Hyperspectral imaging device

Abstract

The spectral imaging device (500) includes an optical correction system (SYS1) for forming an axial light beam (LB2) parallel to the optical axis (AX1) of the imaging device (500) from the received light beam (LB1), a Fabry-Perot interferometer (FPI) for providing a filtered axial light beam (LB3) by filtering the light of the axial light beam (LB2), an image sensor (SEN1), and a plurality of sub-images (SEN1) on the image sensor (SEN1) by focusing the light of the filtered light beam (LB3). 0,0 , S 0,1 ) forming lens (LNS 0,0 , LNS 0,1 ) and an array (ARR1) of

Description

[Technical Field]

[0001] The present invention relates to a spectral imager. [Background technology]

[0002] Referring to the comparative example shown in FIG. 1 , a spectral camera CAM1 may include a focusing lens FLNS, a Fabry-Perot interferometer FPI, and an image sensor SEN1. The Fabry-Perot interferometer FPI can operate as a tunable optical bandpass filter. The lens FLNS focuses light LB1 received from an object onto the image sensor SEN1 via the Fabry-Perot interferometer FPI, thereby forming an image IMG2 of the object on the image sensor SEN1.

[0003] The focusing distance L between the lens FLNS and the image sensor SEN1 IMG2 is the total length L of the spectral camera CAM1 CAM1 The focusing distance L IMG2 may cause, for example, the size of the camera CAM1 to be too large for mobile applications. IMG2 Attempting to decrease θ increases the divergence of the light beam transmitted through the Fabry-Perot FPI, which can adversely affect the spectral resolution of the Fabry-Perot FPI. Summary of the Invention

[0004] The present invention provides a spectral imaging device, a spectral imaging method, and an imaging spectrometer.

[0005] According to one aspect, there is provided an apparatus as claimed in claim 1.

[0006] Further aspects are defined in the other claims.

[0007] The scope of protection sought for various embodiments of the invention is defined by the independent claims. Embodiments described herein (if any) that do not fall within the scope of the independent claims should be interpreted as examples useful for understanding various embodiments of the invention.

[0008] Optical microstructures can be utilized to provide a compact size imaging device. In particular, the imaging device may include a microlens array to reduce the length of the imaging device. The imaging device may include a microlens array to provide a compact size.

[0009] The imager can be used for multispectral imaging. The Fabry-Perot interferometer can act as a tunable bandpass filter for the imager. The imager can simultaneously capture all incident fields in an observation sector at a single wavelength. The spectral position of the passband of the Fabry-Perot interferometer can be scanned to obtain spectral narrowband images of an object at several different wavelengths. The imager can spectrally scan the light incident on the image sensor to generate a bandpass image dataset of the scene.

[0010] The imaging device may be arranged to operate such that the divergence of the light transmitted through the Fabry-Perot interferometer is less than a predetermined limit. Light received from each field angle of the observation sector can be passed simultaneously through the Fabry-Perot interferometer to provide a spectral image of the object. A single spectral image may represent a narrow spectral band of the object's full spectrum. If necessary, several spectral images can be combined to provide a multi-wavelength spectral image.

[0011] The use of a microlens array allows for a significant reduction in the size of the imaging device, whose length may be in the range of, for example, 3 mm to 15 mm.

[0012] In one embodiment, the imaging device may include a telecentric system to form an axial light beam from light beams received from different angles of view of the observation sector.

[0013] In one embodiment, the imager may include an afocal system to reduce the length of the imager. The afocal system may include a negative lens in combination with a limiter unit. The limiter unit may prevent the propagation of light rays outside the acceptance cone.

[0014] In one embodiment, the imaging device may include a combination of a modulator array and a filter array to, for example, enable the use of one of several transmittance peaks of a Fabry-Perot interferometer. The modulator array may, for example, include a plurality of first modulatable regions and a plurality of second modulatable regions. The transmittance of the modulatable regions may be changed, for example, by an external control signal. The filter array may, for example, include a plurality of first optical spectral filter regions and a plurality of second optical spectral filter regions. The spectral transmittance of the first filter regions may be different from the spectral transmittance of the second filter regions. The lateral position of the first modulatable regions may match the lateral position of the first filter regions. The first transmittance peak of the interferometer may be at a first wavelength, and the second transmittance peak of the interferometer may be at a second wavelength. The modulator array may initially be controlled to allow light of a first wavelength to propagate to the image sensor, while the modulator array can prevent light of a second wavelength from propagating. The modulator array may then be controlled to allow light at the second wavelength to propagate to the image sensor, and the modulator array may prevent the propagation of light at the first wavelength.

[0015] The imaging device may be used for, for example, hyperspectral imaging, and may be referred to as, for example, a hyperspectral camera device.

[0016] The imaging device may be, for example, a portable device. The imaging device may be, for example, a wearable device. The imaging device may be a pocket-sized device (i.e., easily carried in a pocket). The imaging device may be, for example, implemented in a smartphone. The imaging device may be, for example, implemented in a vehicle. The imaging device may be, for example, implemented in an unmanned aerial vehicle (drone).

[0017] The imaging device may be easily integrated as part of an optical system, for example, the imaging device may be implemented in an industrial metrology device. [Brief explanation of the drawings]

[0018] In the following examples, some variants are explained in more detail with reference to the accompanying drawings.

[0019] [Figure 1] As an example, a comparative example of a device including a Fabry-Perot interferometer is shown in a side cross-sectional view. [Figure 2] As an example, a cross-sectional side view of an imaging device including a Fabry-Perot interferometer and a microlens array is shown. [Figure 3a] As an example, a cross-sectional side view shows the formation of multiple sub-images by using a microlens array. [Figure 3b] As an example, a microlens array is shown in axial view. [Figure 3c] As an example, multiple sub-images formed by using a microlens array are shown in an axial view. [Figure 4a] An example is shown of forming multiple sub-images from light received from an object. [Figure 4b] As an example, multiple sub-images formed by using a microlens array are shown in an axial view. [Figure 5a] As an example, the spectral transmittance peak of a Fabry-Perot interferometer is shown. [Figure 5b] An example is shown as a filter array overlaid on an image sensor. [Figure 5c] An example is shown as a filter array overlaid on an image sensor. [Figure 5d] As an example, we show the spectral sensitivity of a detector pixel of an image sensor and the spectral transmittance peak of a Fabry-Perot interferometer. [Figure 6] As an example, we demonstrate the creation of a synthetic multi-wavelength image by stitching and combining. [Figure 7a] As an example, a cross-sectional side view of an imaging device including a telecentric system, a Fabry-Perot interferometer, and a microlens array is shown. [Figure 7b] As an example, a three-dimensional view shows the formation of an axial light beam from a received light beam. [Figure 8a] As an example, a cross-sectional side view shows the formation of an image spot by focusing light with a microlens. [Figure 8b] As an example, a cross-sectional side view shows the formation of a first image point when the center of the first axial beam coincides with the center of the first microlens. [Figure 8c] As an example, a side cross-sectional view shows the formation of a second image point when the center of the second axial beam coincides with the center of the second microlens. [Figure 8d] As an example, a cross-sectional side view shows a third axial beam forming a first image point and a second image point when the third axial beam overlaps a first microlens and a second microlens. [Figure 9] As an example, an imaging device including a modulator array and a filter array is shown in cross-sectional side view. [Figure 10a] As an example, an imaging device including an afocal system is shown in cross-sectional side view. [Figure 10b] As an example, a cross-sectional side view of an imaging device including a Fresnel lens is shown. [Figure 10c] As an example, a limiter unit of an afocal system is shown in a side cross-sectional view. [Figure 11] As an example, a Fabry-Perot interferometer is shown in cross-sectional side view. [Figure 12]As an example, a spectral imager is shown. DETAILED DESCRIPTION OF THE INVENTION

[0020] Referring to FIG. 2, the imaging device 500 may include an optical beam modifying system SYS1, a Fabry-Perot interferometer FPI, a microlens array ARR1, and an image sensor SEN1.

