WO2017195256A1

WO2017195256A1 - Optical scanning type observation device and optical scanning type observation method

Info

Publication number: WO2017195256A1
Application number: PCT/JP2016/063770
Authority: WO
Inventors: 森　健
Original assignee: オリンパス株式会社
Priority date: 2016-05-09
Filing date: 2016-05-09
Publication date: 2017-11-16
Also published as: JPWO2017195256A1

Abstract

The purpose of the present invention is to keep the brightness of an obtained image unchanged even when the light quantity of laser light is controlled. An optical scanning type observation device (10) according to the present invention is provided with: an optical scanning unit (20) that causes pulse light to be scanned over an object; a brightness sensing unit (50) that senses information about brightness based on the pulse light; a light detection unit that detects reflected light from the object in response to the pulse light scanning performed over the object by the optical scanning unit (20); and a control unit (31) that performs control, on the basis of the information about the brightness sensed by the brightness sensing unit (50), so as to change the number of times of pulse emission, per unit time, of pulse light.

Description

Optical scanning observation apparatus and optical scanning observation method

The present invention relates to an optical scanning observation apparatus and an optical scanning observation method that perform observation by scanning light on an observation object and detecting light obtained by irradiation of the light.

Conventionally, an optical fiber that guides illumination light from a light source is vibrated so that the tip of the optical fiber forms a spiral orbit (a spiral orbit), and the illumination light emitted from the tip of the optical fiber is observed. Illumination light is emitted from the tip of the optical fiber so as to form a spot on the object, and light such as transmitted light, reflected light, or fluorescence obtained from the observation object irradiated with the illumination light is detected and detected. An optical scanning observation apparatus is known that generates an image by converting the emitted light into an electrical signal by a photoelectric conversion means (see, for example, Patent Document 1).

In such an optical scanning observation apparatus, laser light is used as illumination light emitted from an optical fiber.
In Patent Document 1, in consideration of the safety of laser light to human eyes, the amount of laser light is controlled based on whether or not the scope is inserted into a body cavity.

Japanese Patent No. 5388732

However, in the invention disclosed in Patent Document 1, the amount of laser light is controlled, and the output level of laser light is controlled in order to limit it to a safe level. Therefore, when the output level of the laser beam is lowered, there is a problem that the brightness of the obtained image becomes dark.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical scanning observation apparatus and an optical scanning observation method in which the brightness of an image obtained by controlling the amount of laser light does not change. .

One aspect of the present invention is directed to an optical scanning unit that scans an object with pulsed light, a brightness detection unit that detects information about brightness based on the pulsed light, and the optical scanning unit on the object. A pulse per unit time of the pulsed light based on information relating to the brightness detected by the brightness detection unit and a light detection unit that detects reflected light from the object by scanning the pulsed light An optical scanning observation apparatus including a control unit that controls to change the number of light emission.

In the above aspect, the brightness detection unit may be a light amount detection unit that detects a light amount signal corresponding to the light amount of the pulsed light as information on the brightness.
Moreover, in the said aspect, the said light quantity detection part may detect the light quantity signal proportional to the light quantity of the said pulsed light.

Moreover, in the said aspect, the said light quantity detection part may detect the light quantity signal proportional to the average light quantity of the said pulsed light.
Further, in the above aspect, the control unit decreases the number of pulse emission per unit time of the pulsed light when the information on the brightness detected by the brightness detection unit is equal to or greater than a predetermined threshold. You may control.

Moreover, in the said aspect, the image generation part which produces | generates an image based on the intensity | strength of the reflected light detected by the said light detection part may be provided, and the said brightness detection part may be the said light detection part.
Moreover, in the said aspect, the said image generation part may be provided with the pixel interpolation part which performs the interpolation of the pixel which comprises the said image.

Moreover, in the said aspect, the said pixel interpolation part may change the interpolation method of the pixel which comprises the said image according to the said pulse light emission number controlled by the said control part.
Further, in the above aspect, the control unit decreases the number of pulse emission per unit time of the pulsed light when the information on the brightness detected by the brightness detection unit is equal to or less than a predetermined threshold. You may control.

