JP5812735B2 - Spectral imaging device - Google Patents

Description

  The present invention spectrally captures an image (hereinafter also referred to as a spectral image) in which spectral information such as spectral reflectance, spectral transmittance, and spectral radiance of the subject is recorded by spectrally detecting light from the subject. Relates to the device.

  As this type of spectral imaging apparatus, there is an apparatus that acquires an image of a subject by sequentially acquiring images of a line-shaped region of the subject as if it were read by a scanner, instead of acquiring an image of the subject at once. It is considered (Patent Document 1).

  This will be specifically described. Light from the subject is collected by a condenser lens. Of the collected light, light from the line-shaped region of the subject passes through a slit formed in the light shielding member, and is dispersed for each wavelength by the spectroscopic means, and reaches the two-dimensional image sensor. The two-dimensional image sensor detects the intensity of the dispersed light for each position and wavelength in the longitudinal direction of the linear region. Thereby, a spectral image of the line-shaped region of the subject is acquired.

  Further, after the stage supporting the subject is driven by one line in the scanning direction orthogonal to the optical axis direction, a spectral image of another line-shaped region of the subject is acquired in the same manner as described above. By repeating this operation, spectral images of a plurality of linear regions of the subject are acquired, and spectral images of the subject are acquired by combining the spectral images of these linear regions.

JP 2009-216531 A JP 2009-39280 A JP 2006-322710 A

  However, such a spectral image has a problem that it takes a very long time for focusing. In order to adjust the focus, for example, it is conceivable to adjust the position of a lens, a slit, etc., and acquire and check a spectral image of the subject each time. However, as described above, in order to acquire a spectral image of a subject, it is necessary to sequentially acquire spectral images of a line-shaped region of the subject, which takes time. Therefore, if many spectral images of the subject are acquired until the subject is in focus, it takes a very long time.

  The present invention has been made in order to solve the above-mentioned problems, and its main purpose is to provide a spectral imaging apparatus capable of reducing the time required for focusing.

That is, a spectral imaging apparatus according to the present invention includes a condensing lens that condenses light from a subject, and a slit that allows light from the line-shaped region of the subject to pass among the light collected by the condensing lens. A light-shielding member formed with, a spectroscopic unit that splits the light from the line-shaped region that has passed through the slit, and the intensity and the wavelength of the light split by the spectroscopic unit in the longitudinal direction of the line-shaped region A detection unit that obtains an image of the line-shaped region by detecting each image, and an image obtained by sequentially receiving the image of the line-shaped region from the light detection unit and combining the received images of the line-shaped regions. be one that includes an image acquiring unit that acquires an image of an area, the condenser lens relative to the object, the slit, small of the spectroscopic means or said light detection means Both by changing the relative distance in the optical axis direction of one optical element, wherein further comprising a focusing means for focusing the image of the imaging area by the image acquiring unit acquires, the focusing means, the optical element Is driven by a predetermined first step width between a start position closest to the subject and an end position farthest from the subject, and the image acquisition unit includes the optical element as the first step. In each state driven by the width, each of the images of the focusing area , which includes the portion to be focused and is narrower than the imaging area in the subject , is obtained, and these images are compared, The position of the optical element that has acquired an in-focus image is calculated as a coarse focus position, and the focusing means uses the optical element as a reference based on the coarse focus position. It is further configured to drive by a predetermined second step width shorter than the first step width, and the image acquisition unit is configured to drive the focus in each state in which the optical element is driven by the second step width. Each of the images of the alignment area is acquired, and these images are compared, and the position of the optical element that acquired the most focused image is calculated as a high-precision focal position. An image of the imaging region is acquired in a state where it is in a position .

  In such a case, the image acquisition unit acquires an image of a region that is narrower than the imaging region of the subject including a portion to be focused by setting the relative distance, and acquires the image of the image of the narrow region. Since the image of the imaging region is acquired at the relative distance when the image is in focus, the time required to acquire the image can be shortened compared to the case where the image is focused on the entire image of the imaging region, and the time required for focusing can be shortened. Further, the data amount of the image can be reduced, and the load on the arithmetic device that processes the image can be suppressed. Comparing the spectral imaging apparatus according to the present invention with the inventions described in Patent Documents 1-3, the spectral imaging apparatus according to the present invention is patented in that at least a mechanism for shortening the time required for focusing is provided. This is completely different from the invention described in Document 1-3.

