HYPERSPECTRAL IMAGING SYSTEM

• US 20180095307A1
• Filed: 10/03/2016
• Published: 04/05/2018
• Est. Priority Date: 10/03/2016
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Herloski, Robert P.
• Granted Patent: US 10,768,497 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/137 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
• CPC Class Codes: G02F 2202/022 polymeric
• CPC Class Codes: G02F 2203/12 spatial light modulator
• CPC Class Codes: G03G 15/5041 Detecting a toner image, e.g. density, toner coverage, using a test patch G03G15/553 takes precedence
• CPC Class Codes: G03G 15/5062 by measuring the characteristics of an image on the copy material
• CPC Class Codes: H04N 1/6044 involving a sensor integrated in the machine or otherwise specifically adapted to read the test pattern

Abstract

A hyperspectral imaging system, comprising an input polarizer arranged to receive and polarize a first light, a liquid crystal variable retarder to change a polarization of the first light in a wavelength-dependent manner, an output polarizer arranged to receive the wavelength-dependent polarized first light, a voltage source electrically connected to the liquid crystal variable retarder, a controller connected to the voltage source, the controller configured to control voltages applied to the liquid crystal variable retarder to control a retardance of the first light. A linear image sensor has a length extending in a direction to obtain images of the first light, the linear image sensor synchronized with the controller to collect the images as a function of retardance of the liquid crystal variable retarder after the first light passes through the output polarizer, for generation of an output signal corresponding to a portion of the linear image sensor.

Claims

1. :

A hyperspectral imaging system, comprising;

an input polarizer arranged to receive and polarize a first light;

a liquid crystal variable retarder arranged after the input polarizer along a path of the first light to change a polarization of the first light in a wavelength-dependent manner;

an output polarizer arranged to receive the wavelength-dependent polarized first light and to convert polarization state information of the first light into a form detectable as light intensity;

a voltage source electrically connected to the liquid crystal variable retarder;

a controller connected to the voltage source, the controller configured to control voltages applied to the liquid crystal variable retarder to control a retardance of the first light;

a linear image sensor having a length extending in a direction to obtain images of the first light, the linear image sensor synchronized with the controller to collect the images as a function of retardance of the liquid crystal variable retarder after the first light passes through the output polarizer, for generation of an output signal corresponding to a portion of the linear image sensor; and

an internal light source arranged to output a second light directly towards at least one of;

the input polarizer; and

, the linear image sensor.

2. :

The system of claim 1, wherein the linear sensor is a one-dimensional, sensor array.

3. :

The system of claim 1, wherein the linear sensor is a two-dimensional, sensor array having pixels binned together to form the linear sensor.

4. :

The system of claim 1, wherein the linear image sensor is a full width array sensor.

5. :

The system of claim 1, wherein the portion of the linear sensor corresponds to a single pixel.

6. :

The system of claim 1, wherein the portion of the linear sensor corresponds to a plurality of pixels binned together.

7. :

The system of claim 1, further comprising a processor programmed to perform a transform of the output signal to generate spectral information.

8. :

The system of claim 7, wherein the transform is a Fourier transform.

19. :

The system of claim 1 further comprising;

a photodetector arranged to obtain at least one of;

a portion of the first light; and

a portion of the second light.

9. :

A printer, comprising;

I.) a light source;

II.) an image bearing surface positioned to receive light form the light source and to form an output light from the light incident thereon, the image bearing surface disposed on a drum or a belt to move the image bearing surface in a process direction;

III.) a hyperspectral imaging system comprising;

an input polarizer arranged to receive and polarize the output light;

a liquid crystal variable retarder arranged after the input polarizer along a path of the output light to change polarization of the output light in a wavelength-dependent manner;

an output polarizer arranged to receive the wavelength-dependent polarized output light and to convert polarization state information of the output light into a form detectable as light intensity;

a voltage source electrically connected to the liquid crystal variable retarder;

a controller connected to the voltage source, the controller configured to control voltages applied to the liquid crystal variable retarder to control a retardance of the output light;

a linear image sensor having a length extending in a direction to obtain images of the output light in a cross-process direction, the linear image sensor synchronized with the controller to collect the images as a function of retardance of the liquid crystal variable retarder after the output light passes through the output polarizer, for generation of an output signal corresponding to a portion of the linear image sensor;

an internal light source arranged to output an internal light to directly illuminate at least one of;

the input polarizer; and

, the linear image sensor; and

IV.) a processor to perform transformations of the output signal into spectral information.

10. :

The printer of claim 9, wherein the linear sensor is a one-dimensional, sensor array.

11. :

The printer of claim 9, wherein the linear sensor is a two-dimensional, sensor array having pixels binned together to form the linear sensor.

12. :

The printer of claim 9, wherein the linear image sensor is a full width array sensor.

13. :

The printer of claim 9, wherein the image bearing surface is a photoreceptor.

14. :

The printer of claim 9, wherein the portion of the linear sensor corresponds to a single pixel.

15. :

The printer of claim 9, wherein the portion of the linear sensor corresponds to a plurality of pixels extending along the cross-process direction, the plurality of pixels being binned together.

16. :

The printer of claim 9, wherein the transform is a Fourier transform.

17. :

The printer of claim 9, wherein the image bearing surface is an output sheet of paper.

18. :

The printer of claim 9, wherein the image bearing surface is a photoreceptor belt.

20. :

The printer of claim 9 further comprising;

a photodetector arranged to obtain at least one of;

a portion of the output light; and

a portion of the internal light.