Interpolation method for digital pictures

• US 7,324,708 B2
• Filed: 12/23/2004
• Issued: 01/29/2008
• Est. Priority Date: 12/23/2004
• Status: Expired due to Fees

• Current Assignee: Primax Electronics Limited
• Original Assignee: Primax Electronics Limited
• Inventors: Gao, Yue
• Primary Examiner(s): Alavi, Amir
• Application Number:
  US11/021,521
• Publication Number:
  US 20060140512A1
• Time in Patent Office: 1,132 Days
• Field of Search: 382/162, 382/164, 382/165, 382/173, 382/190, 382/232, 382/233, 382/276, 382/293, 382/298, 382/300, 382/305, 358/515, 358/524, 358/525, 358/530, 375/240.18, 375/240.24, 375/240.25
• US Class Current: 382/300
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• CPC Class Codes: H04N 19/463 by compressing encoding parameters before transmission
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression

Abstract

An interpolation method for processing digital pictures divides blank regions among the pixels equally into several squares. The interpolation parameter of each square corresponding to the sampling point is determined. These interpolation parameters are compressed and stored. When zooming a picture, the interpolating point is made sure to fall within a target square. The interpolation parameter is extracted according to the position of the target square. The brightness of the interpolating point is computed according to the interpolation parameter and the brightness of the sampling point.

Claims

1. An interpolation method for digital pictures, comprising the steps of:

dividing a blank region among pixels equally into a plurality of squares;

determining an interpolation parameter for each of the squares relative to its sampling point according to the position of the square;

compressing and storing the interpolation parameters of all the squares relative to their sampling points;

zooming the picture and making sure that the inerpolating point falls into a target square;

de-compressing the interpolation parameters according to the position of the target square and computing the interpolation parameter corresponding to the square; and

using the interpolation parameters and the brightness of the sampling points to compute the brightness of the interpolating point.

2. The interpolation method of claim 1, wherein the step of dividing a blank region among pixels equally into a plurality of squares divides the blank region into 4*4=16 squares.

3. The interpolation method of claim 1, wherein the step of dividing a blank region among pixels equally into a plurality of squares divides the blank region into 3*3=9 squares.

4. The interpolation method of claim 1, wherein the step of dividing a blank region among pixels equally into a plurality of squares divides the blank region into 2*2=4 squares.

5. The interpolation method of claim 1, wherein the interpolation parameter of each square is the interpolation parameter of the center of each square.

6. The interpolation method of claim 1, wherein the number of sampling points is 4.

7. The interpolation method of claim 1, wherein the number of sampling points is 16.

8. The interpolation method of claim 1, wherein the step of compressing and storing the interpolation parameters of all the squares relative to their sampling points further comprises the steps of:

determining the interpolation parameters of each square relative to its adjacent four sampling points; and

compressing and storing the interpolation parameters according to the coordinates of the interpolation parameters.

9. The interpolation method of claim 1, wherein brightness at the interpolating point is computed using the bicubic algorithm.

10. The interpolation method of claim 1, wherein brightness at the interpolating point is computed using the bilinear algorithm.