[0021] The light beam correction system SYS1 may form axial light beams LB2 from the received light beam LB1, with the radial position (r) of each formed axial beam LB2 being substantially proportional to the field angle (φ) of the corresponding received beam. The correction system SYS1 may be, for example, a telecentric system or an afocal system (FIG. 10a).

[0022] The imaging device 500 may receive light LB1 from an object OBJ1. The imaging device 500 may be arranged to form a spectral image of the object OBJ1 by filtering the light LB1 with a Fabry-Perot interferometer FPI. The object OBJ1 may be located in an observation sector VIEW1 of the device 500. The spectral images may be formed at several different wavelengths, and subsequently, if desired, the spectral images at the different wavelengths can be combined to form a multi-wavelength spectral image (CIMG) of the object OBJ1.

[0023] The object OBJ1 can reflect, emit, and / or transmit light LB1 received by the imaging device 500. The device 500 can be used, for example, to measure the reflection, transmission (absorption), and / or emission of light LB1 of the object OBJ1.

[0024] The object OBJ1 may include a plurality of object points P1a, P1b, P1c, P1d, and P1e. The imaging device 500 can receive light LB1a from point P1a, light LB1b from point P1b, and light LB1c from point P1c.

[0025] The imaging device 500 may have an optical axis AX1. The correction system SYS1 may form an axial light beam from the received light beam, and the angular direction (α, φ) of the received light beam may be mapped to a lateral position (α, r) of the centerline of the axial light beam. For example, the angle of view φ of the light beam LB1b may be b is the radial position r of the center line of the axial beam LB2b b For example, the angle of view φ of the light beam LB1c may be c is the radial position r of the center line of the axial beam LB2c c The correction system SYS1 may be referred to as, for example, an optical mapping system SYS1. The correction system can convert an oblique beam of light into an axial beam. The correction system SYS1 may be referred to as, for example, a conversion system SYS1.

[0026] Each axial beam may be substantially parallel to the optical axis AX1 of the apparatus 500. Each light beam (LB1a, LB1b, LB1c) received from an object point may correspond to an axial beam having a different lateral position (α, r). The lateral position of each axial beam may be defined, for example, by an angle α and a radial distance r. The lateral position (α, r) of each axial beam may be a function of the angular orientation (α, φ) of the corresponding received light beam LB1. The correction system SYS1 may, for example, include a telecentric system. The correction system SYS1 may, for example, include a combination of a negative lens and a limiter unit ( FIG. 10 a). The limiter unit may be arranged to block light rays outside a predetermined acceptance cone ( FIG. 10 b). A negative lens refers to a lens with a negative focal length.

[0027] The imaging device 500 can form an image point P4a by modifying, filtering, and focusing light LB1a received from object point P1a. The imaging device 500 can form an image point P4b by modifying, filtering, and focusing light LB1b received from object point P1b. The imaging device 500 can form an image point P4c by modifying, filtering, and focusing light LB1c received from object point P1c.

[0028] The Fabry-Perot interferometer FPI includes a pair of semi-transparent mirrors M1 and M2 arranged to act as an optical cavity. The spectral position of the transmittance peak (PEAK1) of the Fabry-Perot interferometer FPI depends on the distance (d F ) can be changed (Figure 5a).

[0029] SX, SY, and SZ may represent orthogonal directions. The direction SZ may be parallel to the optical axis AX1 of the device 500. The mirrors M1 and M2 of the Fabry-Perot interferometer may be perpendicular to the optical axis AX1. The mirrors M1 and M2 of the Fabry-Perot interferometer may be parallel to the plane defined by the directions SX and SY.

[0030] L0 may represent the distance between the object OBJ1 and the device 500. 500 may represent the external length of the device 500 in the direction of the axis AX1. SEN may represent the distance between the main surface of the correction system SYS1 and the image sensor SEN1.

[0031] By using the microlens array ARR1 together with the correction system SYS1, the distance L SEN The distance L can be reduced. SEN When the total length L of the imaging device 500 is reduced, 500 can be reduced.

[0032] Referring to FIG. 3a, the correction system SYS1 can form an axial light LB2 from light LB1 received from the observation sector VIEW1 of the imaging device 500. The interferometer FPI can form a transmitted light LB3 from the axial light LB2. The lens array ARR1 can focus the transmitted light LB3 to form a focused light LB4. The focused light LB4 can be incident on the image sensor SEN1 to form an optical image IMG4 on the image sensor SEN1. The lens array ARR1 can focus the transmitted light LB3 to form the optical image IMG4 on the image sensor SEN1.

[0033] The lens array ARR1 generates multiple spatially separated optical sub-images S -6,-6 , …S 0,0 , …S 6,6 The optical image IMG4 can be divided into a plurality of spatially separated sub-images S -6,-6 , …S 0,0 , …S 6,6 The sub-images may be called partial images, for example.

[0034] The light LB3 forming the multiple sub-images can be transmitted through mirrors M1 and M2 of the interferometer FPI simultaneously, or the light LB3 forming the multiple sub-images can be transmitted through the same single interferometer FPI.

[0035] The image sensor SEN1 detects the sub-image S -6,-6 , …S 0,0 , …S 6,6 The image sensor SEN1 can capture the optical sub-image S -6,-6 , …S 0,0 , …S 6,6 The image sensor SEN1 converts the sub-image S -6,-6 , …S 0,0 , …S 6,6 The image data may be provided to one or more data processors.

[0036] Sub-image S -6,-6 , …S 0,0 , …S 6,6can be stitched together to form a single continuous image (IMGλ1) of the object OBJ1. The apparatus 500 may include a data processor (CNT1) for performing the stitching, and the stitching may be performed, for example, on an internet server.

[0037] In one embodiment, stitching may be performed as a device-specific image processing operation, without the need to analyze the captured sub-images to find image points that correspond to common object points.

[0038] Referring to FIG. 3b, the lens array ARR1 includes lenses S -6,-6 , …S 0,0 , …S 6,6 The lenses may be arranged in a rectangular array, which may include, for example, M columns and N rows. The lenses may also be arranged in a staggered array and / or a hexagonal array. The lens array ARR1 may be formed, for example, by integrally molding, etching, or bonding lenses. The lenses may be, for example, spherical lenses or aspherical lenses. The lenses may be, for example, GRIN lenses (GRIN stands for gradient refractive index). The lenses may be Fresnel lenses or diffractive lenses. d 50 may represent the distance between the centers of adjacent lenses. 50 may be referred to as the pitch of the lens array ARR1. 50 may represent the lateral dimension of the clear aperture of a single lens.

