# US 10,319,077 B2 · Image processing method for defect pixel detection, crosstalk cancellation, and noise reduction

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- Number: US 10,319,077 B2
- Document ID: US10319077B2
- Status: Granted
- Kind: B2
- Application number: 15/258,307
- Filed: 2016-09-07
- Published: 2017-05-25
- Granted: 2019-06-11
- Earliest claimed: 2015-11-19
- Assignees: Silicon Optronics, Inc.
- Applicants: Silicon Optronics, Inc.
- Inventors: Chun-Hung Lin
- Web page: https://patentgrep.com/patent/US10319077B2

## CPC

- G06T 5/70: Denoising; Smoothing
- G06T 5/20: using local operators
- G06T 2207/10004: Still image; Photographic image
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

An image processing method is provided. The method includes the steps of: receiving upper image data; calculating a first ratio using a target pixel and a plurality of first reference pixels in the upper image data; calculating a first diffusion coefficient according to the first ratio and a diffusion coefficient mapping equation; calculating a first pixel value of the target pixel according to the target pixel, the first reference pixels, and the first diffusion coefficient; receiving lower image data; calculating a second ratio using the target pixel and a plurality of second reference pixels in the lower image data, wherein the target pixel has the first pixel value; calculating a second diffusion coefficient according to the second ratio and the diffusion coefficient mapping equation; and calculating a second pixel value of the target pixel according to the target pixel, the second reference pixels, and the second diffusion coefficient.

## Claims

### Claim 1

An image processing method, for use in an image-processing circuit having a first line buffer and a second line buffer, the method comprising:
receiving upper image data from an image sensor and storing first two rows of the upper image data in the first line buffer and the second line buffer;
calculating a first ratio using a target pixel in a current row of the upper image data and a plurality of first reference pixels in the upper image data;
calculating a first diffusion coefficient according to the first ratio and a diffusion coefficient mapping equation;
calculating a first pixel value of the target pixel according to the target pixel, the first reference pixels, and the first diffusion coefficient;
updating the first line buffer using the calculated first pixel value of the target pixel in the current row;
receiving lower image data from the image sensor and storing a next row of the lower image data in the second line buffer;
calculating a second ratio using the target pixel stored in the first line buffer and a plurality of second reference pixels in the lower image data, wherein the target pixel has the first pixel value;
calculating a second diffusion coefficient according to the second ratio and the diffusion coefficient mapping equation; and
calculating a second pixel value of the target pixel according to the target pixel, the second reference pixels, and the second diffusion coefficient.

### Claim 2 (depends on 1)

The image processing method as claimed in claim 1, wherein the first ratio is generated according to the steps of:
generating a first pixel average value according to the target pixel and the first reference pixels;
generating a first pixel variance value according to the target pixel and the first reference pixels; and
generating the first ratio according to the first pixel average value and the first pixel variance value.

### Claim 3 (depends on 1)

The image processing method as claimed in claim 1, wherein the second ratio is generated according to the steps of:
generating a second pixel average value according to the target pixel and the second reference pixels;
generating a second pixel variance value according to the target pixel and the second reference pixels; and
generating the second ratio according to the second pixel average value and the second pixel variance value.

### Claim 4 (depends on 1)

The image processing method as claimed in claim 1, further comprising:
determining whether the target pixel is a defect pixel according to the first ratio and/or the second ratio.

### Claim 5 (depends on 4)

The image processing method as claimed in claim 4, further comprising:
when the target pixel is a defect pixel, performing a defect pixel compensation process on the target pixel.

### Claim 6 (depends on 1)

The image processing method as claimed in claim 1, further comprising:
when the target pixel is a green pixel, performing an image crosstalk cancellation process on the target pixel.