Wavelength position related silicon-based hyperspectral imaging device
By combining the imaging chip with a linear gradient filter in a silicon-based hyperspectral imaging device and using a cutoff sheet to eliminate the shortwave response, the problem of excessive out-of-border response is solved, and high-precision spectral measurement is achieved.
Patent Information
- Application Number
- CN202510417724.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2025-07-11
AI Technical Summary
The out-of-band response of the existing silicon-based hyperspectral imaging device based on linear gradient filters is too high and cannot meet the practical application requirements.
Combine the imaging chip with a linear gradient filter to eliminate the spectral response of the short-wave range by setting the cutoff sheet, and use cubic equation fit to obtain the wavelength position correlation formula to ensure the accuracy of spectral measurement.
The accuracy of spectral measurement is improved, the out-of-border response of the short-wave range is avoided, and efficient spectral information acquisition is achieved.
Smart Images
Figure CN120293313A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of spectral imaging, and particularly relates to a silicon-based hyperspectral imaging device related to wavelength position. Background Art
[0002] The spectral characteristic of a linear variable filter is that the spectrum changes linearly with the position of the linear variable filter. The linear variable filter can decompose the incident polychromatic light into a spectrum related to the position of the linear variable filter. Using the linear variable filter as the core spectral splitting element of the imaging chip can replace traditional spectral splitting systems such as gratings and prisms, making the detector have characteristics such as small volume and light weight, higher integration, and faster measurement speed, and is suitable for occasions where high spectral information needs to be obtained quickly and efficiently. However, currently, due to the excessive out-of-band response of the silicon-based hyperspectral imaging device based on the linear variable filter, the silicon-based hyperspectral imaging device based on the linear variable filter cannot meet the actual application requirements. Summary of the Invention
[0003] In view of this, the present invention aims to provide a silicon-based hyperspectral imaging device related to wavelength position to solve the defect that the out-of-band response of the existing silicon-based hyperspectral imaging device is too high and cannot meet the actual application requirements. The present invention combines the imaging chip and the linear variable filter, avoiding the out-of-band response of the silicon-based hyperspectral imaging device in the short-wave range and improving the spectral measurement accuracy.
[0004] To achieve the above object, the technical solution of the present invention is realized as follows: A silicon-based hyperspectral imaging device related to wavelength position, comprising a filter holder, a linear variable filter, a cut-off filter, and a detector arranged in sequence along the optical path direction, wherein, a first placement groove and a second placement groove are provided at the center of the filter holder, the linear variable filter is installed in the first placement groove, the cut-off filter is installed in the second placement groove, and the linear variable filter and the cut-off filter are placed relatively parallel and overlapping in the vertical direction; the filter holder is installed on the housing of the detector, and the cut-off filter and the linear variable filter are located in the installation space of the detector.
[0005] Further, the size of the linear variable filter is smaller than the size of the imaging chip target surface of the detector.
[0006] Further, the total height of the first placement groove and the second placement groove is set to be the same as the total height of the cut-off filter and the linear variable filter, so that the cut-off filter and the linear variable filter are closely attached together.
[0007] Further, the imaging chip of the detector is a silicon-based imaging chip.
[0008] Furthermore, the starting value of the working wavelength band of the linear gradient filter is greater than or equal to 300 nm, and the ending value of the working wavelength band of the linear gradient filter is less than or equal to 1100 nm; The cut-off filter can be a short-wave pass cut-off filter, a band-pass cut-off filter, or a linear gradient short-wave pass cut-off filter.
[0009] Furthermore, the starting position of the coating on the cut-off filter is the position on the cut-off filter corresponding to the position where the starting value of the working wavelength band of the linear gradient filter is located.
[0010] Furthermore, record the long wavelength band where the linear gradient filter has an additional response at the short wavelength, and use the long wavelength band as the marked wavelength band. Also, use the position on the cut-off filter corresponding to the position where the marked wavelength band of the linear gradient filter is located as the ending position of the coating on the cut-off filter.
