# US 11,443,680 B1 · Frame rate-convertible active matrix display

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- Number: US 11,443,680 B1
- Document ID: US11443680B1
- Status: Granted
- Kind: B1
- Application number: 17/565,487
- Filed: 2021-12-30
- Granted: 2022-09-13
- Earliest claimed: 2021-09-30
- Assignees: Solomon Systech (Shenzhen) Limited
- Applicants: Solomon Systech (Shenzhen) Limited
- Inventors: Wing Chi Stephen Chan; Chi Wai Lee; Wai Hon Ng; Chen Jung Chuang
- Web page: https://patentgrep.com/patent/US11443680B1

## CPC

- G09G 3/2044: {using dithering}
- G09G 5/005: {Adapting incoming signals to the display format of the display terminal}
- G09G 5/022: {using memory planes}
- G09G 5/04: using circuits for interfacing with colour displays
- G09G 2320/0242: Compensation of deficiencies in the appearance of colours
- G09G 2320/0261: in the context of movement of objects on the screen or movement of the observer relative to the screen
- G09G 2320/0686: with two or more screen areas displaying information with different brightness or colours
- G09G 2320/106: Determination of movement vectors or equivalent parameters within the image
- G09G 2340/0435: Change or adaptation of the frame rate of the video stream
- G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data
- G09G 2360/18: Use of a frame buffer in a display terminal, inclusive of the display panel
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

The present invention provides a dithering and directional modulation-based frame rate conversion apparatus comprising: a directional delta modulation generator configured to receive a plurality of input color data representing a plurality of input color components of an input pixel color and generate a plurality of modulated data for the plurality of input color data respectively; and a plurality of dithering modules configured to perform K-bit dithering conversion on the plurality of input color data respectively to generate a plurality of output color data for representing a plurality of output color components of an output pixel color with a color depth of K bits per component, where K is an integer equal to or great than 1. The present invention can allow display to support frame rates higher than its standard configuration without observable color depth degradation.

## Claims

### Claim 1

A dithering and directional modulation-based frame rate conversion apparatus, comprising:
a directional delta modulation generator configured to receive a plurality of input color data representing a plurality of input color components of an input pixel color and generate a plurality of modulated data for the plurality of input color data respectively; and
a plurality of dithering modules configured to perform K-bit dithering conversion on the plurality of input color data respectively to generate a plurality of output color data for representing a plurality of output color components of an output pixel color with a color depth of K bits per component, where K is an integer equal to or great than 1, each of the dithering modules comprising:
a respective residue line buffer configured to track a residual error in dithering conversion to generate a respective residual data;
a respective adapter configured to receive a respective input color data, a respective modulated data from the directional delta modulation generator and the respective residual data, and adapt the respective input color data to generate a respective adapted color data by adding the respective input color data with the respective modulated data and the respective residual data; and
a respective dithering engine configured to receive the respective adapted color data and compare the respective adapted color data against a (2K−1) number of dithering threshold values to generate a respective output color data with 2K possible color levels.

### Claim 2 (depends on 1)

The dithering and directional modulation-based frame rate conversion apparatus according to claim 1, wherein the directional delta modulation generator is configured to:
determine a respective modulation direction by comparing the respective input color data against a modulation threshold value and obtaining a respective flag value of modulation for the color component; and
apply a respective delta modulation to the respective input color data based on the respective modulation direction to obtain a respective modulated data.

### Claim 3 (depends on 2)

The dithering and directional modulation-based frame rate conversion apparatus according to claim 2, wherein the modulation threshold value is set as a half of a maximum component value of the input pixel color.

### Claim 4 (depends on 3)

The dithering and directional modulation-based frame rate conversion apparatus according to claim 3, wherein the delta modulation is performed across a sequence of N image frames over a modulation cycle with a sequence of N delta modulation values to obtain a sequence of N modulated data respectively.

### Claim 5 (depends on 4)

The dithering and directional modulation-based frame rate conversion apparatus according to claim 4, wherein an ith modulated data obtained in an ith image frame in the modulation cycle is given by:
Xmi=Xoi+di, for i=1, 2, . . . , N,
where Xmi is the ith modulated data obtained in the ith image frame, Xoi is an original value of the respective input color data in the ith image frame, di, is a delta modulation value used in the ith image frame, and N is the total number of image frames over the modulation cycle.