  In order to set the narrow area appropriately and focus accurately, the image acquisition unit acquires a part or all of the subject as a pre-image with the relative distance set to an arbitrary distance. It is desirable that the narrow area is set based on the pre-image.

  In order to automatically determine whether or not the subject is in focus and further reduce the time required for focusing, the image acquisition unit performs light for a distance on each image in a region narrower than the imaging region in the subject. It is desirable that the relative distance when the change in intensity of the image is the steepest is the relative distance when the image of the narrow area is in focus.

  A spectral imaging system having the light-shielding member, the spectral means, and the light detecting means, wherein the focusing means drives the spectral imaging system in the optical axis direction to If the relative distance in the optical axis direction is changed, it is not necessary to use a lens having a focusing function as a condensing lens as in Patent Document 2, and various lenses can be used. Further, as in Patent Document 1, an imaging apparatus that drives a stage that supports a subject and captures an image captures a subject that is difficult to put on or move on the stage, such as a landscape or a heavy object. It is difficult to take an image. On the other hand, if it is such, various subjects can be easily imaged.

This spectral imaging method of the spectral imaging apparatus is also an embodiment of the present invention. Specifically, in this spectral imaging method, a condensing lens that condenses light from a subject and a slit that allows light from the line-shaped region of the subject to pass through the light collected by the condensing lens are formed. A light shielding member, a spectroscopic unit that splits light from the line-shaped region that has passed through the slit, and an intensity of light dispersed by the spectroscopic unit for each longitudinal position and wavelength of the line-shaped region By doing so, the light detection means for acquiring the image of the line-shaped area, and the image of the imaging area obtained by sequentially receiving the image of the line-shaped area from the light detection means and combining the received images of the line-shaped areas a method of operating a spectroscopic imaging apparatus comprising: an image acquisition unit for acquiring, the condenser lens relative to the object, the slit, the spectroscopic means or said light detection means By changing the relative distance in the optical axis direction of the at least one optical element, a focusing step of focusing of the image of the imaging area by the image acquiring unit acquires, by the focusing step, the said optical elements subject In each state where the image acquisition unit is driven by the first step width between the start position closest to the end position and the end position furthest from the subject , Each of the images of the focusing area, which is a narrower area than the imaging area of the subject, including the portion to be focused is acquired, and these images are compared to obtain the most focused image. The coarse focus position is calculated by the coarse focus position calculating step for calculating the position of the optical element as the coarse focus position and the focusing step The optical element is driven by a predetermined second step width shorter than the first step width, and the image acquisition unit is configured to drive the focus in each state where the optical element is driven by the second step width. A high-accuracy focal position calculation step for obtaining images of the alignment regions, comparing these images, and calculating a position of the optical element that has acquired the most focused image as a high-precision focal position, The image acquisition unit includes an image acquisition step of acquiring an image of the imaging region in a state where the optical element is at the high-precision focal position .

  According to the present invention having the above-described configuration, the image is focused on an image in an area narrower than the imaging area of the subject, so that the time required for focusing can be shortened.

1 is an overall perspective view of a spectral imaging apparatus in an embodiment of the present invention. The block diagram which shows typically the spectral imaging device in the embodiment. 6 is a flowchart showing the operation of the spectral imaging apparatus according to the embodiment. 6 is a flowchart showing the operation of the spectral imaging apparatus according to the embodiment. The figure which shows the image acquired by the spectral imaging device in the embodiment. The figure which shows the change of the light intensity of the image acquired by the spectral imaging device in the embodiment, and each image. The block diagram which shows typically the spectral imaging device in other embodiment. The block diagram which shows typically the spectral imaging device in other embodiment. The block diagram which shows typically the spectral imaging device in other embodiment. The figure which shows the image acquired by the spectral imaging device in other embodiment.

  A spectral imaging apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings. This spectroscopic imaging apparatus 100 is used for various spectroscopic measurements such as measurement of fruit maturity, inspection of industrial products, analysis of lesions of living bodies, analysis of cells and celestial bodies, and the like. As shown in FIGS. 1 and 2, the spectral imaging device 100 has a substantially rectangular parallelepiped shape that houses the condensing lens 10, the spectral imaging system 20, the drive mechanism 30, the arithmetic mechanism 40, and these members. And a housing 50 made of a functional material.

