JP2010060332A - Apparatus and method for observing scatterer interior - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for observing the scatterer interior capable of efficiently acquiring back scattering light from arbitrary depth. <P>SOLUTION: The apparatus for observing the scatterer interior for acquiring the data of the heterogeneous part in the scatterer is equipped with an illumination means for irradiating the scatterer with light containing at least wavelengths having different optical characteristics in the scattering medium constituting the scatterer and the heterogeneous part, an imaging element for imaging the scatterer, an imaging optical system for limiting the detection range imaged by the imaging element, a detection means containing a detection range variable mechanism for performing regulation so that a desired region is contained in the detection range and detecting the back scattering light of the light emitted by the illumination means to acquire the light intensity data of the back scattering light, an analyzing/controlling means for analyzing the light intensity data acquired by the detection means and controlling the detection range variable mechanism, and an image processing means for forming a tomographic image at the arbitrary depth in the scatterer from the light intensity data acquired by the detection means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus and method for observing the inside of a scatterer by measuring backscattered light from the scatterer.

  There are various methods for observing the inside of a scatterer such as a living body. One of the observations using light has the advantage that a specific object can be observed by selecting the wavelength of the light to be used. This method irradiates the scatterer with light of a wavelength that is absorbed by a specific target (heterogeneous portion), and measures the intensity of the backscattered light to obtain the position and depth information of the alien portion present inside the scatterer. Obtainable. It is known that the backscattered light is light that has passed deeper in the scatterer as the distance between the irradiation position and the measurement position increases.

Patent Document 1 discloses a biological light observation apparatus having a configuration in which a plurality of light detection means are provided at positions sequentially away from the position of the light irradiation means. Also disclosed is a means for reconstructing a tomographic image of a living body based on a measurement result obtained by the apparatus.
JP 2006-200943

  In the conventional apparatus as described above, since the light irradiation means and the light detection means are integrally formed, the distance between the irradiation position and the detection position is fixed. Therefore, there is a problem that observation cannot be performed at an arbitrary depth. Further, conventionally, unnecessary backscattered light is also detected, and there is a problem that detection data is wasteful.

  In view of the above problems, an object of the present invention is to provide a scatterer internal observation device and method that can efficiently acquire backscattered light from an arbitrary depth.

  According to the present invention, there is provided a scatterer internal observation device that acquires information on a heterogeneous portion inside a scatterer, the light including at least wavelengths having different optical characteristics between the scattering medium constituting the scatterer and the heterogeneous portion. Illumination means for irradiating the scatterer, an image sensor that images the scatterer, an imaging optical system that limits a detection range captured by the image sensor, and adjustment so that a desired region is included in the detection range A detection means including a detection range variable mechanism, detecting back scattered light of the light irradiated by the illuminating means, and obtaining light intensity data of the back scattered light; and analyzing the light intensity data acquired by the detecting means Analysis / control means for controlling the detection range variable mechanism; and image processing means for creating a tomographic image at an arbitrary depth inside the scatterer from the light intensity data acquired by the detection means. Scattering medium observation device, characterized in that, as well, scattering medium observation method using the apparatus are provided.

  According to the present invention, it is possible to easily and efficiently acquire information at an arbitrary depth by detecting the backscattered light as a two-dimensional image and adjusting the range in which the backscattered light is detected.

  Hereinafter, the scatterer internal observation device of the present invention and the observation method using the device will be described. In the present invention, the scatterer refers to an object mainly composed of a scattering medium, and includes a living body as an example. The scattering medium indicates at least the property of scattering light, and scattering is more dominant than absorption.

  The scatterer internal observation apparatus of the present invention is an apparatus for observing a heterogeneous portion existing in a scattering medium inside the scatterer. In the present invention, the heterogeneous portion is different from the scattering medium in optical characteristics such as transmittance, refractive index, reflectance, scattering coefficient, and absorption coefficient. Examples include, but are not limited to, blood vessels.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given only when necessary.
(First embodiment)
FIG. 1 is a schematic functional block diagram of a scatterer internal observation device 100 according to the first embodiment of the present invention. As shown in the figure, the scatterer internal observation device 100 includes an illumination unit 101, a detection unit 102, an analysis / control unit 103, and an image processing unit 107.

  The illumination unit 101 is a unit that generates light including at least wavelengths having different optical characteristics between the scattering medium and the heterogeneous portion and irradiates the scatterer. As shown in FIG. 1, the scatterer internal observation device 100 according to the present embodiment propagates and is emitted by a light source 101a, a light guide 101b using an optical fiber for guiding generated light, and the optical fiber. An illuminating unit 101 configured by a condensing body 101c that converts a divergent light into a narrow parallel light beam for irradiating a limited area is provided. At this time, the light collector 101c is not limited to making the light beam thin and parallel, but may be condensed to illuminate a narrow range, or a light collector for illuminating a wide range is prepared. Also good. The illumination unit 101 irradiates light toward the scatterer S based on a control signal from the analysis / control unit 103. An area on the surface of the scatterer irradiated with light by the light collector 101c is referred to as an illumination range, and is a range indicated by an arrow 104 in FIG.

  As the light source 101a, a light source that generates light having a wavelength different from that of a scattering medium and a different part is used. At this time, when the optical characteristics of the scattering medium and the extraneous portion are known and the wavelength having the above characteristics can be specified, the light source 101a having a wavelength distribution having a sharp peak at the wavelength is selected. However, the present invention is not limited to this, and a light source having a wide wavelength range may be used as long as it includes a wavelength that can be specified to have different optical characteristics between a scattering medium and a heterogeneous portion. On the other hand, when the optical characteristics of the scattering medium and the extraneous portion are not known, it is preferable to select a light source having a wider wavelength width so as to include wavelengths having different optical characteristics between the scattering medium and the extraneous portion. An optical fiber is preferably used for the light guide body 101b, but the light guide body 101b is not limited to this, and may be configured by a relay lens. A lens is preferably used for the light concentrator 101c, but is not limited thereto, and may be configured by a mirror. Or you may comprise with a prism or a diffraction grating.

  Alternatively, it is not necessary to use laser light or the like with a light beam focused in advance as a light source and use the light collector 101c. Alternatively, the illumination range may be limited by a mask or the like instead of using the light collector 101c.

  The detecting means 102 is a means having sensitivity in a wavelength band including the wavelength of light emitted by the illuminating means 101, detecting backscattered light emitted from the scatterer surface, and acquiring the light intensity data. . The scatterer internal observation device 100 according to the present embodiment has a sensitivity in a wavelength band including the wavelength of light emitted from the light source 101a, and an image sensor 102a that images backscattered light emitted from the surface of the scatterer, An imaging optical system 102b that limits a detection range 105 captured by the imaging device and a detection unit 102 that includes a detection range variable mechanism 102c that adjusts the detection range 105 to include a desired region 106 are provided.

  The desired area 106 means an area on the surface of the scatterer where backscattered light with a desired depth is emitted, and is also referred to as a detection area. The schematic diagram is shown in FIG. FIG. 2 is a view of the surface of the scatterer S as viewed from above. The light emitted from the illumination means 101 irradiates the illumination range 104 on the surface of the scatterer S, and the illuminated light propagates through the scatterer and exits from the scatterer surface. When point illumination is used for the illumination means, the backscattered light generally propagates concentrically. For example, when a tomographic image of a certain depth is to be produced, it is necessary to detect backscattered light at a position separated from the illumination position by a distance corresponding to the depth. Therefore, the area for detecting the backscattered light has a ring shape as shown by the hatched area in FIG.

  Therefore, the detection range variable mechanism 102c provided in the observation apparatus of the present invention adjusts so that the detection range 105 includes the desired region 106 without waste. The detection range varying mechanism 102c may be, for example, an optical system or a zoom lens, but is not limited thereto. By adjusting the detection range by the detection range variable mechanism 102c, detection of unnecessary backscattered light is reduced, and the efficiency of detection and data analysis can be improved.

  In the scatterer internal observation apparatus of the present embodiment, an image sensor such as a CCD that simultaneously detects a plurality of points can be used as the image sensor 102a. For example, a lens or the like can be used for the imaging optical system 102b.

  The analysis / control unit 103 is a unit that analyzes the light intensity data acquired by the detection unit 102 and controls the image sensor 102a and the detection range variable mechanism 102c based on the analysis result. The analysis / control unit 103 is preferably a control device such as a computer in which appropriate software for analysis is installed in advance. In FIG. 1, the analysis / control unit 103 is configured to control both the image sensor 102a and the detection range variable mechanism 102c. However, the present invention is not limited to this, and controls the detection range variable mechanism 102c. The second control unit may be configured such that a signal is transmitted from the analysis / control unit 103 to the second control unit, and the second control unit controls the detection range variable mechanism 102c based on the signal.

  The image processing unit 107 is a unit that creates a tomographic image at an arbitrary depth inside the scatterer based on the light intensity data acquired by the detection unit 102.

  The scatterer internal observation device 100 according to the present embodiment can further include a display unit 108 and an input unit 109. The display unit 108 is a means for displaying a two-dimensional image of the light intensity data imaged by the image sensor 102a and a tomographic image created by the image processing unit 107. For example, a monitor can be used. The input unit 109 is a means for inputting commands such as illumination, detection, or display method. For example, a keyboard is used, but the present invention is not limited to this.

  The illumination unit 101, the detection unit 102, the analysis / control unit 103, the image processing unit 107, the display unit 108, and the input unit 109 may be connected to each other by a signal circuit that transmits an electrical signal. In FIG. 1, the display unit 108 is connected to the image processing unit 107, and the input unit 109 is connected to the analysis / control unit 103. However, the present invention is not limited to this, and the connection relationship can be changed as appropriate.

  The operation of the scatterer internal observation device 100 according to the present embodiment will be described.

  First, light is irradiated from the illumination means 101 to the scatterer. This irradiation light is reflected, scattered and absorbed by the scattering medium inside the scatterer S, and becomes backscattered light. The detection means 102 detects this backscattered light as a two-dimensional image, and acquires light intensity data.

  Next, the acquired light intensity data is analyzed to determine a desired region (detection region) 106 on the scatterer surface. As will be described later, the detection area may be determined automatically based on settings stored in the analysis / control unit 103 in advance, or the display unit 108 may display a two-dimensional image of light intensity data, The user may determine the area on the spot. The detection area 106 is determined by the depth to be observed, the accuracy of the tomographic image obtained, and the like.

  When the detection region 106 is determined, a signal based on the result is transmitted from the analysis / control unit 103 to the detection range variable mechanism 102c. The detection range variable mechanism 102c adjusts the detection range 105 based on the signal. As a result, the detection area 106 is adjusted so as to include the detection range 105 without waste.

  Next, backscattered light is detected again within the determined detection range 105, and light intensity data is acquired. The acquired light intensity data is analyzed, and a tomographic image is created in the image processing unit 107. The produced tomographic image is displayed on the display unit 108.

  As described above, according to the scatterer internal observation device of the present invention, it is possible to efficiently acquire data by determining a detection range including a desired detection region and performing detection within that range. . Further, since the amount of data to be analyzed is reduced, the analysis time can be shortened.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 3 is a schematic functional block diagram of the scatterer internal observation 110 according to the second embodiment. The scatterer internal observation device 110 according to the present embodiment further includes a scan mirror 111 in the detection unit 102 in addition to the same configuration as the scatterer internal observation device 100 of the first embodiment.

  The scan mirror 111 moves the detection range 105 on the scatterer surface based on the signal from the analysis / control unit 103. The scatterer internal observation device 110 according to the present embodiment includes the scan mirror 111, so that the detection range 105 can be moved to an arbitrary position within the field of view of the image sensor.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 4 is a schematic functional block diagram of the scatterer internal observation 200 according to the third embodiment. The scatterer internal observation 200 according to the third embodiment has basically the same configuration as the scatterer internal observation device according to the first embodiment, and includes an illumination unit 201, a detection unit 202, an analysis / control unit 203, An image processing unit 207, a display unit 208, and an input unit 209 are provided.

  In addition to the above configuration, the scatterer internal observation device 200 according to the present embodiment includes an illumination scan mirror 212 in the illumination unit, and a detection scan mirror 211 in the detection unit.

  Furthermore, the scatterer internal observation device 200 according to the present embodiment includes a scan control unit 213 for controlling the scan mirrors 211 and 212.

  The scan mirror can arbitrarily move the detection range and the illumination range on the scatterer surface by changing the angle of the mirror. The scatterer internal observation device 200 according to the present embodiment includes the scan mirror, so that the detection range 105 can be moved so that the detection range 105 includes the detection region 106, and the illumination range 104 and the detection range 105 are also included. Can be scanned.

  Since the scatterer internal observation device 200 according to the present embodiment can scan the illumination range 104 and the detection range 105, detection can be performed at a large number of measurement points without moving the observation device main body. Therefore, more light intensity data can be acquired more easily, and a tomographic image can be acquired easily and in a short time.

  The illumination scan mirror 212 and the detection scan mirror 211 are controlled by a scan control unit 213. The scan control unit 213 controls each scan mirror based on the signal from the analysis / control unit 103. The scanning control unit 213 preferably controls both the scan mirrors in conjunction so that the illumination range 104 and the detection range 105 are scanned while maintaining a fixed positional relationship on the scatterer surface. By controlling both scan mirrors in conjunction with each other, detection can be performed under certain conditions during scanning.

  As the scan mirror, a mirror usually used for scanning may be used. For example, a galvano mirror, a polygon mirror, a MEMS mirror, or the like can be used. A scan mirror using two mirrors such as a galvano mirror or a polygon mirror is inexpensive and easy to control. On the other hand, the MEMS mirror is difficult to control, but the configuration can be simplified.

  The operation of the scatterer internal observation device 200 according to the present embodiment will be described.

  First, as described in the first embodiment, a detection area is determined. Based on the result, the analysis / control unit 203 controls the scan mirror 211 and the detection range variable mechanism 202c to adjust the detection range so that the detection region is included.

  When the detection means captures the detection range 105 through the above steps, the backscattered light is detected while scanning while changing the angles of the illumination scan mirror 212 and the detection scan mirror 211. The scanning is performed by moving the illumination range 104 and the detection range 105 by the scan control unit 213 controlling the scan mirrors 211 and 212 in accordance with a signal from the analysis / control unit 203. During scanning, the illumination scan mirror 212 and the detection scan mirror 211 are controlled in conjunction so that the illumination range 104 and the detection range 105 are maintained in a fixed positional relationship on the scatterer surface.

  Next, the image processing unit 207 creates a tomographic image at an arbitrary depth inside the scatterer from the acquired light intensity data.

  According to the scatterer internal observation device 200 according to the present embodiment, a large amount of light intensity data can be acquired more easily by scanning the illumination range and the detection range, and a tomographic image can be obtained easily and in a short time. Obtainable.

  If necessary, the illumination scan mirror 212 and the detection scan mirror 211 may be controlled and scanned independently.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. FIG. 5 is a schematic functional block diagram of the scatterer internal observation device 300 according to the fourth embodiment. As shown in the figure, the scatterer internal observation device 300 includes an illumination unit 301, a detection unit 302, an analysis / control unit 303, an image processing unit 307, a half mirror 314, a scan mirror 311, and a scan control unit 313. Prepare. Optionally, a display unit 308 and an input unit 309 can be provided. The detection means 302 includes an imaging element 302a, an imaging optical system 302b, and a detection range variable mechanism 102c. The illumination unit 301 includes a light source 301a and an optical system 301b.

  The scatterer internal observation device 300 according to the present embodiment has a configuration in which an illumination unit and a detection unit are arranged so that their optical axes are coaxial. The half mirror 314 is provided to make the optical axes of the illumination unit and the detection unit coaxial, and is disposed between the imaging element 302a and the imaging optical system 302b.

  The optical system 301b included in the illumination means is provided between the light source 301a and the half mirror 314, and plays a role of converting the illumination light into a light beam for illuminating the illumination range 104 in combination with the imaging optical system 302b. is there. For example, a lens or the like is used for the optical system 301b.

  The scan mirror 311 is provided for scanning both the illumination range and the detection range, and is disposed between the half mirror 311 and the imaging optical system 302b.

  The scatterer internal observation device 300 according to the present embodiment can scan the illumination range and the detection range with the same scan mirror by having the above configuration. That is, a set of scan mirrors provided in the scatterer internal observation device can be provided.

  As in the third embodiment, it is difficult to control the two sets of scan mirrors in conjunction with each other. In the scatterer internal observation device 300 according to the present embodiment, the illumination range and the detection range can be scanned with one scan mirror, the scan mirror can be easily controlled, and the configuration of the device is simplified. You can also.

  FIG. 6 is a schematic functional block diagram of a scatterer internal observation device 310 according to a modification of the fourth embodiment. This scatterer internal observation device 310 includes a scan mirror 318. In this modification, a MEMS mirror that performs scanning with a single mirror is used. When the MEMS mirror is used, for example, as shown in FIG. 6, the light source 301a, the optical system 301b, the half mirror 314, and the scan mirror 318 are arranged at right angles to the imaging optical system 302b. Although the imaging element 302a is arranged in the perpendicular direction, the present invention is not limited to this, and various arrangements can be taken. In this modification, the configuration of the apparatus can be simplified by using the MEMS mirror.

  The scatterer internal observation device in each of the embodiments described above can further include detection region determination means for determining a desired region. The detection area determination means can be included in the analysis / control means, for example, but is not limited thereto.

  The detection area determination means is means for analyzing the acquired light intensity data and determining a desired area (detection area) 106 on the scatterer surface. The detection area may be automatically determined based on settings stored in advance in the analysis / control unit or the like, or a two-dimensional image of light intensity data is displayed on the display unit, and the user can change the detection area on the spot. The region may be determined.

  Still further, the scatterer internal observation device may include an input unit for inputting a setting for determining a desired region. The input means may be, for example, a keyboard for inputting settings to the analysis / control unit in advance, or a touch panel type operation panel that indicates an area on a two-dimensional image displayed on the display unit. It may be.

  Here, an example of the detection area will be described with reference to FIG.

  FIG. 7 illustrates the relationship between the illumination range 104 and the detection region 105. As shown in FIGS. 7A and 7B, when the illumination is point illumination, the backscattered light propagates concentrically. The detection area is determined based on the depth to be observed. Therefore, when the depth to be observed is determined, the distance between the illumination range 104 and the detection region 106 is determined. At this time, since the backscattered light has a ring shape, the width of the detection region 106 needs to be determined. The width of the detection region 106 can be appropriately determined depending on the desired accuracy of the observation information. Thereby, the detection area 106 is determined.

  Next, it is determined which part of the detection area 106 the detection range 105 includes. As shown in FIG. 7A, there are a method of including a part of the ring-shaped detection region 106 and a method of including the entire ring-shaped detection region 106 as shown in FIG. 7B.

  As shown in FIG. 7 (a), when a part is included, the number of scanning points increases during the detection process, but since the imaging range is small, it is possible to enlarge and take an image with a high number of pixels. be able to. Therefore, there is an advantage that a fine region can be observed and the resolution is high. On the other hand, as shown in FIG. 7B, when setting the whole, the resolution is low, but there is an advantage that the number of scanning points is small and a tomographic image can be produced easily and in a short time.

  Note that illumination other than point illumination as shown in FIGS. 7A and 7B can also be used. FIG. 7C shows an example of line-shaped illumination. Moreover, as shown in FIG.7 (d), several point illumination can also be used. Also in these cases, the detection region can be determined as appropriate. By using line illumination or multi-point illumination, a large amount of data can be detected by one measurement, and the measurement time can be further shortened. The line-shaped illumination light preferably has a uniform light intensity. Alternatively, it is preferable to provide means for performing correction according to the light intensity. Moreover, when using a some point illumination, it is preferable that each illumination is arrange | positioned in the position away so that the detection data obtained by each light may not mutually interfere.

  The engineer can appropriately set the determination of the detection area and which part of the detection area is included in the detection range in view of various conditions.

  The detection area and detection range as described above can be set manually by the user, but can also be determined automatically. Next, an embodiment in which the detection area is automatically determined will be described.

  First, backscattered light is detected to acquire light intensity data. The acquired light intensity data is analyzed by the analysis / control means to produce spatial light intensity distribution data as shown in FIG.

  Next, in the spatial light intensity distribution data image as shown in FIG. 8A, light intensity information and position information are obtained. Then, the maximum intensity point, that is, the X and Y coordinates of the illumination point are determined. When the change of the light intensity on the line passing through the illumination point is plotted following the determination of the illumination point, a graph as shown in FIG. 8B is obtained. For example, when the entire detection area is included in the detection range, the rising point and the convergence point are determined in this graph, and the coordinates thereof are obtained, whereby the range is determined in the spatial light intensity distribution data image shown in FIG. Can be determined. Alternatively, the range can be determined by determining the center point in the graph as shown in FIG. 8B and truncating the bottom of the graph by statistical processing. Alternatively, a coordinate graph may be obtained by preparing a cumulative graph of light intensity based on a graph as shown in FIG. 8B and calculating a rising point and a convergence point from the slope.

  The detection region can be determined by repeating this process while changing the angle of the line passing through the illumination point on the X and Y coordinates. When the detection area is determined, as shown in FIG. 8 (c), unnecessary portions can be eliminated, and the detection range can include only a desired area.

  In the above description, the change in light intensity on the line passing through the illumination point is plotted. However, the present invention is not limited to this. For example, the change may be plotted on a line parallel to the X and Y coordinate axes. In that case, plotting is performed while moving the line little by little in the spatial light intensity distribution data image shown in FIG. When a part of the ring-shaped detection area is set as the detection range, the corresponding part on the graph of FIG. 8B is determined based on the illumination-detection distance and width calculated from the depth and accuracy to be observed. To do.

  According to the above embodiment, a detection area can be set automatically, and observation inside a scatterer can be performed more simply, quickly and efficiently.

  Next, a scatterer internal observation device having a function of removing noise generated from the vicinity of the surface of the scatterer provided according to another aspect of the present invention will be described.

  The scatterer internal observation device in this aspect is for producing a deep processing image from which noise due to the surface of the scatterer and the vicinity of the surface layer is removed. The backscattered light detected by the detection means includes reflected light from the surface of the scatterer. Since there are minute irregularities on the surface of the scatterer, the reflected light scatters and produces strength, which can be noise when creating a tomographic image. The detected backscattered light also includes backscattered light from a relatively shallow depth, and this also becomes noise when a tomographic image is produced by backscattered light from a deep part.

  Therefore, the scatterer internal observation device according to the present aspect can provide a tomographic image from which noise has been removed.

  A tomographic image from which noise has been removed can be produced by any of the following methods (1) to (3).

  (1) A surface tomographic image and a deep tomographic image are created separately, and the surface tomographic image is subtracted from the deep tomographic image. Here, the surface layer tomographic image is a tomographic image prepared from backscattered light from a relatively shallow portion of the scatterer and reflected light from the surface of the scatterer. On the other hand, the deep tomographic image is a tomographic image having a desired depth, and includes backscattered light from the surface layer.

  In this method, as shown in FIG. 9, the distance between the illumination means and the detection means is changed in order to separately produce the surface layer tomographic image and the deep part tomographic image. When producing a surface layer tomographic image, as shown in FIG. Then, a surface layer tomographic image X as shown in FIG. 9B is obtained. Further, when creating a deep tomographic image, detection is performed at the position β as shown in FIG. As a result, a deep tomographic image Y as shown in FIG. 9D is obtained.

  In FIGS. 9A and 9C, the distance between the illumination unit and the detection unit is changed for the sake of explanation. However, the present invention is not limited to this, and the light intensity data acquired by the detection unit is analyzed. Each tomographic image can be easily obtained by making the distance of the point from which data is extracted to create the surface layer image shorter than the distance of the point from which data is extracted to create the deep tomographic image.

  Next, as shown in FIG. 9E, the surface layer tomographic image X is subtracted from the deep tomographic image Y. Thereby, the deep part processed image Z from which the noise of the surface layer was removed can be obtained. Since the surface tomographic image X has a light intensity higher than that of the deep tomographic image Y, the light intensity is adjusted by multiplying the surface layer tomographic image X by a constant n. The constant n may be determined so that the average light intensity of the surface tomographic image X and the deep tomographic image Y is approximately the same.

  The calculation method can be performed, for example, by calculating the light intensity for each pixel on the produced image. Alternatively, it can be performed by calculating the light intensity for each pixel on the image sensor. Moreover, although the average of the light intensity of several pixels may be calculated and it may calculate using the average value, it is not limited to these, An appropriate method can be selected.

  (2) Similar to the method of (1) above, a surface layer tomographic image and a deep tomographic image are prepared separately. In this method, in order to produce each tomographic image, light of different wavelengths is used as illumination. For example, as shown in FIG. 10A, when producing a surface layer tomographic image, a light source 1 that emits light of wavelength λ1 is used. Then, a surface layer tomographic image X as shown in FIG. Further, when producing a deep tomographic image, as shown in FIG. 10C, a light source 2 that emits light having a wavelength λ2 is used. As a result, a deep tomographic image Y as shown in FIG. 10 (d) is obtained. When a surface layer tomographic image is produced, light having a higher scattering, that is, light having a short wavelength is used. On the other hand, when producing a deep tomographic image, light with less scattering is used.

  Next, as shown in FIG. 10 (e), the surface layer tomographic image X is subtracted from the deep tomographic image Y. The calculation method of the tomographic image is the same as the method (1). Thereby, the tomographic image Z from which the noise on the surface layer is removed can be obtained.

  (3) As shown in FIG. 11A, backscattered light is detected as usual, and a deep tomographic image Y as shown in FIG. 11B is created. When the deep tomographic image Y is two-dimensionally Fourier transformed, as shown in FIG. 11 (c), the horizontal axis represents the horizontal frequency of the deep tomographic image Y, and the vertical axis represents the vertical frequency of the deep tomographic image Y. An image representing the later amplitude spectrum as a luminance value is obtained. In addition, the frequency here is a frequency on an image, and this is also called a spatial frequency.

  In the image shown in FIG. 11 (c), the low frequency component of the spatial frequency of the deep tomographic image Y corresponds to the center of the image shown in FIG. 11 (c), and the high frequency component is the periphery of the image shown in FIG. 11 (c). Corresponding to the part. In the image, the high frequency portion corresponds to the noise component obtained from the surface and surface layer of the scatterer. Conversely, the low frequency part corresponds to the component obtained from the deep part of the scatterer.

  In this image after Fourier transform, only the low frequency part is selected and inverse Fourier transform is performed, whereby a deep processed image Z from which noise has been removed can be obtained.

  Alternatively, as shown in FIG. 11 (d), the deep processing image Z can be obtained by subtracting the surface layer tomographic image X obtained by inverse Fourier transforming the high frequency component from the deep tomographic image Y. .

  Note that the threshold for separating the high frequency and the low frequency can be set as appropriate depending on the size and position of the heterogeneous portion to be observed.

  The method described above can be implemented by the scatterer internal observation device according to the first to fourth embodiments. For example, the deep tomographic image and the surface layer tomographic image can be performed by an image processing unit, and the calculation can be performed by an analysis / processing unit.

  Alternatively, a control unit including an imaging unit and a calculation unit may be provided, and the configuration can be appropriately selected.

  The present invention is not limited to the above embodiment, and various modifications and changes can be made without departing from the scope of the invention. In addition, it is possible to appropriately combine a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  The present invention can be used as an apparatus for observing a living body, and can be used particularly in an endoscope or a rigid endoscope.

The block block diagram of the scatterer inside observation apparatus which concerns on 1st Embodiment. The schematic diagram which shows the detection range of the scatterer surface. The block block diagram of the scatterer inside observation apparatus which concerns on 2nd Embodiment. The block block diagram of the scatterer inside observation apparatus which concerns on 3rd Embodiment. The block block diagram of the scatterer inside observation apparatus which concerns on 4th Embodiment. The block block diagram of the scatterer inside observation apparatus which concerns on the modification of 4th Embodiment. The schematic diagram which shows a detection area and a detection range. The conceptual diagram which shows the determination method of a detection range. The conceptual diagram which shows the 1st method of a noise removal method. The conceptual diagram which shows the 2nd method of a noise removal method. The conceptual diagram which shows the 3rd method of a noise removal method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Scattering body inside observation apparatus, 101 ... Illuminating means, 102 ... Detection means, 103 ... Analysis / control part, 104 ... Illumination range, 105 ... Detection range, 106 ... Detection area, 107 ... Image processing part, 108 ... Display part , 109: input unit, 111, 211, 212 ... scan mirror, 213 ... scan control unit, 314 ... half mirror.

Claims (10)

A scatterer internal observation device that acquires information on a heterogeneous part inside a scatterer,
Illuminating means for irradiating the scatterer with light including at least wavelengths having different optical characteristics between the scattering medium constituting the scatterer and the extraneous portion;
An illuminating unit including: an imaging element that images the scatterer; an imaging optical system that limits a detection range captured by the imaging element; and a detection range variable mechanism that adjusts the detection range to include a desired region. Detecting means for detecting the backscattered light of the light emitted by, and obtaining light intensity data of the backscattered light;
Analysis / control means for analyzing the light intensity data acquired by the detection means and controlling the detection range variable mechanism;
An scatterer internal observation device, comprising: an image processing unit that creates a tomographic image at an arbitrary depth inside the scatterer from the light intensity data acquired by the detection unit.   The scatterer internal observation device according to claim 1, wherein the detection unit further includes a scan mirror capable of moving the detection range. The illumination means comprises an illumination scan mirror;
The detecting means includes a scanning mirror for detection;
The scatterer internal observation according to claim 1, further comprising scanning control means for controlling both scanning mirrors to scan the illumination range illuminated by the illumination means and the detection range on the scatterer surface. apparatus. The illumination means and the detection means are arranged such that their optical paths are coaxial,
The scatterer internal observation device according to claim 1, further comprising a scan mirror that scans the illumination range illuminated by the illumination unit and the detection range on the scatterer surface.   The scatterer internal observation device according to any one of claims 1 to 4, further comprising a detection region determination unit that determines the desired region.   The scatterer internal observation device according to claim 5, further comprising input means for inputting a setting for determining the desired region. A scatterer internal observation method for observing a heterogeneous part inside a scatterer,
Irradiating the scatterer with light including at least wavelengths having different optical characteristics between the scattering medium constituting the scatterer and the extraneous portion; and
Detecting backscattered light of the irradiated light and obtaining light intensity data of the backscattered light;
Analyzing the light intensity data acquired by the step, and determining a detection region on the scatterer surface;
Detecting the backscattered light of the detection region determined by the step, obtaining light intensity data;
A method comprising an image processing step of creating a tomographic image of the scatterer from the light intensity data acquired by the step.   The method according to claim 7, further comprising adjusting the detection range in which the detection of the backscattered light is performed to include the determined detection region.   A step of scanning the illumination range in which light is applied to the scatterer and the detection range while maintaining a fixed positional relationship on the surface of the scatterer to detect backscattered light and acquiring light intensity data; 9. The method of claim 8, comprising.   The method according to claim 7, wherein the step of determining the detection area is performed automatically.

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