In another aspect of the present invention, the optical scanning unit scans the pulsed light on the object, the brightness detecting unit detects information about the brightness based on the pulsed light, and the control unit. A step of controlling to reduce the number of pulse emission per unit time of the pulsed light when the information on the brightness detected by the brightness detection unit is a predetermined threshold value or less; and a light detection unit Receiving light emitted from the object by the controlled irradiation of the pulsed light, and generating an image based on the intensity of the light received by the light detection unit. Is an optical scanning observation method.

According to the present invention, there is an effect that it is possible to prevent the brightness of the obtained image from changing even if the amount of laser light is controlled.

1 is a block diagram illustrating a schematic configuration of an optical scanning endoscope apparatus that is an example of an optical scanning observation apparatus according to a first embodiment of the present invention. It is a figure which shows the relationship between the pulse light emission number per unit time and the light quantity in (a) normal mode and (b) restriction | limiting mode of the optical scanning observation apparatus shown in FIG. FIG. 2 is an overview diagram schematically showing a scope of the optical scanning endoscope apparatus shown in FIG. 1. It is sectional drawing of the front-end | tip part of the scope shown in FIG. 2A is a side view showing an actuator and a swinging portion of an illumination optical fiber of the optical scanning endoscope apparatus shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along line AA of FIG. 3 is a flowchart relating to the operation of the optical scanning endoscope apparatus shown in FIG. 1. It is a figure which shows the pixel arrangement | position regarding the interpolation process at the time of image generation. It is a block diagram which shows schematic structure of the optical scanning type endoscope apparatus which is an example of the optical scanning type observation apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart which concerns on operation | movement of the optical scanning endoscope apparatus shown in FIG.

Embodiments of the present invention will be described below with reference to the drawings.
In addition, this invention is not limited by the following embodiment.
In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals as appropriate. Also, it should be noted that the drawings are schematic, and the relationship between the dimensions of each element, the ratio of each element, and the like may differ from the actual situation.

(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of an optical scanning endoscope apparatus 10 which is an example of an optical scanning observation apparatus according to the first embodiment of the present invention. The optical scanning endoscope apparatus 10 according to the present embodiment includes a scope 20, a control device main body 30, and a display 40.

The control device main body 30 is a control unit 31, a light emission control unit 32, and

laser light sources

33R, 33G, and 33B (hereinafter, also referred to as

lasers

33R, 33G, and 33B. The laser 33R is also controlled. , 33G and 33B are also collectively referred to as “light source 33”.), A coupler 34, a light amount detection unit 50 (brightness detection unit), and a light amount instruction unit 51. The light emission control unit 32 emits light from the three

lasers

33R, 33G, and 33B that emit laser beams of the three primary colors of red (R), green (G), and blue (B), respectively, according to the control signal transmitted by the control unit 31. The timing is controlled, and pulsed light is emitted from the

lasers

33R, 33G, and 33B, respectively.

As the light source 33, for example, a DPSS laser (semiconductor excitation solid-state laser) or a laser diode can be used. Laser light emitted from the light source 33 is coupled by the coupler 34 to the illumination optical fiber 11 that is the same single mode fiber. Of course, the configuration of the light source 33 of the optical scanning endoscope apparatus 10 is not limited to this, and a plurality of other light sources may be used. The light source 33 and the coupler 34 may be housed in a separate housing from the control device main body 30 connected to the control device main body 30 by a signal line.

The illumination optical fiber 11 is connected to the tip of the scope 20. The light incident on the illumination optical fiber 11 from the coupler 34 is guided to the distal end portion of the scope 20 and emitted toward the observation object 100 as illumination light. At this time, the actuator 21 (light scanning unit) provided in the scope 20 is driven to vibrate, so that the illumination light emitted from the illumination optical fiber 11 is spirally trajectory (spiral) on the surface of the observation object 100. The trajectory is drawn and scanned.

The actuator 21 is controlled by the control unit 31 via the actuator driver 38 of the control device main body 30. Light such as reflected light, scattered light, or fluorescence obtained from the observation object 100 by irradiation of illumination light is received by the distal ends 12a of a plurality of detection optical fibers 12 constituted by multimode fibers, and passes through the scope 20. The light is guided to the control device main body 30.

The light amount detection unit 50 detects information about brightness based on the pulsed light emitted from the tip 11 c of the illumination optical fiber 11 from the coupler 34 and outputs the signal to the light amount instruction unit 51. Specifically, the light amount detection unit 50 detects a light amount signal proportional to the laser light amount from the coupler 34 as information related to brightness based on pulsed light, and outputs the light amount signal to the light amount instruction unit 51.
Here, the laser light quantity indicates the total emission amount of the laser emitted from the tip 11c of the illumination optical fiber 11 per unit time.