  The condenser lens 10 is provided between the subject S and the spectral imaging system 20, and emits light from the subject S such as light reflected by the subject S, light transmitted through the subject S, and light emitted from the subject S. The light is condensed and guided to the spectral imaging system 20. Although the condensing lens 10 is a single lens here, a plurality of lenses may be combined.

  The spectral imaging system 20 has a substantially rectangular parallelepiped shape, and spectrally detects line-shaped light from the line-shaped region of the subject S at a time, and acquires an image of the line-shaped region of the subject S. The spectral imaging system 20 is housed in a housing space within the housing 50. The housing space in the housing 50 is set to be larger than that of the spectral imaging system 20 so that the spectral imaging system 20 can be driven to the extent that there is no problem in image acquisition and focusing described later. The spectral imaging system 20 includes a light shielding member 21 in which a slit 21 a is formed, a spectral unit 22, and a light detection unit 26.

  The light shielding member 21 is a case having a substantially rectangular parallelepiped shape and made of a light shielding material. The light shielding member 21 includes a slit 21 a that allows light from the line-shaped region of the subject S to pass through the light collected by the condenser lens 10, other portions of the light collected by the condenser lens 10, and stray light. And a light shielding wall 21b for preventing light from entering the spectroscopic means 22 and the light detecting means 26 accommodated therein. The slit 21 a is an elongated rectangular hole disposed at a position where light is collected by the condenser lens 10. The slit 21a extends a predetermined length in a direction orthogonal to the optical axis of the light from the subject S, and has a predetermined width opening in a direction orthogonal to the optical axis and the longitudinal direction of the slit 21a (hereinafter also referred to as a scanning direction). Yes.

  The spectroscopic means 22 divides the light that has passed through the slit 21a and collects it for each wavelength. Specifically, the spectroscopic unit 22 includes a collimating lens 23 that collimates the light that has passed through the slit 21a, a diffraction grating 24 that disperses the collimated light, and condenses the dispersed light for each wavelength. And an imaging lens 25 that forms an image on the light receiving surface of the light detection means 26. The imaging lens 25 collects light having a short wavelength to light having a long wavelength along a direction orthogonal to the longitudinal direction of the slit 21a (hereinafter also referred to as a wavelength direction).

  The light detection unit 26 acquires the image of the line-shaped region by detecting the intensity of the light separated by the spectroscopic unit 22 for each position and wavelength in the longitudinal direction of the line-shaped region. Specifically, the photodetection means 26 is a two-dimensional image sensor in which photodetection elements are arranged in a plane. Here, the photodetection means 26 is a CCD image sensor, but is suitable for detection of light in a CMOS image sensor or near infrared region. Alternatively, an InGaAs image sensor or the like may be used. The light receiving surface of the light detection means 26 is disposed along the wavelength direction and the longitudinal direction of the slit 21a. Then, light of different wavelengths is incident on different light detection elements along the wavelength direction. In addition, light from different positions in the line-shaped region of the subject S is incident on different light detection elements along the wavelength direction.

  The drive mechanism 30 drives the spectral imaging system 20 in the scanning direction and the optical axis direction, and is an actuator here. The driving mechanism 30 is a focusing unit that drives the spectral imaging system 20 in the optical axis direction to change the relative distance in the optical axis direction of the spectral imaging system 20 with respect to the subject S, thereby focusing the image of the subject S. Function. Focusing using the drive mechanism 30 will be described later.

  The calculation mechanism 40 is a general-purpose or dedicated computer, stores a predetermined program in a memory, and the CPU functions as a peripheral device according to the program, thereby exhibiting a function as the image acquisition unit 41. The image acquisition unit 41 is connected to a display serving as a display unit 42 that displays a spectral image as, for example, an image for each numerical value, graph, or wavelength, or as an RGB image converted from the spectral image.

  The image acquisition unit 41 sequentially receives the image of the line-shaped area of the subject S from the light detection unit 26, and acquires the image of the imaging area A1 that combines the received images of the line-shaped areas. More specifically, the image acquisition unit 41 receives an image of the line-shaped region of one subject S from the light detection means 26 and stores it in a memory (not shown). Next, after the image acquisition unit 41 transmits a control signal to the drive mechanism 30 and the drive mechanism 30 drives the spectral imaging system 20 for one or more lines in the scanning direction, the image acquisition unit 41 moves to another line-shaped region. Are received and stored in the memory. By repeating this operation, images of a plurality of linear regions of the subject S are acquired, and an image of the imaging region A1 is acquired.