[0011] Furthermore, the method for obtaining the wavelength-position correlation formula of the silicon-based hyperspectral imaging device is as follows: Place the silicon-based hyperspectral imaging device in front of the light outlet of the integrating sphere of the monochromator; Let the monochromator emit monochromatic light, where the wavelength value of the monochromatic light is the same as the wavelength value of the starting value of the working wavelength band of the linear gradient filter, and use the silicon-based hyperspectral imaging device to collect the current monochromatic light response image; Increase the wavelength value of the monochromatic light emitted by the monochromator by one, and repeat the above steps until the wavelength value of the monochromatic light emitted by the monochromator is the same as the wavelength value of the ending value of the working wavelength band of the linear gradient filter, and use the silicon-based hyperspectral imaging device to collect all the monochromatic light response images; Accumulate and sum the monochromatic light response images according to the gray values of the pixels in each row to obtain the row coordinate with the maximum response value of each monochromatic light response image; Perform a cubic equation fitting on the wavelength values of the monochromatic light emitted by the monochromator and the row coordinates with the maximum response values of the monochromatic light response images to obtain the wavelength-position correlation formula of the silicon-based hyperspectral imaging device.
[0012] Furthermore, the position-wavelength formula in the wavelength-position correlation formula of the silicon-based hyperspectral imaging device is: ; where, is the wavelength of the silicon-based hyperspectral imaging device related to the wavelength position, is the pixel row coordinate corresponding to the silicon-based hyperspectral imaging device related to the wavelength position at the current wavelength, , , and are the constants of the cubic equation.
[0013] Further, the wavelength position formula in the wavelength position correlation formula of the silicon-based hyperspectral imaging device is as follows: ; wherein, is the pixel row coordinate of the silicon-based hyperspectral imaging device related to the wavelength position, is the wavelength of the silicon-based hyperspectral imaging device related to the wavelength position at the current pixel row coordinate, , , , are the constants of the cubic equation.
[0014] Compared with the prior art, the present invention can achieve the following beneficial effects: In the silicon-based hyperspectral imaging device related to the wavelength position of the present invention, the imaging chip is combined with the linear variable filter, so that several rows of pixels of the detector correspond to a certain spectral band of the linear variable filter, and the acquisition of hyperspectral images is realized by using the traditional imaging chip. At the same time, the response outside the spectral passband in the short-wave range (the actual response of the detector different from the theoretical response value) is avoided, and the spectral measurement accuracy is improved. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is a schematic exploded view of the silicon-based hyperspectral imaging device related to the wavelength position according to the embodiment of the present invention; Figure 2 is a schematic overall structure view of the silicon-based hyperspectral imaging device related to the wavelength position according to the embodiment of the present invention; Figure 3 is a schematic structure view of the filter holder according to the embodiment of the present invention; Figure 4 is the position-wavelength curve of the silicon-based hyperspectral imaging device related to the wavelength position according to the embodiment of the present invention; Figure 5 is the wavelength-position curve of the silicon-based hyperspectral imaging device related to the wavelength position according to the embodiment of the present invention.
[0016] Description of the reference numerals: 1, detector; 2, cut-off sheet; 3, linear variable filter; 4, filter holder; 5, first placement groove; 6, second placement groove. DETAILED DESCRIPTION OF THE INVENTION
[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.
[0018] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.
[0019] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.
[0020] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.
[0021] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.
[0022] As Figures 1 - 3 shown, the silicon-based hyperspectral imaging device related to the wavelength position proposed by the present invention includes a filter holder 4, a linear variable filter 3, a cut-off filter 2, and a detector 1 (the detector 1 is a spectral detector) sequentially arranged along the optical path direction. Among them, The center of the filter holder 4 is provided with a first placement groove 5 and a second placement groove 6. The linear variable filter 3 is installed in the first placement groove 5, and the cut-off filter 2 is installed in the second placement groove 6. The linear variable filter 3 and the cut-off filter 2 are placed relatively parallel and overlapping in the vertical direction; the filter holder 4 is used to fix the linear variable filter 3 and the cut-off filter 2, and keep the linear variable filter 3 and the cut-off filter 2 in close contact.
[0023] The filter holder 4 is installed on the housing of the detector 1, and the linear variable filter 3 and the cut-off filter 2 are located in the installation space of the detector 1.