The light quantity instruction unit 51 adjusts the number of pulse emission per unit time based on the light quantity signal output from the light quantity detection unit 50 and proportional to the laser light quantity emitted from the tip 11c of the illumination optical fiber 11. It has become. That is, assuming that the amount of light per pulse is A, the brightness of the generated image can be adjusted while maintaining the detection sensitivity of the light detection unit 35 by adjusting the number of pulse emission per unit time without changing A. The image is acquired without change.

When the light amount signal output from the light amount detection unit 50 is smaller than a predetermined threshold value as a signal threshold value, the light amount instruction unit 51 sets the number of pulse emission during normal imaging as the normal mode. On the other hand, when the light quantity signal output from the light quantity detection unit 50 is equal to or greater than a predetermined threshold value as a signal threshold value, the limit mode is set to reduce the number of pulse emission (FIGS. 2A and 2B). reference). Note that the number of pulse emissions in the normal mode is greater than the number of pulse emissions in the limited mode, and the number of pulse emissions in each mode can be determined in advance.
As described above, the light quantity instruction unit 51 outputs a setting signal for the number of pulse light emission to the control unit 31. The number of pulse emission is adjusted at the image generation timing of the next frame.

The control device body 30 further includes a light detection unit 35 and an image generation unit 37 including a pixel interpolation unit 36. The light detection unit 35 includes a photodiode or the like, and converts light guided by the detection optical fiber 12 into an electrical signal. The electrical signal may be an analog value or a digital value.

The output of the light detection unit 35 is output to the image generation unit 37 after offset correction. The control unit 31 calculates information on the scanning position on the scanning path from information such as the start time, amplitude, and phase of the oscillating voltage applied to the actuator driver 38, and sends the calculated information to the image generation unit 37. Thereby, the output signal from the light detection unit 35 is associated with the scanning position information.

In addition, the control part 31 may hold | maintain previously the scanning position information calculated as a table. The image generation unit 37 performs interpolation processing of pixels constituting the image by the pixel interpolation unit 36 on each wavelength signal output from the light detection unit 35, and performs necessary image processing such as enhancement processing and gamma processing. Then, an image of the observation object 100 is generated and displayed on the display 40. Note that the pixel interpolation unit 36 may change the interpolation method of the pixels constituting the image in accordance with the number of pulse light emissions output from the control unit 31. Specifically, interpolation processing parameters (such as the number and distance of pixels used for interpolation) may be determined in advance according to the above-described mode.

In each process described above, the control unit 31 synchronously controls the light emission control unit 32, the actuator driver 38, the pixel interpolation unit 36, and the image generation unit 37.

FIG. 3 is an overview diagram schematically showing the scope 20. The scope 20 includes an operation unit 22 and an insertion unit 23. The operation unit 22 is connected to the illumination optical fiber 11, the detection optical fiber 12 and the wiring cable 13 from the control device main body 30. The illumination optical fiber 11, the detection optical fiber 12, and the wiring cable 13 pass through the insertion portion 23 and are led to the distal end portion 24 of the insertion portion 23 (portion in the broken line portion in FIG. 3).

FIG. 4 is an enlarged vertical sectional view showing the distal end portion 24 of the insertion portion 23 of the scope 20 of FIG. The distal end portion 24 includes an actuator 21,

projection lenses

25 a and 25 b, an illumination optical fiber 11 that passes through the central portion, and a detection optical fiber 12 that passes through the outer peripheral portion.

The actuator 21 includes an actuator tube 27 fixed to the inside of the insertion portion 23 of the scope 20 by a mounting ring 26, and a fiber holding member 29 and

piezoelectric elements

28a, 28b, 28c, and 28d arranged in the actuator tube 27 (see FIG. 5 (a) and FIG. 5 (b)).
The illuminating optical fiber 11 is supported by a fiber holding member 29, and a fixed end 11a supported by the fiber holding member 29 to a tip 11c constitute a swinging portion 11b that is swingably supported. On the other hand, the detection optical fiber 12 is disposed so as to pass through the outer peripheral portion of the insertion portion 23 and extends to the distal end of the distal end portion 24. Furthermore, a detection lens (not shown) is provided at the distal end portion 12a of each fiber of the detection optical fiber 12.