  Therefore, in this embodiment, the image acquisition unit 41 has a function of focusing. The image acquisition unit 41 does not focus on the entire image of the imaging area A1 of the subject S, but includes an image of the focusing area A2 that includes a portion to be focused and is narrower than the imaging area A1 of the subject S. To focus. The image acquisition unit 41 sets the relative distance in the optical axis direction of the spectral imaging system 20 with respect to the subject S, acquires one or a plurality of images in the focusing area A2, and the image in the focusing area A2 is in focus. An image of the imaging area A1 is acquired at the relative distance.

  The operation of the spectral imaging apparatus 100 will be described with reference to the flowcharts of FIGS. 3 and 4 and the images shown in FIGS. Here, description will be made assuming that the position L in the optical axis direction of the spectral imaging system 20 can be driven from 0 to Lt. First, as illustrated in FIG. 3, the image acquisition unit 41 places the spectral imaging system 20 at an arbitrary position (here, the center position Lt / 2 in the drivable range of the spectral imaging system 20) (S1). Next, a partial image of the subject S (here, an image of a striped region parallel to the line-shaped region in the subject S) is acquired as a pre-image and displayed on the display unit 42 (S2, FIG. 5A). . Here, the image acquisition unit 41 extracts an image at the RGB three wavelengths from the acquired image, combines the RGB images, and displays them on the display unit 42. The user confirms the entire image of the subject S in the pre-image, and sets the focusing area A2 to be focused (S3, FIG. 5B).

  When receiving the input of the focusing area A2, the image acquisition unit 41 places the spectral imaging system 20 at the start position closest to the subject S (S4), and a part of the focusing area A2 (here, focusing). In the area A2, the image of the area from which the image is acquired as a pre-image) is acquired and stored in the memory (S5, FIG. 5C). Subsequently, the image acquisition unit 41 drives the spectral imaging system 20 in a direction away from the subject S by a predetermined first step width (here, Lt / n) (S6), and then similarly focuses on the focusing region. A part of the image of A2 is acquired and stored. When this is repeated and the spectral imaging system 20 reaches the end position farthest from the subject S (S7), the image acquisition is once ended.

  The image acquisition unit 41 compares a part of the acquired images in each focusing area A2, selects the most focused image, and acquires the position of the spectral imaging system 20 in the optical axis direction when the image is acquired. Is calculated as a rough focus position, which is a position that is roughly in focus (S8). Here, the image acquisition unit 41 calculates the change in the intensity of light with respect to the distance on the image for a part of the image in each focusing area A2, and the light of the spectral imaging system 20 when the change is the most abrupt. The position in the axial direction is calculated as the coarse focus position.

  This will be specifically described. The image acquisition unit 41 selects an arbitrary image (here, the image at the center position (Lt / 2) in the range driven by the spectral imaging system 20) from the acquired partial image of each focusing area A2, and From each line-like region of the image, the one having the largest light intensity change width is extracted. The image acquisition unit 41 calculates the change in the light intensity in the vicinity of the coordinate where the light intensity is maximum for the extracted image of the line-shaped region (FIG. 6). Similarly, the image acquisition unit 41 calculates a change in light intensity in the vicinity of the same coordinate in a partial image of each other focusing area A2. The image acquisition unit 41 compares these changes, and the waveform indicating the change is the shape closest to the rectangular wave, that is, the image when the change is the steepest (here, FIG. 6C) is acquired. The position of the spectral imaging system 20 (here, L = 2Lt / n) is calculated as the coarse focus position.