[0024] The linear variable filter 3 is the core spectral splitting element of the silicon-based hyperspectral imaging device and is used to achieve spectral splitting. The cut-off filter 2 is used to eliminate the response of the spectrum in the long-wave range of the linear variable filter 3 at the short-wave part of the silicon-based hyperspectral imaging device related to the wavelength position, and avoid the influence of its spectral response in the short-wave range on the measured spectrum.
[0025] The imaging chip of the detector 1 is a silicon-based imaging chip. Specifically, the imaging chip of the detector 1 can adopt a silicon-based imaging chip with the model number GMAX2518, and the working band of this silicon-based imaging chip is 300nm - 1100nm, and the target size is 11.27mm (horizontal) × 10.24mm (vertical).
[0026] According to the various index parameters of the silicon-based imaging chip, a linear variable filter 3 with a working wavelength of 400 - 1000nm is selected as the spectral splitting element of the silicon-based imaging chip to ensure that the silicon-based imaging chip can obtain a good QE (quantum efficiency) response in the band of 400 - 1000nm. To ensure that the entire coated effective area of the linear variable filter 3 is within the imaging area of the silicon-based imaging chip of the detector 1, the size of the linear variable filter 3 should be smaller than the target size of the imaging chip of the detector 1, that is, the horizontal size of the linear variable filter 3 should be less than 11.27mm, and the vertical size should be less than 10.24mm (the width of the linear variable filter 3 is less than the width of the imaging area of the imaging chip, and the length of the linear variable filter 3 is less than the length of the imaging area of the imaging chip).
[0027] At the same time, the light in the long-wave range passing through the linear variable filter 3 will be reflected to the short-wave, resulting in an additional response at the short-wave. To eliminate this influence, a cut-off filter 2 is covered at the short-wave range of the linear variable filter 3. This cut-off filter 2 can only transmit light in the short-wave range and cut off light in the long-wave range. The coated area of the cut-off filter 2 only needs to cover the starting band with wavelength response.
[0028] The cutoff film 2 can be a short-wave pass cutoff film, a band-pass cutoff film, or a linearly graded short-wave pass cutoff film. The technical effects of the short-wave pass cutoff film and the band-pass cutoff film are the same, and in the production process, the manufacturing cost of the band-pass cutoff film is higher than that of the short-wave pass cutoff film.
[0029] The technical effect of the linearly graded short-wave pass cutoff film is better than the above two. Since the linearly graded filter 3 is linearly graded, the transmission band of the linearly graded short-wave pass cutoff film can be matched one by one with the transmission band of the linearly graded filter 3, ensuring that only the light of that band can pass through under each band, and can more effectively suppress the stray light in the optical system.
[0030] Without considering the cost, the linearly graded short-wave pass cutoff film is the first preferred solution; when considering the cost, the preferred solution is the short-wave pass cutoff film.
[0031] The starting value of the working band of the linearly graded filter 3 is greater than or equal to 300 nm, and the ending value of the working band of the linearly graded filter 3 is less than or equal to 1100 nm.
[0032] Set the total height of the first placement groove 5 and the second placement groove 6 to be the same as the total height of the cutoff film 2 and the linearly graded filter 3, so that the cutoff film 2 and the linearly graded filter 3 are closely attached together. The starting position of the coating of the cutoff film 2 is the position on the cutoff film 2 corresponding to the position where the starting value of the working band of the linearly graded filter 3 is located.
[0033] Record the long-wave band where the linearly graded filter 3 has an additional response at short waves, and use the long-wave band as the marked band, and use the position on the cutoff film 2 corresponding to the position where the marked band of the linearly graded filter 3 is located as the ending position of the coating of the cutoff film 2.
[0034] That is, the coating area of the cutoff film 2 only needs to cover up to the "starting band of the long wave where the linearly graded filter 3 has an additional response at short waves". For example: if the linearly graded filter 3 also has a response to the light of long wave 650 nm at short wave 400 nm (starting value of the working band), then the coating area of the cutoff film 2 is the position corresponding to the position where the linearly graded filter 3 can transmit the light of 400 nm - 650 nm.
