Method for quickly verifying imaging effect of aperture coding infrared hyperspectral imaging system

Abstract

This invention proposes a rapid verification method for the imaging performance of an aperture-coded infrared hyperspectral imaging system. This method uses an N×M filter array as the indoor imaging target. This array includes a central infrared window and multiple filters with different center wavelengths surrounding the infrared window, containing rich spectral feature information and geometric and spatial positional information of the filters. Utilizing a large-area blackbody and a collimator with a large focal plane, the system can capture all the necessary information from the filter array. After image reconstruction, using the data from the central window as a reference, the spectral transmittance curves of each filter can be calculated quickly and accurately, thereby verifying the system's ability to acquire spectral information. The system's ability to acquire geometric information can also be verified by observing the geometry and relative positions of the filters in each spectral channel. This invention provides an efficient, reliable, and rapid verification method for aperture-coded infrared hyperspectral imaging systems.

Description

Technical Field

[0001] This invention relates to the field of infrared spectral imaging technology, and in particular to a method for rapid verification of the imaging performance of an aperture-coded infrared hyperspectral imaging system. Background Technology

[0002] Infrared spectral imaging technology is based on the infrared spectral characteristics emitted by an object, simultaneously acquiring the object's infrared spectral information and spatial geometric information, and determining the object's composition and structure through spectral analysis. Hyperspectral imaging systems are widely used in materials science, environmental monitoring, biomedicine, and other fields.

[0003] Aperture-coded infrared hyperspectral imaging systems, based on computational optics, significantly improve the signal-to-noise ratio by encoding and aliasing the target signal and then reconstructing the hyperspectral image from the aliased data. However, this imaging principle results in the detector acquiring aliased data, which cannot directly represent the target's spatial and spectral information. Image reconstruction is required after data acquisition to reveal the target information. Traditional methods for verifying the imaging performance of aperture-coded infrared hyperspectral imaging systems typically involve multiple imaging experiments, each with its own data acquisition and reconstruction process. This consumes significant time and resources to verify and evaluate the imaging system.

[0004] In existing technologies, verifying the imaging performance of aperture-coded infrared hyperspectral imaging systems typically requires multiple imaging experiments involving several imaging targets with different spectral and geometric features. Furthermore, for aperture-coded systems, all features of the imaging target cannot be directly displayed on the detector image; observation can only be performed after data reconstruction. Multiple acquisition experiments and data reconstruction require a significant amount of time, which reduces the efficiency of system performance evaluation and optimization. Summary of the Invention

[0005] This invention relates to a rapid verification method for the imaging performance of an aperture-coded infrared hyperspectral imaging system. In existing technologies, verifying the imaging performance of an aperture-coded infrared hyperspectral imaging system typically requires a complex process and significant time investment, which reduces the efficiency of system performance evaluation and optimization. To address this issue, this invention proposes a rapid verification method for the imaging performance of an aperture-coded infrared hyperspectral imaging system, which requires only a single data acquisition and reconstruction to verify the system's imaging performance.

[0006] Therefore, the present invention provides the following technical solution:

[0007] A rapid verification method for the imaging performance of an aperture-coded infrared hyperspectral imaging system includes the following steps:

[0008] (1) Using the filter array as the imaging target, an imaging optical path is built using a surface source blackbody, collimator and aperture-coded infrared hyperspectral imaging system;

[0009] The filter array is arranged in an N×M pattern, where N and M are both odd numbers greater than or equal to 3. In the filter array, the infrared window is located at the center, and the other filters with different center wavelengths surround the infrared window.

[0010] (2) The blackbody emits long-wave infrared radiation, which is then processed by a filter array to form a long-wave infrared signal containing spectral feature information. After passing through a collimator, it is received by an aperture-coded infrared hyperspectral imaging system to complete one coded data acquisition.

[0011] (3) The aperture-coded infrared hyperspectral imaging system performs image reconstruction on the coded data to obtain hyperspectral image data of the filter array;

[0012] (4) Based on the blackbody spectral data of the infrared window area, calculate the transmittance curves of all filters and compare them with the factory test data of the filters to verify the spectral acquisition capability of the aperture-coded infrared hyperspectral imaging system.

[0013] By observing the image data of each spectral channel, analyzing the geometric shape and relative position distribution of the filters in the images, and comparing them with the actual filter array, the spatial acquisition capability of the aperture-coded infrared hyperspectral imaging system is verified.

[0014] Furthermore, the transmission band of the infrared window covers the detection band of the aperture-coded infrared hyperspectral imaging system; the half-width at half-maximum (WHM) of each filter is no greater than 30% of the detection band length of the aperture-coded infrared hyperspectral imaging system; the center wavelength of each filter is within the detection band range of the aperture-coded infrared hyperspectral imaging system, and the center wavelength interval between any two filters is no less than 10% of the detection band length of the aperture-coded infrared hyperspectral imaging system, to ensure that the filter array has rich spectral feature information.

