Methods and Apparatuses For Image Processing

• US 20100046855A1
• Filed: 10/29/2009
• Published: 02/25/2010
• Est. Priority Date: 02/15/2005
• Status: Active Grant

• Current Assignee: Gabriel G. Marcu, Steve Swen
• Original Assignee: Gabriel G. Marcu, Steve Swen
• Inventors: Marcu, Gabriel G., Swen, Steve
• Granted Patent: US 8,077,218 B2
• Time in Patent Office: Days
• US Class Current: 382/284
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/90 Dynamic range modification of images or parts thereof
• CPC Class Codes: G06T 7/136 involving thresholding
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 25/589 with different integration times, e.g. short and long exposures

Abstract

Methods and apparatuses for generating a low dynamic range image for a high dynamic range scene. In one aspect, a method to generate a low dynamic range image from a high dynamic range image, includes: determining one or more regions of the high dynamic range image containing pixels having values that are outside a first range and inside a second range; computing a weight distribution from the one or more regions; and generating the low dynamic range image from the high dynamic range image using the weight distribution. In another aspect, a method of image processing, includes: detecting one or more regions in a first image of a high dynamic range scene according to a threshold to generate a mask; and blending the first image and a second image of the scene to generate a third image using the mask.

Claims

1. A machine readable medium containing executable computer program instructions which when executed by a data processing system cause said system to perform a method to generate a first dynamic range image from a second dynamic range image, the method comprising:

determining a mask showing one or more regions of the second dynamic range image containing pixels having values that are outside a first range and inside a second range;

computing a weight distribution from the mask; and

generating the first dynamic range image from the second dynamic range image using the weight distribution.

2. The medium of claim 1, wherein the first dynamic range image has a dynamic range lower that the second dynamic range image;

the first dynamic range image has an appearance of the second dynamic range image; and

said computing the weight distribution comprises;

blurring the mask to generate the weight distribution.

3. The medium of claim 2, wherein said generating the first dynamic range image comprises:

combining pixels in the first range of the second dynamic range image and pixels in the second range of the second dynamic range image according to the weight distribution to generate the first dynamic range image.

4. The medium of claim 3, wherein the first and second ranges do not overlap with each other;

the pixels in the first range of the second dynamic range image are scaled into a first pixel value range in the first dynamic range image; and

the pixels in the second range of the second dynamic range image are scaled into a second pixel value range in the first dynamic range image.

5. The medium of claim 4, wherein the first pixel value range contains the second pixel value range.

6. The medium of claim 4, wherein the first pixel value range partially overlaps with the second pixel value range.

7. The medium of claim 4, wherein the first pixel value range and the second pixel value range do not overlap with each other.

8. A machine readable medium containing executable computer program instructions which when executed by a data processing system cause said system to perform a method of image processing, the method comprising:

detecting one or more regions in a first image of a high dynamic range scene according to a threshold; and

blending the first image and a second image of the scene to generate a third image according to the one or more regions.

9. The medium of claim 8, wherein said blending comprises:

computing a weight distribution from a mask showing the one or more regions;

wherein the first and second images are blended according to the weight distribution.

10. The medium of claim 8, wherein the first and second images correspond to a first range and a second range of the high dynamic range scene respectively.

11. The medium of claim 10, wherein said blending comprises:

scaling the first and second images into a first and second target pixel value ranges;

wherein the first and second target pixel value ranges are partially overlapping for non-overlapping ranges of the high dynamic range scene.

12. A method to generate a first dynamic range image from a second dynamic range image, the method comprising:

determining data representing one or more regions of the second dynamic range image containing pixels having values that are outside a first range and inside a second range;

computing a weight distribution from the data representing the one or more regions; and

generating the first dynamic range image from the second dynamic range image using the weight distribution.

13. The method of claim 12, wherein the second dynamic range image has a dynamic range larger than the first dynamic range image;

the data comprises a mask showing the one or more regions; and

said computing the weight distribution comprises;

blurring the mask to generate the weight distribution.

14. The method of claim 12, wherein said generating the first dynamic range image comprises:

mapping the first range of the second dynamic range image as a third image;

mapping the second range of the second dynamic range image as a fourth image; and

combining the third and fourth images using the weight distribution to generate the first dynamic range image.

15. The method of claim 14, wherein said combining comprises:

blending the third and fourth images according to the weight function.

16. The method of claim 15, wherein pixels having values outside the first range in the second dynamic range image are clamped according to the first range in the third image.

17. The method of claim 12, wherein two non-overlapping portions of the first and second ranges of the second dynamic range image correspond to two overlapping ranges in the first dynamic range image.

18. The method of claim 12, wherein non-overlapping portions of the first and second ranges of the second dynamic range image correspond to non-overlapping ranges in the first dynamic range image.

19. A method of image processing, the method comprising:

detecting one or more regions in a first image of a high dynamic range scene according to a threshold to generate a mask; and

blending the first image and a second image of the scene to generate a third image using the mask.

20. The method of claim 19, wherein said blending comprises:

generating a weight distribution from the mask;

wherein the first and second images are blended according to the weight distribution.