color shift by imaging at 120 fps and to suppress a decrease in image brightness by executing a binning process even when a high frame rate is set.

In the first embodiment, the gain value may be switched according to the set imaging frame rate. When switching the gain value by the image pickup element 244 side, for example, the 60 fps 12000e ^- set, in 120 fps 8000E ^- set to. Not only the image pickup device 244 but also the gain value may be switched according to the image pickup frame rate when gain adjustment is performed in the image processing unit 31 of the processing device 3. Further, instead of the binning process, the brightness of the image may be secured by the above-described gain value switching process.

Further, in the first embodiment, the imaging condition switching unit 34 may switch the imaging frame rate based on the motion vector when the endoscope 2 capable of high-speed frame sequential correspondence is connected. Specifically, the image processing unit 31 periodically detects the motion vector of the subject from images having different acquisition times. The imaging condition switching unit 34 calculates the magnitude of the detected motion vector, increases the imaging frame rate if the magnitude is greater than or equal to a preset threshold value, and takes the imaging frame if the magnitude is smaller than the threshold value. Set the rate to the normal value. By controlling the imaging frame rate based on the motion vector, when the movement of the subject is large, the imaging frame rate is increased to suppress color misregistration.

Further, in the first embodiment, the imaging condition switching unit 34 may switch the number of binning based on the exposure time at the time of imaging. Specifically, the imaging condition switching unit 34 acquires the latest exposure time, and if this exposure time is equal to or less than a preset threshold value, the binning number is increased and the brightness per image is increased. To do. On the other hand, if the exposure time is larger than the threshold, the imaging condition switching unit 34 determines that a certain level of brightness is secured, and makes the number of binning smaller than when the exposure time is less than or equal to the threshold.

(Modification of Embodiment 1)
Next, a modification of the first embodiment of the present invention will be described with reference to FIG. FIG. 7 is a timing chart illustrating high-speed mode imaging processing performed by the endoscope system according to the modification of the first embodiment of the present invention. Note that the endoscope system according to this modification has the same configuration as the above-described endoscope system, and thus the description thereof is omitted. Hereinafter, processing different from that of the first embodiment will be described.

According to the standard visibility defined by the CIE (Commission Internationale de l'Eclairage), humans feel green light (light in a wavelength band including a wavelength of 555 nm) most strongly in a bright place. For example, in the situation shown in FIG. 3, an image displayed on the display device 4 at the timing of FC = 3 has an output color order from the image processing unit 31 of G ₀ → B ₀ → R ₁ (G ₀ image data → B ₀ image data → R ₁ image data), and two colors (G and R) having high human visibility are output at timings separated in time. Furthermore, according to the above-mentioned standard visibility, humans strongly feel red light (wavelength of 620 to 700 nm) next to green light among the three primary colors RGB. Thereby, the user feels a large color shift visually.

Further, in the situation shown in FIG. 3, the image displayed on the display device 4 at the timing of FC = 4 has an output color order from the image processing unit 31 of B ₀ → R ₁ → G ₁ (B ₀ data → R ₁ data → G ₁ data), and two colors (G and R) having high human visibility are output at timings adjacent to each other in time. For this reason, the color shift that the user feels visually is smaller than the timing when two colors (G and R) having high human visibility are separated in time. Further, for the image displayed on the display device 4 at the timing of FC = 5, the color order of the output from the image processing unit 31 is R ₁ → G ₁ → B ₁ (R ₁ data → G ₁ data → B ₀ data). The two colors (G and R) with high human visibility are output at the timing when they are adjacent in time. For this reason, the color shift that the user feels visually is smaller than the timing when two colors (G and R) having high human visibility are separated in time.

Next, an operation performed by the endoscope system 1 in this modification will be described with reference to FIG. In FIG. 7, from the top, (a) shows the frame counter, (b) shows the illumination light irradiation timing, and (c) to (e) show the timing of the image data of each color held by the frame memory 32. (F) to (h) show the timing of the image data of each color output by the image processing unit 31. In FIG. 7, the control unit 37 causes the imaging device 244 to image at 120 fps, and the illumination control unit 320 sequentially switches illumination light to the light source unit 310 at 120 fps in synchronization with the imaging frame rate of the imaging device 244 for irradiation. High speed mode is shown.

First, the illumination control unit 320 irradiates the light source unit 310 with G ₀ illumination light at the timing of FC = 0. In this case, the control unit 37 causes the image sensor 244 to image the return light by the G ₀ illumination light, and causes the image processing unit 31 to output image data. The image processing unit 31 stores the G ₀ image data to the channel (frame memory G) corresponding frame memory 32, performs various image processing. Further, the control unit 37 causes the image processing unit 31 to output the _G0 image data in the frame memory 32 to the display device 4 at the timing of FC = 0.

Subsequently, the illumination control unit 320 causes the light source unit 310 to emit R ₀ illumination light. In this case, the control unit 37 causes the imaging device 244 to capture the return light from the R ₀ illumination light, and causes the image processing unit 31 to output image data. The image processing unit 31 stores digital R ₀ image data in a corresponding channel (frame memory R) of the frame memory 32 and performs various image processing. At this time, the control unit 37 causes the image processing unit 31 to output the R ₀ image data in the frame memory 32 to the display device 4 at the timing of FC = 1.

Thereafter, the illumination control unit 320 causes the light source unit 310 to emit G ₁ illumination light. In this case, the control unit 37 causes the image sensor 244 to image the return light from the G ₁ illumination light and causes the image processing unit 31 to output image data. The image processing unit 31 stores digital G ₁ image data in a corresponding channel (frame memory G) of the frame memory 32 and performs various image processing. At this time, the control unit 37 causes the image processing unit 31 to output the G ₁ image data in the frame memory 32 to the display device 4 at the timing of FC = 2.

Subsequently, the illumination control unit 320 causes the light source unit 310 to emit B ₀ illumination light. In this case, the control unit 37 causes the image sensor 244 to capture the return light from the B ₀ illumination light and causes the image processing unit 31 to output image data. The image processing unit 31 stores digital B ₀ image data in a corresponding channel (frame memory B) of the frame memory 32 and performs various image processing. At this time, the control unit 37 causes the image processing unit 31 to output the B ₀ image data in the frame memory 32 to the display device 4 at the timing of FC = 3.

In the modification described above, the illumination control unit 320 causes the light source unit 310 to sequentially switch and irradiate the illumination light until the end of imaging with the process of G illumination light → R illumination light → G illumination light → B illumination light as one cycle. In this case, the control unit 37 is a timing at which the frame counter becomes an odd number (for example, FC = 3, FC = 5, etc.), and B illumination light (B ₀ illumination light) or R illumination light (R ₁ illumination light). At the timing when the image processing unit 31 is irradiated, the image processing unit 31 receives an image corresponding to the image data composed of the R ₀ image data, the G ₁ image data, and the B ₀ image data, the R ₁ image data, the G ₂ image data, and the B ₀ image. An image corresponding to the image data composed of data is output to the display device 4. Thereby, since the G image data is constantly updated, it is possible to prevent color misregistration that can be visually perceived. Furthermore, when the transfer rate (display frame rate) to the display device 4 is 60 fps, the endoscope system 1 doubles the switching rate of the illumination light emitted from the light source unit 310 (the imaging frame rate of the imaging device 244). 120 fps.

Moreover, in this modification, the illumination control unit 320 is not a simple repetition of the three primary colors of the conventional method described above (R illumination light → G illumination light → B illumination light), but green light with high human visibility. The illumination unit 3a is sequentially switched and irradiated in the color order that doubles the time resolution of red light and blue light, specifically G illumination light → R illumination light → G illumination light → B illumination light. Therefore, the smoothness of movement can be improved.

Moreover, in this modification, the illumination control unit 320 irradiates the light source 310 with illumination light by G illumination light → R illumination light → G illumination light → B illumination light, and has two colors with high visibility, that is, G illumination light. Since the G illumination light and the R illumination light are prevented from being separated in time by bringing the R illumination light and the R illumination light next to each other in time, the color shift feeling is reduced when capturing a still image at an arbitrary timing. Can do.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 8 is a block diagram illustrating a schematic configuration of the endoscope system according to the second embodiment of the present invention.

An endoscope system 1A shown in FIG. 8 generates an endoscope 2 that captures an image in a subject by inserting a tip portion into the subject, and illumination light emitted from the tip of the endoscope 2. A processing device 3A that has an illumination unit 3a, performs predetermined signal processing on the image signal captured by the endoscope 2, and controls the overall operation of the endoscope system 1, and signal processing of the processing device 3A And a display device 4 for displaying the in-vivo image generated by. The endoscope system 1A according to the second embodiment has the same configuration except that the processing device 3 of the endoscope system 1 described above is changed to the processing device 3A. Hereinafter, a processing apparatus 3A having a configuration different from that of the first embodiment will be described.

The processing device 3A includes an illumination unit 3a, an image processing unit 31, a frame memory 32, a communication unit 33, an imaging condition switching unit 34, a synchronization signal generation unit 35, an input unit 36, a control unit 37, A storage unit 38 and an enlargement processing unit 39 are provided. The processing device 3A has a configuration in which an enlargement processing unit 39 is added to the processing device 3 described above. Hereinafter, the enlargement processing unit 39 will be described.

The enlargement processing unit 39 switches the electronic enlargement rate of the image data according to the set number of binning. Here, since the binned image data handles four pixels as one point on the image, the image size is reduced. The enlargement processing unit 39 suppresses image reduction due to the binning process by interpolating and enlarging the image data. For example, when the number of binning is 4 pixels, it is not enlarged (1 time), and when the number of binning is 9 pixels, it is enlarged 2 times.

In the second embodiment described above, the same effects as in the first embodiment can be obtained. Furthermore, according to the second embodiment, since the image is enlarged according to the number of binning, it is possible to prevent the image displayed on the display device 4 from being reduced.

In the first and second embodiments described above, the illumination unit 3a has been described as being configured separately from the endoscope 2. However, for example, a semiconductor light source is provided at the tip of the endoscope 2, etc. The structure which provided the light source device in the endoscope 2 may be sufficient. Furthermore, the function of the processing device 3 may be given to the endoscope 2.

In the first and second embodiments described above, the binning control unit 244c has been described as being provided in the image sensor 244. However, the binning controller 244c may be provided outside the image sensor 244 (in the endoscope 2), or may be processed. You may provide in apparatus 3, 3A.

In the first and second embodiments described above, the illumination unit 3a is described as being integral with the processing devices 3 and 3A. However, the illumination unit 3a and the processing device 3 are separate, for example, the processing device. 3, the light source unit 310 and the illumination control unit 320 may be provided outside.

In the first and second embodiments described above, the illumination unit 3a uses a white light source (for example, a xenon lamp or a halogen lamp) instead of the LED light source and a red wavelength on the optical path of the illumination light emitted by the white light source. A rotation filter having three transmission filters that transmit each of the band, the green wavelength band, and the blue wavelength band, and rotating the rotation filter to thereby include each of the red, green, and blue wavelength bands You may make it irradiate light.

In

Embodiments

1 and 2 described above, when the video output method is switched between NTSC that displays 60 fields per second and PAL that displays 50 fields per second, images are thinned out at the time of switching. At this time, a number is assigned to an image before being thinned out for system conversion, and the number and parameters relating to the image data of the number are stored in a memory (for example, provided in the display device 4). After the switching process is completed, the image data of each number and its parameters are read and the process for displaying is continued.

In the first and second embodiments described above, in order to perform optical transmission between the patient substrate and the secondary substrate in the processing devices 3 and 3A, when an optical cable made of an optical fiber is connected by an optical connector, The optical fiber may be configured to notify the replacement time before image data (optical signal) is not transmitted due to aging. For example, the optical transmission current on the signal receiving side in the optical connector is monitored, the monitor value is converted into a voltage, and the deterioration is determined by comparing with a threshold value.

In the first and second embodiments described above, the endoscope system according to the present invention is the endoscope system 1 using the flexible endoscope 2 whose observation target is a living tissue or the like in the subject. As described above, it is used as an eyepiece for optical endoscopes such as rigid endoscopes, industrial endoscopes that observe material properties, capsule endoscopes, fiberscopes, and optical endoscopes. Even an endoscope system using a camera head connected can be applied.

As described above, the endoscope system according to the present invention is useful for acquiring an image in which a decrease in brightness is suppressed even when the imaging frame rate is increased.

DESCRIPTION OF SYMBOLS 1 Endoscope system 2 Endoscope 3 Processing apparatus 3a Illumination part 4 Display apparatus 21 Insertion part 22 Operation part 23 Universal code 24 Tip part 25 Bending part 26 Flexible pipe part 31 Image processing part 32 Frame memory 33 Communication part 34 Imaging Condition switching unit 35 Sync signal generation unit 36 Input unit 37 Control unit 38 Storage unit 381 Imaging information storage unit 310 Light source unit 320 Illumination control unit

Claims

An illumination unit that sequentially switches a plurality of illumination lights including different wavelength bands and irradiates the subject; and
An endoscope having a plurality of pixels that photoelectrically convert return light from the subject to generate an image signal, and an imaging unit that reads out the image signal generated by the pixel in synchronization with irradiation timing of the illumination unit With a mirror,
An image processing unit that performs a synchronization process on the image signal read out by the imaging unit using a plurality of the image signals generated based on return lights of illumination light in different wavelength bands;
Based on the identification information of the endoscope, the imaging unit is switched to either a normal mode in which an image is captured at a preset imaging frame rate or a high-speed mode in which the imaging frame rate is higher than the normal mode. An imaging condition switching unit for switching,
A binning control unit that, when set to the high-speed mode, causes the imaging unit to execute a readout process with a larger number of pixels as a readout unit than the normal mode;
An endoscope system comprising:
The illumination unit is
A red semiconductor light emitting element that emits red illumination light in a red wavelength band; and
A green semiconductor light emitting element that emits green illumination light in the green wavelength band;
A blue semiconductor light emitting element that emits blue illumination light in a blue wavelength band; and
An illumination control unit that switches emission of illumination light from the red semiconductor light emitting element, the green semiconductor light emitting element, and the blue semiconductor light emitting element according to the setting of the imaging frame rate;
Have
When the illumination control unit is set to the high-speed mode, the lighting order of illumination light is the red illumination light, the green illumination light, the blue illumination light, and the green illumination light. The endoscope system according to claim 1.
An enlargement processing unit for performing electronic enlargement processing on the image signal;
Further comprising
The endoscope system according to claim 1, wherein the enlargement processing unit switches an electronic enlargement ratio according to the number of pixels as the readout unit that is executed by the imaging unit by the binning control unit.
The endoscope system according to claim 1, wherein the imaging condition switching unit switches the imaging frame rate and / or the number of pixels used as the readout unit based on a parameter related to the image signal.