[0039] Referring to FIG. 3c, the image IMG4 formed on the image sensor SEN1 is divided into a plurality of spatially separated sub-images S -6,-6 , …S 0,0 , …S 6,6 The lateral positions of the sub-images may match the lateral positions of the lenses of the array ARR1. The center of each sub-image may coincide with the center of the corresponding microlens.

[0040] Referring to Figures 4a and 4b, the sub-image S-1,0 , …S 1,1 may be a partial image of an object OBJ1 (the object OBJ1 may be, for example, a piece of printed paper).

[0041] Referring to FIG. 4b, the first sub-image S 0,0 is the first image F1′ of feature F1 of object OBJ1 0,0 and an adjacent second sub-image S 0,1 is a second image F1′ of the same feature F1 of object OBJ1. 0,1 The feature F1 may be, for example, the intersection of a horizontal line of the letter "H" and a vertical line of the letter "H". 0,0 , S 0,1 is the image F1′ of the same feature F1 of object OBJ1. 0,0 , F1′ 0,1 , so that the sub-image S 0,0 , S 0,1 By stitching these together, a continuous spectrum image IMGλ1 can be formed.

[0042] In particular, four or more adjacent sub-images (S 0,0 , S 0,1 , S -1,0 , S -1,1 ) may contain images F1′ of the same object point, so that they can be stitched together to form a larger continuous image. For example, the first sub-image S 0,0 Vertically adjacent images of S 0,1 is the second image F1′ of feature F1 0,1 The horizontally adjacent image S of the first sub-image S0,0 may include -1,0 is the third image F1′ of feature F1 -1,0 The first sub-image S 0,0 The diagonal adjacent image S -1,1 is the fourth image F1′ of feature F1 -1,1 may include:

[0043] The spectral transmittance peak (PEAK1) of the Fabry-Perot interferometer FPI may be tuned to, for example, a first wavelength λ1 to capture a first set of sub-images S. The first set of sub-images S may be stitched together to form a continuous spectral image IMGλ1 of the object OBJ1.

[0044] Figure 5a shows the spectral transmittance T of a Fabry-Perot interferometer FPI as an example. F (λ) is the spectral transmittance T F (λ) is the ratio I LB3 (λ) / I LB2 (λ) can also be referred to as I LB2 (λ) may represent the intensity of the axial light beam LB2 incident on the interferometer FPI, and I LB3 (λ) may represent the intensity of the corresponding light beam LB3 transmitted through the interferometer FPI.

[0045] Spectral width Δλ of transmittance peak PEAK1 FWHM For example, FWHM may be in the range of 5 nm to 30 nm.

[0046] Spectral transmittance T F (λ) may have one or more adjacent transmittance peaks PEAK1, PEAK2, PEAK3 of the Fabry-Perot interferometer FPI. For example, at a mirror distance d F is the first value d F,1 In the situation where λ is equal to λ, the first transmittance peak PEAK1 may be at wavelength λ1, the second transmittance peak PEAK2 may be at wavelength λ2, and the third transmittance peak PEAK3 may be at wavelength λ3. F may be scanned by changing

[0047] The spectral positions λ1, λ2, and λ3 of the transmission peaks PEAK1, PEAK2, and PEAK3 depend on the Fabry-Perot transmission function and the mirror distance d. F The spectral position of the transmission peak may depend on the mirror gap d FIt may be changed by making a change. The transmission peaks PEAK1, PEAK2, and PEAK3 may be referred to as the passband of the Fabry - Perot interferometer.

[0048] Mirror distance d F By changing it, the spectral positions of the transmission peaks PEAK1, PEAK2, and PEAK3 may shift. For example, for the mirror distance d F equal to the second value d F,2 in the situation where, the first transmission peak PEAK1′ may be at the wavelength λ 1b and the second transmission peak PEAK2′ may be at the wavelength λ 2b and the third transmission peak PEAK3′ may be at the wavelength λ 3b as well.

[0049] The apparatus 500 may optionally include one or more optical filters (e.g., CFA1, FIL1, FIL2) to limit the spectral response of the apparatus 500. The one or more filters together can provide a spectral transmittance. For example, the one or more filters can enable the use of a single selected transmission peak (e.g., PEAK1, PEAK2, or PEAK3) of the Fabry - Perot interferometer by preventing the transmission of light at the wavelengths of other transmission peaks.

[0050] For example, the apparatus 500 may include one or more filters (CFA1, FIL1, FIL2) to provide a first band - pass region PB1 defined by, for example, cut - off wavelengths λ 11 and λ 12 For example, the apparatus 500 may include one or more filters (CFA1, FIL1, FIL2) to provide a second band - pass region PB2 defined by, for example, cut - off wavelengths λ 21 and λ 22 For example, the apparatus 500 may include one or more filters (CFA1, FIL1, FIL2) to provide a third band - pass region PB3 defined by, for example, cut - off wavelengths λ 31 and λ 32 as well.

[0051] In one embodiment, the device 500 may include a modulator (MODI) and a filter array (FIL1) that alternately allows transmission of light through a first passband PB1 or a second passband PB2 (FIG. 14). The first passband PB1 has a cutoff wavelength λ 11 and λ 12 The second passband PB1 may be defined by a cutoff wavelength λ 21 and λ 22 The filter array may include a plurality of first filter regions to provide a first passband PB1 and a plurality of second filter regions to provide a second passband PB2.

[0052] Referring to FIG. 5b, the device 500 may include a filter array CFA1 that may be overlaid on the image sensor SEN1. The filter array CFA1 may be, for example, an RGB Bayer array. The filter array CFA1 may include a first filter region (R) to provide a first spectral transmittance. The filter array CFA1 may include a second filter region (G) to provide a second spectral transmittance. The filter array CFA1 may include a third filter region (B) to provide a third spectral transmittance. The first filter region (R) may, for example, provide a first spectral sensitivity to a first detector pixel DPX1 of the image sensor SEN1. The second filter region (G) may, for example, provide a second spectral sensitivity to a second detector pixel DPX2 of the image sensor SEN1. The third filter region (G) may, for example, provide a third spectral sensitivity to a third detector pixel DPX3 of the image sensor SEN1. For example, the first detector pixel DPX1 can selectively detect light transmitted at a first transmittance peak PEAK1 of the interferometer, and the first detector pixel DPX1 can be insensitive to light transmitted at other transmittance peaks (PEAK2, PEAK3). For example, the second detector pixel DPX2 can selectively detect light transmitted at a second transmittance peak PEAK2. For example, the third detector pixel DPX3 can selectively detect light transmitted at a third transmittance peak PEAK3.

[0053] Referring to Figures 5c and 5d, the filter array CFA1 may include a first filter region (R) to provide a first spectral transmittance, a second filter region (G) to provide a second spectral transmittance, a third filter region (B) to provide a third spectral transmittance, and a fourth filter region (IR) to provide a fourth spectral transmittance.

[0054] The first filter region (R) can provide, for example, a first spectral sensitivity to a first detector pixel DPX1 of image sensor SEN1. The second filter region (G) can provide, for example, a second spectral sensitivity to a second detector pixel DPX2 of image sensor SEN1. The third filter region (G) can provide, for example, a third spectral sensitivity to a third detector pixel DPX3 of image sensor SEN1. The fourth filter region (IR) can provide, for example, a fourth spectral sensitivity to a fourth detector pixel DPX4 of image sensor SEN1.

