# US 9,519,951 B2 · Downsampling based display method and apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,519,951 B2
- Document ID: US9519951B2
- Status: Granted
- Kind: B2
- Application number: 14/396,057
- Filed: 2014-09-15
- Published: 2016-03-03
- Granted: 2016-12-13
- Earliest claimed: 2014-08-27
- Assignees: Shenzhen China Star Optoelectronics Technology Co., Ltd.
- Applicants: Shenzhen China Star Optoelectronics Technology Co., Ltd.
- Inventors: Houliang Hu; Hao Li; Li-wei Chu
- Web page: https://patentgrep.com/patent/US9519951B2

## CPC

- G06T 3/4007: based on interpolation, e.g. bilinear interpolation (image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL

## Abstract

Downsampling based display method and apparatus are provided. An input image including multiple pixels is obtained. At least two pixels neighboring with a to-be-calculated DS pixel on each of at least two directions from the pixels are obtained to get at least four first neighboring pixels. Theoretical values of each first neighboring pixel on the at least two directions are calculated. Errors of the theoretical values of each first neighboring pixel and a corresponding original value are obtained. Weight coefficients for calculating the DS pixel are determined according to the errors. An estimation value of the DS pixel is calculated according to the weight coefficients and the weighted cubic interpolation calculation model. As to the other DS pixels of target image, corresponding estimation values are calculated using the above steps, and then a downsampling processed image is obtained. The color aliasing is avoided and sharp image is obtained.

## Claims

### Claim 1

A downsampling based display method comprising:
obtaining an input image, wherein the input image comprises a plurality of pixels;
obtaining at least two pixels, which are neighboring with a to-be-calculated downsampling pixel in a target image, on each of at least two directions from the plurality of pixels of the input image to obtain at least four first neighboring pixels, and calculating theoretical values of the at least four first neighboring pixels on the at least two directions;
obtaining errors between the theoretical values of the at least four first neighboring pixels and a corresponding original value, and determining weight coefficients for calculating the downsampling pixel according to the errors;
calculating an estimation value of the downsampling pixel according to the weight coefficients and a weighted cubic interpolation calculation model built in advance for the downsampling pixel, using the above steps to calculate corresponding estimation values of the other downsampling pixels in the target image, and thereby obtaining a downsampling processed image; and
displaying the downsampling processed image.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein after the step of obtaining an input image, further comprises:
obtaining at least four pixels neighboring with the downsampling pixel on each of at least two directions from the plurality of pixels of the input image to obtain at least eight second neighboring pixels, and building the weighted cubic interpolation calculation model according to the at least eight second neighboring pixels.

### Claim 3 (depends on 2)

The method as claimed in claim 2, wherein the at least two directions are four directions of 0-degree, 45-degree, 90-degree and 135-degree with respect to the downsampling pixel, the correspondingly sixteen second neighboring pixels are obtained; the weighted cubic interpolation calculation model is:
pm=k0(λ1A+λ2B+λ3C+λ4D)+k45(λ1Ph1+λ2Ph2+λ3Ph3+λ4Ph4)+k90(λ1E+λ2F+λ3G+λ4H)+k13 5(λ1Ph5+λ2Ph6+λ3Ph7+λ4Ph8);
where pm is the downsampling pixel, λ1, λ2, λ3, λ4 are cubic interpolation coefficients, Ph1˜Ph4 are four pixels neighboring with pm on a 45-degree direction of pm in the plurality of pixels of the input image, Ph5˜Ph8 are four pixels neighboring with pm on a 135-degree direction of pm in the plurality of pixels of the input image; A, B, C, D are four pixels neighboring with pm on a 0-degree direction of pm in the plurality of pixels of the input image; E, F, G, H are four pixels neighboring with pm on a 90-degree direction of pm in the plurality of pixels of the input image; k0, k45, k90, k135 are weight coefficients, and k0+k45+k90+k135=1.

### Claim 4 (depends on 3)

The method as claimed in claim 3, wherein values of A, B, C, D, E, F, G, H are determined according to the following formulas:
W1=λ1Pn1+λ2Pn2+λ3Pn3+λ4Pn4 (1)
W2=λ1Pm1+λ2Pm2+λ3Pm3+λ4Pm4 (2)
where, the obtained four pixels on each of the four directions of 0-degree, 45-degree, 90-degree and 135-degree with respect to the downsampling pixel constitute a pixel array of 4*4; the formula (1) is used to calculate the values of A, B, C, D; Pn1, Pn2, Pn3, Pn4 are four pixels in each column of the pixel array; the formula (2) is used to calculate the values of E, F, G, H; and Pm1, Pm2, Pm3, Pm4 are four pixels in each row of the pixel array.

