WO2017168785A1

WO2017168785A1 - Endoscope

Info

Publication number: WO2017168785A1
Application number: PCT/JP2016/076461
Authority: WO
Inventors: 紗依里齋藤
Original assignee: オリンパス株式会社
Priority date: 2016-03-30
Filing date: 2016-09-08
Publication date: 2017-10-05
Also published as: JPWO2017168785A1; JP6275357B1

Abstract

Provided is an endoscope, comprising: an image capture element 22 which is capable of setting a pre-blanking interval which is an interval which corresponds to the number of lines from the timing at which one frame is commenced to a timing of valid pixel commencement; an illumination unit 29 which is capable of irradiating illumination light from a light source 44 which is provided with a light emitting interval and a blanking interval; a read-out timing setting unit 26 which sets the pre-blanking interval which corresponds to a monitor display pixel from among the valid pixels, and which sets a commencement timing of the pre-blanking interval according to a vertical synchronization signal; and a signal read-out circuit 25 which reads out, in the blanking interval, an image capture signal which is commenced at the commencement timing and which relates to the monitor display pixel according to the pre-blanking interval.

Description

Endoscope

The present invention relates to an endoscope, and more particularly to an endoscope that can correct pixel shift caused by decentration of an imaging optical system.

An endoscope system including an endoscope that captures an object inside a subject and an image processing device that generates an observation image of the object captured by the endoscope is widely used in the medical field, the industrial field, and the like. It is used.

In such an endoscope system, conventionally, the pixel shift of the imaging signal due to the eccentricity of the imaging optical system or an imaging system using a plurality of imaging elements (for example, a 3D imaging system or a prism separates an optical image). In addition, there is known a technique for electrically correcting a positional deviation between image pickup devices in an image pickup system such as a 3CCD that receives light by two or more image pickup devices.

As this type of correction technique, for example, a technique that realizes the correction of the pixel shift using a “cutout function” that selectively reads out only an arbitrary range of pixels in the image sensor is known (Japanese Patent Laid-Open No. 2006-2006). -239052).

However, in recent years, an image sensor mounted on an endoscope has been required to be further downsized. For this reason, it is necessary to limit the functions to be mounted, and it is difficult to use the “cutout function” described above as a technique for correcting pixel shift.

In addition, when the endoscope system as described above employs a so-called frame sequential observation method, it is necessary to drive the imaging device in synchronization with the light emission and light shielding timing of the light source. In order to perform pixel shift (position shift) correction, it is necessary to shorten the light emission time of the light source.

The reason why it has been necessary to shorten the light emission time of the light source in order to perform this correction is as follows.

That is, in the endoscope system that employs the observation method as described above, it is necessary to read at least the effective pixel portion displayed on the monitor among the effective pixels related to the image sensor during the light shielding period of the light source.

Here, if it is assumed that correction of pixel shift as described above is not performed, only the effective pixel portion displayed on the monitor needs to be read during the light-shielding period of the light source.

On the other hand, when correcting pixel shift, conventionally, depending on the correction method (for example, shifting upward or downward on the screen), the effective pixel portion displayed on the monitor is effective for the image sensor. Since the position in the pixel is not uniquely determined, the entire effective pixel has to be read during the light-shielding period of the light source.

This requires a longer light-shielding period of the light source, in other words, a shorter light-emitting period of the light source, which may lead to insufficient illumination brightness.

The present invention has been made in view of the above-described circumstances, and does not use a “cutout function” that selectively reads out only pixels in an arbitrary range in an image sensor, and does not shorten the light emission period of the light source. An object of the present invention is to provide an endoscope capable of performing the correction process.

An endoscope according to an aspect of the present invention is an imaging element that captures an image of a subject and generates a predetermined imaging signal, and has the number of lines from the timing of starting one frame to the starting timing of effective pixels related to the imaging element. An imaging device capable of setting a pre-blanking period, which is a corresponding period, and an illumination unit capable of emitting illumination light for irradiating the subject and irradiating the subject with the illumination light from a light source having a light emission period and a light shielding period A pre-blanking period setting unit that sets a predetermined pre-blanking period corresponding to a monitor display pixel to be displayed on a monitor in effective pixels related to the image sensor, and the pre-blanking according to a predetermined vertical synchronization signal A start timing setting unit for setting a start timing of a period, and the start timing setting unit in the light shielding period of the light source It started at the set the start timing comprises a signal reading circuit for reading out an image signal according to the monitor display pixel in accordance with the pre-blanking period set by the pre-blanking period setting unit.