[0055] The first detector pixel DPX1 can detect, for example, light having a wavelength (λ1) of the first transmittance peak PEAK1 of the interferometer. The second detector pixel DPX2 can detect, for example, light having a wavelength (λ2) of the second transmittance peak PEAK2. The third detector pixel DPX3 can detect, for example, light having a wavelength (λ3) of the third transmittance peak PEAK3. The fourth detector pixel DPX4 can detect, for example, light having a wavelength (λ4) of the fourth transmittance peak PEAK4.

[0056] The first detector pixel DPX1 can, for example, spectrally selectively detect red light (R). The second detector pixel DPX2 can, for example, spectrally selectively detect green light (G). The third detector pixel DPX3 can, for example, spectrally selectively detect blue light (B). The fourth detector pixel DPX4 can, for example, spectrally selectively detect infrared light (IR).

[0057] The filter regions (R, G, B, IR) of the filter array CFA1 do not need to reject all spectral components outside the primary passband of each filter region. For example, the first filter region (R) may allow transmission of light of wavelengths λ1 and λ4. For example, the spectral components of light LB1 of wavelengths λ1, λ2, λ3, λ4 can be determined from the detected signals of the detector pixels (DPX1, DPX2, DPX3, DPX4) and the known spectral sensitivity functions of the detector pixels by solving a system of equations.

[0058] 6, a spectral transmittance peak (e.g., PEAK1) of a Fabry-Perot interferometer FPI may be tuned to a first wavelength λ1 to capture a first set of sub-images S. The first set of sub-images S may be stitched together to form a first spectral image IMGλ1 of the object OBJ1.

[0059] The spectral transmittance peak (e.g., PEAK1) of the Fabry-Perot interferometer FPI may be tuned to a second wavelength λ2 to capture a second set of sub-images S. The second set of sub-images S may be stitched together to form a second spectral image IMGλ2 of the object OBJ1.

[0060] The spectral transmittance peak (e.g., PEAK1 or PEAK2) of the Fabry-Perot interferometer FPI may be tuned to a third wavelength λ3 to capture a third set of sub-images S. The third set of sub-images S may be stitched together to form a third spectral image IMGλ3 of the object OBJ1.

[0061] The spectral transmittance peak (e.g., PEAK1 or PEAK2) of the Fabry-Perot interferometer FPI may be tuned to a fourth wavelength λ4 to capture a fourth set of sub-images S. The fourth set of sub-images S may be stitched together to form a fourth spectral image IMGλ4 of the object OBJ1.

[0062] The spectral images IMGλ1, IMGλ2, IMGλ3, and IMGλ4 can be combined to form a multispectral image CIMG. The multispectral image CIMG may be referred to, for example, as a hyperspectral cube. The image CIMG may include a three-dimensional array of pixel values, each pixel value representing a measured intensity value associated with the pixel's lateral coordinate (x, y) and the pixel's wavelength value (λ1, λ2, λ3, or λ4).

[0063] The number of spectral positions (λ1, λ2, λ3 or λ4) used to capture image data for a single image CIMG may be in the range of 2 to 100, for example.

[0064] In one embodiment, it may be sufficient to form a single spectral image IMGλ1 without forming a multispectral image CIMG.

[0065] In one embodiment, the image data of the captured sub-images S can be used without stitching the sub-images S. For example, changes in the object OBJ1 can be detected by comparing the captured sub-images S to reference data without stitching the sub-images S. Changes in the optical properties of the object OBJ1 can be detected by comparing the captured sub-images S to reference data.

[0066] In one embodiment, the interferometer FPI may be tuned to a selected wavelength to capture multiple sub-images S, and image data of the captured sub-images S may be used, for example, for background correction. The method may include capturing sub-images S, without stitching the sub-images S together.

[0067] 7a, the correction system SYS1 may include a telecentric system. The correction system SYS1 may be an image-space telecentric lens system including an aperture APE1 and a lens LNS1. The distance between the aperture APE1 and the lens LNS1 may be selected such that the light beam LB2 formed by the correction system SYS1 is substantially parallel to the optical axis AX1 of the apparatus 500.

[0068] The apparatus 500 can receive a first light beam LB1a from a first object point P1a. The correction system SYS1 can form a first axial beam AX1a from the light of the received first light beam LB1a. The angular direction (φ a ) is the radial position (r a )

[0069] The correction system SYS1 may form a substantially axial beam LB2 from the light of each light beam LB1 received from the observation sector VIEW1 of the device 500, and the radial position r of the formed axial beam AX2 may depend on the field angle φ of the received light beam LB1. The field angle φ may represent the angle between the center line of the received beam LB1 and the optical axis AX1 of the device 500. The radial position r may indicate the distance between the center line of the formed axial beam LB2 and the optical axis AX1 of the device 500. To a first approximation, the radial position (r) may be substantially proportional to the field angle (φ). For example, the correction system SYS1 may be configured such that r=k SYS1 The axial beam LB2 can be formed such that φ is k SYS1 may represent a proportionality constant.

[0070] The apparatus 500 can receive a second light beam LB1b from a second object point P1b. The correction system SYS1 can form a second axial beam AX1b from the light of the received second light beam LB1b. The angular direction (φ b ) is the radial position (r b)

[0071] The apparatus 500 can receive a third light beam LB1c from a third object point P1c. The correction system SYS1 can form a third axial beam AX1c from the light of the received third light beam LB1c. The angular direction (φ c ) is the radial position (r c )

[0072] The Fabry-Perot interferometer FPI can form transmitted light beams LB3a, LB3b, and LB3c by filtering the axial light beams LB2a, LB2b, and LB2c.

[0073] The lens array ARR1 can form a plurality of sub-images S by focusing the light of the transmitted light beams LB3a, LB3b, and LB3c onto the image sensor SEN1.

[0074] The distance L1 between the opening APE1 and the principal surface of the lens LNS1 is, for example, the focal length f of the lens LNS1 of the telecentric system SYS1. LNS1 The focal length of the lens LNS1 may for example be in the range 2 mm to 20 mm, advantageously in the range 4 mm to 8 mm.

[0075] The opening APE1 may be, for example, circular or rectangular. The diameter or width w of the opening APE1 APE1 may be, for example, in the range of 0.2 mm to 2 mm.

[0076] Diameter or width w of opening APE1 APE1 may be selected to provide the desired spectral resolution of the Fabry-Perot interferometer FPI. Selecting a smaller aperture APE1 can improve the spectral resolution. The apparatus 500 may include a diaphragm DIA1 to define the aperture APE1.

[0077] L4 may represent the distance between the image sensor SEN1 and the major surface of the lenses of the lens array ARR1. The distance L4 may be selected so that the lenses of the lens array ARR1 can form a substantially sharp sub-image of the object OBJ1 on the image sensor SEN1. For example, the distance L4 may be less than the focal length of the lenses LNS of the lens array ARR1. The apparatus 500 may be arranged to operate such that the lens array ARR1 does not form a sharp image of the entrance aperture APE1 on the image sensor SEN1.

[0078] The distance L4 may be selected such that at least one of the lenses of the array ARR1 can form a sharp image F1' of the feature F1 of the object OBJ1 on the image sensor SEN1. The distance L4 may be selected such that at least one of the lenses of the array ARR1 can form a sharp image point (P4) of the object point (P1) on the image sensor SEN1. In one embodiment, the distance L0 between the object OBJ1 and the device 500 is, for example, equal to the length L of the device 500. 500 In one embodiment, the object OBJ1 may be at an infinite distance. The distance L4 may be selected to provide a sharp image point of an object point located at an infinite distance.

[0079] L SEN may represent the distance between the image sensor SEN1 and the main surface of the lens LNS1 of the telecentric system SYS1. By using the lens array ARR1, the distance L SEN By using the lens array ARR1, the total external length L of the spectral imager 500 in the direction of the optical axis AX1 can be significantly reduced. 500 can be significantly reduced.

[0080] Referring to FIG. 7b, the correction system SYS1 can convert each received light beam LB1 into a corresponding axial light beam LB2. Each received light beam LB1 has a centerline CEN1. Each axial beam has a centerline CEN2. The direction of each received light beam LB1 may be defined, for example, by an angle (α, φ). The angle α may be referred to, for example, as an azimuth angle. The azimuth angle α may represent the angle between the direction SY and the projection (PRJ) of the centerline CEN1 on the plane defined by the directions SY and SX. The angle φ may be referred to, for example, as a field angle. The field angle may represent the angle between the optical axis AX1 and the centerline CEN1 of the light beam LB1. The lateral position of each corresponding axial beam LB2 may be defined, for example, by a radial position (r) and an azimuth angle (α). The radial position r may represent the distance between the centerline CEN2 and the optical axis AX1. The lateral position of the centerline CEN2 may be defined by Cartesian coordinates (x, y). The coordinate x defines a position in the direction SX, and the coordinate y defines a position in the direction SY.

[0081] The correction system may form an axial beam LB2 from light of the received light beam LB1, the radial position (r) of the axial beam LB2 being substantially proportional to the field angle φ of the received beam.

[0082] The correction system SYS1 can form an axial beam LB2k from the light of the received incident beam LB1k. The incident beam LB1k is deflected in the direction (α k ,φ k The axial beam has a lateral position (α k ,r k )

[0083] Referring to Figure 8a, the transmitted beam LB3 may be convergent or divergent. LB3 may represent the maximum angle between the rays of beam LB3 and the optical axis AX1. Each transmitted beam LB3 propagating through lens array ARR1 to image sensor SEN1 has a divergence angle Δθ LB3 The divergence angle Δθ LB3The divergence angle Δθ can affect the spectral resolution of the Fabry-Perot interferometer FPI. LB3 By reducing the σ, the resolution can be improved.

[0084] The transmitted light beam LB3 has a width w LB3 d 50 are the adjacent lenses (LNS) of array ARR1. 0,0 , LNS 0,1 ) center (AX 0,0 , AX 0,1 ) may be expressed as the distance between the array ARR1 and the pitch distance d 50 is set to a width w to provide sufficient spatial resolution and facilitate stitching of the sub-images S. LB3 It may be in the range of 25% to 100% of the above.

[0085] The lens array ARR1 may include a plurality of lenses arranged in a rectangular M x N array. The number of rows (N) of the lens array ARR1 may be, for example, 8 or more, and the number of columns (M) of the lens array may be, for example, 8 or more.

[0086] The number of rows (N) of the lens array ARR1 may be, for example, 2 or more, and the number of columns (M) of the lens array may be, for example, 2 or more. By using a 2x2 lens array, the length of the device can be significantly reduced.

[0087] The apparatus 500 can form an image point P4a from the light of the light beam LB1a received from the object point P1a, the apparatus 500 can form an image point P4b from the light of the light beam LB1b received from the object point P1b, and the apparatus 500 can form an image point P4c from the light of the light beam LB1c received from the object point P1c.

[0088] FIG. 8b shows how light from a light beam LB1a received from an object point P1a is reflected in a first sub-image S 0,0 The first lens LNS of the array ARR1 forms an image point P4a. 0,0is the first sub-image S 0,0 can be formed.

[0089] FIG. 8c shows how light from a light beam LB1e received from an object point P1e is reflected in a second sub-image S 0,1 1 shows how the image point P4e of the second adjacent lens LNS of the array ARR1 is formed. 0,0 is the second sub-image S 0,1 can be formed.

[0090] Figure 8d shows that the light of the light beam LB1d received from the same object point P1d is reflected in two adjacent sub-images (S 0,0 , S 0,1 ) appear at two different image points (P4d 0,0 , P4d 0,1 This function shows how to form a sub-image (S 0,0 , S 0,1 ) can be stitched together to form a larger continuous image (IMGλ1).

[0091] First lens LNS of array ARR1 0,0 is the first sub-image S 0,0 The adjacent second lens LNS of the array ARR1 can be formed. 0,1 is the second adjacent sub-image S 0,1 can be formed.

[0092] The system SYS1 can form an axial light beam LB2d from the light of the received light beam LB1d. The interferometer FPI can filter the light of the axial light beam LB2d to form an axial filtered light beam LB3d. The transmitted light beam LB3d is then filtered by the first lens LNS of the array ARR1. 0,0 and the adjacent second lens LNS 0,1 The first lens LNS may overlap with the first lens LNS. 0,0 focuses a first portion of the transmitted light beam LB3d to form a first focused beam LB4d 0,0 It is possible to form a converging beam LB4d 0,0is incident on the image sensor SEN1 and is detected as a first image point P4d 0,0 A first sub-image S 0,0 is the first image point P4d 0,0 The second lens LNS may include: 0,1 focuses a second portion of the transmitted light beam LB3d to form a second focused beam LB4d 0,1 It is possible to form a converging beam LB4d 0,1 is incident on the image sensor SEN1 and is generated as a second image point P4d 0,1 A second sub-image S 0,1 is the second image point P4d 0,1 may include:

[0093] In one embodiment, the second image point P4d 0,1 The first image point P4d relative to the lateral position of 0,0 The lateral position of may depend on the distance (L0) between the object point P1d and the spectral imager 500. This phenomenon occurs when the distance L0 is small, e.g., the ratio w APE1 This method may be significant at distance L0 when / L0 is greater than 1%. Therefore, the first image point (P4d 0,0 ) for the second image point (P4d 0,1 ) to determine (by triangulation) a distance (L0) between the object point (P1d) and the spectral imager 500. The apparatus may be arranged to determine distance values of a plurality of different object points, for example to measure the three-dimensional geometry of the object. The determined distance may also be used, for example, for autofocusing. The determined distance may also be used, for example, to verify a distance determined by another method.