### Claim 5 (depends on 3)

The method as claimed in claim 3, wherein calculating theoretical values of each of the at least four first neighboring pixels on the at least two directions comprises:
substituting an original value of each pixel of the at least four first neighboring pixels into a cubic interpolation formula to calculate the theoretical values of the pixel on the at least two directions, wherein the cubic interpolation formula is:
P′j1(x)=λ1Pj2+λ2Pj3+λ3Pj4+λ4Pj5;
where, x is a value of a corresponding one of the at least two directions, Pj2, Pj3, Pj4, Pj5 are pixels neighboring with the downsampling pixel on the corresponding direction of the downsampling pixel in the plurality of pixels of the input image; P′j1 is an interpolation value of Pj2, Pj3, Pj4, Pj5.

### Claim 6 (depends on 2)

The method as claimed in claim 2, wherein the at least two directions are two directions of 45-degree and 135-degree with respect to the downsampling pixel, and correspondingly eight second neighboring pixels are obtained; the weighted cubic interpolation calculation model is:
pm=k45(λ1Ph1+λ2Ph2+λ3Ph3+λ4Ph4)+k135(λ1Ph5+λ2Ph6+λ3Ph7+λ4Ph8);
where, pm is the downsampling pixel, λ1, λ2, λ3, λ4 are cubic interpolation coefficients, Ph1˜Ph4 are four pixels neighboring with pm on a 45-degree direction of pm in the plurality of pixels of the input image, and Ph5˜Ph8 are four pixels neighboring with pm on a 135-degree direction of pm in the plurality of pixels of the input image; k45, k135 are weight coefficients, and k45+k135=1.

### Claim 7 (depends on 6)

The method as claimed in claim 6, wherein calculating theoretical values of each of the at least four first neighboring pixels on the at least two directions comprises:
substituting an original value of each pixel of the at least four first neighboring pixels into a cubic interpolation formula to calculate the theoretical values of the pixel on the at least two directions, wherein the cubic interpolation formula is:
P′j1(x)=λ1Pj2+λ2Pj3+λ3Pj4+λ4Pj5;
where, x is a value of a corresponding one of the at least two directions, Pj2, Pj3, Pj4, Pj5 are pixels neighboring with the downsampling pixel on the corresponding direction of the downsampling pixel in the plurality of pixels of the input image; P′j1 is an interpolation value of Pj2, Pj3, Pj4, Pj5.

### Claim 8

A downsampling based display apparatus adapted for being inputted with an image including a plurality of pixels; the display apparatus comprising:
a pixel theoretical value calculation unit, configured to obtain at least two pixels, which are neighboring with a to-be-calculated downsampling pixel in a target image, on each of at least two directions from the plurality of pixels of the input image to thereby obtain at least four first neighboring pixels, and calculate theoretical values of the at least four first neighboring pixels on the at least two directions;
a weighted cubic interpolation calculation unit, configured to obtain at least four pixels, which are neighboring with the downsampling pixel, on each of at least two directions from the plurality of pixels of the input image to thereby obtain at least eight second neighboring pixels, and build a weighted cubic interpolation calculation model for calculating the downsampling pixel in advance according to the at least eight second neighboring pixels;
a weight coefficient calculation unit, configured to obtain errors of the theoretical values of the at least four first neighboring pixels and a corresponding original value, and determines weight coefficients for calculating the downsampling pixel according to the errors; and
a downsampling pixel calculation unit, configured to select a corresponding weighted cubic interpolation calculation model according to the weight coefficients to calculate an estimation value of the downsampling pixel;
wherein the display apparatus calculates a corresponding estimation value of each downsampling pixel in the target image, and thereby a downsampling processed image is obtained and is displayed on the downsampling based display apparatus.