FIG. 1 is a diagram illustrating a configuration of an endoscope system including an endoscope according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating an electrical configuration of the endoscope system including the endoscope according to the first embodiment. FIG. 3 is a timing chart showing the frame start timing and sensor readout timing for each pixel shift correction position corresponding to the frame sequential light source operation timing in the endoscope of the first embodiment. FIG. 4 is a diagram showing the relationship between the read pixel position for each pixel shift correction position and the pixel position displayed on the monitor in the endoscope of the first embodiment. FIG. 5 is a timing chart showing the frame start timing and sensor readout timing for each pixel shift correction position corresponding to the frame sequential light source operation timing in the endoscope of the second embodiment of the present invention. FIG. 6 is a timing chart showing a frame start timing and a sensor readout timing for each pixel shift correction position corresponding to the frame sequential light source operation timing in the conventional endoscope.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a diagram illustrating a configuration of an endoscope system including an endoscope according to a first embodiment of the present invention, and FIG. 2 is a diagram of an endoscope system including an endoscope according to the first embodiment. It is a block diagram which shows an electric structure.

As shown in FIGS. 1 and 2, an endoscope system 1 having the endoscope of the first embodiment is connected to an endoscope 2 that observes and images a subject, and to the endoscope 2. A video processor 3 that inputs the imaging signal and performs predetermined image processing; a light source device 4 that supplies illumination light for illuminating the subject; and a monitor device 5 that displays an observation image corresponding to the imaging signal. Have.

The endoscope 2 includes an elongated insertion portion 6 that is inserted into a body cavity or the like of a subject, and an endoscope operation portion 10 that is disposed on the proximal end side of the insertion portion 6 and is operated by being grasped by an operator. And a universal cord 11 provided with one end portion so as to extend from the side portion of the endoscope operation unit 10.

The insertion portion 6 includes a rigid distal end portion 7 provided on the distal end side, a bendable bending portion 8 provided at the rear end of the distal end portion 7, and a long and flexible portion provided at the rear end of the bending portion 8. And a flexible tube portion 9 having flexibility.

A connector 12 is provided on the base end side of the universal cord 11, and the connector 12 is connected to the light source device 4. That is, a base (not shown) serving as a connection end of a fluid conduit projecting from the tip of the connector 12 and a light guide base (not shown) serving as an illumination light supply end are provided to the light source device 4. It is designed to be detachably connected.

Furthermore, one end of the connection cable 13 is connected to the electrical contact portion provided on the side surface of the connector 12. The connection cable 13 is provided with a signal line for transmitting an image pickup signal from the image pickup element 22 (see FIG. 2) in the endoscope 2, for example, and the other end connector portion is connected to the video processor 3. It has come to be.

The connector 12 is provided with an FPGA 23 to be described later, and endoscope specific information in the endoscope 2 (for example, information related to a pixel shift value of the image sensor or the like according to the pixel shift value). In addition, an ID memory 27 or the like storing information such as numerical values of the pre-blanking period) is disposed (these components will be described in detail later).

As shown in FIG. 2, the endoscope 2 is provided with an illumination unit 29 disposed at the distal end portion 7 of the insertion unit 6 and capable of irradiating a subject with a plurality of types of illumination light, and the subject image is incident. An objective optical system 21 including a lens for performing imaging, and an imaging element 22 disposed on an image forming surface of the objective optical system 21.

The illumination unit 29 is disposed at the distal end portion of the light guide that extends from the light source device 4 to the inside of the endoscope 2. And the illumination part 29 irradiates the illumination light by which the light emission period and the light-shielding period which were generated in the said light source device 4 were controlled.

The objective optical system 21 receives reflected light related to the subject according to predetermined illumination light (frame sequential light) irradiated to the subject by the illumination unit 29.

The image sensor 22 is constituted by a CMOS image sensor in the present embodiment. Note that the endoscope system 1 of the present embodiment adopts a frame sequential observation method.

The light receiving unit in the imaging element 22 includes a plurality of photodiodes (PD) 22a that are photoelectric conversion units that photoelectrically convert light according to incident light to generate signal charges, and the signal charges generated in the photoelectric conversion unit. A plurality of pixels for generating and outputting an imaging signal based on the above.

Then, when an optical image from the subject is formed on the imaging surface, the imaging element 22 photoelectrically converts light incident on each pixel in a photoelectric conversion unit and outputs a predetermined imaging signal.

Further, the image sensor 22 can set a preblanking period, which is a period corresponding to the number of lines from the start timing of one frame to the start timing of the effective pixels related to the image sensor 22.

The “timing for starting one frame” is set by the “start timing setting unit”, and the “preblanking period” is set by the “preblanking period setting unit”. The details will be described later. To do.

The image sensor 22 also includes an AFE (analog front end) 22b. The AFE 22b is a circuit that performs predetermined processing on the imaging signal, and includes a known CDS (Correlation Double Sampling) circuit and an analog / digital converter (ADC), and outputs the imaging signal as a digital imaging signal. To do.

The image sensor 22 further includes a timing generator (TG) 22c that gives a predetermined timing to the photodiode (PD) 22a and the AFE 22b.

The endoscope 2 includes the FPGA 23 in the connector 12 described above. The FPGA 23 is configured by a so-called FPGA (field-programmable gate array), and performs various digital signal processing on the digital image signal output from the AFE 22b.

