JP2017079930A - Scan type endoscope apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scan type endoscope apparatus capable of easily acquiring a detection value indicating the brightness of an endoscope image even when there is a variation in a scan trajectory, etc.SOLUTION: Return light detected by a light receiving optical fiber 15 is converted to a detection signal at a detection part 23. A first image signal corresponding to a spiral scan trajectory is generated at a first image generation part 31, and converted to an image signal of a rectangular coordinate system by a raster conversion part 32. A detection value indicating the brightness of a designated area is calculated at a detection part 33.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a scanning endoscope apparatus that generates an endoscopic image by scanning illumination light.

In recent years, endoscopes have been widely used in the medical field and industrial field. Various scanning endoscopes have been proposed in which illumination light is guided by an optical fiber, and the guided illumination light is scanned on a subject to generate an endoscope image. The scanning endoscope is suitable for reducing the diameter of the insertion portion.
For example, in the scanning endoscope apparatus disclosed in Japanese Patent Application Laid-Open No. 2014-046141 as the first conventional example, the average value of the fluorescence level is set between the central region and the peripheral region of the image in order to reduce the fading of the fluorescence. It is calculated and fed back to the light source so that an endoscopic image with uniform brightness can be acquired.
Further, in the scanning endoscope apparatus disclosed in Japanese Patent Application Laid-Open No. 2014-061227 as the second conventional example, in order to reduce discoloration of the endoscope image, the light source pulses are densely arranged in the central region of the image, In the region, light source pulses are sparse so that an endoscopic image with uniform brightness can be acquired.

In a scanning endoscope, a predetermined area on the screen is set in order to set an endoscopic image displayed on a monitor to a brightness suitable for examination, diagnosis, etc., as in the case of a normal endoscope. Detection may be performed to calculate the statistic of the pixel value.
In the scanning endoscope, the scanning trajectory and the scanning speed are deviated from the design value by an amount unique to the scanning endoscope due to individual differences during manufacturing, manufacturing variations, vibration control variations, and the like. As a result, the number of the sampled signal when the brightness of a certain area on the screen is obtained by sequentially illuminating the illumination light varies depending on the scanning endoscope.
That is, when trying to detect a predetermined area on the screen using the conventional scanning endoscope apparatus or method, how to take the statistical amount (for example, average value) of the signal sampled, It must be changed for each scanning endoscope. For this reason, it is necessary to increase the amount of calculation related to detection and increase the circuit scale.

JP 2014-0461141 A JP 2014-061227 A

However, neither the first conventional example nor the second conventional example discloses the contents for reducing the amount of calculation related to the detection.
The present invention has been made in view of the above points, and a scanning endoscope apparatus that can easily obtain a detection value representing the brightness of an endoscopic image even when there is a variation in a scanning trajectory or the like. The purpose is to provide.

  The scanning endoscope apparatus according to one aspect of the present invention includes a light source unit that generates illumination light, a light guide unit that guides the illumination light incident on the first end to the second end, and the guide. A scanning unit that vibrates the second end of the light unit so as to draw a spiral trajectory; a detection unit that detects reflected light according to illumination light applied to the subject from the second end; and the detection unit The detection signal corresponding to the detected subject image is converted to generate an image signal corresponding to the generated image represented in the orthogonal coordinate system, and the image signal intensity statistic of the specified area specified in the image signal And a signal processing unit that calculates a detection value representing the brightness of the designated region as the statistic.

  According to the present invention, even when there are variations in the scanning trajectory or the like in the scanning endoscope, a detection value representing the brightness of the endoscope image can be easily obtained.

FIG. 1 is a diagram showing an overall configuration of a scanning endoscope apparatus according to a first embodiment of the present invention. − FIG. 2 is a diagram showing a state in which the tip of an illumination-like optical fiber is driven by a scanning unit, and the irradiation position of pulsed illumination light draws a spiral scanning locus. FIG. 3 is a table showing the contents of the LUT in which the ordinal number and the coordinates of the irradiation position are associated with each other when the light source emits pulses. FIG. 4 is a block diagram illustrating a configuration of a signal processing unit and the like. FIG. 5 is an explanatory diagram when converting the first image signal of the spiral scan into the image signal of the raster scan. FIG. 6 is a diagram schematically illustrating a state in which the first image signal of the spiral scan is converted into the raster scan image signal by raster conversion. FIG. 7A is a diagram schematically illustrating a state in which the first pixel signal of the spiral scan is raster-converted, converted into a raster-scan pixel signal, and stored in the memory. FIG. 7B shows a pixel signal in which the gradation of the detection signal of the spiral scan becomes 0 by the offset process for shifting the gradation scanning pixel signal by one gradation, and the gradation is 0 for the non-detection signal. The figure which shows a mode that it divided in the gradation so that it might distinguish from the pixel signal which becomes. FIG. 8 is a flowchart showing typical processing contents of the first embodiment. FIG. 9 is a flowchart showing detailed processing contents of the raster conversion processing in FIG. FIG. 10 is a diagram illustrating a state in which a designated area is set as an area for obtaining a detection value for a generated image in the display area. FIG. 11 is a diagram illustrating an example in which the detection signal is shifted by one gradation before and after performing A / D conversion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, a scanning endoscope apparatus 1 according to a first embodiment of the present invention is inserted into, for example, a patient 2 as a subject, and a scanning endoscope for examining the inside of the patient 2. The mirror 3, a scanning endoscope control device (abbreviated as a main body device) 4 to which the scanning endoscope 3 is detachably connected, and an image signal generated by the main body device 4 is input. And a monitor 5 for displaying the generated image as an endoscopic image. Further, a user such as an operator can select or control the operation of the scanning endoscope apparatus 1 by operating the input unit 6 including a keyboard or the like with respect to the main body apparatus 4. For example, it is possible to designate (or set) a designated region (or a detection region) as a region for calculating a detection value from the input unit 6 using the detection unit 33 described later, or to select an operation mode of the present embodiment. For this reason, the input unit 6 has a function of a designated region setting unit 6a for setting a designated region (or detection region). Also, it has a function of an operation mode selection unit for selecting an operation mode.
The scanning endoscope 3 includes an elongated insertion portion 11, and an illumination optical fiber 12 that forms a light guide portion that guides illumination light is disposed in the insertion portion 11. Illumination light generated by the light source unit 21 provided in the main body device 4 is incident on the base end serving as the first end of the illumination optical fiber 12.

