Methods and apparatuses for image processing

• US 7,612,804 B1
• Filed: 02/15/2005
• Issued: 11/03/2009
• Est. Priority Date: 02/15/2005
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Marcu, Gabriel G., Swen, Steve
• Primary Examiner(s): Tran; Nhan T
• Assistant Examiner(s): Diep; Trung
• Application Number:
  US11/059,110
• Time in Patent Office: 1,722 Days
• Field of Search: 348/222.1, 348/218.1, 348/239, 348/362, 382/254
• US Class Current: 348/222.1
• 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 data processing system of image processing, the data processing system comprising:

means for detecting one or more regions in a first image of a high dynamic range scene by comparing values for pixels of the first image with a threshold to generate a mask; and

means for blurring the mask to generate a weight distribution;

means for blending the first image and a second image of the high dynamic range scene to generate a third image of the high dynamic range scene according to the weight distribution.

2. The data processing system of claim 1, wherein the first and second images are taken from a same scene using different exposure settings.

3. The data processing system of claim 1, wherein the first and second images are low dynamic images derived from a high dynamic image.

4. An image capturing device, comprising:

memory;

an image sensing device coupled to the memory to generate a plurality of images of a scene with a plurality of exposure durations; and

a processing circuit coupled to the image sensing device, the processing circuit to detect one or more regions in a first image of the plurality of images by comparing values for pixels of the first image with a threshold to generate a mask, the processing circuit to blur the mask to generate a weight distribution, and the processing circuit to blend the first image and a second image of the plurality of images to generate a third image of the scene according to the weight distribution.

5. The device of claim 4, further comprising:

a housing; and

a lens coupled to the housing;

wherein the processing circuit and the image sensing device are enclosed within the housing.

6. The device of claim 4, wherein the processing circuit is to further scale the first and second images into a first and second target pixel value ranges.

7. The device of claim 6, wherein the first and second target pixel value ranges are partially overlapping.

8. The device of claim 7, further comprising:

a housing; and

a lens coupled to the housing;

wherein the processing circuit and the image sensing device are enclosed within the housing.