The FPGA 23 includes a read timing setting unit 26 and a signal read unit 25. In the present embodiment, the read timing setting unit 26 serves as a “preblanking period setting unit” and a “start timing setting unit”. In addition, the signal reading unit 25 serves as a “signal reading unit” that reads an imaging signal related to the monitor display pixel in accordance with the preblanking period in the light shielding period related to the light source device 4. The read timing setting unit 26 and the signal read unit 25 will be described in detail later.

Furthermore, the endoscope 2 uses the connector 12 to identify the endoscope specific information (for example, information related to the pixel shift value of the image sensor, which will be described later, or the pre-appropriate information corresponding to the pixel shift value). An ID memory 27 storing information (such as numerical values of ranking periods) is disposed and connected to the read timing setting unit 26.

<Regarding pixel shift in imaging signal>
Next, “detection of pixel shift” and “storage of information relating to pixel shift” in the present embodiment will be described.

As described above, the “pixel shift” of the imaging signal may occur due to the eccentricity of the imaging optical system. When this “pixel shift” occurs, if the image signal is read without taking any countermeasures, the image displayed on the monitor will naturally shift depending on the degree of “pixel shift”. There is a possibility that an accurate image cannot be displayed.

FIG. 4 is a diagram showing the relationship between the read pixel position for each pixel shift correction position and the pixel position displayed on the monitor in the endoscope of the first embodiment. Refer to FIG. A problem caused by “pixel shift” will be briefly described.

As shown in FIG. 4, the endoscope 2 is displayed on the monitor 5 in the pixel group 60 </ b> A of the image sensor 22, for example, a normal type endoscope in which “pixel shift” has not occurred is “type A”. It is assumed that a pixel group to be indicated is denoted by reference numeral 61. In FIG. 4, a pixel area indicated by “OB” is a so-called optical black area.

In this case, since there is no “pixel shift” in the endoscope 2, the pixel group 61 can be displayed as the display image 51 on the monitor 5 without correcting the pixel shift.

On the other hand, when the endoscope 2 has a “pixel shift”, the endoscope is now referred to as “type B” and “type C”.

In the type B endoscope 2, for example, the pixel group to be displayed on the monitor 5 is compared with the type A in the pixel group 60 </ b> B indicated by “type B” in FIG. 4 from the position of the pixel group 61. Assume that the position is shifted upward as indicated by the pixel group 61b. In the type C endoscope 2, the pixel group to be displayed on the monitor 5, for example, is compared with the type A described above. In FIG. 4, it is assumed that the position is shifted upward from a position indicated by a pixel group 61c in a pixel group 60C indicated by "type C" in FIG.

In the case of these type B or type C endoscopes 2, the image displayed on the monitor 5 is naturally displayed when the processing of reading the image signal is performed without taking any measures, that is, when reading is performed at the position of the normal pixel 61. Shifts according to the degree of “pixel shift”.

As described above, when the “pixel shift” of the image pickup signal occurs due to the eccentricity of the image pickup optical system or the endoscope in which the “pixel shift” occurs, an accurate image may not be displayed. However, for this problem, for example, when a “pixel shift” occurs, a “cutout function” that specifies the coordinate position of the shifted pixel and selectively reads out only the pixel corresponding to the coordinate position If the technique of correcting using is used, the problem of the “pixel shift” can be dealt with. However, the present invention makes it possible to correct the pixel shift without using the “cutout function”.

<Pixel shift detection and storage of pixel shift information>
In the present embodiment, as a premise for correcting the pixel shift, for example, when the “pixel shift” of the imaging signal due to the eccentricity of the imaging optical system is detected at the time of manufacturing the endoscope, the “pixel shift” is determined. Such information is stored in the ID memory 27.

The information related to the “pixel shift” includes, for example, information related to the actual pixel shift value of the image sensor or information such as a numerical value of a preblanking period corresponding to the pixel shift value.

Thus, the endoscope according to the present embodiment detects the degree of pixel shift, and the endoscope itself stores information corresponding to the degree of pixel shift as information for each endoscope. ing.

In the present embodiment, information related to the “pixel shift” of the imaging signal caused by the eccentricity of the imaging optical system is stored in the storage unit inside the endoscope. Or the like.

<Pixel shift correction and pre-blanking period>
Here, the pixel shift correction method according to the present embodiment, the preblanking period, the setting unit for the preblanking period, and the start timing setting unit will be described in detail.

As described above, the read timing setting unit 26 in the FPGA 23 serves as a “preblanking period setting unit” and a “start timing setting unit” in the present embodiment.

The read timing setting unit 26 first sets a “monitor display pixel” in the effective pixels related to the image sensor 22, that is, a “preblanking period” corresponding to the position of the pixel actually displayed on the monitor. Acts as a “ranking period setting section”.

In the present embodiment, the “preblanking period” is a period corresponding to the number of lines from the start timing of one frame in the image sensor 22 to the start timing of effective pixels related to the image sensor 22.

In addition, since the position of the “monitor display pixel” in the effective pixel also changes depending on the degree of “pixel shift” determined for each endoscope, the “pre-blanking period” corresponding to the position also changes in each endoscope. It will be set for each mirror.