The illumination optical fiber 12 guides the illumination light incident on the proximal end to the distal end serving as the second end. The illumination light guided to the tip is condensed and irradiated from the tip to an examination site (subject) 2a such as an affected part of the patient 2 through a condenser lens (not shown). The illumination light is controlled to emit pulses.
A scanning unit 13 is provided in the vicinity of the distal end of the illumination optical fiber 12, and a drive signal output from the drive unit 22 of the main body device 4 is applied via the drive line 14. The tip of the fiber 12 is vibrated so as to draw a spiral or spiral scanning locus. The illumination position of the illumination light applied to the subject 2a changes so as to draw a spiral or spiral scanning locus.
FIG. 2 is an ordinal number showing the irradiation position of the illumination light pulsed when acquiring an image for one frame with respect to the reference subject. When pulsed light is emitted at the scanning start position, it becomes an irradiation position indicated by ordinal number O1 (simply 1 in FIG. 2, the same applies to the following O2 etc.), and when pulsed light is emitted sequentially while drawing a spiral scanning locus. The irradiation position is the ordinal number O2, O3,..., And the irradiation position when the pulse emission is performed at the scanning end position is the ordinal number On.

As shown in FIG. 1, a light receiving optical fiber 15 that forms a second light guide for detecting illumination light reflected by the subject is disposed in the insertion portion 11. The distal end of the light receiving optical fiber 15 is disposed at the distal end of the insertion portion 11 and guides the reflected light incident on the distal end to the proximal end of the light receiving optical fiber 15.
The reflected light guided to the base end enters the detection unit 23 including the photoelectric conversion element in the main body device 4 and is photoelectrically converted into a detection signal. This detection signal is input to the signal processing unit 24, and the signal processing unit 24 generates an image signal of a generated image to be displayed on the monitor 5.
Further, the scanning endoscope 3 has a memory 16 provided in a connector part 11 a provided at the proximal end of the insertion part 11. The memory 16 stores information (placement information) associated with the ordinal number Oi and the two-dimensional coordinate position (Xi, Yi) of the irradiation position, for example, as a lookup table (LUT) 16a.
FIG. 3 shows an example of the LUT 16a. As shown in FIG. 3, in the LUT 16a, the ordinal number Oi at the time of pulse light emission and the coordinates (Xi, Yi) of the irradiation position are stored in association with each other. Accordingly, the signal processing unit 24 refers to the arrangement information of the LUT 16a with respect to the detection signal corresponding to the ordinal number Oi, thereby generating a detection signal for the coordinate position, that is, a detection signal for the pixel whose coordinate position is specified. Can do.

As shown in FIG. 1, the main body device 4 photoelectrically converts reflected light detected by a light source unit 21 that generates illumination light, a drive unit 22 that generates a drive signal to be applied to the scanning unit 13, and a light receiving optical fiber 15. And a signal processing unit 24 that generates an image signal from the detection signal generated by the detection unit 23.
The main body device 4 includes a controller 25 that controls operations of the light source unit 21, the drive unit 22, the detection unit 23, and the signal processing unit 24 inside the main body device 4. An input signal or input data input from the input unit 6 is input to the controller 25, and the controller 25 performs a control operation according to the input signal or input data. The user can specify the address of the designated area where the detection unit 33 calculates the detection value from the keyboard constituting the input unit 6, or can designate the frame of the designated area from the mouse constituting the input unit 6. Then, the controller 25 sends address range information representing the region range of the designated region to the detection unit 33, and the detection unit 33 performs a process of calculating the statistic of the image signal intensity of the designated region as a detection value.

As shown in FIG. 1, the signal processing unit 24 includes a first image generation unit 31 that generates a first image signal as an image signal for spiral scanning from the detection signal of the detection unit 23, and a first image signal. A raster conversion unit 32 that converts the image signal into a raster scan image signal represented by an orthogonal coordinate system, and an image (or generated image) of the raster scan image signal from the raster scan image signal converted by the raster conversion unit 32 A detection unit 33 that calculates a detection value of a designated region in the image processing unit, and an image processing unit 34 that performs image processing such as brightness adjustment and edge enhancement by gain adjustment on an image signal of raster scanning.
Further, the signal processing unit 24 reads out the arrangement information stored in the memory 16 of the scanning endoscope 3 and stores it in the memory 35 inside the signal processing unit 24. That is, the memory 35 stores the same information as the LUT 16a of the memory 16 as the LUT 35a. Note that the LUT 16a of the memory 16 may be used without using the LUT 35a of the memory 35.
FIG. 4 shows a more detailed configuration of the signal processing unit 24 and the like. The detection unit 23 includes, for example, an avalanche photodiode (abbreviated as APD) 23a. The APD 23a is a photodiode whose gain (gain) can be varied by applying a reverse bias voltage. Then, the multiplication factor (gain) of the detection signal output from the APD 23a can be varied according to the value of the reverse bias voltage from the controller 25.