[0015] Furthermore, the radiation surface size of the blackbody and the focal plane size of the collimator are both larger than the size of the filter array, to ensure that all information from the filter array can be received by the aperture-coded infrared hyperspectral imaging system.

[0016] Furthermore, the filter array is arranged in a 3×3 configuration; in the filter array, the infrared window is located at the center, and surrounding the infrared window are 8 filters with different center wavelengths.

[0017] Furthermore, in the filter array, the central element is a fully infrared window.

[0018] The advantage of this invention lies in its significantly improved efficiency in performance evaluation and optimization of aperture-coded infrared hyperspectral imaging systems. Comprehensive verification of imaging results can be completed with only a single data acquisition and image reconstruction. This not only saves time and cost but also provides accurate and reliable data for optimizing aperture-coded infrared hyperspectral imaging systems. Therefore, this invention provides an efficient, reliable, and rapid verification method for aperture-coded infrared hyperspectral imaging systems, contributing to technological progress and development in this field. Attached Figure Description

[0019] Appendix Figure 1 This is a schematic diagram of the distribution of the filter array.

[0020] Appendix Figure 2 To verify the imaging experimental block diagram.

[0021] The attached figures are labeled as follows: 1. Blackbody source; 2. Blackbody radiating surface; 3. Filter array; 4. Collimator; 5. Collimator focal plane; 6. Aperture-coded infrared hyperspectral imaging system. Detailed Implementation

[0022] The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the solution and to implement it in accordance with the description, the following provides a detailed description of specific examples applicable to the solution based on the content of the present invention.

[0023] This embodiment constructs a rapid verification method for the imaging effect of an aperture-coded infrared hyperspectral imaging system, wherein the detection band of the aperture-coded infrared hyperspectral imaging system is 8 to 12.5 μm.

[0024] Figure 1 The diagram shows a 3×3 filter array suitable for this aperture-coded infrared hyperspectral imaging system. The array includes a central infrared window and eight surrounding filters. The central window has a transmission band of 7 to 14 μm; the center wavelengths of the remaining eight filters are all within the detection band of the aperture-coded infrared hyperspectral imaging system, with a full width at half maximum (FWHM) of 700 nm. This includes two filters with center wavelengths of 8 μm and 12.5 μm, demonstrating the detection capability of the aperture-coded infrared hyperspectral imaging system (i.e., the "imaging system") at the boundaries of the detection band.

[0025] Figure 2The diagram shows the experimental block diagram for verifying the imaging experiment, which includes a blackbody source, a filter array, a collimator, and an imaging system. The filter array measures 32mm × 32mm, the blackbody radiating surface measures 50mm × 50mm, and the collimator focal plane measures 36mm × 36mm, ensuring that all information from the filter array is received by the imaging system. The verification imaging experiment based on this block diagram can quickly, accurately, and comprehensively verify the imaging system's ability to detect spatial and spectral information.

[0026] Preferably, the filter array can be arranged in an N×M pattern, where N and M are both odd numbers greater than or equal to 3. The filter array includes a central window located at the center of the array, with the remaining filters surrounding the central window. The number of filters is N×M-1. For example, when N=3 and M=3, the filter array contains one central window and 8 filters (e.g., ...). Figure 1 (As shown).

[0027] The core of this invention lies in using a specially designed 3×3 array of filters as the indoor imaging target. This filter array has a unique design: a fully infrared window at its center, whose transmission band covers the detection band range of the aperture-coded infrared hyperspectral imaging system. Surrounding this central window (i.e., the fully infrared window) are eight filters with different center wavelengths. The half-width at half-maximum (FWHM) of each filter is no greater than 30% of the detection band length of the aperture-coded infrared hyperspectral imaging system. The center wavelength of each filter is within the detection band range of the aperture-coded infrared hyperspectral imaging system, and the center wavelength interval between any two filters is no less than 10% of the detection band length of the aperture-coded infrared hyperspectral imaging system. This design ensures that the filter array contains both rich spectral feature information and geometric and spatial position information of the filters.

[0028] The purpose of using a filter array in this scheme is to artificially construct an imaging target containing various spectral and geometric features. Conducting one experiment on this filter array is equivalent to completing multiple experiments on various targets.

[0029] Testing the transmittance curve of each filter requires two sets of data: the spectrum of the light source itself and the spectrum after passing through the filter. With the filter array layout of this scheme, the spectrum of the light source itself and the spectrum after passing through different filters can be collected simultaneously in one experiment, thereby quickly calculating the transmittance curves of multiple filters.

[0030] In addition, since the filter will be provided with the transmittance curve of the factory test by the manufacturer, it can be used as a standard to compare the difference between the transmittance curve of the imaging system to be verified and the standard curve. This saves the system developer from the experiment of collecting the target standard curve.

[0031] The steps of the rapid verification method for the imaging effect of the aperture-coded infrared hyperspectral imaging system of the present invention are briefly as follows:

[0032] (1) Using a 3×3 array of filters as the imaging target, an imaging optical path is constructed using a blackbody source, a collimator, and an aperture-coded infrared hyperspectral imaging system.

[0033] In the filter array, the central element is a fully infrared window, surrounded by eight filters with different center wavelengths; for example... Figure 1 As shown.

[0034] The verification process begins with setting up the experimental optical path. The verification experiment uses a blackbody as the light source, a collimator for collimation, and a filter array as the imaging target, positioned at the focal plane of the collimator. Both the radiating surface size of the blackbody and the focal plane size of the collimator are larger than the size of the filter array to ensure that all information from the filter array can be received by the imaging system.

[0035] (2) The blackbody emits long-wave infrared radiation, which is then processed by a filter array to form a long-wave infrared signal containing spectral feature information. This signal is then received by an aperture-coded infrared hyperspectral imaging system after passing through a collimator, completing one coded data acquisition. The experimental block diagram of the imaging experiment is shown below. Figure 2 As shown.

[0036] (3) The aperture-coded infrared hyperspectral imaging system performs image reconstruction on the coded data to obtain hyperspectral image data of the filter array;

[0037] (4) Using the blackbody spectral data of the infrared window region as a benchmark, calculate the ratio of the spectral data of the filter region and the infrared window region, which is the measured value of the transmittance curve of the filter. Compare it with the factory data of the filter and evaluate it with the spectral angle matching (SAM) index to verify the spectral acquisition capability of the aperture-coded infrared hyperspectral imaging system.

[0038] In addition, by observing the image data of each spectral channel, analyzing the geometric shape and relative position distribution of the filters in the images, and comparing them with the actual filter array, the spatial acquisition capability of the aperture-coded infrared hyperspectral imaging system was verified.

[0039] This method uses a specially designed filter array as the imaging target, acquiring data on multiple different spectral features in a single data acquisition and reconstruction process. These features are distributed across the system's detection band and have available standard data for reference. Essentially, a single imaging experiment achieves the observational results of multiple imaging experiments. Therefore, this method allows for rapid performance evaluation of aperture-coded infrared hyperspectral imaging systems. This approach not only simplifies the verification process and improves verification efficiency but also accurately reflects the system's true performance in spectral and geometric information acquisition, providing strong data support for system optimization and upgrades. Therefore, this invention has promising application prospects in aperture-coded infrared hyperspectral imaging systems.

Claims

1. A rapid verification method for the imaging effect of an aperture-coded infrared hyperspectral imaging system, characterized in that, Includes the following steps: (1) Using a filter array as the imaging target, an imaging optical path is constructed using a surface source blackbody, a collimator, and an aperture-coded infrared hyperspectral imaging system; The filter array is arranged in an N×M pattern, where N and M are both odd numbers greater than or equal to 3. In the filter array, the infrared window is located at the center, and the other filters with different center wavelengths surround the infrared window. The transmission band of the infrared window covers the detection band of the aperture-coded infrared hyperspectral imaging system; the half-width at half-maximum (WHM) of each filter is no greater than 30% of the detection band length of the aperture-coded infrared hyperspectral imaging system; the center wavelength of each filter is within the detection band range of the aperture-coded infrared hyperspectral imaging system, and the center wavelength interval between any two filters is no less than 10% of the detection band length of the aperture-coded infrared hyperspectral imaging system, to ensure that the filter array has rich spectral feature information. (2) The blackbody emits long-wave infrared radiation, which is then processed by a filter array to form a long-wave infrared signal containing spectral feature information. This signal is then received by an aperture-coded infrared hyperspectral imaging system after passing through a collimator, thus completing one coded data acquisition. (3) The aperture-coded infrared hyperspectral imaging system performs image reconstruction on the coded data to obtain hyperspectral image data of the filter array; (4) Using the blackbody spectral data of the infrared window area as a reference, calculate the transmittance curves of all filters and compare them with the factory test data of the filters to verify the spectral acquisition capability of the aperture-coded infrared hyperspectral imaging system. By observing the image data of each spectral channel, analyzing the geometric shape and relative position distribution of each filter in the image, and comparing it with the actual filter array, the spatial acquisition capability of the aperture-coded infrared hyperspectral imaging system is verified.

2. The rapid verification method for the imaging effect of the aperture-coded infrared hyperspectral imaging system according to claim 1, characterized in that, The radiation surface size of the blackbody and the focal plane size of the collimator are both larger than the size of the filter array, to ensure that all information from the filter array can be received by the aperture-coded infrared hyperspectral imaging system.

3. The rapid verification method for the imaging effect of the aperture-coded infrared hyperspectral imaging system according to claim 1, characterized in that, The filter array is arranged in a 3×3 configuration; in the filter array, the infrared window is located at the center, and there are 8 filters with different center wavelengths surrounding the infrared window.

4. The rapid verification method for the imaging effect of the aperture-coded infrared hyperspectral imaging system according to claim 1, characterized in that, In the filter array, the central element is the all-infrared window.

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