Furthermore, the

projection lenses

25a and 25b and the detection lens (not shown) are arranged at the forefront of the tip portion 24. The

projection lenses

25 a and 25 b are arranged so that the laser light emitted from the tip 11 c of the illumination optical fiber 11 is substantially condensed on the observation object 100. Therefore, the

projection lenses

25a and 25b constitute an optical system that irradiates the observation object 100 with the light emitted from the illumination optical fiber 11.

Further, the detection lens is arranged after the detection lens by taking in the light reflected or scattered or refracted by the observation object 100 or the fluorescence or the like by the laser light condensed on the observation object 100. The optical fiber for detection 12 is arranged so as to be condensed and coupled. The

projection lenses

25a and 25b are not limited to the two-lens configuration, and may be configured by one lens or a plurality of other lenses.

FIG. 5A is a diagram showing a vibration drive mechanism of the actuator 21 and the swinging portion 11b of the illumination optical fiber 11 of the optical scanning endoscope apparatus 10, and FIG. FIG. The illumination optical fiber 11 passes through the center of the fiber holding member 29 having a prismatic shape, and is thereby fixed and held by the fiber holding member 29. The four side surfaces of the fiber holding member 29 face the + Y direction and the + X direction and the opposite directions, respectively. The pair of

piezoelectric elements

28a and 28c for driving in the Y direction are fixed in the + Y direction and the −Y direction of the fiber holding member 29, and the pair of piezoelectric elements 28b for driving in the X direction are fixed in the + X direction and the −X direction. 28d is fixed.

The wiring cable 13 from the actuator driver 38 of the control device main body 30 is connected to each

piezoelectric element

28a, 28b, 28c, 28d.

The

piezoelectric elements

28b and 28d arranged opposite to each other with the fiber holding member 29 interposed therebetween cause the fiber holding member 29 to bend when one of the

piezoelectric elements

28b and 28d expands, and the vibration is generated in the X direction by repeating this. Can be made. The same applies to the vibration in the Y direction. For example, as the

piezoelectric elements

28b and 28d in the X direction, piezoelectric elements having the same expansion / contraction direction with respect to the polarity of the voltage to be applied are used, and voltages having the same magnitude but opposite polarity are always applied. Similarly, between the

piezoelectric elements

28a and 28c in the Y direction, piezoelectric elements having the same expansion / contraction direction with respect to the polarity of the applied voltage are used, and voltages having the same magnitude in the opposite direction are always applied.

The actuator driver 38 controls the

piezoelectric elements

28a, 28b, 28c, and 28d so that the tip 11c of the illumination optical fiber 11 draws a spiral orbit (a spiral orbit). Specifically, an AC voltage whose amplitude changes from 0 to the maximum value is applied to the

piezoelectric elements

28b and 28d for driving in the X direction and the

piezoelectric elements

28a and 28c for driving in the Y direction. The AC voltages are 90 ° out of phase with each other, and the frequency is set in the vicinity of the same resonance frequency. Thus, the laser light emitted from the tip 11c sequentially scans the surface of the observation object 100 so as to draw a spiral locus.

In the present embodiment, the above-described functions of the control unit 31, the light amount detection unit 50, and the light amount instruction unit 51 are realized by, for example, a general-purpose or dedicated computer. Specifically, the computer includes a central processing unit (CPU), a main storage device such as a RAM, and an auxiliary storage device such as a hard disk and various memories, and the control unit described above is included in the auxiliary storage device. 31, a program for causing the CPU to execute the processes of the light quantity detection unit 50 and the light quantity instruction unit 51 is stored. The program is loaded from the auxiliary storage device to the main storage device and executed, so that the CPU realizes the processing of the control unit 31, the light amount detection unit 50, and the light amount instruction unit 51.

Next, the operation of the optical scanning endoscope apparatus 10 according to the present embodiment configured as described above will be described with reference to the flowchart of FIG.
In order to observe the observation object 100 using the optical scanning endoscope apparatus 10 according to the present embodiment, the distal end of the insertion portion 23 is opposed to the observation object 100. As a result, laser light is emitted from the tip 11 c of the illumination optical fiber 11 to the observation object 100. At this time, the tip 21 c of the illumination optical fiber 11 is spirally vibrated by the actuator 21 (light scanning unit), so that laser light as pulse light is spirally scanned on the observation object 100. At this time, the scanning of the pulsed light of the

lasers

33R, 33G, and 33B of the respective colors may be emitted sequentially or simultaneously. In the present embodiment, it is assumed that light is emitted sequentially.