By the way, the endoscope 2 of the present embodiment needs to read only the effective pixel portion (“monitor display pixel”) to be displayed on the monitor among the effective pixels of the image sensor 22 during the light-shielding period of the light source. In view of the above, the reading timing of the “monitor display pixel” and the light-shielding period of the light source are made to substantially coincide with each other regardless of the presence or absence of “pixel shift” of the image sensor 22.

That is, in the endoscope 2 of the present embodiment, the readout timing of the entire effective pixel of the image sensor 22 is not necessarily determined during the light-shielding period of the light source, regardless of whether or not there is a “pixel shift” of the image sensor 22. However, the present invention is characterized in that a part of the effective pixels other than the “monitor display pixel” can be read out outside the light-shielding period of the light source, that is, within the light-emitting period of the light source.

As described above, the position of the “monitor display pixel” in the effective pixel changes depending on the degree of “pixel shift” determined for each endoscope. The endoscope 2 of the present embodiment adjusts the reading start timing of the effective pixels and further adjusts the reading start timing of the effective pixels so that the timing substantially coincides with the light shielding period (charge reading period) of the light source. The length of the “pre-blanking period” is set according to the condition.

In other words, the length of the “pre-blanking period” is variably set according to the degree of “pixel deviation” determined for each endoscope, so that the “monitor” The readout timing of the “display pixel” is always substantially coincident with the light-shielding period (charge readout period) of the light source, whereby the light-shielding period of the light source can be shortened, that is, the light emission time can be set longer.

The read timing setting unit 26 serves as a “start timing setting unit” that sets the start timing of the pre-blanking period according to the vertical synchronization signal VSYNC from the drive signal generation unit 35 in the video processor 3.

In the first embodiment, it is assumed that the start timing of the pre-blanking period is set to be the same even for endoscopes having different “pixel shifts” determined for each endoscope.

As described above, when the endoscope 2 is operated in a state where “information relating to pixel shift” is stored in the ID memory 27 as individual information of the endoscope, the read timing as the “preblanking period setting unit” The setting unit 26 reads out information related to pixel shift of the image sensor from among various unique information stored in the ID memory 27 and sets a “preblanking period” determined for each endoscope. It is like that.

As described above, the preblanking period is started at the start timing set in the “start timing setting unit” in the read timing setting unit 26, and the preblanking period is read timing setting unit 26. According to the position of the “monitor display pixel” in the “preblanking period setting unit” in other words, in other words, according to the information related to “pixel shift” stored as individual information for each endoscope, A period is set.

On the other hand, as described above, the signal reading unit 25 serves as a “signal reading unit” that reads an imaging signal related to the monitor display pixel in accordance with the pre-blanking period in the light shielding period related to the light source device 4. .

In the first embodiment, the signal reading unit 25 reads the effective pixel after the pre-blanking period ends. In the light shielding period related to the light source device 4, the “monitor display pixel” in the effective pixel, that is, the image pickup signal related to the pixel actually displayed on the monitor in the effective pixel of the image sensor 22 is read out.

On the other hand, the video processor 3 inputs a video signal from the endoscope 2 and a control unit 31 that controls various circuits in the connected endoscope 2 and the light source device 4 in addition to the video processor 3. An image processing unit 32 that performs image processing, a video output unit 33 that inputs an image signal processed in the image processing unit 3 and generates a video signal for display on the monitor device 5, a predetermined vertical synchronization signal VSYNC, and the like And a drive signal generation unit 35 for generating the drive signal.

The light source device 4 includes a light source 44, a light source driver 42, a rotary filter 46, a drive unit 45, a drive driver 43, and a light source control unit 41.

The light source 44 is configured by using a white LED (Light Emitting Diode), a xenon lamp, or the like, and generates white light under the control of the light source control unit 41.

The light source driver 42 generates white light in the light source 44 by supplying current to the light source 44 under the control of the light source control unit 41. Light generated by the light source 44 is emitted from the illumination unit 29 of the endoscope 2 via the rotary filter 46, a condenser lens (not shown), and the light guide.

The rotary filter 46 is arranged on the optical path of white light emitted from the light source 44, and transmits only the light having a predetermined wavelength band through the white light emitted from the light source 44 by rotating. Specifically, the rotary filter 46 includes a red filter 46R, a green filter 46G, and a blue filter 46B that transmit light having respective wavelength bands of red light (R), green light (G), and blue light (B). Have.

The driving unit 45 rotates the rotary filter 46 with reference to the synchronization signal transmitted from the video processor 3. The drive driver 43 supplies a predetermined current to the drive unit 45 under the control of the light source control unit 41.

The light source control unit 41 controls the amount of current supplied to the light source 44 according to the dimming signal transmitted from the control unit 31 in the video processor 3. In the present embodiment, the operation timing of the light source by the light source control unit 41 is fixed regardless of the degree of “pixel shift” described later, that is, regardless of whether or not the pixel shift is corrected.