### Claim 9 (depends on 8)

The display apparatus as claimed in claim 8, wherein the at least two directions are four directions of 0-degree, 45-degree, 90-degree and 135-degree with respect to the downsampling pixel, the correspondingly sixteen second neighboring pixels are obtained; the weighted cubic interpolation calculation model built by the weighted cubic interpolation calculation unit in advance is:
pm=k0(λ1A+λ2B+λ3C+λ4D)+k45(λ1Ph1+λ2Ph2+λ3Ph3+λ4Ph4)+k90(λ1E+λ2F+λ3G+λ4H)+k13 5(λ1Ph5+λ2Ph6+λ3Ph7+λ4Ph8);
where pm is the downsampling pixel, λ1, λ2, λ3, λ4 are cubic interpolation coefficients, Ph1˜Ph4 are four pixels neighboring with pm on a 45-degree direction of pm in the plurality of pixels of the input image, Ph5˜Ph8 are four pixels neighboring with pm on a 135-degree direction of pm in the plurality of pixels of the input image; A, B, C, D are four pixels neighboring with pm on a 0-degree direction of pm in the plurality of pixels of the input image; E, F, G, H are four pixels neighboring with pm on a 90-degree direction of pm in the plurality of pixels of the input image; k0, k45, k90, k135 are weight coefficients, and k0+k45+k90+k135=1.

### Claim 10 (depends on 9)

The display apparatus as claimed in claim 9, wherein the pixel theoretical value calculation unit substitutes an original value of each pixel of the at least four first neighboring pixels into a cubic interpolation formula to calculate the theoretical values of the pixel on the at least two directions, and the cubic interpolation formula is:
P′j1(x)=λ1Pj2+λ2Pj3+λ3Pj4+λ4Pj5;
where, x is a value of a corresponding one of the at least two directions, Pj2, Pj3, Pj4, Pj5 are pixels neighboring with the downsampling pixel on the corresponding direction of the downsampling pixel in the plurality of pixels of the input image; P′j1 is an interpolation value of Pj2, Pj3, Pj4, Pj5.

### Claim 11 (depends on 8)

The display apparatus as claimed in claim 8, wherein the at least two directions are two directions of 45-degree and 135-degree with respect to the downsampling pixel, and correspondingly eight second neighboring pixels are obtained; the weighted cubic interpolation calculation model is:
pm=k45(λ1Ph1+λ2Ph2+λ3Ph3+λ4Ph4)+k135(λ1Ph5+λ2Ph6+λ3Ph7+λ4Ph8);
where, pm is the downsampling pixel, λ1, λ2, λ3, λ4 are cubic interpolation coefficients, Ph1˜Ph4 are four pixels neighboring with pm on a 45-degree direction of pm in the plurality of pixels of the input image, and Ph5˜Ph8 are four pixels neighboring with pm on a 135-degree direction of pm in the plurality of pixels of the input image; k45, k135 are weight coefficients, and k45+k135=1.

### Claim 12 (depends on 11)

The display apparatus as claimed in claim 11, wherein the pixel theoretical value calculation unit substitutes an original value of each pixel of the at least four first neighboring pixels into a cubic interpolation formula to calculate the theoretical values of the pixel on the at least two directions, and the cubic interpolation formula is:
P′j1(x)=λ1Pj2+λ2Pj3+λ3Pj4+λ4Pj5;
where, x is a value of a corresponding one of the at least two directions, Pj2, Pj3, Pj4, Pj5 are pixels neighboring with the downsampling pixel on the corresponding direction of the downsampling pixel in the plurality of pixels of the input image; P′j1 is an interpolation value of Pj2, Pj3, Pj4, Pj5.

### Claim 13

A downsampling based display method comprising:
obtaining an input image, wherein the input image comprises a plurality of pixels;
obtaining at least four pixels, which are neighboring with a to-be-calculated downsampling pixel in a target image, on each of at least two directions from the plurality of pixels of the input image to obtain at least eight second neighboring pixels, and building a weighted cubic interpolation calculation model according to the at least eight second neighboring pixels;
obtaining at least two pixels, which are neighboring with the downsampling pixel, on each of at least two directions from the plurality of pixels of the input image to obtain at least four first neighboring pixels, and calculating theoretical values of the at least four first neighboring pixels on the at least two directions;
obtaining errors between the theoretical values of the at least four first neighboring pixels and a corresponding original value, and determining weight coefficients for calculating the downsampling pixel according to the errors;
calculating an estimation value of the downsampling pixel according to the weight coefficients and the weighted cubic interpolation calculation model, using the above steps to calculate corresponding estimation values of the other downsampling pixels in the target image, and thereby obtaining a downsampling processed image; and
displaying the downsampling processed image.