As will be described later, the light source unit 21 also has a function of adjusting the amount of illumination light emitted in pulses generated by the light source unit 21 based on a light amount control signal from the controller 25.
The first image generation unit 31 converts the detection signal output from the APD 23a into a digital detection signal by the A / D conversion circuit 31a and, for example, in the ordinal order in the memory 31b in the first image generation unit 31. Store. The coordinate providing circuit 31c reads position information corresponding to the ordinal number Oi in the detection signal from the LUT 35a of the memory 35, and generates a pixel signal having position information when each detection signal is detected. In other words, the coordinate applying circuit 31c adds position information to each detection signal when scanning in a spiral shape, generates a first image signal as an image signal of the spiral scan, and stores it in the memory 31d. To do. Note that the first image signal may be stored in the memory 35 instead of being stored in the memory 31d.
The first image signal is input to an interpolation circuit (or correction circuit) 32a constituting the raster conversion unit 32. The interpolation circuit 32a converts the first image signal of the spiral scan into the image signal of the raster scan. Interpolation processing is performed.

FIG. 5 is an explanatory diagram for converting the first image signal into an image signal for raster scanning. The diagram on the left side in FIG. 5 schematically shows a state in which a coordinate system of a spiral scanning locus (indicated by Tr in FIG. 5) and an orthogonal coordinate system of raster scanning are overlapped. In FIG. 5, each pixel position forming an image signal for raster scanning is a grid point position.
The vicinity of the target lattice point Pg in the left side of FIG. 5 is as shown in the enlarged view on the right side. Note that the grid point Pg of interest in this case means a grid point to be generated (or an interpolation process target) for generating a raster scan pixel signal.
As shown in the enlarged view, since the position of the lattice point of raster scanning is generally deviated from the position of the pixel signal of spiral scanning, the interpolation circuit 32a has a spiral shape existing in the vicinity of each lattice point. An interpolation process is performed as a process for generating a pixel signal of each grid point using the pixel signal of the scanning.
In the example shown in FIG. 5, there are pixel signals SO1, SO2 and SO3 along one curve passing through the vicinity of the grid point Pg of interest. Also, there is a pixel signal SO4 along a curve that is more distant from the grid point Pg than these pixel signals SO1, SO2, SO3.

The interpolation circuit 32a gives priority to the pixel signal that exists at the smallest distance from the grid point Pg, and generates a pixel signal at the grid point Pg.
Specifically, as shown in FIG. 5, a plurality of pixel signals SO1 and SO1 are set in the setting area A set based on the distance between adjacent grids on both sides in the vertical and horizontal directions around the target grid point Pg. When SO2,..., SOk,... Exist, the pixel signal Sgi at the lattice point Pg is, for example, Sgi = ΣCk × SOk / ΣCk (1)
You may calculate by. Here, Σ represents the sum of Ck × SOk or Ck in the setting area A, and Ck represents a weighting coefficient that increases as the distance from the grid point Pg decreases. In addition, it is divided by the sum of the weighting coefficients Ck. Note that the setting area A is not limited to a rectangular area, and may be a circular area.
For example, when the pixel signal is present in the vicinity region of the lattice point Pg whose distance from the lattice point Pg is equal to or less than the threshold value Lth, the interpolation circuit 32a determines the lattice point Pg from only the pixel signal present in the vicinity region. Are generated. As shown in FIG. 5, when only one pixel signal SO2 exists in the region where the distance is equal to or less than the threshold value Lth, the pixel signal Sgi at the lattice point Pg is set to Sgi = SO2 to generate the pixel signal Sgi. May be. When there are a plurality of pixel signals in an area where the distance is equal to or less than the threshold value Lth, the average value of the plurality of pixel signals is calculated.

Also, as shown in FIG. 5, when no pixel signal exists in the setting area A set around the lattice point Pg as a center, defective pixels generated in a normal image sensor or (pixel value is missing) In the same manner as in the case of missing pixels, the pixel is generated by interpolation from pixel signals of surrounding grid points adjacent to the grid point Pg.
Specifically, with respect to the lattice point Pg in the case where no pixel signal (in a spiral scan) exists in the setting area A, two lattice points Pgl adjacent to both sides in the left-right direction of the lattice point Pg, The average value of both image signals of Pgr, the average value of both image signals of two lattice points Pgu and Pgd adjacent to both sides in the vertical direction of the lattice point Pg, and the like may be used as the image signal of the lattice point Pg.
On the other hand, for example, at the grid point Pga outside the scanning trajectory Tr in FIG. 5, for example, one pixel signal does not exist in the setting area A, and only pixel signals of only one grid point at the grid points on both sides thereof are present. The pixel signal at the lattice point does not exist.

Therefore, in this case, the interpolation circuit 32a is not a missing pixel as described above, but is a region outside the scanning region (scanning range) Rs of the scanning locus Tr, that is, the detection signal is not actually detected. Assuming that raster conversion is being performed in the detection area (unscanned area), the pixel signal of the grid point is not interpolated using the pixel signals of the surrounding grid points.
However, since the lattice point Pga is included in a quadrangular region (in other words, a square or a rectangle) as a region for generating an image signal by raster scanning, the interpolating circuit 32a eventually results in this undetected region. Pixel or image signals are also output (signal processing in such a case will be described later).
In this way, the interpolation circuit 32a generates a raster scan image signal in a region that substantially matches the spiral scan region from the first image signal in the spiral scan region, and the generated raster scan image. The signal is stored in the memory 32b.
FIG. 6 schematically shows, for example, a conversion from the first image signal of the spiral scan shown in FIG. 2 to the image signal of the raster scan.

The first image signal SO of the circular scanning region Rs shown on the left side in FIG. 6 is converted into the image signal Sga of the circular corresponding region Rr corresponding to the circular scanning region Rs and the circular corresponding region after raster conversion. Outside of Rr, it is converted into an image signal Sgu of the undetected area Ru. Here, the circular corresponding region Rr and the undetected region Ru become the display region Rd. Further, the image signal Sga and the image signal Sgu form an image signal Sg for raster scanning.
FIG. 7A shows a processing result obtained by converting the first pixel signal forming the first image signal SO in FIG. 6 into the raster scanning pixel signal forming the raster scanning image signal Sg.
The left first pixel signal in FIG. 7A is converted into a right pixel signal by the interpolation circuit 32a. In FIG. 7A, the left first pixel signal is indicated by SOi (i = 1, 2, 3,..., I, n), and the right pixel signal is indicated by Sgi (i = 1, 2, 3,... i, m). In general, the number n of the first pixel signals SOi and the number m of the pixel signals Sgi are different from each other by the interpolation processing described with reference to FIG. FIG. 7A also shows an address Ai where the pixel signal Sgi is stored in the memory 32b.

As shown in FIG. 6, the right pixel signal Sgi is a pixel signal that forms the image signal Sga of the corresponding region Rr and the image signal Sgu of the undetected region Ru. Therefore, the right pixel signal Sgi is composed of a pixel signal Sgai (see FIG. 7B) that forms an image signal of the corresponding region Rr and a pixel signal Sgui (see FIG. 7B) that forms an image signal of the undetected region Ru. .
In the present embodiment, in order to facilitate the detection unit 33 to calculate the detection value with high accuracy, when the pixel signal Sgi of the raster scan is stored in the memory 32b, the pixel signal Sgai of the corresponding region Rr and the undetected region Ru Identification information that enables identification of the pixel signal Sgui is added and stored in the memory 32b.
As the identification information, for example, information of one gradation is used. For example, when the number of gradations representing the gradation of the pixel value (or signal level) of the pixel signal based on the detection signal after A / D conversion is 0 to 4095 (processing in a 12-bit range), the undetected region Ru Is provided with an offset processing circuit 32c that performs offset processing that is assigned to the number of gradations of 0 for the pixel signal Sgib, and assigned to the number of gradations of 1 to 4095 for the pixel signal Sgia of the corresponding region Rr (FIG. 4). Is abbreviated as OFFSET).

As shown in FIG. 4, an offset processing circuit 32 c is provided inside the raster conversion unit 32, but more specifically, outside the raster conversion unit 32, more specifically, for example, on the upstream side of the signal input to the raster conversion unit 32. You may make it provide in the 1st image generation part 31. FIG.
By the offset processing circuit 32c, for example, in the pixel signal Sgia in the corresponding region Rr, a pixel having a gradation of 0 before the offset process becomes a pixel signal having a gradation of 1 after the offset process. For this reason, the gradation of the detection signal detected in the scanning region Rs due to the gradation shift by the offset process is 0, and the signal that the gradation becomes 0 even after the raster conversion and the pixel for the undetected region. Since there is no value, a pixel signal whose gradation is 0 by raster conversion can be identified by whether the gradation is 0 or 1.
In other words, in the case of the conventional example in which processing such as offset processing is not performed, the pixel signal of the detection signal detected in the scanning region Rs is 0 and (outside the region of the scanning region Rs). ) There is a drawback that it is impossible to distinguish a pixel signal whose gradation is set to 0 because the pixel value is not detected due to the undetected area.

And this embodiment has eliminated this fault. In addition, since the pixel signal in the scanning region Rs and the corresponding region Rr is generated by the pixel signal in which the pixel value is detected, the scanning region Rs or the corresponding region Rr is also referred to as the detection region R.
The pixel signal Sgia of the corresponding region Rr has a gradation Q (Q = 0 to 4095) within a range of 0 to 4095 before the offset process is performed. You may move to the gradation of Q + 1 so that the number becomes high. In this case, when the number of gradations before the offset process is maximum (Q = 4095) and when it is smaller than the maximum (Q = 4094), the maximum gradation (Q = 4095) is obtained after the offset process. That is, the maximum gradation (Q = 4095) before offset becomes a saturated signal, and gradation information is lost. However, in many cases, the human eye is less sensitive to the difference when the number of gradations is larger than the difference when the number of gradations is small. Therefore, in many cases, the above-described configuration in which the gradation information of the pixel signal other than the maximum gradation is not impaired by adding one gradation to generate the pixel signal is suitable.
However, the offset processing method is not limited to the method of adding one gradation. For example, the gradation information other than the minimum gradation (Q = 0) may not be lost by subtracting one gradation. Further, the number of gradations at which gradation information is lost may be changed for each screen area.
FIG. 7B shows a state in which the pixel signal Sgai (forming the image signal Sga) in the corresponding region Rr and the pixel signal Sgui (forming the image signal Sgu) in the undetected region Ru are divided by gradation (signal level). . As can be seen from FIG. 7B, the pixel signals in both areas can be easily identified by the gradation of 1 or more and the gradation of 0 where the gradation is less than 1. Note that a half gradation threshold value may be used, and pixel signals in both regions may be identified by a comparison result (by a comparator) whether or not the gradation threshold value is exceeded.
As described above, by using the information for one gradation as the offset processing, the pixel signal Sgia of the corresponding region Rr and the pixel signal Sgib of the undetected region Ru in the pixel signal Sgi of raster scanning are converted into gradations or signals. It can be easily identified by level.

As shown in FIG. 4, the raster scanning image signal stored in the memory 32 b is stored in a designated area as a designated area in the generated image displayed on the monitor 5 by the detection value calculation circuit 33 a forming the detection unit 33. A detection value representing brightness is calculated.
The raster scanning image signal Sg stored in the memory 32b is subtracted by one shifted gradation and then amplified by the digital amplifier 34a in the image processing unit 34. Thereafter, an image signal subjected to image processing such as contour enhancement in the image processing circuit 34b is generated, output to the monitor 5, and displayed as a generated image. Note that in the case of an image signal in which the shift of one gradation can be ignored, the digital amplifier 34a may not perform the process of subtracting one gradation.
As shown in FIG. 4, the detection unit 33 is formed by a detection value calculation circuit 33 a that calculates a detection value representing the brightness of the designated region.

Information of an address corresponding to a designated area designated by the user is input from the input unit 6 to the detected value calculation circuit 33a via the controller 25.
Based on the address information input from the controller 25, the detection value calculation circuit 33a calculates, for example, the sum of the pixel values of the pixel signal as a statistic of the pixel signal in the specified region in the image signal of the generated image displayed on the monitor 5. An average value obtained by dividing the area of the net detection region excluding the undetected region Ru in the region is calculated as a detection value.
In the present embodiment, when the simple mode is selected as the operation mode, the detection value calculation circuit 33a does not distinguish between the detection area and the non-detection area in the designated area, and the pixel of the pixel signal in the designated area. The total value of the values is calculated, and a statistic obtained by dividing by the area of the designated region is calculated as a detection value.
On the other hand, when the standard mode is selected as the operation mode, the detection value calculation circuit 33a calculates the sum value of the pixel signals in the net detection area (excluding the undetected area Ru in the designated area). And the average value divided by the area of the net detection region (excluding the undetected region Ru in the designated region) is calculated as the detection value. In this case, the sum value of the pixel signals in the net detection region for one frame to several frames T is calculated, and the average value obtained by dividing the sum of the areas Sd and T of the net detection region is calculated as the detection value. You may make it do.

The detection value calculated by the detection value calculation circuit 33a is input to the controller 25. The controller 25 determines the brightness of the generated image displayed on the monitor 5 based on the calculated detection value and the selected operation mode. A control operation for adjusting the height is performed.
As shown in FIG. 4, the reference brightness information or the reference detection value corresponding to the reference brightness is stored in the memory 25 a inside the controller 25. That is, the memory 25a forms a reference brightness information storage unit.
As shown in FIG. 4, the light source unit 21 includes a laser diode (abbreviated as LD in FIG. 4) 21a that generates laser light serving as illumination light, and a laser that controls a pulse voltage at which the laser diode 21a generates laser light. And a control circuit 21b.

The scanning endoscope apparatus 1 according to this embodiment includes a light source unit 21 that generates illumination light, and an illumination that forms a light guide unit that guides the illumination light incident on the first end to the second end. The optical fiber 12, the scanning unit 13 that vibrates the second end of the light guide unit so as to draw a spiral trajectory, and the illumination light applied to the patient 2 that forms the subject from the second end. A detection unit 23 that detects the reflected light according to the detection unit, and a detection signal corresponding to the subject image detected by the detection unit 23 is converted to generate an image signal corresponding to the generation image represented by the orthogonal coordinate system. A signal processing unit 24 that performs a process of calculating a statistic of the image signal intensity of the specified area specified in the image signal and calculating a detection value representing the brightness of the specified area as the statistic. It is characterized by.
Next, the operation of this embodiment will be described.
After setting the scanning endoscope apparatus 1 of this embodiment as shown in FIG. 1, the power switch of the main body apparatus 4 is turned ON. Then, the scanning endoscope apparatus 1 is in an operating state.

In the first step S1, the surgeon performs input for selecting a plurality of operation modes from the input unit 6. In the present embodiment, for example, two operation modes, a simple mode and a standard mode, are prepared, and the user selects one operation mode. Three or more operation modes may be prepared. Then, the operator inserts the scanning endoscope 3 into the patient 2.
In the next step S2, the controller 25 operates the light source unit 21, the drive unit 22, the detection unit 23, etc., drives the scanning unit 13 provided near the tip of the illumination optical fiber 12, and causes the illumination light to emit pulses. To start optical scanning.
In the next step S3, the signal processing unit 24 (the first image generation unit 31 thereof) generates a first image signal. The reflected light of the illumination light applied to the subject such as the examination site of the patient 2 is received (detected) by the light receiving optical fiber 15 and becomes a detection signal photoelectrically converted by the detecting unit 23, and the first image generating unit 31 A first image signal corresponding to the spiral scanning trajectory is generated.

In the next step S4, the raster conversion unit 32 performs raster conversion on the first image signal. The raster conversion unit 32 performs raster conversion on the first image signal to generate an image signal for raster scanning.
FIG. 9 is an example showing details of raster conversion processing.
When the raster conversion process is started, in the first step S21, the interpolation circuit 32a sets a setting area A as shown in FIG. 5 around each grid point in the display area Rd.
In the next step S <b> 22, the interpolation circuit 32 a specifies each grid point when the pixel signal of the spiral scan exists in the setting area A around each grid point.
In the next step S23, the interpolation circuit 32a generates the pixel signal of the lattice point using the spiral scanning pixel signal in consideration of the distance from the lattice point. The process for generating the pixel signal of the lattice point has been described with reference to FIG.

In the next step S24, the interpolation circuit 32a determines whether or not the processing in step S23 has been completed for all the lattice points in step S22.
If the processing in step S23 has not been completed for all the lattice points in step S22, the processing in step S23 is repeated. Then, in the case of the determination result obtained by completing the process of step S23 for all the lattice points of step S22, the process proceeds to the process of step S25.
In step S25, the interpolation circuit 32a determines that grid points other than the above-described grid points (included in the display area Rd) have no spiral scan pixel signal in the setting area A around the grid points. It is determined whether or not there is.
If there is a grid point where there is no spiral scanning pixel signal, in the next step S26, the interpolation circuit 32a determines whether each of the grid points above and below the grid point or on both the left and right sides has a pixel signal. judge.
When each grid point on both sides has a pixel signal, in the next step S27, the interpolation circuit 32a generates a pixel signal of the grid point based on the average value of the pixel signals at each grid point on both sides, and step S29. Move on to processing.

On the other hand, in the determination process of step S26, when only the grid point adjacent to one side has the pixel signal at all, the interpolation circuit 32a determines that the process target grid point in step S28. The lattice point is determined to be a lattice point of the undetected region Ru outside the scanning region Rs or the corresponding region Rr, and the process proceeds to step S29.
In step S29, the interpolation circuit 32a determines whether or not the processing for all the lattice points in step S25 has been completed. If the determination result indicates that the processing for all the lattice points in step S25 has not been completed, the processing returns to step S26 and the above-described processing is repeated.
Thus, when the process for all the lattice points in step S25 is completed, the process proceeds to step S30. Further, in the determination process in step S25, if a pixel signal for spiral scanning exists in the setting area A, the process proceeds to step S30.

In step S30, the interpolation circuit 32a (offset processing circuit 32c thereof) generates a pixel signal of a grid point in the undetected area Ru as an image signal of 0 gradation, and a corresponding area Rr (or detection area) other than the undetected area Ru. For the pixel signal at the grid point R), a process of generating a pixel signal having a gradation obtained by adding one gradation to the pixel signal generated in step S23 or step S27 is performed. Then, the process of FIG. 9 is terminated, and the process proceeds to the next step S5 in FIG.
If there is a 0 gradation pixel signal in the corresponding region Rr (or detection region R) by the processing in step S9, the gradation of the pixel signal becomes 1, and the 0 gradation pixel signal included in the undetected region Ru Can be identified or distinguished.
In step S5 in FIG. 8, the signal processing unit 24 (the image processing unit 34 thereof) outputs an image signal of raster scanning subjected to contour enhancement or the like to the monitor 5, and the monitor 5 displays the generated image.

In the next step S <b> 6, the controller 25 determines whether or not a designated area is designated from the input unit 6. Then, the controller 25 waits for the designated area to be designated from the input unit 6.
FIG. 10 shows a designated region Rb designated from the input unit 6 in the generated image displayed in the display region Rd. In general, the designated region Rd may be set (designated) to include the detection region R and the undetected region Ru. In the simple mode, it is approximated that the designated area Rd is substantially equal to the detection area R, and in the operation mode other than the simple mode, the detection area R is calculated in the designated area Rd. As shown in FIG. 10, when designating a rectangular designation region Rb including the case of a square, the addresses of two points P1 and P2 facing diagonally may be designated, or two points may be designated with a mouse or the like. May be specified.
In addition, as indicated by a two-dot chain line, it is possible to designate a designated region Rb having a more complicated shape.

In the next step S7, the controller 25 determines whether or not the simple mode is selected in step S1.
When the simple mode is selected, in the next step S8, the detection unit 33 (the detection value calculation circuit 33a forming the calculation unit) calculates the detection value of the designated region (as opposed to the simple mode as will be described later). In other modes, the detection area in the specified area is calculated, and the detection value in the detection area is calculated). The detection unit 33 sends the calculated detection value to the controller 25.
In the next step S9, the controller 25 compares the detection value with the reference brightness (corresponding reference detection value), and adjusts the digital gain of the digital amplifier 34a of the image processing unit 34 so that the reference brightness is obtained. (Control.
In the next step S <b> 10, the controller 25 determines whether or not an instruction input for ending the endoscopy has been made from the input unit 6. When the instruction input for ending the endoscopic examination is not made, the controller 25 controls to return to the process of step S8, and when the instruction input for ending the endoscopic examination is made, the process of FIG. 8 is finished. To do.

If the simple mode is not selected in step S7, the controller 25 determines in step S11 that the standard mode is selected, and sends information on the determination result to the detection unit 33.
In the next step S12, the detection unit 33 calculates a detection area in the designated area. In the case of FIG. 10, the detection area R (or corresponding area Rr) in the designated area Rb is calculated. In other words, the undetected area Ru in the specified area Rb is calculated, and the detected area R (or corresponding area Rr) in the specified area Rb is calculated by subtracting the undetected area Ru indicated by hatching from the specified area Rb.
In the next step S13, the detection unit 33 calculates a detection value in the detection region R (or the corresponding region Rr) in the designated region Rb. The detection unit 33 sends the calculated detection value to the controller 25.
In the next steps S14a to S14f, the controller 25 compares the detection value with a reference detection value corresponding to the reference brightness. Then, the controller 25 performs brightness adjustment in consideration of the priority in the order of the digital amplifier 34a, the APD 23a, and the light source unit 21 so that the reference detection value is obtained.

Specifically, when the detection value is different from the reference detection value corresponding to the reference brightness, in step S14a, the controller 25 sets the digital gain of the digital amplifier 34a of the image processing unit 34 to a preset gain. Within this range, the gain is adjusted (controlled) so that the detected value becomes equal to the reference detected value. In the next step S14b thereafter, the controller 25 determines whether or not the detection value matches the reference detection value.
If the detection value does not match the reference detection value in step S14b, in the next step S14c, the controller 25 sets the multiplication value of the APD 23a to the reference detection value within a preset multiplication factor range. Adjust (control) in the same direction. In the next subsequent step S14d, the controller 25 determines whether the detected value matches the reference detected value.
If the detection value does not match the reference detection value in step S14d, in the next step S14e, the controller 25 adjusts the light amount of the laser diode 21a in the light source unit 21 within a predetermined range, and the detection value is the reference detection value. Adjust to match the value. In subsequent step S14f, the controller 25 determines whether the detection value matches the reference detection value. If the detection value does not match the reference detection value in step S14f, the process returns to step S14a and the same process is repeated.

On the other hand, if the detection value matches the reference detection value in step S14b, step S14d, or step S14f, the process proceeds to step S15. In step S <b> 15, the controller 25 determines whether or not an instruction to end the endoscopy has been input from the input unit 6. When the instruction input for ending the endoscopic examination is not made, the controller 25 controls to return to the process of step S13.
On the other hand, when the instruction input for ending the endoscopic examination is made, the processing in FIG. 8 is ended.
According to the first embodiment that operates in this way, even when there are variations in the scanning trajectory or the like in the scanning endoscope 2, a detection value that represents the brightness of the endoscopic image can be easily obtained. .
More specifically, even after the raster conversion, even when there are individual differences or variations in the spiral scanning trajectory in the scanning unit 13 or the like mounted on the scanning endoscope 3 connected to the main body device 4. The address of the image signal or generated image expressed in the orthogonal coordinate system is always the same regardless of the variation. As a result, it is possible to set the designated area for obtaining the detection value on the orthogonal coordinate system without being affected by the individual difference or the scanning trajectory of the scanning unit 13 and the like, and to detect the detection value representing the brightness of the generated image in the designated area. As compared with the case before raster conversion, it can be easily obtained with a small calculation amount, and the circuit scale can be reduced.
Further, in the present embodiment, detection of an image signal (or pixel signal) as a detection signal in a detection area actually detected by optical scanning and detection of an undetected area included in the raster conversion. Since an image signal (or pixel signal) as a signal can be identified or distinguished by an identification signal such as a gradation signal representing gradation, an undetected area is included as a designated area for acquiring a detection value. Even when designated, the detection value (that is, the brightness of the image) for the detection region within the designated region can be calculated with high accuracy.
Further, according to the present embodiment, when the detection value is calculated, it is easy to observe using one or more of a plurality of brightness adjusting means (brightness adjusting devices) that can adjust the brightness of the generated image. The brightness can be adjusted. Further, in this case, in a plurality of brightness adjustments, the brightness adjustment can be performed with priority given to the one having a higher priority.
Further, according to the present embodiment, even when there is a region where sampling density (detection density) from other regions is concentrated, such as the center of the image before raster conversion, the pixel density after raster conversion Since it is not different from other regions, it is not necessary to calculate a detection value as a statistic using more pixel values than necessary. As a result, the amount of calculation for calculating the detection value can be reduced as compared with the case of calculating from the detection signal before raster conversion.

In the above-described embodiment, when raster conversion is performed as described with reference to FIG. 9, the pixel signal of the undetected area is converted to the pixel signal of 0 gradation in the detection area (or corresponding area), for example, the detection area ( Alternatively, the pixel signals in both areas can be easily distinguished by shifting to a gradation obtained by adding one gradation to the pixel signal in the corresponding area), so that a highly accurate detection value can be calculated.
In this way, when making it possible to distinguish the pixel signals of both regions, for example, a flag bit for identification is added to the pixel signal of one region, and a flag bit is not attached to the pixel signal of the other region. You may make it distinguishable (identification).
In the above-described embodiment, the image signals in both areas can be distinguished (identified) by one-tone offset processing at the end of the raster conversion processing. However, as shown in FIG. One-tone offset processing may be performed on the preceding stage.

In the example illustrated in FIG. 11, for example, when A / D conversion is performed in the A / D conversion circuit 31 a, the signal before the first image signal in the detection area is generated and the signal in the undetected area An example of offsetting by one gradation so that it can be distinguished by the gradation of the signal is shown.
When the gradation range of the analog signal Sai before A / D conversion shown on the left side in FIG. 11 is 0 to 4095, the gradation range of the digital signal Saai after A / D conversion is 1 to 4095. In this way, it may be offset by one gradation.
More specifically, an analog signal Qai of gradation Qi before A / D conversion (Qi = 0 to 4095) is converted to a digital signal Saai of gradation Qi ′ (Qi ′ = Qi + 1) after A / D conversion. It may be offset by one gradation. However, only in the case of the maximum gradation, Qi ′ = Qi.
However, when raster conversion is performed, the raster conversion is performed in consideration of the addition of one gradation to the detection signal (first image signal or first pixel signal) before the raster conversion. There is a need to do.

Note that the above-described embodiment may be modified. For example, different embodiments may be configured in the simple mode and the standard mode. Further, the operation in the simple mode and the standard mode may be modified. For example, in the simple mode described above, the detection value may be calculated only.
Further, as an operation in the above-described standard mode, when adjustment (control) is performed in the priority order of the digital amplifier 34a, the APD 23a, and the laser light source so that the calculated detection value matches the reference detection value, the digital amplifier 34a performs once. The higher the priority order, the larger the gain adjustment amount, the gain adjustment amount per time by the APD 23a, and the light amount adjustment amount per time by the laser light source may be increased.
In addition, the user may be able to specify the priority order when adjusting (controlling) the calculated detection value to match the reference detection value from the digital amplifier 34a, the APD 23a, and the laser light source, or the digital amplifier 34a, It is not limited to using three APDs 23a and laser light sources, but it may be possible to select one or two.

DESCRIPTION OF SYMBOLS 1 ... Scanning endoscope apparatus, 2 ... Subject, 3 ... Scanning endoscope, 4 ... Main body apparatus, 5 ... Monitor, 6 ... Input part, 11 ... Insertion part, 12 ... Optical fiber for illumination, 13 ... Scanning unit, 15 ... scanning unit, 16 ... memory, 16a ... LUT, 21 ... light source unit, 22 ... driving unit, 23 ... detection unit, 23a ... APD, 24 ... signal processing unit, 25 ... controller, 31 ... first Image generation unit, 31a ... A / D conversion circuit, 31c ... coordinate application circuit, 32 ... raster conversion unit, 32a ... interpolation circuit, 32b ... memory, 32c ... offset processing circuit, 33 ... detection unit, 33a ... detection value calculation Circuit 34... Image processor 34 a Digital amplifier 35 Memory 35 a LUT

Claims (9)

A light source unit that generates illumination light;
A light guide that guides the illumination light incident on the first end to the second end;
A scanning unit that vibrates the second end of the light guide unit so as to draw a spiral trajectory;
A detection unit that detects reflected light according to illumination light applied to the subject from the second end;
A detection signal corresponding to the subject image detected by the detection unit is converted to generate an image signal corresponding to a generated image represented by an orthogonal coordinate system, and an image signal of a specified region specified in the image signal A signal processing unit that calculates an intensity statistic and calculates a detection value representing the brightness of the specified region as the statistic;
A scanning endoscope apparatus comprising: The image signal intensity is expressed in gradation.
2. The scanning type according to claim 1, wherein a value corresponding to one gradation of the image signal intensity is given to a pixel included in the generated image where the detection signal is not obtained. Endoscopic device. The detection signal intensity of the detection signal is expressed in gradation.
3. The scanning type according to claim 2, wherein the image signal intensity, which is included in the generated image and from which the detection signal is obtained, is shifted by one gradation from the detection signal intensity. 4. Endoscopic device. The detection signal intensity of the detection signal is expressed in gradation.
The detected intensity signal is expressed without using one gradation of the gradation expression,
The scanning endoscope according to claim 2, wherein a value corresponding to the one gradation that is not used is assigned to a pixel in which the detection signal is not obtained, which is included in the generated image. apparatus.   The scanning endoscope apparatus according to claim 1, wherein the statistic is an average value of the image signal intensity of the designated region.   A control unit that controls at least one of an amplification factor of a digital amplifier provided in the signal processing unit, an amplification factor of the detection unit, and an irradiation light intensity of the light source unit so that the detection value becomes a reference detection value; The scanning endoscope apparatus according to claim 1, comprising:   Sequential control by a predetermined amount in order of priority of the amplification factor of the digital amplifier provided in the signal processing unit, the amplification factor of the detection unit, and the irradiation light intensity of the light source unit so that the detection value becomes a reference detection value The scanning endoscope apparatus according to claim 1, further comprising a control unit that performs the operation.   When calculating the detection value representing the brightness of the designated area, the signal processing unit excludes an undetected area where the detection signal included in the designated area is not detected, and detects the detection signal by the detection section. 2. The scanning endoscope apparatus according to claim 1, wherein a detection value corresponding to a net detection area in which is detected is calculated as the detection value representing brightness of the designated area. Sequential control by a predetermined amount in order of priority of the amplification factor of the digital amplifier provided in the signal processing unit, the amplification factor of the detection unit, and the irradiation light intensity of the light source unit so that the detection value becomes a reference detection value The scanning endoscope apparatus according to claim 8, further comprising a control unit that performs the control.

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