When laser light is emitted from the tip 11c of the illumination optical fiber 11 to the observation object 100, a light quantity signal proportional to the emitted laser light is detected and output by the light quantity detector 50 (step S1). Next, the light amount instruction unit 51 compares the light amount signal with a predetermined threshold value (step S2). Here, the threshold value of the light amount signal is set to a value smaller than the signal level corresponding to 5 mW, for example, when the tip light amount of the tip 11c of the illumination optical fiber 11 is to be 5 mW or less. Then, the comparison result is sent to the control unit 31, and a signal for changing the pulse emission number of the next frame in the control unit 31 is sent to the light emission control unit 32.

Specifically, when the light amount signal is smaller than the threshold value (step S2 / Yes), the control unit 31 controls the pulse emission number so as to be the normal mode pulse emission number (step S3). On the other hand, when the light quantity signal is equal to or greater than the threshold value (step S2 / No), the control unit 31 reduces the number of pulse light emission so as to be the number of pulse light emission in the limit mode (step S4).

Based on the setting of the control unit 31, the light emission control unit 32 determines the number of pulse light emission per unit time of the pulsed light and controls the light amount (step S5). Laser irradiation is performed to control the amount of light and acquire an image of the next frame (step S6), and the reflected light of the pulsed light reflected on the surface of the observation object 100 is received by the detection optical fiber 12 and light The detection unit 35 performs photoelectric conversion to an electrical signal. As a result, R, G, and B signal values indicating the intensity of the reflected light of R, G, and B are obtained, and the image of the observation object 100 is associated with the laser light irradiation position in the image generation unit 37. Generated (step S7), and the generated image is displayed on the display 40 (step S8).

Here, a pixel interpolation method when generating an image will be described with reference to FIG. In FIG. 7, for each pixel to be interpolated (in the figure: black circles), interpolation processing is performed using pixels (in the figure: white circles) arranged on a spiral scanning locus. Is called. Here, using four pixels close to the pixel to be interpolated, weighting is performed according to the distance between each of the four points and the pixel to be interpolated, thereby generating an interpolated pixel. If the brightness of the pixel to be interpolated in FIG.
I = V33 / A + V24 / B + V23 / C + V32 / D
It is calculated by. Here, A, B, C, and D are coefficients corresponding to the distance, and V is the brightness of the pixel.

In this way, a smooth image can be obtained by generating an image supplemented from a plurality of points.
In addition, the pixel here shows the information used for the image generation which scanned the light and received the light reflected from the observation object 100, and is different from the pixel of 1 dot at the time of displaying on the display 40.

According to the present embodiment, when the light amount signal is equal to or greater than the threshold value, the image data can be generated without changing the detection sensitivity of the light detection unit 35 by reducing the number of pulse emission per unit time. . That is, the amount of laser light from the end of the fiber can be reduced without changing the amount of light emitted per pulse, and observation can be performed without changing the brightness of the image. As a result, it is possible to provide an optical scanning observation apparatus in which the brightness of an image obtained does not change even when the amount of laser light is controlled.

In the present embodiment, the number of pulse emission in the limit mode is set to 1/3. However, the number of pulse emission may be changed according to the degree of reduction of the light amount.
As for the interpolation method, a general interpolation method may be used in which a plurality of pixels to be interpolated are added and then averaged with the number of used pixels.

In the present embodiment, the light quantity instruction unit 51 may receive a signal from the outside without receiving a signal from the light quantity detection unit 50, for example. For example, when it is desired to adjust the laser light amount according to the observation conditions or the user's intention, a signal may be manually input to the light amount instruction unit 51.

In the present embodiment, the light amount detection unit 50 detects the light amount signal proportional to the light amount of the pulsed light. However, the present invention is not limited thereto, and the light amount signal corresponding to the light amount of the pulsed light may be detected. For example, a light amount signal proportional to the average light amount of pulsed light may be used.
The light amount of pulsed light here includes an average light amount that is a light amount obtained by averaging the light amount per pulse and the light amount per unit time indicated by symbol A in FIGS. 2 (a) and 2 (b). The average amount of pulsed light decreases when the number of pulse emission per unit time decreases, so that the emission time decreases, and when the number of pulse emission per unit time increases, it increases because the emission time increases. .

