IMAGE CORRECTION METHOD AND RELATED IMAGE CORRECTION SYSTEM THEREOF

• US 20120114262A1
• Filed: 04/21/2011
• Published: 05/10/2012
• Est. Priority Date: 11/09/2010
• Status: Active Grant

• Current Assignee: Avisonic Technology Corporation (Elan Microelectronics Corporation)
• Original Assignee: Avisonic Technology Corporation (Elan Microelectronics Corporation)
• Inventors: Yu, Chi-Chang, Lin, Meng-Chun, Chen, Homer H.
• Granted Patent: US 9,153,014 B2
• Time in Patent Office: Days
• US Class Current: 382/254
• CPC Class Codes: G06T 2207/20021 Dividing image into blocks, subimages or windows
• CPC Class Codes: G06T 5/80 Geometric correction

Abstract

The present invention provides an image correction method and a related image correction system which can correct images captured via a fisheye lens or a ultra-wide angle lens camera so as to alleviate geometrical distortion in the images, and geometrically adjust the images according to user'"'"'s requirements. Wherein, the present invention further enhances the processing performance of image correction computation by a memory allocation technique.

Claims

1. An image correction method, for outputting a corrected image according to an image to be corrected, the corrected image comprising a plurality of corrected pixel blocks, the image correction method performing a plurality of pixel value computations, each pixel value computation being utilized for generating a pixel value of each corrected pixel within a corrected pixel block, and comprising:

establishing a coordinate transformation relation between the image to be corrected and the corrected image, such that a first coordinate value of each corrected pixel within the corrected pixel block corresponds to a second coordinate value within the image to be corrected;

according to the coordinate transformation relation, determining a pixel block to be corrected corresponding to the corrected pixel block, and selecting a pixel block to be processed which comprises at least the pixel block to be corrected from the image to be corrected, wherein the pixel block to be processed has a plurality of rows of pixels to be processed;

temporarily storing a pixel value of each pixel to be processed into a memory device having a plurality of memory banks, wherein pixel values of pixels to be processed that are located at different rows are temporarily stored into different memory banks of the memory device, respectively; and

utilizing the second coordinate value corresponding to the corrected pixel for determining a plurality of specific pixels to be processed that correspond to the corrected pixel, reading a plurality of pixels values of the specific pixels to be processed from the memory device, and generating a pixel value of the corrected pixel by performing an interpolation computation upon the pixels values of the specific pixels;

wherein the pixel values of the specific pixels to be processed are temporarily stored in different memory banks.

2. The image correction method of claim 1, wherein a number of the specific pixels to be processed is m*n, a number of the memory banks within the memory device is m, and m and n are both positive integers.

3. The image correction method of claim 1, wherein the image to be corrected is captured via a fisheye lens camera.

4. The image correction method of claim 3, wherein the coordinate transformation relation is determined by at least a perspective distortion correction coordinate transformation;

and in the perspective distortion correction coordinate transformation, an angle parameter corresponding to an object plane and an image plane is determined by an incidence angle of an incident beam corresponding to the image to be corrected, where the incident beam passes through an optical center of the fisheye lens.

5. An image correction method, for outputting a corrected image according to an image to be corrected, the corrected image comprising a plurality of corrected pixel blocks, the image to be corrected being captured by a fisheye lens camera, the image correction method performing a plurality of pixel value computations, each pixel value computation being utilized for generating a pixel value of each corrected pixel within a corrected pixel block, and comprising:

establishing a coordinate transformation relation between the image to be corrected and the corrected image, such that a first coordinate value of each corrected pixel within the corrected pixel block corresponds to a second coordinate value within the image to be corrected, wherein the coordinate transformation relation is determined by at least a perspective distortion correction coordinate transformation, and in the perspective correction distortion coordinate transformation, an angle parameter corresponding to an object plane and an image plane is determined by an incidence angle of an incident beam corresponding to the image to be corrected, where the incident beam passes through an optical center of the fisheye lens;

according to the coordinate transformation relation, determining a pixel block to be corrected that corresponds to the corrected pixel block, and selecting a pixel block to be processed which comprises at least the pixel block to be corrected from the image to be corrected; and

utilizing the second coordinate value corresponding to the corrected pixel for determining a plurality of specific pixels to be processed that correspond to the corrected pixel, and generating a pixel value of the corrected pixel by performing an interpolation computation upon a plurality of pixel values of the specific pixels to be processed.

6. An image correction system, for outputting a corrected image according to an image to be corrected, the corrected image comprising a plurality of corrected pixel blocks, the image correction system performing a plurality of pixel value computations, each pixel value computation being utilized for generating a pixel value of each corrected pixel within a corrected pixel block, the image correction system comprising:

a coordinate transformation relation generating circuit, for establishing a coordinate transformation relation between the image to be corrected and the corrected image, such that a first coordinate value of each corrected pixel within the corrected pixel block corresponds to a second coordinate value within the image to be corrected;

a block selecting circuit, coupled to the coordinate transformation relation generating circuit, for referring to the coordinate transformation relation for determining a pixel block to be corrected that corresponds to the corrected pixel block, and selecting a pixel block to be processed which comprises at least the pixel block to be corrected from the image to be corrected, wherein the pixel block to be processed has a plurality of rows of pixels to be processed;

a memory device, coupled to the block selecting circuit, the memory device having a plurality of memory banks for temporarily storing a pixel value of each pixel to be processed; and

an interpolation computation circuit, coupled to the memory device and the coordinate transformation relation generating circuit, the interpolation computation circuit utilizing the second coordinate value corresponding to the corrected pixel for determining the specific pixels to be processed that correspond to the corrected pixel, reading a plurality of pixel values of the specific pixels to be processed from the memory device, and generating a pixel value of the corrected pixel by performing an interpolation computation upon the pixel values of the specific pixels to be processed;

wherein the pixel values of the specific pixels to be processed are temporarily stored in different memory banks.

7. The image correction system of claim 6, wherein a number of the specific pixels to be processed is m*n, a number of the memory banks within the memory device is m, and m and n are both positive integers.

8. The image correction system of claim 6, wherein the image to be corrected is captured via a fisheye lens camera.

9. The image correction system of claim 8, wherein the coordinate transformation relation generating circuit comprises at least a perspective distortion correction coordinate transformation circuit, and the coordinate transformation relation is determined by at least the perspective distortion correction coordinate transformation circuit, and an angle parameter utilized in the perspective distortion correction coordinate transformation circuit and corresponding to an object plane and an image plane is determined by an incidence angle of an incident beam corresponding to the image to be corrected, where the incident beam passes through an optical center of the fisheye lens.

10. An image correction system, for outputting a corrected image according to an image to be corrected, the corrected image comprising a plurality of corrected pixel blocks, the image to be corrected being captured by a fisheye lens camera, the image correction system performing a plurality of pixel value computations, each pixel value computation being utilized for generating a pixel value of each corrected pixel within the corrected pixel block, the image correction system comprising:

a coordinate transformation relation generating circuit, for establishing a coordinate transformation relation between the image to be corrected and the corrected image, such that a first coordinate value of each corrected pixel within the corrected pixel block corresponds to a second coordinate value within the image to be corrected, wherein the coordinate transformation relation generating circuit comprises at least a perspective distortion correction coordinate transformation circuit, and the coordinate transformation relation is determined by at least the perspective distortion correction coordinate transformation circuit, and an angle parameter utilized by the perspective distortion correction coordinate transformation circuit and corresponding to an object plane and an image plane is determined by an incidence angle of an incident beam corresponding to the image to be corrected, where the incident beam passes through an optical center of the fisheye lens;

a block selecting circuit, coupled to the coordinate transformation relation generating circuit, for referring to the coordinate transformation relation for determining a pixel block to be corrected that corresponds to the corrected pixel block, and selecting a pixel block to be processed which comprises at least the pixel block to be corrected from the image to be corrected; and

an interpolation computation circuit, coupled to the coordinate transformation relation generating circuit, the interpolation computation circuit utilizing the second coordinate value corresponding to the corrected pixel for determining a plurality of specific pixels to be processed that correspond to the corrected pixel, and generating a pixel value of the corrected pixel by performing an interpolation computation upon a plurality of pixel values of the specific pixels to be processed.