As will be described later, the number of lines corresponding to the “monitor display pixel” is the same as when no pixel deviation is corrected, even when the pixel light-shielding period is controlled by the light source control unit 41. It can be set as a time during which minutes can be read out.

Also in the video processor 3 to which the endoscope 2 is connected, the image processing unit 32 executes the image processing operation without providing a difference between “when the pixel shift is corrected” and “when no pixel shift is corrected”. Be able to.

Also, the light source control unit 41 rotates the rotary filter 46 by driving the drive unit 45 via the drive driver 43.

The display device 5 has a function of receiving and displaying the in-vivo image generated by the video processor 3 from the video processor 3 via the video cable.

<Operation of First Embodiment>
Next, the operation of the first embodiment of the present invention will be described with reference to FIGS.

FIG. 3 is a timing chart showing the frame start timing and sensor readout timing for each pixel shift correction position corresponding to the frame sequential light source operation timing in the endoscope of the first embodiment. It is the figure which showed the relationship between the read-out pixel position for every pixel shift correction position and the pixel position displayed on a monitor in the endoscope of 1 embodiment. FIG. 9 is a timing chart showing the frame start timing and sensor readout timing for each pixel shift correction position corresponding to the frame sequential light source operation timing in the conventional endoscope.

Here, prior to describing the operation of the present embodiment, a conventional example for the present invention will be briefly described.

As described above, for the “pixel shift” of the imaging signal due to the eccentricity of the imaging optical system, as described above, the coordinate position of the shifted pixel is specified, and the pixel corresponding to the coordinate position A technique for performing correction using a “cutout function” for selectively reading only the image is known.

In addition, with respect to the “pixel shift”, for example, when the “pixel shift” occurs, pixels to be actually displayed on the monitor among the effective pixels related to the image sensor 22 (that is, pixels to be actually read). There is also a conventionally known technique for dealing with this by shifting the position in the effective pixel in accordance with the degree of “pixel shift”.

FIG. 9 shows a conventional endoscope that employs a frame sequential observation method, in which the position of a pixel to be actually displayed on the monitor is shifted in the effective pixel in accordance with the degree of “pixel shift”. 4 is a timing chart showing a frame start timing and a sensor readout timing for each pixel shift correction position corresponding to the frame sequential light source operation timing.

As shown in FIG. 9, even in the conventional example, it is necessary to read at least the effective pixel portion displayed on the monitor among the effective pixels related to the image sensor during the light shielding period of the light source.

Here, similarly to the example shown in FIG. 4, for example, an endoscope of the normal type in which “pixel shift” has not occurred is referred to as “type A”, and an endoscope in which “pixel shift” has occurred. The mirrors are referred to as “type B (upshift type)” and “type C (downshift type)”.

At this time, in the case of Type A in which the endoscope has no “pixel shift” and correction of pixel shift is not performed, the effective pixel portion displayed on the monitor during the light-shielding period (charge reading period) of the light source Need only be read.

However, in the case of Type B or Type C in which the endoscope has a “pixel shift”, it is not uniquely determined where the effective pixel portion displayed on the monitor is located in the effective pixel of the image sensor.

As a result, in the conventional example, the entire effective pixel has to be read during the light-shielding period of the light source (during the charge reading period) so as to correspond to the type B or type C endoscope.

This requires a longer light shielding period, in other words, a shorter light emission period (lighting time for each R light, G light, and B light), which in turn reduces the brightness of the light. There was a risk of inviting.

That is, in the conventional example, as shown in FIG. 9, during the period of reading out the effective pixels, the light source that performs the frame sequential light emission operation (irradiation of each R light, G light, and B light) is performed. However, the light emission time has been shortened.

The present invention has been made in view of the above-described circumstances, and does not use a “cutout function” that selectively reads out only pixels in an arbitrary range in an image sensor, and does not shorten the light emission period of the light source. An endoscope capable of executing the correction process is provided.

Hereinafter, with reference to FIG. 3, description will be given of how to correct the pixel shift, the setting of the pre-blanking period, and the setting of the start timing according to the first embodiment.

Here, as in the above-described example, the normal type endoscope in which the “pixel shift” of the imaging signal does not occur is referred to as “type A”, and the endoscope in which the “pixel shift” occurs is referred to as “type B ( "Type that shifts upward") and "Type C (type that shifts downward)".

First, the endoscope 2 detects a “pixel shift” of an image pickup signal caused by the eccentricity of the image pickup optical system or the like at the time of manufacturing the endoscope, and the information related to the “pixel shift” is stored in the ID memory 27. To remember.

As described above, the information related to the “pixel shift” is, for example, information related to a pixel shift value of an actual image sensor or information such as a numerical value of a pre-blanking period corresponding to the pixel shift value.

Then, when the endoscope 2 is operated in a state where “information relating to pixel shift” as information specific to the endoscope is stored in the ID memory 27, the read timing setting unit 26 as a “preblanking period setting unit”. Reads out information related to pixel shift of the image sensor from among the various unique information of the endoscope 2 stored in the ID memory 27.

Thereafter, the read timing setting unit 26 sets a “preblanking period” and a “timing to start one frame” determined for each endoscope according to the read information.

