DUAL-APERTURE RANGING SYSTEM

• US 20170118418A1
• Filed: 08/31/2016
• Published: 04/27/2017
• Est. Priority Date: 10/22/2015
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: WANG, Guo-Zhen, CHEN, Yi-Lei
• Granted Patent: US 10,368,014 B2
• Time in Patent Office: Days
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 7/571 from focus
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/57 Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/131 including elements passing infrared wavelengths
• CPC Class Codes: H04N 25/135 based on four or more different wavelength filter elements
• CPC Class Codes: H04N 25/61 the noise originating only from the lens unit, e.g. flare, shading, vignetting or "cos4"

Abstract

A ranging system including a first aperture stop, a second aperture stop, an image sensor and a processing unit is provided. The first aperture stop includes a sheet of IR-cut filter material. The second aperture stop includes a sheet of opaque material. The image sensor receives light passing through the first and second aperture stops to output an image frame. The processing unit respectively calculates a convolution between a first color subframe of the image frame and a plurality of first blur kernels to generate a plurality of blurred first frames, respectively calculates a convolution between a second color subframe of the image frame and a plurality of second blur kernels to generate a plurality of blurred second frames, and performs a best matching between the blurred first frames and the blurred second frames.

Claims

1. A ranging system comprising:

a first aperture stop comprising a sheet of IR-cut material and having a first diaphragm aperture;

a second aperture stop comprising a sheet of opaque material and having a second diaphragm aperture, wherein the second diaphragm aperture is larger than the first diaphragm aperture; and

a pixel array composed of IR pixels and green pixels or composed of IR pixels and blue pixels, and configured to receive light passing through the first aperture stop and the second aperture stop.

2. The ranging system as claimed in claim 1, wherein a cutoff wavelength of IR-cut material is between 550 nm and 650 nm.

3. The ranging system as claimed in claim 1, further comprising a processor configured to

respectively calculate a convolution of a first color subframe of an image frame outputted by the pixel array and a plurality of first blur kernels to generate a plurality of blurred first subframes;

respectively calculate a convolution of a second color subframe of the image frame and a plurality of second blur kernels to generate a plurality of blurred second subframes; and

compare the blurred first subframes and the corresponding blurred second subframes to obtain a pair of best matching subframes.

4. The ranging system as claimed in claim 3, wherein the comparison is performing a subtraction operation or a correlation between one of the blurred first subframes and the corresponding blurred second subframe.

5. The ranging system as claimed in claim 3, wherein the processor is further configured to perform at least one of filtering and lens shading compensation on the first color subframe and the second color subframe.

6. The ranging system as claimed in claim 3, wherein the processor is further configured to perform an interpolation on the image frame to generate the first color subframe and the second color subframe.

7. The ranging system as claimed in claim 3, wherein the processor further comprise an storage unit configured to store the first blur kernels, the second blur kernels and depth data corresponding to the first blur kernels and the second blur kernels.

8. The ranging system as claimed in claim 1, wherein the ranging system further comprises an IR-cut filter, and a cutoff wavelength of the IR-cut filter is 810 nm.

9. The ranging system as claimed in claim 1, wherein the ranging system further comprises a lens holder configured to dispose the first aperture stop and the second aperture stop, and the lens holder has an accommodation space for accommodating the pixel array.

10. A ranging system comprising:

a first aperture stop comprising a sheet of IR-cut material and having a first diaphragm aperture;

a second aperture stop comprising a sheet of opaque material and having a second diaphragm aperture, wherein the second diaphragm aperture is larger than the first diaphragm aperture;

an image sensor configured to receive light passing through the first aperture stop and the second aperture stop, and output an image frame; and

a processor configured to

divide the image frame into a first color subframe and a second color subframe;

respectively calculate a convolution of the first color subframe and a plurality of first blur kernels to generate a plurality of blurred first subframes;

respectively calculate a convolution of the second color subframe and a plurality of second blur kernels to generate a plurality of blurred second subframes; and

perform a best matching between the blurred first subframes and the blurred second subframes.

11. The ranging system as claimed in claim 10, wherein the first color is green light or blue light, and the second color is infrared light.

12. The ranging system as claimed in claim 10, wherein the best matching is performing a subtraction operation or a correlation between each of the blurred first subframes and the corresponding blurred second subframe.

13. The ranging system as claimed in claim 10, wherein the processor is further configured to determine a depth according to depth information of at least one of the first blur kernels and the second blur kernels corresponding to a set of best matching subframes.

14. The ranging system as claimed in claim 10, wherein the processor is further configured to perform at least one of filtering and lens shading compensation on the first color subframe and the second color subframe.

15. The ranging system as claimed in claim 10, wherein the processor is further configured to perform an interpolation on the image frame to generate the first color subframe and the second color subframe.

16. An operating method of a ranging system, the ranging system comprising a first aperture stop, a second aperture stop and an image sensor, the first aperture stop made of IR-cut material and the second aperture stop made of opaque material, and a diaphragm aperture of the second aperture stop is larger than that of the first aperture stop, the operating method comprising:

receiving, by the image sensor, light passing through the first and second aperture stops to generate an image frame;

calculating a convolution of a first color subframe of the image frame respectively with a plurality of first blur kernels to generate a plurality of blurred first subframes;

calculating a convolution of a second color subframe of the image frame respectively with a plurality of second blur kernels to generate a plurality of blurred second subframes;

performing a best matching between the blurred first subframes and the blurred second subframes to obtain a set of best matching subframes; and

obtaining a depth according to the set of best matching subframes.

17. The operating method as claimed in claim 16, further comprising:

performing at least one of filtering and lens shading compensation on the first color subframe and the second color subframe.

18. The operating method as claimed in claim 16, further comprising:

performing an interpolation on the image frame to generate the first color subframe and the second color subframe.

19. The operating method as claimed in claim 16, wherein the best matching is performing a subtraction operation or a correlation between each of the blurred first subframes and the corresponding blurred second subframe.

20. The ranging system as claimed in claim 16, wherein the first color is green light or blue light, and the second color is infrared light.