IMAGE SENSOR AND OPERATING METHOD THEREOF

• US 20140232893A1
• Filed: 11/26/2013
• Published: 08/21/2014
• Est. Priority Date: 11/26/2012
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: LEE, CHUAN-HSIN, YAO, WEN-HAN
• Granted Patent: US 9,313,412 B2
• Time in Patent Office: Days
• US Class Current: 348/222.1
• CPC Class Codes: G06T 7/13 Edge detection
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06V 10/44 Local feature extraction by analysis of parts of the pattern, e.g. by detecting edges, contours, loops, corners, strokes or intersections; Connectivity analysis, e.g. of connected components
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene

Abstract

There is provided an image sensor including a light sensitive device and a digital signal processing circuit. The light sensitive device is configured to output a digital image. The digital signal processing circuit is configured to detect at least one feature point in the digital image and calculate a feature point coordinate of the at least one feature point.

Claims

1. An image sensor, comprising:

a light sensitive device configured to output a digital image; and

a digital signal processing circuit comprising a feature detection circuit configured to detect at least one corner feature in the digital image and calculate a feature point coordinate of the at least one corner feature.

2. The image sensor as claimed in claim 1, wherein the feature detection circuit further comprises a sparsity arithmetic logic configured to select an extreme corner feature within a predetermined pixel range.

3. The image sensor as claimed in claim 2, wherein the sparsity arithmetic logic is configured to calculate a corner response value of each the corner feature and select the extreme corner feature having a maximum corner response value within the predetermined pixel range.

4. The image sensor as claimed in claim 1, wherein the feature detection circuit further comprises a feature describing arithmetic logic configured to calculate a recognition feature of each the corner feature.

5. The image sensor as claimed in claim 1, wherein the digital signal processing circuit further comprises a feature matching circuit configured to match the corner features having most similar recognition features in successive digital images.

6. The image sensor as claimed in claim 1, wherein the digital signal processing circuit further comprises a feature tracking circuit configured to track the at least one corner feature in successive digital images.

7. The image sensor as claimed in claim 1, further comprising an image signal processing circuit configured to output a preview image according to the digital image.

8. An image sensor, comprising:

a light sensitive device configured to output a digital image;

a memory unit; and

a feature detection circuit, comprising;

a corner detecting arithmetic logic configured to detect at least one corner coordinate in the digital image for being saved in the memory unit;

a corner response arithmetic logic configured to calculate a corner response value corresponding to each the corner coordinate; and

a non-maximum suppression arithmetic logic configured to remove the corner coordinate, within a predetermined pixel range, that does not have a maximum response value from the memory unit.

9. The image sensor as claimed in claim 8, wherein the feature detection circuit further comprises a feature describing arithmetic logic configured to calculate a recognition feature of the corner coordinate having the maximum corner response value.

10. The image sensor as claimed in claim 9, further comprising a feature matching circuit configured to match the corner coordinates having most similar recognition features in successive digital images.

11. The image sensor as claimed in claim 9, wherein the recognition feature is at least one of a rotation angle, a brightness distribution and an included angle.

12. The image sensor as claimed in claim 8, further comprising a feature tracking circuit configured to track the corner coordinate having the maximum corner response value in successive digital images.

13. The image sensor as claimed in claim 8, further comprising an image signal processing circuit configured to output a preview image according to the digital image.

14. An operating method of an image sensor, comprising:

capturing a digital image with a light sensitive device; and

calculating and outputting, using a processing circuit, a feature point coordinate of at least one feature point in the digital image.

15. The operating method as claimed in claim 14, further comprising:

calculating a feature response value of each the feature point; and

selecting a maximum feature response value within a predetermined pixel range.

16. The operating method as claimed in claim 14, further comprising:

calculating a recognition feature of each the feature point.

17. The operating method as claimed in claim 15, further comprising:

calculating a recognition feature of each the feature point.

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

matching the corner features having most similar recognition features in successive digital images.

19. The operating method as claimed in claim 14, further comprising:

tracking the at least one feature point in successive digital images.

20. The operating method as claimed in claim 14, further comprising:

outputting a preview image according to digital image.