[0035] The method for obtaining the wavelength position correlation formula of the silicon-based hyperspectral imaging device is as follows: Place the silicon-based hyperspectral imaging device in front of the light outlet of the integrating sphere of the monochromator; Make the monochromator emit monochromatic light, the wavelength value of the monochromatic light is the same as the wavelength value of the starting value of the working band of the linearly graded filter 3, and use the silicon-based hyperspectral imaging device to collect the current monochromatic light response image; Increment the wavelength value of the monochromatic light emitted by the monochromator by one, and repeat the above steps until the wavelength value of the monochromatic light emitted by the monochromator is the same as the wavelength value of the termination value of the working band of the linear variable filter 3, so that the silicon-based hyperspectral imaging device acquires all monochromatic light response images; Accumulate and sum the monochromatic light response images according to the gray values of the pixels in each row to obtain the row coordinate with the maximum response value of each monochromatic light response image; Perform a cubic equation fitting on the wavelength values of the monochromatic lights emitted by the monochromator and the row coordinates with the maximum response values of the monochromatic light response images to obtain the wavelength position correlation formula of the silicon-based hyperspectral imaging device.
[0036] The position-wavelength formula in the wavelength position correlation formula of the silicon-based hyperspectral imaging device is: ; where, is the wavelength of the silicon-based hyperspectral imaging device related to the wavelength position, is the pixel row coordinate corresponding to the silicon-based hyperspectral imaging device related to the wavelength position at the current wavelength, 、 、 and are the constants of the cubic equation.
[0037] The position-wavelength formula in the wavelength position correlation formula of the silicon-based hyperspectral imaging device is: ; where, is the pixel row coordinate of the silicon-based hyperspectral imaging device related to the wavelength position, is the wavelength of the silicon-based hyperspectral imaging device related to the wavelength position at the current pixel row coordinate, 、 、 、 are the constants of the cubic equation.
[0038] For example, use a monochromator to traverse the silicon-based hyperspectral imaging device related to the wavelength position of the present invention. Place the silicon-based hyperspectral imaging device related to the wavelength position in front of the light outlet of the monochromator integrating sphere. Set the wavelength of the emitted monochromatic light to 400 nm and acquire a monochromatic light response image. Then set the wavelength of the emitted monochromatic light to 401 nm and acquire a monochromatic light response image. Repeat the above operations until the wavelength of the emitted monochromatic light is 1000 nm. At this time, a total of 601 images are obtained.
[0039] Analyze the group of images, and the analysis steps are as follows: For the monochromatic light response image at 400 nm, sum up the gray values of each pixel row by row in the row direction to obtain the row coordinate with the maximum response value at 400 nm. Then, for the monochromatic light response image at 401 nm, sum up the gray values of each pixel row by row in the row direction to obtain the row coordinate with the maximum response value at 401 nm. Repeat the above steps to obtain the row coordinates corresponding to the maximum gray value response for each wavelength in the range of 400 - 1000 nm. Fit this set of data with a cubic equation x + to obtain the position-wavelength curve and the wavelength-position curve.
[0040] The obtained position-wavelength curve is as shown in Figure 4 . The position-wavelength formula in the wavelength position correlation formula of the silicon-based hyperspectral imaging device is: ; wherein, is the wavelength of the silicon-based hyperspectral imaging device related to wavelength position, is the pixel row coordinate corresponding to the silicon-based hyperspectral imaging device related to wavelength position at the current wavelength, , , and are the constants of the cubic equation.
[0041] The obtained wavelength-position curve is as shown in Figure 5 . Through curve fitting, the wavelength-position formula in the wavelength position correlation formula of the silicon-based hyperspectral imaging device is: ; wherein, is the pixel row coordinate of the silicon-based hyperspectral imaging device related to wavelength position, is the wavelength of the silicon-based hyperspectral imaging device related to wavelength position at the current pixel row coordinate, , , , are the constants of the cubic equation.
[0042] It should be understood that various forms of the processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved. This is not limited herein.