In the present embodiment, the “pre-blanking period” is a period corresponding to the number of lines from the timing of starting one frame in the image sensor 22 to the start timing of the effective pixel related to the image sensor 22 as described above. To do.

Further, since the position of the “monitor display pixel” in the effective pixel also changes depending on the degree of “pixel shift” determined for each endoscope, the “preblanking period” corresponding to the position also varies for each endoscope. Set to

In the first embodiment, the “timing for starting one frame” is set at a fixed timing regardless of the degree of “pixel shift”.

Also, by setting the length of the “pre-blanking period” variably according to the degree of “pixel deviation” determined for each endoscope, the “monitor display pixel” regardless of the degree of “pixel deviation”. Is always substantially coincident with the light shielding period (charge reading period) of the light source.

More specifically, in the first embodiment, as shown in FIG. 3, when the endoscope 2 is a type A endoscope in which “pixel shift” of the imaging signal does not occur, a readout timing setting unit 26 acquires information relating to “pixel shift” from the ID memory 27 in the endoscope 2 of type A, and sets the length of the “preblanking period” and “timing to start one frame”.

At this time, the “length of the pre-blanking period” and the “timing to start one frame” set by the read timing setting unit 26 are the same as the light-shielding period of the light source (the monitor display pixel) read timing by the signal read unit 25. In the “charge readout period” and with a “length” that allows reading out some of the effective pixels before and after the “monitor display pixel” outside the light-shielding period of the light source, that is, within the light-emitting period of the light source Yes, “timing”.

As shown in FIG. 4, when the endoscope 2 is type A, the pixel group 61 to be displayed on the monitor 5 out of the pixel group 60A in the image sensor 22 is left as it is without correcting the pixel shift. In this state, it can be displayed as a display image 51 on the monitor 5.

On the other hand, when the endoscope 2 is a type B or type C endoscope in which the “pixel shift” of the imaging signal has occurred, the readout timing setting unit 26 performs the type B or type C endoscope similarly to the above. Information related to “pixel shift” is acquired from the ID memory 27 in the mirror 2, and the length of “preblanking period” and “timing to start one frame” are set.

In this case as well, the “preblanking period length” and the “timing to start one frame” set by the read timing setting unit 26 are the same as the “monitor display pixel” read timing by the signal read unit 25. During the period (charge readout period), the readout of a part of the effective pixels on the back side (see type B) or the front side (see type C) of the “monitor display pixel” is outside the light shielding period of the light source, that is, the light source It is “length” and “timing” that is allowed to be performed within the light emission period.

Further, as shown in FIG. 4, when the endoscope 2 is “type B” or “type C”, the pixel group 61b or the pixel to be displayed on the monitor 5 out of the pixel group 60B or the pixel group 60C in the image sensor 22. Since the readout timing is also adjusted appropriately for the group 61c, the monitor 5 can display the display image 51 at an appropriate position on the monitor screen as in the case of no pixel shift correction. .

As described above, according to the first embodiment, the length of the “pre-blanking period” is variably set according to the degree of “pixel shift” determined for each endoscope, and “pixel shift” is set. Regardless of the degree, the reading timing of the “monitor display pixel” is substantially coincident with the light shielding period (charge reading period) of the light source, and the reading of a part of the effective pixels other than the “monitor display pixel” is shielded from the light source. By allowing it to be performed outside the period, that is, within the light emission period of the light source, it is possible to prevent color mixing of the image displayed on the monitor, and to set the light emission period shorter, that is, the light emission time can be set longer. Become.

Further, according to the first embodiment, the pixel shift correction process is performed without using a “cutout function” that selectively reads out only an arbitrary range of pixels in the image sensor and without shortening the light emission period of the light source. A viable endoscope can be provided.

Furthermore, according to the endoscope of the first embodiment, the above-described correction processing can be performed without changing the operations of the video processor and the light source device connected to the endoscope. It can be combined with an endoscope system having an apparatus or the like without any trouble.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.

FIG. 5 is a timing chart showing the frame start timing and sensor readout timing for each pixel shift correction position corresponding to the frame sequential light source operation timing in the endoscope of the second embodiment of the present invention.

In the endoscope 2 according to the first embodiment described above, the length of the “pre-blanking period” is variably set according to the degree of “pixel shift” determined for each endoscope, so that “pixel” Regardless of the degree of “shift”, the readout timing of the “monitor display pixel” is substantially coincident with the light-shielding period (charge readout period) of the light source, and a part of the effective pixels other than the “monitor display pixel” is read out. However, the endoscope according to the second embodiment makes the length of the “pre-blanking period” constant while the length of the “pre-blanking period” is constant. By variably setting “timing to start one frame = start timing of pre-blanking period” according to the degree of “pixel deviation” determined for each endoscope, regardless of the degree of “pixel deviation”, The readout timing of the “monitor display pixel” is substantially coincided with the light shielding period (charge readout period) of the light source, and reading of a part of the effective pixels other than the “monitor display pixel” is performed outside the light shielding period of the light source, that is, the light emission of the light source. It is characterized by allowing it to be done within a period.