[0094] Referring to FIG. 9 , the spectral imaging device 500 may include a combination of a modulator array MOD1 and a filter array FIL1 to enable use of one of several transmittance peaks (PEAK1, PEAK2) of a Fabry-Perot interferometer FPI. The modulator array MOD1 may include, for example, a plurality of first modulatable regions and a plurality of second modulatable regions. The transmittances of the modulatable regions may be changed, for example, by a control signal. The filter array FIL1 may include, for example, a plurality of first optical spectral filter regions and a plurality of second optical spectral filter regions. The spectral transmittance of the first filter regions may be different from the spectral transmittance of the second filter regions. The lateral positions of the first modulatable regions may match the lateral positions of the first filter regions. The first transmittance peak PEAK1 of the interferometer may be at a first wavelength (λ1), and the second transmittance peak of the interferometer may be at a second wavelength (λ2). First, the modulator array MOD1 may be controlled to allow light of a first wavelength (λ1) to propagate to the image sensor SEN1, and the modulator array MOD1 may prevent the propagation of light of a second wavelength (λ2). Next, the modulator array ARR1 may be controlled to allow light of the second wavelength (λ2) to propagate to the image sensor SEN1, and the modulator array MOD1 may prevent the propagation of light of the first wavelength (λ1). The modulator array MOD1 may be, for example, a liquid crystal modulator.

[0095] Referring to FIG. 10a, the correction system SYS1 may include a combination of a negative lens LNS2 and a limiter unit NAL2. The lens LNS2 may have a negative focal length. The limiter unit NAL2 limits the amount of light received within a predetermined acceptance cone (θ LIM ) can prevent the propagation of rays outside the negative lens LNS2 and limiter unit NAL2. The negative lens LNS2 and limiter unit NAL2 can form an afocal system. The afocal system of FIG. 10a can further reduce the axial length of the device 500.

[0096] In one embodiment, a limiter unit NAL2 of the afocal system SYS1 may also be arranged between the Fabry-Perot interferometer FPI and the lens array ARR1. The limiter unit NAL2 may allow the axially filtered light beam LB3 to propagate to the lens array ARR1, and the limiter unit NAL2 may filter out unwanted light rays outside the acceptance cone. The limiter unit NAL2 may be, for example, a stack of aperture arrays. The limiter unit NAL2 may be, for example, an optical fiber array.

[0097] The system SYS1 may form axial light beams (LB2a, LB2b, LB2c) from the received light beams (LB1a, LB1b, LB1c), the radial position (r) of each axial beam depending on the angle of view (φ) of the corresponding received beam. The system SYS1 may form axial light beams (LB2a, LB2b, LB2c) from the received light beams (LB1a, LB1b, LB1c), the radial position (r) of each axial beam being substantially proportional to the angle of view (φ) of the corresponding received beam.

[0098] 10b, the correction system SYS1 may include one or more Fresnel and / or diffractive lenses. By using a Fresnel or diffractive lens, the length L of the device 500 can be reduced. 500 can be further reduced.

[0099] For example, the afocal system may include a combination of a Fresnel lens LNS2 and a limiter unit NAL2. The limiter unit NAL2 may be, for example, a stack of aperture arrays. The limiter unit NAL2 may be, for example, an optical fiber array.

[0100] Referring to Figure 10c, θ2 represents the angle between the light ray LR2 and the optical axis AX1. θ3 represents the angle between the light ray LR3 and the optical axis AX1. The angles θ2 and θ3 may be referred to as, for example, angles of incidence. θ LIMis the acceptance angle of the limiter unit NAL2. The limiter unit NAL2 is configured such that the incident angle θ of the light ray is smaller than the acceptance angle θ LIM The limiter unit NAL2 may allow propagation of said ray through the limiter unit NAL2 if the angle of incidence θ of the ray is less than the angle of acceptance θ LIM If the angle of incidence of the limiter unit NAL2 is larger than θ, the propagation of the ray through the limiter unit NAL2 can be prevented. The limiter unit NAL2 may be implemented, for example, by an array of optical fibers. The limiter unit NAL2 may be, for example, an optical fiber array. The limiter unit NAL2 may be, for example, a stack of aperture arrays (FIG. 10b). The acceptance angle θ LIM may be in the range of 1 to 10°, for example.

[0101] 11, the interferometer FPI may include a first semi-transparent mirror M1 mounted on a first mirror plate 100 and a second semi-transparent mirror M2 mounted on a second mirror plate 200. The interferometer has a distance d between the first mirror M1 and the second mirror M2. F may include one or more actuators ACU1 to change

[0102] The width of the interferometer mirrors M1, M2 may be, for example, in the range of 2 mm to 50 mm. The interferometer semi-transparent mirrors M1, M2 may be manufactured with high precision. The deviation of the semi-transparent mirrors from a perfectly flat shape may initially be, for example, less than λ / 200. The flatness of the mirrors M1, M2 may be adjusted to, for example, a better λ to provide adequate finesse (i.e., the ratio of the free spectral range to the spectral width of the transmission peak). N / 200. N represents the predetermined operating wavelength. N The distance d between the semi-transparent mirrors M1 and M2 may be in the range of 500 nm to 4000 nm, for example. F may be, for example, in the range of 0.2 μm to 1 mm, depending on the desired spectral resolution and the desired free spectral range.

[0103] The width of the photodetection region of the image sensor SEN1 may be, for example, equal to or greater than the width of the mirrors M1 and M2. The width of the lens array ARR1 may be, for example, equal to or greater than the width of the mirrors M1 and M2.

[0104] The second mirror M1 may be substantially parallel to the first mirror M1 during operation. The mirrors M1, M2 may have, for example, a substantially circular or substantially rectangular shape.

[0105] Distance d between mirrors M1 and M2 F may be adjusted to provide constructive interference to transmitted light of one or more given wavelengths to allow light to pass through the interferometer FPI. F may also be adjusted to provide destructive interference to transmitted light of a given wavelength, allowing the interferometer FPI to reflect the light.

[0106] Mirror distance d F may be adjusted by one or more actuators ACU1, ACU2. The one or more actuators may be arranged to move the second mirror plate 200 relative to the first mirror plate 100. The actuators ACU1, ACU2 may be, for example, piezoelectric actuators, electrostatic actuators, electrostrictive actuators or flexoelectric actuators.

[0107] The semi-transparent mirrors M1, M2 may be, for example, a dielectric multilayer coating deposited on a transparent substrate. The semi-transparent mirrors M1, M2 may be, for example, a metal coating deposited on a transparent substrate. The substrate material of the mirror plates 100, 200 may be transparent in the operating wavelength range of the interferometer 300. The material of the mirror plates 100, 200 may be, for example, glass, silica, silicon, or sapphire. The mirror plates 100, 200 may include a ceramic material. The mirror plates 100, 200 may include a dimensionally stable material that is transparent in the operating wavelength range of the spectral imager 500.

[0108] The FPI interferometer is located at a mirror distance dF The sensor electrodes G1a, G1b, and G2 may optionally include capacitive sensor electrodes G1a, G1b, and G2 for capacitively monitoring the mirror distance d. The sensor electrodes G1a, G1b, and G2 may form a sensor capacitor C1, whose capacitance is proportional to the mirror distance d. F Therefore, the mirror distance d F may be monitored by monitoring the capacitance value of the sensor capacitor C1, which may be connected to the capacitance monitoring unit 410 by, for example, conductors CONa, CONb (FIG. 12).

[0109] 12, the imaging device 500 may include a control unit CNT1. The control unit CNT1 controls a mirror gap d F To adjust the control signal SET D The interferometer FPI may be arranged to transmit a digital control signal SET to the interferometer FPI. The interferometer FPI may include a driver unit 420. The driver unit 420 may be arranged to transmit a digital control signal SET D into an analog signal suitable for driving one or more actuators. The driver unit 420 can provide the signal HV1 for driving the actuators. The driver unit 420 can provide, for example, a high-voltage signal HV1 for driving a piezoelectric actuator.

[0110] The FPI interferometer is configured by measuring the distance d between the mirrors and / or mirror plates. F The interferometric FPI may optionally include means for monitoring distance. The interferometric FPI may, for example, include capacitive means for monitoring distance. The interferometric FPI may, for example, include inductive means for monitoring distance. The interferometric FPI may, for example, include interferometric means for monitoring distance.

[0111] Interferometer FPI, for example, has a mirror distance d F The sensor electrodes may include a capacitive sensor electrode that capacitively monitors the mirror distance d. The sensor electrodes may form a sensor capacitor C1, whose capacitance is proportional to the mirror distance d. F Therefore, the mirror distance dF may be monitored by monitoring the capacitance value of the sensor capacitor C1. The sensor capacitor C1 may be connected to the capacitance monitoring unit 410 by, for example, conductors CONa and CONb. The capacitance monitoring unit 410 determines the mirror distance d F The sensor signal S indicates d can be provided.

[0112] The capacitance monitoring unit 410 receives the sensor signal S d The sensor signal can provide the mirror gap d F The spectral response of the interferometer FPI can be monitored, for example, by the mirror gap d F The apparatus 500 may include a memory MEM2 for storing the spectral calibration parameter DPAR2. The mirror gap d F and / or the spectral position λ is calculated using, for example, the spectral calibration parameter DPAR2, d It may be determined from

[0113] The image sensor SEN1 outputs an image data signal S SEN The image data signal S may be transmitted as SEN may, for example, contain pixel values of an image frame captured at a selected wavelength.

[0114] The apparatus 500 may include a memory MEM1 for storing intensity calibration parameters CALPAR1. The apparatus 500 may be arranged to acquire pixel values from the image sensor SEN1 and determine intensity values X(λ) from the pixel values using the one or more intensity calibration parameters CALPAR1. The intensity values X(λ) of the light LB1 are determined from the pixel values of the captured image frame as a function of the pixel position (x,y) and / or the mirror distance value d using the one or more intensity calibration parameters CALPAR1. F A calibrated intensity value may be determined for each pixel of the captured wavelength image.

[0115] The image sensor SEN1 may be, for example, a CMOS sensor or a CCD sensor, where CMOS stands for Complementary Metal Oxide and CCD stands for Charge Coupled Device.

[0116] The apparatus 500 may include a memory MEM3 for storing an output OUT1. The output OUT1 may include, for example, pixel values of one or more captured images IMGλ1, IMGλ2, one or more calibrated intensity values, and / or one or more combined images CIMG.

[0117] The apparatus 500 may optionally include one or more filters FIL2 to at least partially define one or more passbands PB1.

[0118] The device 500 may optionally include a modulator array MOD1, a filter array FIL1, and a driver unit 430 for changing the state of the modulator array MOD1. The driver unit 430 is configured to control the modulator array MOD1 in response to a modulator control signal SET received from the control unit CNT1. MOD Depending on this, the state of the modulator array MOD1 can be changed.

[0119] The device 500 may include a memory MEM4 for storing a computer program PROG1, which, when executed by one or more data processors (e.g., CNT1), causes the device 500, the FPI, to: Distance d between mirrors M1, M2, and M1 F measuring adjusting the parallelism (tilt angle) of the mirrors M1 and M2; setting the transmission peak of the interferometer FPI at a selected location (e.g., λ1); controlling an optical modulator (MOD1) to enable or disable a passband (PB1); performing a spectral scan (e.g., from λ to λ) of the interferometer FPI; Multiple sub-images S 0,0 , S0,1 , ...; Sub-image S 0,0 , S 0,1 , ... to form a spectral image IMGλ1; forming a combined image CIMG; and forming a calibrated spectral image from the captured pixel values.

[0120] The device 500 may optionally include a user interface USR1, for example, for displaying information to a user and / or receiving commands from a user. The user interface USR1 may include, for example, a display, a keypad, and / or a touch screen.

[0121] The device 500 may optionally include a communication unit RXTX1. The communication unit RXTX1 can transmit and / or receive a signal COM1, for example, to receive commands, receive calibration data, and / or transmit output data OUT1. The communication unit RXTX1 may, for example, have wired and / or wireless communication capabilities. The communication unit RXTX1 may, for example, be arranged to communicate with a local wireless network (Bluetooth, WLAN), the Internet, and / or a mobile communication network (4G, 5G).

[0122] The object OBJ1 may be, for example, a real object or a virtual object. The real object OBJ1 may be, for example, in the form of a solid, liquid, or gas. The real object OBJ1 may be, for example, a cuvette filled with gas. The real object OBJ1 may be, for example, a plant (e.g., a tree or a flower), a burning flame, or an oil spill floating on water. The real object OBJ1 may be, for example, the sun or a star observed through a layer of absorbing gas. The real object may be, for example, an image printed on paper. The virtual object OBJ1 may be, for example, an optical image formed by another optical device.

[0123] The object may be a living object, such as a human body, an animal body, a tissue sample, or a plant. The object may be an inorganic object, such as a mineral sample or a gaseous sample. The formed spectral image (CIMG) may be compared with reference data, for example, to identify the object OBJ1. The formed spectral image (CIMG) may be compared with reference data, for example, to determine whether the object belongs to a given category. The formed spectral image (CIMG) may be compared with reference data, for example, to determine whether the state of the object is normal or abnormal.

[0124] The device 500 may be arranged to capture a spectral image representing two or more wavelengths (λ1, λ2, λ3, λ4) selected from the range of, for example, 600 nm to 1050 nm. The device 500 may be arranged to capture a spectral image representing several wavelengths (λ1, λ2, λ3, λ4) selected from the visible range and / or the near-infrared range.

[0125] The apparatus 500 may be arranged to capture spectral images representing two or more wavelengths (λ1, λ2, λ3, λ4) selected from, for example, the range 950 nm to 1700 nm. The apparatus 500 may be arranged to capture spectral images representing two or more wavelengths (λ1, λ2, λ3, λ4) selected from, for example, the short wave infrared (SWIR) range. The image sensor SEN1 may be, for example, an InGaAs image sensor.

[0126] The dimensions of the spectral imaging device 500 are determined by, for example, the angular distribution (Δθ LB3 ) may be chosen to be as narrow as possible.

[0127] To minimize the length of the device 500, the F-number of the lenses of the lens array may, for example, be made as small as possible. The F-number of a lens is equal to the ratio f / D, where f represents the focal length of the lens and D represents the diameter of the lens.

[0128] One or more dimensions of the device 500 may be selected to optimize performance, such as the width w of the entrance aperture APE1. APE1 , the focal length of the lens (LNS1 or LNS2) of the optical beam modifying system SYS1, the focal length of the lens of the lens array ARR1, and / or the pitch dimension d between the centers of adjacent lenses of the lens array ARR1. 50 may include:

[0129] Small opening size (w APE1 The spectral resolution of the Fabry-Perot interferometer can be improved by selecting the aperture size (w APE1 ) may be chosen to be large enough to allow stitching of the sub-images.

[0130] As an example, the width w of the aperture APE1 of the telecentric system SYS1 APE1 may be, for example, substantially equal to 1.2 mm. The focal length of the lens LNS1 of the telecentric system SYS1 may be, for example, substantially equal to 6 mm. The width of the mirrors M1, M2 may be, for example, substantially equal to 5 mm. The length L of the spectral imager 500 500 may be, for example, substantially equal to 9 mm. The lens array ARR1 may, for example, include a rectangular 15x15 array of microlenses LNS. The pitch dimension d of the lens array ARR1 50 may be, for example, substantially equal to 0.25 mm. The focal length of the lenses of the lens array ARR1 may be, for example, substantially equal to 1 mm. The image sensor SEN1 may, for example, include a rectangular 640x480 array of detector pixels. The diagonal field of view (VIEW1) may, for example, be substantially equal to 40°. The distance L0 between the object OBJ1 and the device 500 may, for example, be substantially equal to 500 mm.

[0131] It will be apparent to those skilled in the art that modifications and variations of the apparatus and methods of the present invention may be used. The figures are schematic. With reference to the accompanying drawings, the specific embodiments described above are for illustrative purposes only and do not limit the scope of the invention as defined by the appended claims.

Claims

1. a correction system (SYS1) for forming from the received light beam (LB1) an axial light beam (LB2) parallel to the optical axis (AX1) of the imaging device (500); a Fabry-Perot interferometer (FPI) for filtering light of said axial light beam (LB2) to provide a filtered axial light beam (LB3); an image sensor (SEN1); By focusing the light of the filtered axial light beam (LB3), a plurality of sub-images (S ０，０ , S ０，１ ) forming lens (LNS) ０，０ , L.N.S. ０，１ ) array (ARR1); Including, The correction system (SYS1) and the Fabry-Perot interferometer (FPI) are arranged to form an axial filtered light beam (LB3d) from the received light beam (LB1d) such that the axial filtered light beam (LB3d) overlaps a first lens (LNS0,0) of the array (ARR1) and an adjacent second lens (LNS0,1) of the array (ARR1), the first lens (LNS0,0) focuses light of the axial filtered light beam (LB3d) onto the image sensor (SEN1) to form a first image point (P4d0,0) of a first sub-image (S0,0), and the second lens (LNS0,1) focuses light of the axial filtered light beam (LB3d) onto the image sensor (SEN1) to form a second image point (P4d0,1) of a second sub-image (S0,1). ), wherein the first image point (P4d 0,0 ) and the second image point (P4d 0,1 ) are spatially separated, and the first image point (P4d 0,0 ) and the second image point (P4d 0,1 ) image the same object point (P1d).

2. The apparatus (500) of claim 1, wherein the correction system (SYS1) is a telecentric lens system.

3. The correction system (SYS1) is an afocal system including a combination of a lens (LNS2) and a limiter unit (NAL2), the focal length of the lens (LNS2) being negative, and the limiter unit (NAL2) having a predetermined acceptance cone (θ ＬＩＭ 2. The apparatus (500) of claim 1, wherein the apparatus (500) is arranged to prevent propagation of a ray (LR3) outside of the ray (LR4).

4. The apparatus (500) of claim 3, wherein the limiter unit (NAL2) comprises an optical fiber array.

5. 5. The device (500) of claim 1, comprising a light modulator (MOD1) and a filter array (FIL1), the filter array (FIL1) comprising a plurality of first filter regions, the transmittance of the modulator (MOD1) being modulatable to alternately enable or disable transmission of light (LB2) through the first filter regions of the filter array (FIL1).

6. The sub-image (S) captured by the image sensor (SEN1) ０，０ , S ０，１ ) image data of the captured sub-image (S ０，０ , S ０，１ 6. The apparatus (500) of claim 1, further comprising one or more data processors (CNT1) for stitching together image data of the plurality of pixels.

7. receiving light beams (LB1b, LB1c) from object points (P1b, P1c) of an object (OBJ1); forming axial light beams (LB2b, LB2c) from the received light beams (LB1b, LB1c) using an optical correction system (SYS1), wherein the axial light beams (LB2) are parallel to an optical axis (AX1) of the imaging device (500); providing filtered axial light beams (LB3b, LB3c) from said axial light beams (LB2b, LB2c) by using a Fabry-Perot interferometer (FPI) as an optical filter; Lens (LNS ０，０ , L.N.S. ０，１ ) is used to focus the light of said filtered axial light beams (LB3b, LB3c) onto an image sensor (SEN1) to form a plurality of sub-images (S ０，０ , S ０，１ ) forming a Including, The correction system (SYS1) and the Fabry-Perot interferometer (FPI) are arranged to form an axial filtered light beam (LB3d) from the received light beam (LB1d) such that the axial filtered light beam (LB3d) overlaps a first lens (LNS0,0) of the array (ARR1) and an adjacent second lens (LNS0,1) of the array (ARR1), the first lens (LNS0,0) focuses light of the axial filtered light beam (LB3d) onto the image sensor (SEN1) to form a first image point (P4d0,0) of a first sub-image (S0,0), and the second lens (LNS0,1) focuses light of the axial filtered light beam (LB3d) onto the image sensor (SEN1) to form a second image point (P4d0,1) of a second sub-image (S0,1). ), wherein the first image point (P4d 0,0 ) and the second image point (P4d 0,1 ) are spatially separated, and the first image point (P4d 0,0 ) and the second image point (P4d 0,1 ) image the same object point (P1d).

8. The plurality of sub-images (S ０，０ , S ０，１ 8. The method of claim 7, comprising forming a spectral image (IMGλ1) of the object (OBJ1) by stitching together:

9. 9. The method according to claim 7 or 8, wherein the correction system (SYS1) is a telecentric lens system.

10. The correction system (SYS1) includes a negative lens (LNS2) and a limiter unit (NAL2), and the limiter unit (NAL2) has a predetermined acceptance cone (θ ＬＩＭ 9. The method according to claim 7 or 8, wherein the propagation of a ray (LR3) outside the ray (LR4) is prevented.

11. setting a transmittance peak (PEAK1) of the Fabry-Perot interferometer (FPI) to a first wavelength (λ1); When the transmittance peak (PEAK1) of the Fabry-Perot interferometer (FPI) is at the first wavelength (λ1), a plurality of first sub-images (S ０，０ , S ０，１ ) and setting a transmittance peak (PEAK1) of the Fabry-Perot interferometer (FPI) to a second wavelength (λ2); When the transmittance peak (PEAK1) of the Fabry-Perot interferometer (FPI) is at the second wavelength (λ2), a plurality of second sub-images (S ０，０ , S ０，１ ) and The plurality of first sub-images (S ０，０ , S ０，１ forming a first spectral image (IMGλ1) of the object (OBJ1) by stitching together the first spectral image (IMGλ1) of the object (OBJ1); The plurality of second sub-images (S ０，０ , S ０，１ forming a second spectral image (IMGλ2) of the object (OBJ1) by stitching together the first and second spectral images (IMGλ2); - forming a multispectral image (CIMG) of the object (OBJ1) by combining the first spectral image (IMGλ1) with the second spectral image (IMGλ2); The method according to any one of claims 7 to 10, comprising:

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