### Claim 6 (depends on 5)

The dithering and directional modulation-based frame rate conversion apparatus according to claim 5, wherein the sequence of N delta modulation values is selected to have a sum equal to zero.

### Claim 7 (depends on 6)

The dithering and directional modulation-based frame rate conversion apparatus according to claim 6, wherein the respective dithering engine is further configured to determine, based on the sequence of N modulated data, a N number of modulated color levels across the N number of image frames respectively.

### Claim 8 (depends on 7)

The dithering and directional modulation-based frame rate conversion apparatus according to claim 7, wherein an ith modulated color level determined in the ith image frame is given by:
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where Ci is the ith color level determined in the ith image frame, Lk is the kth color levels defined in the color space with the color depth of K bits per component.

### Claim 9 (depends on 8)

The dithering and directional modulation-based frame rate conversion apparatus according to claim 8, wherein the respective dithering engine is further configured to:
average the N number of modulated color levels to obtain an average display color value; and
set the average display color value as the color level for the respective output color data.

### Claim 10 (depends on 1)

A frame rate convertible active matrix display device comprising the dithering and directional modulation-based frame rate conversion apparatus according to claim 1.

### Claim 11

A dithering and directional modulation-based frame rate conversion method, comprising:
receiving, by a directional delta modulation generator, a plurality of input color data representing a plurality of input color components of an input pixel color;
generating, by the directional delta modulation generator, a plurality of modulated data for the plurality of input color data respectively;
performing, by a plurality of dithering modules, K-bit dithering conversion on the plurality of the input color data respectively to generate a plurality of output color data for representing a plurality of output color components of an output pixel color with a color depth of K bits per component, where K is an integer equal to or great than 1;
wherein each K-bit dithering conversion comprises:
tracking, by a respective residue line buffer, a respective residual error in dithering conversion to generate a respective residual data;
adapting, by a respective adapter, the respective input color data to generate a respective adapted color data by adding the respective input color data with the respective modulated data and the respective residual data; and
comparing, by a respective dithering engine, the respective adapted color data against a (2K−1) number of dithering threshold values to generate a respective output color data with 2K possible color levels.

### Claim 12 (depends on 11)

The dithering and directional modulation-based frame rate conversion method according to claim 11, further comprising:
determining, by the directional delta modulation generator, a respective modulation direction by comparing the respective input color data against a modulation threshold value and obtaining a respective flag value of modulation for the color component; and
applying, by the directional delta modulation generator, a respective delta modulation to the respective input color data based on the respective modulation direction to obtain a respective modulated data.

### Claim 13 (depends on 12)

The dithering and directional modulation-based frame rate conversion method according to claim 12, wherein the modulation threshold value is set as a half of a maximum component value of the input pixel color.

### Claim 14 (depends on 13)

The dithering and directional modulation-based frame rate conversion method according to claim 13, wherein the delta modulation is performed across a sequence of N image frames over a modulation cycle with a sequence of N delta modulation values to obtain a sequence of N modulated data respectively.

### Claim 15 (depends on 14)

The dithering and directional modulation-based frame rate conversion method according to claim 14, wherein an ith modulated data obtained in an ith image frame in the modulation cycle is given by:
Xmi=Xoi+di, for i=1, 2, . . . , N,
where Xmi is the ith modulated data obtained in the ith image frame, Xoi is an original value of the respective input color data in the ith image frame, di, is a delta modulation value used in the ith image frame, and N is the total number of image frames over the modulation cycle.

### Claim 16 (depends on 15)

The dithering and directional modulation-based frame rate conversion method according to claim 15, wherein the sequence of N delta modulation values is selected to have a sum equal to zero.

### Claim 17 (depends on 16)

The dithering and directional modulation-based frame rate conversion method according to claim 16, further comprising determining, by a respective dithering engine, based on the sequence of N modulated data, a N number of modulated color levels across the N number of image frames respectively.

### Claim 18 (depends on 17)

The dithering and directional modulation-based frame rate conversion method according to claim 17, wherein an ith modulated color level for of the respective input color data obtained in the ith image frame is given by:
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where Ci, is the ith color level determined in the ith image frame, Lk is the kth color levels defined in the color space with the color depth of K bits per component to be displayed.

### Claim 19 (depends on 18)

The dithering and directional modulation-based frame rate conversion method according to claim 18, further comprising:
averaging, by the respective dithering engine, the Nnumber of modulated color levels to obtain an average display color value; and
setting the average display color value as the color level for the respective output color data.