Therefore, the endoscope according to the second embodiment has the same basic configuration as that of the first embodiment. Therefore, only the differences from the first embodiment will be described here, and common parts will be described. The description of is omitted.

Similarly to the first embodiment, the endoscope system 1 having the endoscope 2 of the second embodiment is also connected to the endoscope 2 that observes and images the subject, and the endoscope 2. A video processor 3 that inputs the imaging signal and performs predetermined image processing; a light source device 4 that supplies illumination light for illuminating the subject; and a monitor device 5 that displays an observation image corresponding to the imaging signal. Have.

In addition, the connector 12 in the endoscope 2 is provided with the FPGA 23 as in the first embodiment, and an ID memory 27 and the like storing endoscope identification information in the endoscope 2 is provided. However, in the second embodiment, for example, information related to the pixel shift value of the image sensor or the “timing to start one frame” corresponding to the pixel shift value is stored in the ID memory 27 as the endoscope specific information. = Numerical information such as “= pre-blanking period start timing” is stored.

Also in the second embodiment, the image sensor 22 can set a pre-blanking period, which is a period corresponding to the number of lines from the start timing of one frame to the start timing of effective pixels related to the image sensor 22. It has become.

Also in the second embodiment, the FPGA 23 includes a read timing setting unit 26 and a signal read unit 25. The read timing setting unit 26 serves as a “preblanking period setting unit” and a “start timing setting unit”. In addition, the signal reading unit 25 serves as a “signal reading unit” that reads an imaging signal related to the monitor display pixel in accordance with the pre-blanking period in the light shielding period related to the light source device 4.

<Pixel shift correction and pre-blanking period>
Here, a pixel shift correction method, a preblanking period, a setting unit for the preblanking period, and a start timing setting unit according to the second embodiment will be described.

In the second embodiment, the read timing setting unit 26 sets the start timing of the preblanking period according to the vertical synchronization signal VSYNC from the drive signal generation unit 35 in the video processor 3. To fulfill the role of

Specifically, “timing to start one frame = start timing of pre-blanking period” corresponding to the position of the “monitor display pixel” in the entire effective pixel is set for each endoscope.

Also in the present embodiment, the reading timing of the “monitor display pixel” and the light-shielding period (charge reading period) of the light source are substantially matched regardless of the presence or absence of “pixel shift” of the image sensor 22.

Further, also in the second embodiment, the readout timing of the entire effective pixel of the image sensor 22 is not necessarily set during the light-shielding period of the light source, regardless of whether or not there is a “pixel shift” of the image sensor 22. However, reading of a part of the effective pixels other than the “monitor display pixel” is allowed to be performed outside the light-shielding period of the light source, that is, within the light-emitting period of the light source.

As described above, the position of the “monitor display pixel” in the effective pixel changes depending on the degree of “pixel shift” determined for each endoscope. The endoscope 2 according to the second embodiment adjusts the reading start timing of the effective pixels so that the timing substantially coincides with the light-shielding period (charge reading period) of the light source, and further starts reading of the effective pixels. According to the timing adjustment, “timing to start one frame = start timing of pre-blanking period” is set.

In other words, by variably setting “timing to start one frame = start timing of the pre-blanking period” according to the degree of “pixel shift” determined for each endoscope, Similarly, regardless of the degree of “pixel shift”, the readout timing of the “monitor display pixel” always coincides substantially with the light-shielding period (charge readout period) of the light source, thereby shortening the light-shielding period of the light source. That is, the light emission time can be set longer.

In the second embodiment, unlike the first embodiment, the length of the pre-blanking period is the same even for endoscopes having different “pixel shifts” determined for each endoscope. Shall be set to

As described above, when the endoscope 2 is operated in a state where “information relating to pixel shift” as individual information of the endoscope is stored in the ID memory 27, the read timing setting as the “start timing setting unit” is performed. The unit 26 reads out information related to the pixel shift of the image sensor from among the various pieces of unique information stored in the ID memory 27 and determines “one frame start timing = previous” determined for each endoscope. The ranking period start timing is set.

That is, in the endoscope 2 of the second embodiment, the preblanking period is determined by the readout timing setting unit 26 according to information related to “pixel shift” stored as individual information for each endoscope. The operation is started at the start timing set in the “start timing setting unit”.

Also in the second embodiment, the signal readout unit 25 actually performs the “monitor display pixel”, that is, the effective pixel of the image sensor 22 in the light shielding period of the light source device 4 after the preblanking period ends. An imaging signal relating to the pixel displayed on the monitor is read out.

In the second embodiment, the operation timing of the light source by the light source control unit 41 is fixed regardless of the degree of “pixel shift”.

<Operation of Second Embodiment>
Next, the operation of the second embodiment of the present invention will be described with reference to FIG.

Also in FIG. 5, as in the above-described example, the normal type endoscope in which the “pixel shift” of the imaging signal does not occur is “type A”, and the endoscope in which the “pixel shift” occurs is “type”. “B (upshift type)” and “type C (downshift type)”.