(Second Embodiment)
Next, an optical scanning endoscope apparatus 60 which is an example of the optical scanning endoscope apparatus 60 according to the second embodiment of the present invention will be described with reference to FIG.
The optical scanning endoscope apparatus 60 according to the present embodiment is the first embodiment in that the determination of changing the light amount by the light amount instruction unit 51 is determined from the obtained image instead of the signal from the light amount detection unit 50. It is different from the form. Therefore, in the present embodiment, a method for judging from the obtained image will be mainly described, and the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted.

In the present embodiment, the image generation unit 37 receives a signal obtained by receiving the reflected light from the observation object 100 by the detection optical fiber 12 and converting it into an electrical signal by the light detection unit 35. The light detection unit 35 also functions as a brightness detection unit, and outputs the signal converted into the electrical signal to the light amount instruction unit 51 as information on brightness based on pulsed light.

The light quantity instruction unit 51 adjusts the number of pulse emission based on the electrical signal from the light detection unit 35.
Specifically, the light quantity instruction unit 51 performs pulse light emission based on whether or not the number of pixels whose luminance level is equal to or lower than a predetermined threshold in the electrical signal from the light detection unit 35 is more than half of the total number of pixels. Give instructions to change the number. That is, when the number of pixels equal to or less than the threshold value is smaller than half of the total number of pixels, the light quantity instruction unit 51 further checks whether or not a plurality of frames are continuous. Instructs the number to enter normal mode.
On the other hand, when the number of pixels equal to or less than the above threshold value is half or more of the total number of pixels, the light quantity instruction unit 51 checks whether or not a plurality of frames are continued. Is instructed to enter the restricted mode.

Next, the operation of the thus configured optical scanning endoscope apparatus 60 will be described with reference to FIG.
The operation of the optical scanning endoscope apparatus 60 according to the present embodiment is different in the determination method used for adjusting the number of pulse emission, and the other steps are the same as those in the first embodiment. Therefore, a determination method used for adjusting the number of pulse emission will be described.

When laser light is emitted from the tip 11c of the illumination optical fiber 11 to the observation object 100, reflected light is detected by the detection optical fiber 12 in the light detection unit 35 (step S11). The detected reflected light is converted into an electric signal and transmitted to the light quantity instruction unit 51 (step S12). As described above, the light quantity instruction unit 51 calculates the number of pixels having a brightness equal to or lower than a predetermined threshold (step S13). Then, it is compared whether or not the number of pixels below the threshold is less than half of the total number of pixels (step S14). The comparison result is sent to the control unit 31, and a signal for changing the number of pulse emission of the next frame in the control unit 31 is sent to the light emission control unit 32.

Specifically, when the number of pixels equal to or less than the threshold is less than half of the total number of pixels (step S14 / Yes), the light quantity instruction unit 51 compares whether or not this condition continues for a plurality of frames (step S14 / Yes). Step S15). As a result of the comparison, when a plurality of frames are continuous (step S15 / Yes), it is determined that the distance from the observation object 100 is short, so the control unit 31 sets the pulse emission number to the pulse emission number in the normal mode. Control is performed (step S16).

On the other hand, when the number of pixels equal to or less than the threshold is more than half (step S14 / No), the light quantity instruction unit 51 compares whether or not this condition continues for a plurality of frames (step S17). As a result of the comparison, when a plurality of frames are continuous (step S17 / Yes), since it is determined that the distance from the observation object 100 is long, the control unit 31 sets the pulse emission number so that the pulse emission number in the limit mode is obtained. (Step S18).

Based on the setting of the control unit 31, the light emission control unit 32 determines the number of pulse light emission per unit time of the pulsed light, and controls the laser light quantity (step S19). Then, the laser light quantity is controlled to perform laser irradiation for acquiring an image of the next frame (step S20), and an image of the observation object 100 is generated in the image generation unit 37 (step S21). It is displayed on the display 40 (step S22).
In the above, when a plurality of frames are not continuous ((Step S15 / No) and (Step S17 / No)), laser irradiation for acquiring an image of the next frame is performed without changing the pulse emission number ( Step S20) and subsequent steps are the same.