[0043] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A silicon-based hyperspectral imaging device related to wavelength position, characterized in that: It includes a filter holder, a linear variable filter, a cut-off filter and a detector which are arranged in sequence along the optical path direction. Among them, a first placement groove and a second placement groove are formed at the center of the filter holder. The linear variable filter is installed in the first placement groove, the cut-off filter is installed in the second placement groove, and the linear variable filter and the cut-off filter are placed in parallel and overlapped in the vertical direction; the filter holder is installed on the housing of the detector, and the cut-off filter and the linear variable filter are located in the installation space of the detector.
2. The silicon-based hyperspectral imaging device related to the wavelength position according to claim 1, characterized in that: The size of the linear variable filter is smaller than the size of the imaging chip target surface of the detector.
3. The silicon-based hyperspectral imaging device related to the wavelength position according to claim 1, wherein: The total height of the first placement groove and the second placement groove is set to be the same as the total height of the cut-off filter and the linear variable filter, so that the cut-off filter and the linear variable filter are closely attached together.
4. The silicon-based hyperspectral imaging device related to a wavelength position according to claim 1, characterized in that: The imaging chip of the detector is a silicon-based imaging chip.
5. The silicon-based hyperspectral imaging device related to the wavelength position according to claim 1, wherein: The starting value of the working band of the linear variable filter is greater than or equal to 300 nm, and the ending value of the working band of the linear variable filter is less than or equal to 1100 nm; The cut-off filter includes a short-wave pass cut-off filter, a band-pass cut-off filter and a linear variable short-wave pass cut-off filter.
6. The silicon-based hyperspectral imaging device related to the wavelength position according to claim 1, wherein: The starting position of the coating of the cut-off filter is the position corresponding to the starting value position of the working band of the linear variable filter on the cut-off filter.
7. The silicon-based hyperspectral imaging device related to the wavelength position according to claim 1, wherein: The long-wave band where the linear variable filter has an additional response at the short wave is recorded, and the long-wave band is used as the marked band, and the position corresponding to the marked band position of the linear variable filter on the cut-off filter is used as the ending position of the coating of the cut-off filter.
8. The silicon-based hyperspectral imaging device related to the wavelength position according to claim 1, wherein: The method for obtaining the wavelength position correlation formula of the silicon-based hyperspectral imaging device is as follows: Place the silicon-based hyperspectral imaging device in front of the light outlet of the integrating sphere of the monochromator; Make the monochromator emit monochromatic light, the wavelength value of the monochromatic light is the same as the wavelength value of the starting value of the working band of the linear variable filter, and use the silicon-based hyperspectral imaging device to collect the current monochromatic light response image; Increase the wavelength value of the monochromatic light emitted by the monochromator by one, and repeat the above steps until the wavelength value of the monochromatic light emitted by the monochromator is the same as the wavelength value of the ending value of the working band of the linear variable filter, and make the silicon-based hyperspectral imaging device collect all the monochromatic light response images; Accumulate and sum the monochromatic light response images according to the gray values of each row of pixels, and obtain the row coordinates with the maximum response value of each monochromatic light response image; Perform a cubic equation fitting on the wavelength values of the monochromatic light emitted by the monochromator and the row coordinates with the maximum response value of each monochromatic light response image to obtain the wavelength position correlation formula of the silicon-based hyperspectral imaging device.
9. The silicon-based hyperspectral imaging device related to the wavelength position according to claim 8, characterized in that: The position-wavelength formula in the wavelength position correlation formula of the silicon-based hyperspectral imaging device is: ； Among them, is the wavelength of the silicon-based hyperspectral imaging device related to the wavelength position, is the pixel row coordinate corresponding to the silicon-based hyperspectral imaging device related to the wavelength position at the current wavelength, , , and are the constants of the cubic equation.
10. The silicon-based hyperspectral imaging device related to wavelength position according to claim 8, wherein: The wavelength-position formula in the wavelength position correlation formula of the silicon-based hyperspectral imaging device is: ； Among them, is the pixel row coordinate of the silicon-based hyperspectral imaging device related to the wavelength position, is the wavelength of the silicon-based hyperspectral imaging device related to the wavelength position at the current pixel row coordinate, , , , are the constants of the cubic equation.