The information related to this “pixel shift” is, for example, information related to the pixel shift value of the actual image sensor or information such as “timing to start one frame = start timing of the preblanking period” corresponding to the pixel shift value. It is.

Thereafter, the read timing setting unit 26 sets “preblanking period” and “timing to start one frame = start timing of preblanking period” determined for each endoscope according to the read information.

Further, since the position of the “monitor display pixel” in the effective pixel also changes depending on the degree of “pixel shift” determined for each endoscope, “timing for starting one frame = preblanking” corresponding to the position. The “period start timing” is also set for each endoscope.

In the second embodiment, the “pre-blanking period” is set to a fixed length regardless of the degree of “pixel shift”.

More specifically, in the second embodiment, when the endoscope 2 is a type A endoscope in which no “pixel shift” occurs, the read timing setting unit 26 sets the type A endoscope. 2 is acquired from the ID memory 27 and the length of the “preblanking period” and “the timing for starting one frame = the starting timing of the preblanking period” are set.

On the other hand, when the endoscope 2 is a type B or type C endoscope in which the “pixel shift” of the imaging signal has occurred, the readout timing setting unit 26 performs the type B or type C endoscope similarly to the above. Information related to “pixel shift” is acquired from the ID memory 27 in the mirror 2, and the length of “preblanking period” and “timing of starting one frame = starting timing of preblanking period” are set.

As described above, according to the second embodiment, “the timing to start one frame = the start timing of the pre-blanking period” is variably set according to the degree of “pixel shift” determined for each endoscope. Regardless of the degree of “pixel shift”, the readout timing of the “monitor display pixel” is made to substantially coincide with the light-shielding period (charge readout period) of the light source, and one of the effective pixels other than the “monitor display pixel” is selected. Part reading is allowed outside the light-shielding period of the light source, that is, within the light-emitting period of the light source, thereby preventing color mixing of the image displayed on the monitor and shortening the light-shielding period of the light source, that is, reducing the light emission time. It can be set longer.

In addition, according to the second embodiment, the pixel shift correction process is performed without using a “cutout function” that selectively reads out only an arbitrary range of pixels in the image sensor and without shortening the light emission period of the light source. A viable endoscope can be provided.

Furthermore, according to the endoscope of the second embodiment, the correction processing described above can be performed without changing the operations of the video processor and the light source device connected to the endoscope, as in the first embodiment. Therefore, it can be combined with an endoscope system having a conventional video processor and light source device without any trouble.

In each of the above-described embodiments, the signal readout unit 25 and the readout timing setting unit 26 are formed in the FPGA 23 in the endoscope 2, but the present invention is not limited to this, and other parts of the endoscope 2, For example, it may be disposed in the operation unit or the like, or may be disposed in the video processor 3 so as to control the image sensor 22 from the video processor 3.

In each of the above embodiments, an observation method using a surface sequential light source is adopted. However, the present invention is not limited to this, and an example of performing PWM control using an LED light source or the like, or narrowband light observation (NBI) as special light observation : Narrow Band Imaging), infrared light observation (IRI: InfraRed Imaging), or fluorescence observation (AFI: Auto Fluorescence Imaging).

The present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the present invention.

This application is filed on the basis of the priority claim of Japanese Patent Application No. 2016-68668 filed in Japan on March 30, 2016, and the above disclosure is included in the present specification and claims. Shall be quoted.

Claims

An image pickup device that picks up an image of a subject and generates a predetermined image pickup signal. A preblanking period that is a period corresponding to the number of lines from the start timing of one frame to the start timing of effective pixels related to the image pickup device can be set. An image sensor,
An illumination unit that emits illumination light for illuminating the subject and that can irradiate the illumination light from the light source having a light emission period and a light shielding period toward the subject;
A pre-blanking period setting unit that sets a predetermined pre-blanking period corresponding to a monitor display pixel to be displayed on a monitor in the effective pixels related to the image sensor;
A start timing setting unit for setting a start timing of the pre-blanking period according to a predetermined vertical synchronization signal;
In the light shielding period of the light source, an imaging signal that is started at the start timing set by the start timing setting unit and is related to the monitor display pixel according to the preblanking period set by the preblanking period setting unit. A signal readout circuit to read out;
An endoscope comprising:
The preblanking period setting unit sets the preblanking period according to a position of the monitor display pixel in an effective pixel related to the image sensor, which changes corresponding to a pixel shift related to the image sensor. The endoscope according to claim 1, wherein the endoscope is characterized in that:
The start timing setting unit sets the start timing of the preblanking period according to the position of the monitor display pixel in the effective pixels related to the image sensor, which changes corresponding to the pixel shift related to the image sensor. The endoscope according to claim 1.
The preblanking period setting unit sets the preblanking period to a constant value regardless of the position of the monitor display pixel in the effective pixel related to the image sensor, which changes corresponding to the pixel shift related to the image sensor. The endoscope according to claim 3, wherein: