JP6738465B2 - Endoscope system - Google Patents

Description

The present invention relates to an endoscope system, and more particularly to an endoscope system that measures a subject using laser light.

In the field of measuring devices such as endoscopes, the distance to a subject is measured using laser light and the shape information of the subject is calculated. For example, in Patent Document 1, laser light is irradiated as spot-shaped measurement light onto an object to be observed, the point where the spot light is located on the object to be observed is measured, and this measurement result is measured in advance. There is described a measuring endoscope apparatus that calculates two-dimensional information or three-dimensional information of an object to be observed by comparing the reference value with the reference value.

Patent Document 2 describes an endoscope system that performs stereo measurement using a grid-shaped mask pattern. In this technique, a mask means as a projection means for irradiating a lattice pattern with a laser is provided at the tip of a laser guide for guiding the laser light, and the lattice pattern is irradiated with the laser on a measurement target. Then, this lattice pattern is used for matching left and right images to perform stereo measurement.

Furthermore, Patent Document 3 describes an endoscope apparatus that measures a test object using a striped image in which a light-dark pattern is projected on the test object.

Japanese Patent No. 3853954 Japanese Patent No. 4358494 JP2012-239834A

In order to calculate the shape information of the observed object with the technique described in Patent Document 1, it is necessary to accurately know the size of the spot light on the observed object. However, if the distance to the observed object changes, or if the surface condition of the observed object or the exposure condition of the imaging system changes, the spot light size will be observed differently. It was difficult to make accurate measurements regardless of

Further, in the technique described in Patent Document 2, since the collimator lens does not exist between the mask and the laser guide, the mask pattern is projected by the laser light that has transmitted through the mask and diverged. Therefore, as the distance to the subject increases, the mask pattern is projected darker, and the luminance of the mask pattern greatly changes depending on the distance, making it difficult to perform accurate measurement regardless of the distance. .. Further, in the technique described in Patent Document 3, since the mask pattern is projected by the lens, the mask forms an image only within the depth of field of the lens. To increase the depth of field, it is necessary to increase the F value of the lens, which requires an illumination light source with high brightness.

As described above, according to the conventional technique, it is difficult to perform accurate measurement regardless of the distance to the subject and the exposure conditions.

The present invention has been made in view of such circumstances, and provides a measuring device, an endoscope system, and a measuring method capable of performing accurate measurement even if the distance to the subject or the exposure condition changes. The purpose is to

In order to achieve the above-mentioned object, the measuring device according to the first aspect of the present invention includes a laser light source that emits laser light, a collimator that emits the emitted laser light into parallel light flux, and the collimator emits the light. A diffraction grating that generates a plurality of spot lights from the light flux, an imaging unit that acquires images of a plurality of diffraction spots formed on the subject by the plurality of spot lights via an image sensor, and an image based on the acquired images. The measuring unit includes a measuring unit that measures the intervals between the plurality of diffraction spots on the image plane of the element, and a calculator that calculates the distance to the subject based on the measured intervals between the diffraction spots.

According to the first aspect, since a plurality of spot lights are formed by the diffraction grating from the parallel light flux emitted from the collimator, the size of the spot light does not change depending on the distance to the subject. Further, since the distance between the plurality of diffraction spots is measured, even if the size of the spot light changes due to the change in the exposure condition, the measurement accuracy can be maintained by measuring the distance between the diffraction spots. As described above, the measurement apparatus according to the first aspect can perform accurate measurement even if the distance to the subject or the exposure condition changes.

A measuring device according to a second aspect is the measuring device according to the first aspect, in which the calculating unit calculates the distance to the subject based on the relationship between the distances to the subject that are stored in advance between the plurality of diffraction spots on the imaging plane. Calculate the distance. The second aspect defines one aspect of a method of calculating the distance to the subject from the intervals of the plurality of diffraction spots.

In the measuring device according to the third aspect, in the second aspect, the relationship stored in advance differs depending on the image heights of the plurality of diffraction spots on the image plane. When acquiring images of a plurality of diffraction spots, the distance between the diffraction spots changes depending on the image height (distance from the center of the image pickup surface) of the diffraction spots on the image forming surface depending on the angle of view of the image pickup lens. In the aspect, accurate measurement can be performed even in such a case.

In the third aspect of the measurement apparatus according to the fourth aspect, in the relationship stored in advance, the higher the image height of the plurality of diffraction spots is, the higher the image height of the plurality of diffraction spots corresponding to the same interval of the plurality of diffraction spots on the imaging plane is. The distance to the sample is long. The fourth aspect is one of how the relationship between the distance between the diffraction spots on the image plane (corresponding to the number of pixels of the image sensor) and the distance to the subject differs depending on the image height of the diffraction spot. It defines an aspect.

The measuring device according to a fifth aspect is the measuring device according to any one of the first to fourth aspects, wherein the diffraction grating is a diffraction grating that generates a plurality of spot lights having a cycle in a two-dimensional direction as a plurality of spot lights. is there. According to the fifth aspect, since a plurality of spot lights having a cycle in a two-dimensional direction are generated, it is not necessary to change the direction of the spot light in order to perform measurement in different directions, and the measurement can be performed quickly and easily. It can be performed. In the fifth aspect, a single diffraction grating may be used to generate a plurality of spot lights having a cycle in the two-dimensional direction, or a plurality of diffraction gratings may be combined.

The measuring device according to a sixth aspect is the measuring device according to any one of the first to fifth aspects, wherein the imaging element is provided on a plurality of pixels including a plurality of light-receiving elements that are two-dimensionally arranged, and arranged on the plurality of pixels. A color image sensor having a plurality of filter colors, and the measuring unit is an image of a pixel in which a color filter having a filter color having the highest sensitivity to the wavelength of laser light among the plurality of filter colors is arranged. The spacing of the diffraction spots is measured based on the image produced by the signal. According to the sixth aspect, among the plurality of filter colors of the color filter, a plurality of color filters based on the image generated by the image signal of the pixel in which the color filter of the filter color having the highest sensitivity to the wavelength of the laser light is disposed. Since the distance between the diffraction spots is measured, an image in which the diffraction spots are clear can be obtained, which enables accurate measurement.

In the measuring apparatus according to the seventh aspect, in any one of the first to sixth aspects, the calculating unit calculates the two-dimensional information or the three-dimensional information of the subject based on the calculated distance to the subject. .. According to the seventh aspect, it is possible to accurately calculate information such as the two-dimensional or three-dimensional shape or size of the subject based on the accurate measurement result.

An eighth aspect of the measurement apparatus according to any one of the first to seventh aspects is an optical fiber that guides laser light from a laser light source to a collimator and that propagates laser light in a single transverse mode. Prepare According to the eighth aspect, since the optical fiber propagates the laser light in the single transverse mode, it is possible to form a sharp diffraction spot having a small diameter, which enables accurate measurement.

A measuring device according to a ninth aspect is the measuring device according to any one of the first to eighth aspects, wherein the collimator is a graded index type lens whose refractive index is highest in the optical axis and decreases toward the outer side in the radial direction. According to the ninth aspect, since the collimator is a graded index lens, the module that emits the laser light can be made smaller (smaller in diameter).

In order to achieve the above-mentioned object, an endoscope system according to a tenth aspect of the present invention includes the measuring device according to any one of the first to ninth aspects. Since the endoscope system according to the tenth aspect includes the measuring device according to any one of the first to ninth aspects, accurate measurement is performed even if the distance to the subject or the exposure condition changes. be able to.

In the tenth aspect, the endoscope system according to the eleventh aspect is an insertion section that is inserted into the subject, and includes a distal rigid portion and a bending portion connected to a proximal end side of the distal rigid portion, An insertion section having a flexible section connected to the base end side of the bending section, and an operation section having an operation section connected to the base end side of the insertion section, including a diffraction grating and a plurality of diffraction spots An image pickup lens for forming an optical image on the image pickup element is provided on the tip end side end surface of the tip end hard portion. The eleventh aspect defines one aspect of the configuration of the distal end hard portion of the endoscope.

The endoscope system according to the twelfth aspect is the endoscope system according to the eleventh aspect, wherein a module including a joined body of the diffraction grating and the collimator is provided in the distal end hard portion. The twelfth aspect defines one aspect of the arrangement of the module including the joined body of the diffraction grating and the collimator.

In the endoscope system according to a thirteenth aspect, in the twelfth aspect, a conduit communicating with a forceps port opened at the distal end hard portion is provided in the insertion portion, and the module is inserted into the conduit so that the module can be inserted and removed. .. According to the thirteenth aspect, since the module can be inserted using the conduit communicating with the forceps port, the device can be downsized.

An endoscope system according to a fourteenth aspect, according to any one of the tenth to thirteenth aspects, has an illumination light source that emits illumination light, and a control unit that controls the illuminance of the illumination light. In the measurement mode in which the imaging unit acquires images of a plurality of diffraction spots, the unit lowers the illuminance of the illumination light as compared with the normal observation mode in which the subject is irradiated with the illumination light and the subject is observed. If the illuminance of the illumination light at the time of imaging the diffraction spot is too high, the diffraction spot may become unclear in the obtained image and affect the measurement accuracy. However, in the thirteenth aspect, the control unit controls In the measurement mode in which multiple diffraction spots are imaged, the illuminance of the illumination light is lower than in the normal observation mode in which the illumination light is irradiated onto the subject to observe the subject, so an image with clear diffraction spots can be captured. Therefore, accurate measurement can be performed. In the thirteenth aspect, how much the illuminance of the illumination light is reduced when imaging the diffraction spot may be set according to the type, size, brightness, etc. of the subject, and the illumination light is turned off as necessary. You may.

In order to achieve the above-mentioned object, a measuring method according to a fifteenth aspect of the present invention is such that a laser light source that emits laser light, a collimator that emits the emitted laser light into parallel light flux, and the collimator emits the light. A diffraction grating that generates a plurality of spot lights from a light beam, and a measurement method using a measuring device, an imaging step of acquiring images of a plurality of diffraction spots formed on a subject by the plurality of spot lights, A measurement step of measuring the intervals of the plurality of diffraction spots based on the acquired image, and a calculation step of calculating the distance to the subject based on the measured intervals of the plurality of diffraction spots are provided. According to the fifteenth aspect, similar to the first aspect, accurate measurement can be performed even if the distance to the subject or the exposure condition changes.

As described above, according to the measuring device, the endoscope system, and the measuring method of the present invention, accurate measurement can be performed even if the distance to the subject or the exposure condition changes.

FIG. 1 is a diagram showing an overall configuration of an endoscope system according to a first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the endoscope system according to the first embodiment of the present invention. FIG. 3 is a diagram showing a configuration of a tip side end surface of the tip rigid portion. FIG. 4 is a diagram showing the configuration of the laser module. FIG. 5 is a diagram showing a two-dimensional diffraction grating. FIG. 6 is a sectional view showing the laser light source module. FIG. 7 is a diagram showing a state in which the insertion portion of the endoscope is inserted into the subject. FIG. 8 is a diagram showing a two-dimensional diffraction spot. FIG. 9 is a flowchart showing the flow of measurement processing. FIG. 10 is a diagram showing how a two-dimensional diffraction spot is formed on the subject. FIG. 11 is a diagram showing the relationship between the wavelength and the sensitivity of the color filter. FIG. 12 is a diagram showing directions and distances of diffraction spots. FIG. 13 is a diagram showing a one-dimensional diffraction grating according to the second embodiment of the present invention. FIG. 14 is a diagram showing a laser module according to the second embodiment of the present invention. FIG. 15 is a diagram showing a one-dimensional diffraction spot according to the second embodiment of the present invention. FIG. 16 is a diagram showing a state in which a one-dimensional diffraction spot is formed on a subject according to the second embodiment of the present invention. FIG. 17 is a diagram showing a laser module according to the third embodiment of the present invention. FIG. 18 is a diagram showing a diffraction grating according to the third embodiment of the present invention. FIG. 19 is another diagram showing a diffraction grating according to the third embodiment of the present invention. FIG. 20 is a diagram showing a laser module according to the fourth embodiment of the present invention.

Hereinafter, embodiments of a measuring apparatus, an endoscope system, and a measuring method according to the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is an external view showing an endoscope system 10 (measuring device, endoscope system) according to the first embodiment, and FIG. 2 is a block diagram showing a main configuration of the endoscope system 10. .. As shown in FIGS. 1 and 2, the endoscope system 10 includes an endoscope device 100 including an endoscope body 110 (endoscope), an endoscope processor 200, a light source device 300, and a monitor 400. Contains.

<Structure of the endoscope body>
The endoscope main body 110 includes a hand-side operation unit 102 and an insertion unit 104 that is connected to the hand-side operation unit 102. The operator grasps and operates the hand operation unit 102, inserts the insertion unit 104 into the body of the subject, and observes. The insertion portion 104 is composed of a flexible portion 112, a bending portion 114, and a distal end hard portion 116 in order from the hand operation portion 102 side. An imaging optical system 130 (imaging unit), an illuminating unit 123, a forceps opening 126, a laser module 500, and the like are provided in the distal end hard section 116 (see FIGS. 1 to 3A and 4).

At the time of observation or treatment, either or both of visible light and infrared light can be emitted from the illumination lenses 123A and 123B of the illumination unit 123 by operating the operation unit 208 (see FIG. 2). Further, by operating the operation unit 208, cleaning water is discharged from a water supply nozzle (not shown), and the imaging lens 132 of the imaging optical system 130 and the illumination lenses 123A and 123B can be cleaned. A conduit (not shown) communicates with the forceps opening 126 opened at the distal end hard portion 116, and a treatment tool (not shown) for tumor resection or excision is inserted through the conduit and is advanced/retracted as appropriate. The necessary measures can be taken.

As shown in FIGS. 1 to 3A, an image pickup lens 132 is provided on the front end side end surface 116</b>A of the front end hard portion 116, and a CMOS (Complementary MOS) type image pickup device is provided inside the image pickup lens 132. A color image sensor (134), a drive circuit 136, and an AFE (Analog Front End) 138 are arranged to output an image signal. The image pickup device 134 is a color image pickup device, and is arranged in a matrix (two-dimensional) in a predetermined pattern arrangement (Bayer arrangement, G stripe R/G perfect checkerboard, X-Trans (registered trademark) arrangement, honeycomb arrangement, etc.). A plurality of pixels configured by a plurality of light receiving elements, each pixel including a microlens, red (R), green (G), or blue (B) color filter and a photoelectric conversion unit (photodiode, etc.) I'm out. The image pickup optical system 130 can generate a color image from pixel signals of three colors of red, green, and blue, or generate an image from pixel signals of any one color of red, green, and blue. You can also

In the present embodiment, the case where the image pickup device 134 is a CMOS type image pickup device will be described, but the image pickup device 134 may be a CCD (Charge Coupled Device) type.

An image of the subject or an optical image of a diffraction spot (described later) is formed on the light receiving surface (image forming surface) of the image pickup element 134 by the image pickup lens 132, converted into an electric signal, and viewed through a signal cable (not shown). It is output to the mirror processor 200 and converted into a video signal. As a result, the observation image and the captured image of the diffraction spot (see FIG. 10) are displayed on the monitor 400 connected to the endoscope processor 200.

Further, on the tip side end surface 116A of the tip rigid portion 116, illumination lenses 123A (for visible light) and 123B (for infrared light) of the illumination portion 123 are provided adjacent to the imaging lens 132. An exit end of a light guide 170, which will be described later, is disposed inside the illumination lenses 123A and 123B, and the light guide 170 is inserted into the insertion portion 104, the hand operation portion 102, and the universal cable 106, and the light guide 170 The incident end is arranged in the light guide connector 108.

A laser head 506 of the laser module 500 is further provided on the front end side end surface 116A, and a plurality of spot lights are emitted via the diffraction grating 512. The configuration of the laser module 500 will be described later. In the present embodiment, the case where the laser head 506 is provided separately from the forceps port 126 as shown in FIG. 3A has been described. However, in the measuring device and the endoscope system according to the present invention, As shown in FIG. 3( b ), the laser head 506 may be removably inserted into a conduit (not shown) communicating with the forceps opening 126 opened at the distal end hard portion 116. In this case, it is not necessary to provide a dedicated conduit for the laser head 506, and the conduit communicating with the forceps port 126 can be shared with other treatment tools.

<Laser module configuration>
As shown in FIGS. 2 and 4, the laser module 500 includes a laser light source module 502 (laser light source), an optical fiber 504, and a laser head 506 (module). The optical fiber 504 is inserted into a ferrule 508, adhered with an adhesive, and the end face is polished. A GRIN (Graded Index) lens 510 (collimator) is attached to the tip side of the ferrule 508, and a diffraction grating 512 is attached to the tip side of the GRIN lens 510 to form a bonded body. The ferrule 508 is a member for holding and connecting the optical fiber 504, and a hole for inserting the optical fiber 504 is formed in the center portion in the axial direction (left and right direction in FIG. 4). The ferrule 508, the GRIN lens 510, and the diffraction grating 512 are housed in a housing 509, which constitutes a laser head 506.

The laser module 500 configured as described above is attached to the insertion portion 104. Specifically, as shown in FIG. 2, the laser light source module 502 is provided in the hand operation unit 102 portion, the laser head 506 is provided in the distal end hard portion 116, and the optical fiber 504 emits laser light from the laser light source module 502. The light is guided to the head 506. The laser light source module 502 may be provided in the light source device 300, and the laser light may be guided to the distal end hard portion 116 by the optical fiber 504.

The laser light source module 502 includes a VLD (Visible Laser Diode) that is supplied with power from a power source (not shown) and emits laser light in the visible wavelength range, and a condenser lens 503 that condenses the laser light emitted from the VLD. It is a pigtail type module (TOSA; Transmitter Optical Sub Assembly) provided (see FIG. 6). The laser light can be emitted as necessary under the control of the CPU 210. The laser light is emitted only when performing distance measurement by irradiation of the spot light and acquisition of two-dimensional and three-dimensional information of the subject. It can be used like an ordinary endoscope.

In the present embodiment, the laser light emitted from the VLD can be red laser light having a wavelength of 670 nm generated by a semiconductor laser. However, the wavelength of the laser beam in the present invention is not limited to this mode. The laser light condensed by the condenser lens 503 is guided to the GRIN lens 510 by the optical fiber 504. The optical fiber 504 is an optical fiber that propagates laser light in a single transverse mode, and can form a sharp diffraction spot (see FIGS. 8 and 10) having a small diameter, so that accurate measurement can be performed. A relay connector may be provided in the middle of the optical fiber 504.

The GRIN lens 510 is a cylindrical graded index lens (radial type) whose refractive index is highest along the optical axis and decreases toward the outer side in the radial direction, and parallels the laser light guided by the optical fiber 504 and incident. It functions as a collimator that emits a light beam. The spread of the light flux emitted from the GRIN lens 510 can be adjusted by adjusting the length of the GRIN lens 510, and in order to emit the laser light of the parallel light flux, (λ/4) pitch (λ is the wavelength of the laser light) It should be about.

A diffraction grating 512 is mounted on the tip side of the GRIN lens 510. In the diffraction grating 512, as shown in FIG. 5A as a front view and FIG. 5B as a side view, the projections 512A are formed with a period P1 in the two-dimensional direction, which results in the two-dimensional direction. A plurality of spot lights having a period is generated (see FIGS. 8 and 10) and is irradiated in the left direction of FIG. The irradiation direction of the spot light is determined depending on the wavelength λ of the laser light and the period P1 of the protrusion 512A. In the present embodiment, five protrusions 512A are formed in the horizontal/vertical direction, and a total of 25 protrusions are formed at a square lattice point. Five diffraction spots are also formed in the horizontal/vertical direction, five in total, and a total of 25 diffraction gratings are formed in the square lattice. The case of forming dots (see FIGS. 8 and 10) will be described, but the number and arrangement of the projections formed on the diffraction grating in the present invention are not limited to such an aspect. The number and arrangement of the protrusions can be determined in consideration of the estimated measurement distance, the size of the subject, the measurement accuracy, and the like. The shape of the protrusion is not limited to the circular shape like the protrusion 512A, and may be another shape such as a rectangle.

<Structure of light source device>
As shown in FIG. 2, the light source device 300 includes a light source 310 (illumination light source) for illumination, a diaphragm 330, a condenser lens 340, a light source control unit 350 (control unit), etc. Light or infrared light) is incident on the light guide 170. The light source 310 includes a visible light source 310A (illumination light source) and an infrared light source 310B (illumination light source), and can emit one or both of visible light and infrared light. The illuminance of the illumination light by the visible light source 310A and the infrared light source 310B is controlled by the light source control unit 350 (control unit), and as will be described later, the illuminance of the illumination light is lowered as necessary when the diffraction spot is imaged. , You can turn off the lighting.

By connecting the light guide connector 108 (see FIG. 1) to the light source device 300, the illumination light emitted from the light source device 300 is transmitted to the illumination lenses 123A and 123B via the light guide 170, and the illumination lens 123A, The observation range is irradiated from 123B.

<Structure of endoscope processor>
Next, the configuration of the endoscope processor 200 will be described with reference to FIG. The endoscope processor 200 inputs the image signal output from the endoscope device 100 via the image input controller 202, performs necessary image processing in the image processing unit 204 (measurement unit, calculation unit), and outputs the video. It is output via the unit 206. As a result, the observation image is displayed on the monitor 400. These processes are performed under the control of a CPU (Central Processing Unit) 210 (measurement unit, calculation unit, control unit). In the image processing unit 204, in addition to image processing such as white balance adjustment, switching and superimposition display of images displayed on the monitor 400, electronic zoom processing, display/switching of images according to operation modes, and specific components from image signals ( For example, the luminance signal) is extracted. The image processing unit 204 also measures the distance between diffraction spots, calculates the distance to the subject based on the measured distance, and calculates the two-dimensional information or three-dimensional information of the subject based on the calculated distance ( See below). The memory 212 stores information necessary for the processing performed by the CPU 210 and the image processing unit 204, for example, the distance between a plurality of diffraction spots on the imaging surface of the image sensor 134 and the distance to the subject (the tip end side end surface 116A of the tip end hard portion 116A. To the subject) is stored in advance.

The endoscope processor 200 also includes an operation unit 208. The operation unit 208 includes an operation mode setting/changeover switch (not shown), a water supply instruction button, and the like, and can operate irradiation of visible light/infrared light.

<Observation with an endoscopic device>
FIG. 7 is a diagram showing a state in which the insertion section 104 of the endoscope apparatus 100 is inserted into the subject, and shows a state in which an observation image is acquired via the imaging optical system 130. In FIG. 7, reference numeral IA indicates an imaging range, and reference numeral tm indicates a tumor (a black and raised portion in FIG. 7).

<Distance to subject and distance between diffraction spots>
FIGS. 8A and 8B are diagrams showing the relationship between the distance to the subject and the diffraction spot. FIG. 8A shows a diffraction spot DS1 (distance D1) when the distance to the subject is long, and FIG. 8B shows diffraction when the distance to the subject is shorter than that in FIG. 8A. A spot DS1 (interval D2 (<D1)) is shown. Since the spot light emitted from the laser head 506 is emitted at a constant angle, the distance between the diffraction spots DS1 changes according to the distance from the end face of the laser head 506. Therefore, the distance can be measured and the distance can be calculated based on the distance.

In this embodiment, since the spot light is generated by the diffraction grating (diffraction grating 512) from the parallel light emitted from the collimator (GRIN lens 510), the spot light corresponding to one protrusion of the diffraction grating is constant due to the principle of light diffraction. Is emitted at an angle of, and the spread of light is small. Therefore, the size of the diffraction spot DS1 hardly changes even if the distance to the subject changes, and the brightness of the diffraction spot DS1 hardly changes even if the distance to the subject changes. Since the distance between the diffraction spots DS1 is measured, even if the size of the diffraction spots DS1 changes due to the change in the exposure conditions, the measurement accuracy can be maintained by measuring the distance between the diffraction spots DS1. .. As described above, in the endoscope system 10 according to the first embodiment, accurate measurement can be performed even if the distance to the subject or the exposure condition changes.

<Flow of measurement processing>
Next, the measurement processing of the subject by the endoscope system 10 will be described. FIG. 9 is a flowchart showing the flow of measurement processing.

<Diffraction spot imaging>
First, as shown in FIG. 7, the insertion portion 104 is inserted into the subject, and the laser module 500 irradiates the subject (the portion of the tumor tm) with a plurality of spot lights, so that as shown in FIG. Form DS1. Then, the image of the diffraction spot DS1 is acquired by the image pickup optical system 130 (image pickup unit) (step S100; image pickup step). At the time of imaging, the bending portion 114 is appropriately bent vertically and horizontally by the operation of the hand operation unit 102 to change the direction of the tip hard portion 116, and the diffraction spot DS1 is formed in the observation target portion (the portion of the tumor tm in FIG. 10). To be done. Note that in the endoscope system 10, the subject is illuminated by the visible light source 310A or the infrared light source 310B, but the illuminance of the illumination light by the visible light source 310A and the infrared light source 310B is controlled by the light source control unit 350 (control unit), and imaging is performed. In the mode (measurement mode) in which the diffraction spot is imaged by the optical system 130, the illuminance of the illumination light is lowered (or the illumination light is turned off) as compared with the mode in which the illumination light is applied to the subject to observe the subject (normal observation mode). You can do it. As a result, the endoscope system 10 according to the present embodiment can capture an image with a clear diffraction spot, and accurate measurement can be performed. It should be noted that how much the illuminance of the illumination light is reduced when imaging the diffraction spot may be set according to the type, size, brightness, etc. of the subject, and the illumination light may be turned off as necessary.

<Diffraction spot spacing measurement>
Next, the image processing unit 204 (measurement unit, calculation unit) measures the distance D3 between the diffraction spots DS1 based on the image acquired in step S100 (step S110; measurement step). The distance D3 between the diffraction spots DS1 corresponds to the number of pixels on the image plane of the image sensor 134. In addition, you may make it measure the space|interval (For example, space|interval near the center of an image plane) in the specific part of several diffraction spot DS1.

In an endoscope system, the imaging angle of an imaging lens is generally wide, and when a diffraction spot is imaged by such an imaging lens, the distance between the diffraction spots in the captured image (corresponding to the number of pixels on the image plane of the image sensor) Changes depending on the image height (distance from the center of the image plane) of the diffraction spot on the image plane of the image sensor. Specifically, if the imaging angle of the imaging lens is wide, the diffraction spot on the imaging surface will increase as the image height increases (that is, as the image sensor approaches the periphery), even if the distance to the subject does not change. The intervals between are narrowed. Therefore, assuming that the relationship between the distance between the diffraction spots on the image plane of the image sensor and the distance to the subject does not depend on the image height of the diffraction spot, the distance between the diffraction spots (the number of pixels ) Is measured shorter than it actually is, and the distance to the subject is calculated shorter than it actually is. As a result, the two-dimensional and three-dimensional information of the subject cannot be calculated accurately. Therefore, in the endoscope system 10 of the present embodiment, as the relationship between the distance between the diffraction spots on the image forming surface of the image sensor 134 and the distance to the subject, a different relationship depending on the image height of the diffraction spots on the image forming surface ( For example, the higher the image height of the diffraction spot, the longer the distance to the subject corresponding to the same interval (the number of pixels) of the diffraction spots is measured in advance and stored in the memory 212.

Various modes such as a table format and a function format can be adopted as the mode of storing the above-mentioned relationship. As a result, the endoscope system 10 according to the present embodiment can accurately measure the intervals of the diffraction spots even if the imaging angle of view of the imaging lens 132 is wide, and as a result, the distance to the subject and the subject It is possible to accurately calculate two-dimensional and three-dimensional information (described later). Note that the relationship stored in the memory 212 varies depending on the shooting angle of view of the imaging lens 132 (for example, the wider the shooting angle of view of the imaging lens 132, the more corresponding to the same interval (the number of pixels) at the same image height). The distance to the subject is long).

The relationship between the distance between the diffraction spots and the distance to the subject is measured and stored in a partial area (for example, the central portion) of the image plane, and the distance between the diffraction spots in such a partial area is calculated. The distance to the subject and the two-dimensional and three-dimensional information of the subject may be calculated based on the measurement.

The measurement of the spacing between the diffraction spots in step S110 is performed by the image generated by the pixel signal of the pixel provided with the color filter of the red (R) color. Here, the relationship between the wavelength and the sensitivity in the color filters of each color (red, green, blue) arranged in each pixel of the image pickup device 134 is as shown in FIG. 11, and is emitted from the laser light source module 502. The laser light is red laser light having a wavelength of 670 nm. That is, the measurement of the spacing of the diffraction spots is performed on the image generated by the image signal of the pixel in which the red color filter having the highest sensitivity to the wavelength of the laser light among the (red, green, blue) color filters is arranged. It is done based on. As a result, the endoscope system 10 according to the present embodiment can acquire an image with a clear diffraction spot, and accurate measurement can be performed.

<Calculation of distance to subject>
When the distance between the diffraction spots is measured in step S110, the direction and distance to the subject are calculated based on the measurement result (step S120; calculation step). This processing is performed based on the relationship between the distance to the subject and the distance between the diffraction spots (the number of pixels) on the imaging surface of the image sensor 134, which is measured in advance and stored in the memory 212. In step S120, specifically, as shown in FIG. 12, the direction (α, β) and the distance (r) of the diffraction spot DS1 to be measured are calculated. In FIG. 12, the center of the image plane of the image sensor 134 may be the origin O of the coordinate system, the Z axis may be orthogonal to the image plane, and the X and Y axes may be orthogonal to each other in the image plane. it can.

<Two-dimensional information and three-dimensional information of subject>
When the direction and distance to the subject (diffraction spot DS1 to be measured) are calculated in step S120, two-dimensional information or three-dimensional information of the subject is calculated based on the calculated direction and distance (step S130; measurement). Process). The two-dimensional information and the three-dimensional information of the object include the shape of the object (or its measurement target portion) in the two-dimensional space (XY plane in FIG. 12) or in the three-dimensional space (XYZ space in FIG. 12). The size, area, etc. can be calculated. The conversion from (α, β, r) to (X, Y, Z) can be performed by the following equations (1) to (3), and (X, Y, Z) at each point of the subject. The shape, size, area, etc. can be calculated from the coordinates.

X=r×cos α×cos β (1)
Y=r×cos α×sin β (2)
Z=r×sin α (3)
Thereby, for example, when the user of the endoscope system 10 designates a desired region (for example, the tumor tm of FIG. 10) on the monitor 400 by operating the operation unit 208 or the like, the size of the designated region is calculated. It can be displayed on the monitor.

As described above, in the endoscope system 10 according to the first embodiment, the distance to the subject and the two-dimensional and three-dimensional information of the subject are accurately calculated regardless of the distance to the subject and the exposure condition. , Can be measured.

<Second Embodiment>
Next, a second embodiment of the present invention will be described. In the above-described first embodiment, the plurality of spot lights are generated by using the diffraction grating 512 in which the protrusion 512A is formed in a two-dimensional shape, but in the second embodiment, a plurality of spot lights are generated by using the one-dimensional diffraction grating. Generate spot light. The configuration of the second embodiment is the same as that of the first embodiment except for the diffraction grating, and thus detailed description thereof will be omitted.

FIG. 13A is a front view showing the diffraction grating 514 according to the second embodiment, and FIG. 13B is a side view of the diffraction grating 514. As shown in FIGS. 13A and 13B, a one-dimensional (linear) projection 514A is formed on the diffraction grating 514 at a period P2, and a plurality of spot lights are generated by these projections 514A. It In the second embodiment, a laser head 515 is configured to include such a diffraction grating 514, and a laser module 520 is configured to include this laser head 515 (see FIG. 14).

Here, the relationship between the interval between the protrusions 514A and the spread of the spot light will be illustrated. When the wavelength λ of the laser light is 670 nm and the period P2 of the protrusions 514A is 2 μm (500 in 1 mm) as in the first embodiment, the irradiation direction of the spot light is θ on the surface on which the protrusions 514A are formed. The angle from the vertical direction is represented by θ=sin ⁻¹ (λ/P2), which is about 19.6 (deg).

15A and 15B are diagrams showing a plurality of diffraction spots DS2 formed in the one-dimensional direction (linear direction) by the diffraction grating 514. FIG. 15A shows a state in which the distance to the subject is long, and the distance between the diffraction spots DS2 is wide. On the other hand, FIG. 15B shows a state in which the distance to the subject is shorter than that in FIG. 15A, and the distance between the diffraction spots DS2 is narrower than that in FIG. 15A.

FIG. 16 is a diagram showing a state in which the diffraction spot DS2 (the interval is D4) shown in FIGS. 15A and 15B is formed on the subject (the portion of the tumor tm). Based on this diffraction spot DS2, the distance to the subject and the two-dimensional information and three-dimensional information of the subject can be accurately calculated and measured as in the first embodiment. In the second embodiment, as shown in FIG. 16, the diffraction spot DS2 is formed in a one-dimensional shape (straight line shape), but the bending portion 114 is bent vertically and horizontally by the operation of the hand-side operation portion 102, and the tip end is hard. By changing the direction of the portion 116 (diffraction grating 514) so that the diffraction spot DS2 is formed in a direction different from that in FIG. 16 (for example, a direction orthogonal to the direction in FIG. 16), information on such a different direction is obtained. Can be obtained.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. In the above-described first embodiment, a plurality of spot lights are generated using the diffraction grating 512 in which the protrusion 512A is formed in a two-dimensional shape, but in the third embodiment, the same as in the second embodiment. A plurality of spot lights are generated by a laser module using a plurality of one-dimensional diffraction gratings. The configuration of the third embodiment is the same as that of the first embodiment except for the laser module, and detailed description thereof will be omitted.

FIG. 17 is a diagram showing the configuration of the laser module 530 according to the third embodiment. The laser module 530 includes a laser light source module 502 and an optical fiber 504 similar to those in the first embodiment, and includes a ferrule 508 and a GRIN lens 510 as in the first embodiment. In the second embodiment, diffraction gratings 516 and 518 are used instead of the diffraction grating 512 (see FIGS. 4 and 5) according to the first embodiment.

18A and 18B are a front view and a side view, respectively, of the diffraction grating 516 mounted on the tip side of the laser head 532, and FIGS. 19A and 19B are the base end side of the laser head 532. FIG. 3 is a front view and a side view of a diffraction grating 518 mounted on the device. A plurality of one-dimensional projections 516A and 518A are formed on the diffraction gratings 516 and 518, respectively. In the laser head 532, the diffraction gratings 516 and 518 are arranged so that the directions of these projections 516A and 518A are orthogonal to each other. .. The ferrule 508, the GRIN lens 510, and the diffraction gratings 516 and 518 are housed in the housing 509 to form a laser head 532 (FIG. 17).

Under the above configuration, also in the third embodiment, the distance to the subject and the two-dimensional information and three-dimensional information of the subject can be accurately calculated and measured in the same manner as in the first and second embodiments. it can.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described. In the first to third embodiments described above, the ferrule, the GRIN lens, and the diffraction grating were housed in the housing, but in the fourth embodiment, the ferrule 508 and GRIN are used without using the housing as shown in FIG. The lens 510 and the diffraction grating 512 are bonded with a transparent adhesive to form the laser head 542, and the laser module 540 is formed including the laser head 542. In the fourth embodiment, since the housing is not used, the diameter of the laser head 542 can be reduced. Note that, in FIG. 20, members given the same reference numerals as those of the laser module 500 according to the first embodiment have the same configurations as those of the first embodiment.

Also in the fourth embodiment having the above-described configuration, the distance to the subject and the two-dimensional information and the three-dimensional information of the subject can be accurately calculated and measured in the same manner as in the first to third embodiments. it can.

<Modification>
In the above-described first to fourth embodiments, the case where the interval measurement of the diffraction spots is performed based on the image generated by the image signal of the pixel provided with the red color filter has been described. In, the measurement of the diffraction spot interval may be performed by an image generated by an image signal of a pixel provided with a color filter of any one color of (red, green, blue), or (red , Green, blue) may be used for the color image generated by the image signals of all three colors.

Moreover, although the case where the red laser beam is used has been described in the above-described first to fourth embodiments, the wavelength of the laser beam is limited to red in the measuring device, the endoscope system, and the measuring method of the present invention. However, it is possible to use a laser beam having a different wavelength depending on the type of the subject and the purpose of measurement.

The measuring device, the endoscope system, and the measuring method of the present invention can be applied to the case of measuring a non-living subject such as a pipe, in addition to measuring the living subject. Further, the measuring device, the endoscope system, and the measuring method of the present invention can be applied not only to the endoscope but also to the case of measuring the size and shape of industrial parts and products.

Although the examples of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

10... Endoscope system, 100... Endoscope device, 102... Hand operation part, 116... Tip hard part, 126... Forceps mouth, 130... Imaging optical system, 132... Imaging lens, 134... Imaging element, 200... Inside Scope processor, 300... Light source device, 350... Light source control unit, 500, 520, 530, 540... Laser module, 502... Laser light source module, 504... Optical fiber, 506, 515, 532, 542... Laser head, 508... Ferrule , 509... Housing, 510... GRIN lens, 512, 514, 516, 518... Diffraction grating, 512A, 514A, 516A, 518A... Protrusion, DS1, DS2... Diffraction spot

Claims (11)

A laser light source that emits laser light,
A collimator that emits the emitted laser light into a parallel light flux,
A first-order diffraction grating for generating a plurality of spot lights from the light flux emitted by the collimator, the diffraction grating generating a plurality of spot lights having a constant cycle in a one-dimensional direction as the plurality of spot lights,
An imaging unit that acquires images of a plurality of diffraction spots formed on a subject by the plurality of spot lights via an imaging element,
Based on the acquired image, a measuring unit that measures the intervals of the plurality of diffraction spots on the image plane of the image sensor,
An endoscope system including a measuring device including: a calculating unit that calculates a distance to the subject based on the intervals between the plurality of measured diffraction spots,
An insertion part to be inserted into the subject, a distal end hard part, a bending part connected to the proximal end side of the distal end hard part, and a flexible part connected to the proximal end side of the bending part. An endoscope having an insertion section having and an operation section connected to a proximal end side of the insertion section,
An endoscope system in which the diffraction grating and an imaging lens for forming optical images of the plurality of diffraction spots on the imaging element are provided on a distal end side end surface of the distal end hard portion. The said calculation part calculates the distance to the said test object based on the relationship of the distance to the said test object and the space|interval of the said several diffraction spot in the said imaging surface memorize|stored beforehand. Endoscope system. The endoscope system according to claim 2, wherein the pre-stored relationship differs depending on image heights of the plurality of diffraction spots on the image plane. In the relationship stored in advance, the higher the image height of the plurality of diffraction spots, the longer the distance to the subject corresponding to the same interval of the plurality of diffraction spots on the image plane. The described endoscope system. The image pickup device is a color image pickup device including a plurality of pixels formed of a plurality of light receiving elements arranged two-dimensionally and color filters of a plurality of filter colors arranged on the plurality of pixels,
Of the plurality of filter colors, the measuring unit detects the plurality of diffraction spots based on an image generated by an image signal of a pixel in which a color filter of the filter color having the highest sensitivity to the wavelength of the laser light is disposed. Measure the distance,
The endoscope system according to any one of claims 1 to 4. The endoscope system according to claim 1, wherein the calculator calculates two-dimensional information or three-dimensional information of the subject based on the calculated distance to the subject. The endoscope system according to any one of claims 1 to 6, further comprising an optical fiber that guides the laser light from the laser light source to the collimator, the optical fiber propagating the laser light in a single transverse mode. .. The endoscope system according to any one of claims 1 to 7, wherein the collimator is a graded index lens in which a refractive index is highest in an optical axis and decreases toward an outer side in a radial direction. The endoscope system according to any one of claims 1 to 8, wherein a module including a joined body of the diffraction grating and the collimator is provided in the distal end hard portion. The endoscope system according to claim 9, wherein the insertion portion is provided with a conduit communicating with a forceps opening opened at the distal end hard portion, and the module is inserted into the conduit so that the module can be inserted into and removed from the conduit. An illumination light source that emits illumination light, and a control unit that controls the illuminance of the illumination light,
In the measurement mode in which the control unit acquires the images of the plurality of diffraction spots by the imaging unit, the illuminance of the illumination light is higher than in the normal observation mode in which the illumination light is applied to the subject to observe the subject. The endoscope system according to claim 1, wherein the endoscope system is lowered.

Images