Spatial resolution enhancement in hyperspectral imaging
In a hyperspectral imaging system and method, a pixilated imaging sensor array receives light reflected from, transmitted through, or scattered by a target scene. Images of the target scene are acquired at a number of times and these images are processed to generate hyperspectral data for each pixel of the imaging sensor array based on data for the pixel included in each of the acquired images. This processing can include spatially aligning two or more of the images that were spatially shifted with respect to each other when acquired based on at least one common image feature in the images.
1. A hyperspectral imaging system comprising:
a plurality of illumination sources in fixed positions to output light toward a target scene;
an imaging sensor array including an array of pixels configured for outputting electrical signals in response to receiving light reflected from, transmitted through, or scattered by the target scene;
an array of light filters over the imaging sensor array, the array of light filters configured to filter light before reaching the pixels of the imaging sensor array; and
a controller coupled to the imaging sensor array, the controller having a memory;
wherein the controller is adapted to:
acquire into the memory from the imaging sensor array a plurality of images of the target scene during movement or dithering of the combination of the imaging sensor array and the array of light filters, wherein said plurality of images as acquired are spatially shifted with respect to each other, and wherein at least one single image of the plurality of images includes hyperspectral information; and
process the plurality of acquired images in the memory of the controller to spatially align said plurality of images based on at least one common image feature in said plurality of images.
2. The hyperspectral imaging system of claim 1 , wherein each image includes the electrical signals output by the array of pixels of the imaging sensor array at the same time or substantially the same time.
3. The hyperspectral imaging system of claim 1 , wherein the array of light filters includes light filters that are configured to filter different center, peak transmission wavelengths of light.
4. The hyperspectral imaging system of claim 3 , wherein adjacent light filters of at least a portion of the array of light filters are configured to filter different center, peak transmission wavelengths of light.
5. The hyperspectral imaging system of claim 1 , wherein:
the array of light filters includes an N by N array of light filters, where N is a positive integer that is greater than one; and
one or more of the light filters in the N by N array of light filters are configured to filter different center, peak transmission wavelengths of light.
6. The hyperspectral imaging system of claim 5 , wherein sums of optical power transmitted by the light filters of each row and column of the array of light filters are the same or substantially the same.
7. The hyperspectral imaging system of claim 1 , further including a device for moving or dithering the combination of the imaging sensor array and the array of light filters.
8. The hyperspectral imaging system of claim 7 , further including the controller adapted to synchronize said movement or dithering and said acquiring of images such that the plurality of images as acquired are spatially shifted with respect to each other.
9. A hyperspectral imaging system comprising:
a plurality of illumination sources in fixed positions, each illumination source having a different spectrum, for outputting light for reflection by, transmission through, or scattering by a target scene;
an imaging sensor array including an array of pixels configured for outputting electrical signals in response to receiving the light reflected from, transmitted through, or scattered by the target scene;
an array of light filters over the imaging sensor array, the array of light filters configured to filter light before reaching the pixels of the imaging sensor array; and
a controller adapted to:
acquire into a memory of the controller from the imaging sensor array a first image of the target scene illuminated by a first one of the plurality of illumination sources during movement or dithering of the combination of the imaging sensor array and the array of light filters, wherein the first image includes hyperspectral information;
acquire into the memory of the controller from the imaging sensor array a second image of the target scene illuminated by a second one of the plurality of illumination sources during movement or dithering of the combination of the imaging sensor array and the array of light filters, wherein the second image includes hyperspectral information; and
generate hyperspectral data for each pixel of the imaging sensor array based on data for said pixel being included in the first and second acquired images.
10. The hyperspectral imaging system of claim 9 , wherein each image includes the electrical signals output by the array of pixels of the imaging sensor array at the same time or substantially the same time.
11. The hyperspectral imaging system of claim 9 , wherein the first and second illumination sources have either overlapping or non-overlapping spectra.
12. The hyperspectral imaging system of claim 9 , wherein at least one of the illumination sources is a monochromatic illumination source.
13. The hyperspectral imaging system of claim 9 , wherein at least one of the illumination sources is a white illumination source.
14. A hyperspectral imaging system comprising:
a plurality of illumination sources in fixed positions to output light toward a target scene;
an imaging sensor array including an array of pixels configured to generate electrical signals in response to receiving light associated with the target scene;
an array of light filters over the imaging sensor array, the array of light filters being adapted to filter light before it reaches the array of pixels of the imaging sensor array; and
a controller coupled to the imaging sensory array; and
a storage device coupled to the controller;
wherein the controller is adapted to:
receive the electrical signals from the imaging sensor array;
store data representing the electrical signals into a storage device to capture a plurality of images of the target scene, wherein the plurality of images of the target scene are captured during movement of the imaging sensor array and/or the array of light filters or the dithering of the imaging sensor array such that they are spatially shifted with respect to each other, and wherein at least one single image of the plurality of images includes hyperspectral information; and
spatially align the plurality of images of the target scene based on at least one common image feature in the plurality of images.
15. The hyperspectral imaging system of claim 14 , wherein the storage device is memory.
16. The hyperspectral imaging system of claim 14 , wherein a frame of data stored in the storage device represents the capture of an image by the array of pixels of the imaging sensor array at the same time.
17. The hyperspectral imaging system of claim 14 , wherein adjacent light filters of at least a portion of the array of light filters are configured to filter different center, peak transmission wavelengths of light.
18. The hyperspectral imaging system of claim 14 , wherein:
the array of light filters includes an N by N array of light filters, where N is a positive integer that is greater than one; and
one or more light filters in the N by N array of light filters are configured to filter different center, peak transmission wavelengths of light.
19. The hyperspectral imaging system of claim 18 , wherein sums of optical power transmitted by the light filters of each row and column of the array of light filters are similar.
20. The hyperspectral imaging system of claim 1 , further comprising:
a dithering device to move or dither the imaging sensor array and/or the array of light filters.