  Further, as shown in FIG. 4, the image acquisition unit 41 moves the spectral imaging system 20 from the position closer to the subject S by the first step width than the coarse focus position to the subject S by the first step width from the coarse focus position. Similarly, a part of the image in the focusing area A2 is acquired and stored while being moved to a position far from the center (S9 to S12, FIG. 5C). At this time, the image acquisition unit 41 acquires the image while moving the spectral imaging system 20 by a second step width (Lt / (n × m)) shorter than the first step width (Lt / n). Can focus more finely. When the coarse focus position is the start position, the range in which the spectral imaging system 20 is driven is from the start position to a position farther than the subject S by the first step width (0 <L <Lt / n ). When the coarse focus position is the end position, the range in which the spectral imaging system 20 is driven is set from the position close to the subject S by the first step width from the end position to the end position (Lt (n−1)). ) / N <L <Lt). When acquisition of a part of the image in the focusing area A2 is completed, the image acquisition unit 41 is more accurate than the coarse focus position based on the part of the image in each focusing area A2, as in the procedure in S8. A high-precision focal position, which is a focal position, is calculated (S13).

  The image acquisition unit 41 places the spectral imaging system 20 at a high-precision focal position (S14), acquires all the images of the focusing area A2, and displays them on the display unit 42 (S15, FIG. 5D). The user confirms whether or not the displayed image is in focus (S16). When the displayed image is in focus, the image acquisition unit 41 acquires all images of the imaging area A1 of the subject S (here, all images of the subject S), and the image acquisition flow of the spectral imaging apparatus ends. (S17, FIG. 5E). At this time, the position where the light is collected by the condenser lens 10 and the position of the slit 21 a substantially coincide with each other, the position where the light is collected by the imaging lens 25 of the spectroscopic means 22, and the light detection means 26. Is substantially coincident with the light receiving surface.

  If the displayed image is not in focus, the manual mode is entered. When the user inputs the position of the spectral imaging system 20 by operating an input bar (not shown) as an input interface (S18), the image acquisition unit 41 places the spectral imaging system 20 at the input position. Then, a partial image of the focusing area A2 is acquired and displayed (S19). If the displayed image is not in focus, the user sets the position of the spectral imaging system 20 again, and acquires a partial image of the focusing area A2. If the displayed image is in focus, the image acquisition unit 41 acquires the entire image of the imaging area A1 of the subject S, and the image acquisition flow ends (S17).

  According to the spectral imaging apparatus 100 of the present embodiment, the image acquisition unit 41 sets the relative distance of an image in the focusing area A2 that includes a portion to be focused and is narrower than the imaging area A1 in the subject S. Since the image of the imaging area A1 is acquired at the relative distance when the image of the focusing area A2 is in focus, it is necessary to acquire the image as compared with the case of focusing on the entire imaging area A1. Time can be shortened and the time required for focusing can be shortened. In addition, the amount of image data can be reduced, and the load on the arithmetic mechanism 40 that processes the image can be suppressed.

  Furthermore, since the focus position is roughly determined and then the focus position is searched finely, the image is focused in a plurality of stages, so the number of images is smaller than in the case where the image is focused in one stage. The image can be focused with high accuracy.

  The present invention is not limited to the above embodiment. For example, the spectroscopic means 22 is not limited to the one using the diffraction grating 24. For example, the spectroscopic means 22 using the prism 27 (FIG. 7) or the spectroscopic means 22 using the optical member 28 in which the diffraction grating 28a and the prism 28b are combined may be used. As this optical member 28, for example, as shown in FIG. 8, there is one in which a diffraction grating 28a is combined between two prisms 28b, also called a grism. As a result, the optical axis of the light emitted from the optical member 28 proceeds along the original optical axis without being refracted. Further, instead of the transmission type spectroscopic means 22, a reflection type spectroscopic means 22 such as a spectroscopic means 22 using two concave mirrors 29 and a diffraction grating 24 may be used (FIG. 9). In order to reduce aberration, it is preferable to use a parabolic mirror instead of a concave mirror.

  In the embodiment, when focusing the image of the focusing area, the image acquisition unit calculates a change in light intensity in the vicinity of one coordinate in each partial image of the focusing area, The changes are compared, but the present invention is not limited to this. For example, the image acquisition unit may calculate a value indicating a change in light intensity near a plurality of coordinates, and compare the values. The plurality of coordinates may be selected from images of the same line-shaped region in a partial image of the focusing region, or may be selected from images of different line-shaped regions. Further, when comparing values indicating changes, an average value of values indicating changes in light intensity at each coordinate may be used, or a value appropriately weighted for each importance of coordinates may be used.

  In addition, the image acquisition unit calculates the change in the light intensity with respect to the distance on the image that is oblique or orthogonal to the line area, not the change in the light intensity with respect to the distance on the image parallel to the line area. It may be.

  Furthermore, the image acquisition unit may calculate a change in light intensity at a predetermined wavelength, or may calculate a change in the total value of light intensities at a plurality of wavelengths.

  In addition, the image acquisition unit is in the position of the spectral imaging system (L = 0, Lt / n, 2Lt / n, 3Lt / n,..., Lt) when the image of the focusing area is acquired. From the value indicating the change in the light intensity, the position between the positions (for example, L = 2.13Lt / n) is not selected from the coarse focus position or the high-precision focus position. Alternatively, it may be calculated as a high-precision focal position.

  When calculating the focal position, the image acquisition unit acquires images of a plurality of linear regions in the focusing region as a partial image of the focusing region, but the image of one linear region in the focusing region You may make it acquire only. Further, when calculating the focal position, the image acquisition unit may acquire images of the entire focusing area.

  When calculating the reference position, the image acquisition unit is driven in the direction away from the subject, but may be driven in the approaching direction.

  The image acquisition unit calculates the coarse focus position and the high-accuracy focus position so that the image is focused in two stages, but may be focused in three or more stages or in one stage.

  When the displayed image is not sufficiently focused, the image acquisition unit enters the manual mode. However, the spectral imaging system is driven with a step width shorter than the second step width, or spectral imaging is performed. The driving range of the system may be changed or expanded to acquire an image of the focusing area, and the focal position may be calculated.

  In the embodiment, the entire area of the subject S is the imaging area A1, but the imaging area A1 may be a partial area of the subject S. For example, as shown in FIG. 10, a part of the skin of an apple that is the subject S may be set as the imaging region A1, and the shaft portion of the apple may be set as the focusing region A2. At this time, the focusing area A2 may be set outside the imaging area A1, may be set within the imaging area A1, or may be set from inside the imaging area A1 to outside the imaging area A1. The point is that the focusing area A2 includes a part to be focused on the imaging area A1, or a part whose position in the optical axis direction substantially coincides with the part to be focused, and from the imaging area A1. May be a narrow region.

  In the above embodiment, the driving mechanism drives the spectral imaging system. However, by driving the condenser lens and the stage that supports the subject, the condenser lens, slit, spectroscopic means, and / or light detection for the subject are driven. You may make it change the relative position of the optical axis direction of a means.

  For example, if the subject has a small color or brightness difference, such as white paper, a focus assisting member with a large color or brightness difference, such as a black and white bar, can be placed near the subject, It is desirable to provide it on a stage that supports the subject.

  You may provide the lens holding | maintenance part which hold | maintains a condensing lens in the said housing | casing so that replacement | exchange is possible. If it is such, for example, a spectral image of a forest landscape and a spectral image of a leaf collected from the forest can be acquired by the same spectral imaging device 100, and errors due to individual differences of the spectral imaging devices can be obtained. Can be reduced. At this time, it is desirable to set the distance (for example, 150 mm) between the micro imaging lens and the slit larger than the distance (for example, 20 mm) between the macro imaging lens and the slit.

  Although the image acquisition unit acquires a part of the subject as the pre-image, the image acquisition unit may acquire all the images of the subject. Further, instead of the user confirming the pre-image and setting the focusing area, the center area or the like of the pre-image may be automatically set as the focusing area.

  Furthermore, when the lens diameter of the condensing lens is large compared to the length of the slit, it is not possible to image the entire region where the condensing lens condenses, and in particular, the region that can be imaged in the longitudinal direction of the slit is limited. There is a problem of being done. In contrast, the driving mechanism drives the spectral imaging system in three directions orthogonal to each other, that is, the spectral imaging system is driven in the longitudinal direction of the slit in addition to the scanning direction and the optical axis direction. Is desirable. If it is such, the area | region which can be imaged in the longitudinal direction of a slit can be expanded, and it also becomes possible to image all the area | regions which a condensing lens condenses. This effect is particularly remarkable when the spectral imaging system is downsized. In addition, the present invention is not limited to the above-described embodiments, and may be configured by appropriately combining some or all of the various configurations described above without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Spectral imaging device 10 ... Condensing lens 20 ... Spectral imaging system 21 ... Light shielding member 21a ... Slit 22 ... Spectral means 26 ... Light detection means 30 ... Drive Mechanism (focusing means)
41 ... Image acquisition unit S ... Subject A1 ... Imaging area A2 ... Focusing area (narrow area)

