Imaging system and method for acquisition of multi-spectral images

Patent metadata

Field	Value
Publication number	US-11758294-B2
Application number	US-202217814614-A
Country	US
Kind code	B2
Filing date	Jul 25, 2022
Priority date	Aug 2, 2021
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

Example embodiments relate to imaging systems and methods for acquisition of multi-spectral images. One example imaging system includes a detector that includes an array of light sensitive elements arranged in rows and columns. Each light sensitive element is configured to generate a signal dependent on an intensity of light incident onto the light sensitive element. The imaging system also includes a plurality of wavelength separating units. Each wavelength separating unit is configured to spatially separate incident light within a wavelength range into a number of wavelength bands distributed along a line. The line is a straight line. Each wavelength band along the line is associated with a mutually unique light sensitive element. Further, the imaging system includes a processing unit configured to define a number of mutually unique clusters of light sensitive elements for summing signals from the light sensitive elements within the respective clusters.

First claim

What is claimed is:

1. An imaging system comprising:
a detector comprising an array of light sensitive elements arranged in rows and columns, wherein each light sensitive element is configured to generate a signal dependent on an intensity of light incident onto the light sensitive element;
a plurality of wavelength separating units, wherein each wavelength separating unit is configured to spatially separate incident light within a wavelength range into a number of wavelength bands distributed along a line, wherein the line is a straight line, wherein each wavelength band along the line is associated with a mutually unique light sensitive element, wherein each of the rows is associated with more than one wavelength separating unit of the plurality of wavelength separating units, and wherein each of the columns is associated with more than one wavelength separating unit of the plurality of wavelength separating units; and
a processing unit configured to define a number of mutually unique clusters of light sensitive elements for summing signals from the light sensitive elements within the respective clusters, wherein each cluster respectively forms a continuous area of the light sensitive elements, wherein each cluster comprises light sensitive elements associated with more than one wavelength separating unit of the plurality of wavelength separating units, wherein each cluster comprises light sensitive elements associated with wavelength bands such that the summed signals represent a combination of the spectral information of the wavelength bands, and wherein the processing unit is configured to perform hardware binning for summing the signals from the light sensitive elements within each of the mutually unique clusters respectively.

2. The imaging system according to claim 1 , wherein each cluster comprises light sensitive elements associated with wavelength bands being overlapping or adjacent with respect to wavelength such that the summed signals of each respective cluster represent a wavelength interval within the wavelength range.

3. The imaging system according to claim 1 ,
wherein the line of wavelength bands of each of the wavelength separating units is arranged to extend along a row of the light sensitive elements such that each wavelength band along the line is associated with the mutually unique light sensitive element along the row, and
wherein, along the respective rows, the wavelength separating units are arranged continuously, one after the other.

4. The imaging system according to claim 3 , wherein the wavelength separating units are identical, and wherein, along the respective rows, the wavelength separating units are arranged with alternating orientation with respect to an order of the wavelength bands along the line.

5. The imaging system according to claim 3 , wherein the wavelength separating units in adjacent rows are arranged side by side forming columns of wavelength separating units parallel to the columns of light sensitive elements.

6. The imaging system according to claim 3 , wherein the wavelength separating units in adjacent rows are arranged to be offset with respect to each other.

7. The imaging system according to claim 1 , wherein the wavelength bands of each wavelength separating unit are ordered along the line in a descending manner with respect to wavelength.

8. The imaging system according to claim 1 , wherein each wavelength separating unit is configured to separate the incident light into three wavelength bands.

9. The imaging system according to claim 1 , wherein each wavelength separating unit is configured to separate the incident light into four wavelength bands.

10. The imaging system according to claim 9 , wherein the wavelength range corresponds to a visible spectrum of light, and wherein the wavelength bands comprise the red, green, and blue portions of the visible spectrum of light.

11. The imaging system according to claim 10 , wherein the clusters are configured such that the summed signals being combinations of the red, green, and blue wavelength bands represent:
the colors red, green, and blue; or
the colors yellow, cyan, and magenta; or
the colors red, yellow, cyan, and blue.

12. The imaging system according to claim 1 , wherein each of the wavelength separating units respectively comprise:
a first waveguide portion extending in a first direction and being configured to be a single-mode waveguide for the incident light within the wavelength range covering the number of wavelength bands;
a funnel element configured to receive the incident light and to funnel the incident light into a first end of the first waveguide portion; and
a second waveguide portion extending along the first direction and in parallel with the first waveguide portion and being configured to selectively guide light within one of the wavelength bands of the number of wavelength bands,
wherein the second waveguide portion is coupled to the first waveguide portion and configured to out-couple light from the first waveguide portion, within the wavelength band, and
wherein a second end of the first waveguide portion and an end of the second waveguide portion are configured to separately allow light transmitted through the first waveguide portion and the second waveguide portion to exit the respective waveguide portions in the first direction, thereby enabling the light to reach the light sensitive elements of the detector.

13. The imaging system according to claim 1 , wherein the clusters are arranged in a set of cluster rows, wherein each cluster row of the set of cluster rows extend in a straight line in parallel with the rows of light sensitive elements, and wherein the clusters in adjacent cluster rows are arranged to be spatially offset with respect to each other.

14. A method for acquisition of a multi-spectral image, wherein the method comprises:
collecting incident light;
passing the incident light within a wavelength range through a plurality of wavelength separating units, each wavelength separating unit being configured to spatially separate the incident light into a number of wavelength bands distributed along a line, wherein the line is a straight line;
detecting the light in the number of wavelength bands, by a detector comprising an array of light sensitive elements arranged in rows and columns, wherein each light sensitive element is configured to generate a signal dependent on an intensity of light incident onto the light sensitive element, wherein each wavelength band along the line is associated with a mutually unique light sensitive element, wherein each of the rows is associated with more than one wavelength separating unit of the plurality of wavelength separating units, and wherein each of the columns is associated with more than one wavelength separating unit of the plurality of wavelength separating units;
defining a number of mutually unique clusters of light sensitive elements, wherein each cluster respectively forms a continuous area of the light sensitive elements; and
summing signals from the light sensitive elements within the respective clusters, wherein each cluster comprises light sensitive elements associated with more than one wavelength separating unit of the plurality of wavelength separating units, wherein each cluster comprises light sensitive elements associated with wavelength bands such that the summed signals represent a combination of the spectral information of the wavelength band, and wherein the summing the signals from the light sensitive elements within each of the mutually unique clusters respectively, is performed using hardware binning.

15

Assignees

• Imec Vzw

Inventors

• Kim Joo Hyoung
• Lee Jiwon
• Genoe Jan
• Gehlhaar Robert

Classifications

• G01J3/36 Primary

  Investigating two or more bands of a spectrum by separate detectors · CPC title

• H04N25/135 Primary

  based on four or more different wavelength filter elements · CPC title

• G01J3/2803

  using photoelectric array detector · CPC title

• G01J2003/2826

  Multispectral imaging, e.g. filter imaging · CPC title

• G01J3/0205

  Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows · CPC title