From the above, in the brightness of the acquired image, when the number of pixels whose luminance level is less than or equal to the threshold value is less than half of the total number of pixels, whether or not the observation object 100 is close is confirmed by confirming whether a plurality of frames are continuous. Can be determined. When the observation object 100 is close, an image suitable for normal observation can be acquired by imaging in the normal mode.

Similarly, in the brightness of the acquired image, when the number of pixels whose luminance level is less than or equal to the threshold value is more than half of the total number of pixels, when a plurality of frames are continuous, the observation object 100 is far away, that is, in the observation object It is determined that there is no state suitable for observation, and an image can be acquired with the number of pulse emission in the limited mode. By doing in this way, it can be judged from the feature of an image whether it is an observation object.

Furthermore, the image can be acquired by changing the laser light quantity without changing the brightness of the obtained image. In particular, according to the second embodiment, since the light detection unit 35 also functions as the light amount detection unit 50 of the first embodiment, the configuration as a device can be simplified.

In this embodiment, the brightness of the image is determined based on whether or not the number of pixels below the threshold for the luminance level is half of the total number of pixels. However, the present invention is not limited to this. An arbitrary value such as / 3 or 4/5 may be set.

In this embodiment, the brightness level is determined as the brightness of the image. However, the present invention is not limited to this, and the determination may be made using the average brightness of the obtained image, or a histogram based on the brightness of the pixels. The determination may be made based on whether or not intermediate luminance is generated from the shape. By doing in this way, when the observation object 100 is close, the pixel has a certain level of brightness, so that the distance can be determined and controlled from the brightness.

Further, in the present embodiment, the light quantity instruction unit 51 may be able to input a signal from the outside without receiving a signal from the light detection unit 35, for example. For example, when it is desired to adjust the laser light quantity according to the observation conditions, a signal can be manually input to the light quantity instruction unit 51.

In this embodiment, the determination of the adjustment of the pulse emission number is performed at the timing of image generation of the next frame. However, the present invention is not limited to this, and a plurality of frames may be consecutive.

In the present invention, the interpolation method for generating an image has generated an image regardless of the number of pulse emission, but the interpolation method of pixels constituting the image may be changed according to the number of pulse emission.

For example, the number of pixels used for interpolation processing when generating an image may be changed in accordance with the number of light pulses emitted.
Specifically, when an image is generated with the number of light pulses emitted in the normal mode, here, four pixels close to the pixel to be interpolated are used, depending on the distance between each of the four points and the pixel to be interpolated. Weighting is performed to generate interpolated pixels.

On the other hand, when the number of pulse emission is reduced in the limit mode, the number of emission of the pulse light is reduced to, for example, 1/3 of the normal mode, so that the pulse interval is wider than that in the normal mode. That is, the number of pixels used for image generation is smaller than that before thinning. Therefore, interpolation processing is performed using two pixels close to the stored pixel. The two pixels necessary for the interpolation processing are weighted according to the distance between each of the two points and the pixel to be interpolated to generate a pixel to be interpolated. At this time, if the brightness of the interpolated pixel is I ′,
I ′ = V12 / A ′ + V21 / B ′
It is calculated by. Here, A ′ and B ′ are coefficients corresponding to the distance, and V is the brightness of the pixel.
Thus, by generating an image using only pixels close to the pixel to be interpolated, image noise due to using pixels with low reliability is reduced.

Furthermore, for example, the range used for the interpolation processing when generating the image may be changed according to the number of light pulses emitted.
Specifically, when an image is generated with the number of light pulses of the normal mode, interpolation processing is performed using pixels within a predetermined distance X from the pixel to be interpolated.

On the other hand, in the limited mode, when the number of pulse emission is reduced and the image is generated when the pulse interval is wider than in the normal mode, interpolation is performed using pixels within a predetermined distance Y from the pixel to be interpolated. Process. Here, the distances X and Y are set so that X <Y, and the range is set so that at least one pixel is included.
Thus, when the pulse interval is relatively dense, interpolation is performed using a narrow range of pixels, and when the pulse interval is open, interpolation is performed using a wide range of pixels, which is sufficient for storage. As a result, a smooth image can be generated.

The present invention is not limited to the above-described embodiments, and various changes and applications can be made without departing from the spirit of the invention. The present invention is applicable not only to medical endoscope apparatuses but also to so-called industrial endoscope apparatuses such as chemical plants and aircraft engines. Furthermore, the present invention can be applied to an optical scanning microscope apparatus. In the present invention, the optical scanning unit that performs spiral scanning is not limited to the actuator 21 using the

piezoelectric elements

28a, 28b, 28c, and 28d. For example, the optical scanning unit includes a permanent magnet and an electromagnetic coil and is driven by electromagnetic force. It is also possible to use an actuator or a galvanometer mirror that generates a force.

In each of the above embodiments, laser beams of three colors R, G, and B are used. However, the present invention is not limited to this. For example, two colors of B and G may be used, or R, G, and B may be used. A combination of colors other than B may be used.

In each of the above embodiments, the illumination light emitted from the illumination optical fiber 11 is scanned so as to draw a spiral trajectory on the observation surface of the observation object 100. However, the scanning trajectory is not limited to this. Alternatively, other shapes (for example, a raster shape or a Lissajous shape) may be used. Further, the scanning is not limited to the scanning using the illumination optical fiber 11, and other scanning methods (for example, a galvano mirror scanner) may be used.

DESCRIPTION OF

SYMBOLS

10,60 Optical scanning observation apparatus 11 Illumination optical fiber 11a Fixed end 11b Oscillating part 11c End 12 Detection optical fiber 13 Wiring cable 20 Scope 21 Actuator (optical scanning part)
22 Operation part 23 Insertion part 24

Tip part

25a, 25b Projection lens 26 Mounting ring 27

Actuator tube

28a, 28b, 28c, 28d Piezoelectric element 29 Fiber holding member 30 Control device main body 31 Control part 32 Light

emission control part

33R, 33G, 33B Laser light source (laser)
34 coupler 35 light detector (brightness detector)
36 pixel interpolation unit 37 image generation unit 38 actuator driver 40 display 50 light quantity detection unit (brightness detection unit)
51 Light intensity instruction unit 100 Observation object (object)

Claims

An optical scanning unit that scans an object with pulsed light; and
A brightness detector for detecting information on brightness based on the pulsed light;
A light detection unit that detects reflected light from the object by scanning the pulsed light on the object by the light scanning unit;
An optical scanning observation apparatus comprising: a control unit that controls to change the number of pulsed light emission per unit time of the pulsed light based on information on the brightness detected by the brightness detecting unit.
2. The optical scanning observation apparatus according to claim 1, wherein the brightness detection unit is a light amount detection unit that detects a light amount signal corresponding to the light amount of the pulsed light as information on the brightness.
3. The optical scanning observation apparatus according to claim 2, wherein the light amount detection unit detects a light amount signal proportional to the light amount of the pulsed light.
4. The optical scanning observation apparatus according to claim 3, wherein the light amount detection unit detects a light amount signal proportional to an average light amount of the pulsed light.
The said control part is controlled so that the pulse light emission number per unit time of the said pulsed light may be decreased when the information regarding the said brightness detected by the said brightness detection part is more than a predetermined threshold value. Item 5. The optical scanning observation device according to any one of Items 4 to 6.
An image generation unit that generates an image based on the intensity of the reflected light detected by the light detection unit;
The optical scanning observation apparatus according to claim 1, wherein the brightness detection unit is the light detection unit.
The optical scanning observation apparatus according to claim 6, wherein the image generation unit includes a pixel interpolation unit that performs interpolation of pixels constituting the image.
The optical scanning observation apparatus according to claim 7, wherein the pixel interpolation unit changes a method of interpolating pixels constituting the image in accordance with the number of pulse emission controlled by the control unit.
The said control part is controlled so that the pulse emission number per unit time of the said pulsed light may be decreased when the information regarding the said brightness detected by the said brightness detection part is below a predetermined threshold value. Item 9. The optical scanning observation apparatus according to any one of Items 6 to 8.
The optical scanning unit scanning the object with pulsed light; and
A brightness detection unit detecting information on brightness based on the pulsed light;
A control unit, when the information on the brightness detected by the brightness detection unit is less than or equal to a predetermined threshold, controlling to reduce the number of pulse emission per unit time of the pulsed light;
A light detection unit receiving light emitted from the object by the controlled irradiation of the pulsed light; and
And a step of generating an image based on an intensity of light received by the light detection unit.