Claims (6)

A condensing lens that condenses the light from the subject, a light shielding member formed with a slit through which light from the line-shaped region of the subject out of the light collected by the condensing lens, and the slit Spectroscopic means for spectrally separating the light from the line-shaped region that has passed through, and detecting the intensity of light dispersed by the spectroscopic means for each position and wavelength in the longitudinal direction of the line-shaped region, thereby the linear region A light detection unit that acquires an image of the first region, and an image acquisition unit that sequentially receives the image of the line-shaped region from the light detection unit and acquires an image of the imaging region that is a combination of the received images of the line-shaped regions. Comprising
An image of the imaging region acquired by the image acquisition unit by changing a relative distance in the optical axis direction of at least one optical element of the condenser lens, the slit, the spectroscopic unit, or the light detection unit with respect to the subject. Further comprising a focusing means for focusing
The focusing means is configured to drive the optical element by a predetermined first step width between a start position closest to the subject and an end position furthest from the subject;
In each state in which the optical element is driven by the first step width , the image acquisition unit includes an image of a focusing area that includes a portion to be focused and is narrower than the imaging area in the subject. With each acquisition, comparing these images, the position of the optical element that acquired the most focused image is calculated as the coarse focus position,
The focusing means is further configured to drive the optical element by a predetermined second step width shorter than the first step width based on the rough focus position;
In each state where the optical element is driven by the second step width, the image acquisition unit acquires images of the focusing area, and compares these images to obtain the most focused image. The spectral imaging apparatus is characterized in that the position of the optical element that has acquired the above is calculated as a high-precision focal position, and the image of the imaging region is obtained in a state where the optical element is at the high-precision focal position .   The image acquisition unit acquires a part or all of the subject as a pre-image in a state where the relative distance is an arbitrary distance, and the narrow region is set based on the pre-image. The spectral imaging apparatus according to claim 1.   The relative distance when the image of the narrow area is in focus is the relative distance when the change in light intensity with respect to the distance on the image of each narrow area is the most rapid. The spectral imaging apparatus according to claim 1 or 2.   A spectral imaging system having the light-shielding member, the spectral means, and the light detecting means, wherein the focusing means drives the spectral imaging system in the optical axis direction to The spectral imaging apparatus according to claim 1, wherein the relative distance in the optical axis direction is changed.   The spectral imaging apparatus according to claim 1, further comprising a lens holding unit that holds the condenser lens in a replaceable manner. A condensing lens that condenses the light from the subject, a light shielding member formed with a slit through which light from the line-shaped region of the subject out of the light collected by the condensing lens, and the slit Spectroscopic means for spectrally separating the light from the line-shaped region that has passed, and by detecting the intensity of the light dispersed by the spectral means for each position and wavelength in the longitudinal direction of the line-shaped region, A light detection unit that acquires an image; and an image acquisition unit that sequentially receives an image of the line-shaped region from the light detection unit and acquires an image of an imaging region obtained by combining the received images of the line-shaped regions. An operating method of the spectral imaging apparatus,
An image of the imaging region acquired by the image acquisition unit by changing a relative distance in the optical axis direction of at least one optical element of the condenser lens, the slit, the spectroscopic unit, or the light detection unit with respect to the subject. A focusing step to focus
The focusing step drives the optical element by a predetermined first step width between a start position closest to the subject and an end position furthest from the subject, and the image acquisition unit includes the optical element In each state driven by the first step width, each of the images of the focusing area that is a narrower area than the imaging area of the subject including the portion to be focused is acquired, and these images are compared. A coarse focus position calculating step for calculating the position of the optical element that acquired the most focused image as a coarse focus position;
In the focusing step, the optical element is driven by a predetermined second step width shorter than the first step width on the basis of the coarse focus position, and the image acquisition unit includes the optical element in the second step width. In each driven state, each image of the focusing area is acquired, and these images are compared, and the position of the optical element that acquired the most focused image is calculated as a high-precision focal position. A high-accuracy focal position calculating step,
A spectral imaging method comprising: the image acquiring unit acquiring an image of the imaging region in a state where the optical element is at the high-precision focal position .