Efficient lossless compression for peripheral interface data transfer

Patent metadata

Field	Value
Publication number	US-9524052-B2
Application number	US-201514608750-A
Country	US
Kind code	B2
Filing date	Jan 29, 2015
Priority date	Apr 24, 2014
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A method, an apparatus, and a computer program product for processing touchscreen information are provided. The method may include receiving touchscreen data that includes node values representative of signals generated by a touchscreen panel, generating a first data frame including difference values, and transmitting the first data frame over a control data bus. Each of the difference values may be calculated as a difference between one of the node values and a different node-related value wherein the first data frame has a predefined size. The first data frame may be configured to permit a receiver of the first data frame to reconstruct the touchscreen data without information loss.

First claim

What is claimed is:

1. A method for processing touchscreen information, comprising:
receiving first touchscreen data comprising node values representative of touch inputs detected by a plurality of touch sensors of a touchscreen panel;
calculating difference values for the node values, each difference value representing a difference between one of the node values and a reference node value, wherein the difference values are independently calculated for each row of a plurality of rows when the node values are organized as a plurality of rows corresponding to physical rows of sensors on the touchscreen panel, and the difference values are independently calculated for each column of a plurality of columns when the node values are organized as a plurality of columns corresponding to physical columns of sensors on the touchscreen panel;
determining a maximum difference value in the difference values;
determining a minimum number of bits needed to encode the maximum difference value;
generating a first data frame, wherein the first data frame comprises difference values when the minimum number of bits does not exceed a threshold number of bits, and wherein the first data frame comprises node values when the minimum number of bits exceeds the threshold number of bits; and
transmitting the first data frame over a control data bus, wherein the first data frame has a fixed size.

2. A method for processing touchscreen information, comprising:
receiving first touchscreen data comprising node values representative of touch inputs detected by a plurality of touch sensors of a touchscreen panel;
calculating difference values for the node values, each difference value representing a difference between one of the node values and a reference node value;
determining a maximum difference value in the difference values;
determining a minimum number of bits needed to encode the maximum difference value;
generating a first data frame, wherein the first data frame comprises difference values when the minimum number of bits does not exceed a threshold number of bits, and wherein the first data frame comprises node values when the minimum number of bits exceeds the threshold number of bits;
transmitting the first data frame over a control data bus, wherein the first data frame has a fixed size; and
transmitting a raw data frame comprising reference node values representative of touch inputs received in previously-received second touchscreen data,
wherein the first touchscreen data can be reconstructed from the first data frame and the raw data frame when the first data frame comprises the difference values.

3. The method of claim 1 , wherein the node values are organized as a plurality of rows, and further comprising:
independently calculating a set of difference values for each row, wherein calculating a set of difference values for each row comprises:
designating a first node in the each row as a reference node;
determining a first difference value as a mathematical difference between the reference node and a second node in the each row, the first node and the second node corresponding to physically adjacent sensors on the touchscreen panel;
determining a second difference value as a mathematical difference between the second node and a third node in the each row, the second node and the third node corresponding to physically adjacent sensors on the touchscreen panel; and

determining the maximum difference value from maximum difference values determined for each set of difference values.

4. The method of claim 1 , wherein the node values are organized as a plurality of columns, and further comprising:
independently calculating a set of difference values for each column, wherein calculating a set of difference values for each column comprises:
designating a first node in the each column as a reference node;
determining a first difference value as a mathematical difference between the reference node and a second first node in the each column, the first node and the second node corresponding to physically adjacent sensors on the touchscreen panel;
determining a second difference value as a mathematical difference between the second node and a third node in the each column, the second node and the third node corresponding to physically adjacent sensors on the touchscreen panel; and

determining the maximum difference value using the maximum difference value determined for each set of difference values.

5. The method of claim 1 , wherein the reference node value corresponds to at least one sensor on the touchscreen panel that is physically adjacent to a sensor corresponding to the one of the node values.

6. A method for processing touchscreen information, comprising:
receiving first touchscreen data comprising node values representative of touch inputs detected by a plurality of touch sensors of a touchscreen panel;
calculating difference values for the node values, each difference value representing a difference between one of the node values and a reference node value;
determining a maximum difference value in the difference values;
determining a minimum number of bits needed to encode the maximum difference value;
generating a first data frame, wherein the first data frame comprises difference values when the minimum number of bits does not exceed a threshold number of bits, and wherein the first data frame comprises node values when the minimum number of bits exceeds the threshold number of bits; and
transmitting the first data frame over a control data bus, wherein the first data frame has a fixed size,
wherein calculating the difference values for the node values includes:
organizing the node values in a plurality of blocks corresponding to blocks of physically proximate sensors on the touchscreen panel; and
calculating a set of difference values for each of the plurality of blocks, wherein a reference node value is defined for each of the plurality of blocks.

7. The method of claim 1 , wherein generating the first data frame comprises:
generating a payload by encoding each difference value using the number of bits needed to encode the maximum difference value, when the minimum number of bits does not exceed the threshold number of bits.

8. The method of claim 7 , further comprising:
packing a plurality of data elements in the payload; and
adding a header to the payload to obtain the first data frame,
wherein the header identifies a number of bits needed to encode the maximum difference value.

9. The method of claim 7 , further comprising:
providing at least a portion of the payload in a second data frame that carries a different payload, wherein the first data frame and the second data frame are equal in size.

10. The method of claim 1 , wherein generating the first data frame comprises:
generating a predicted value for a first node; and
generating one of the difference values based on a difference calculated between the predicted value for the first node and one of the node values in the first touchscreen data that corresponds to the first node.

11. The method of claim 10 , wherein generating the predicted value for the first node comprises:
using a spatial predictive algorithm.

12. The method of claim 10 , wherein generating the predicted value for the first node comprises:
using a temporal predictive algorithm.

13. A touchscreen interface, comprising:
a communications interface adapted to communicate data over a serial bus; and
a touchscreen controller configured to:
receive first touchscreen data comprising node values representative of touch inputs detected by a plurality of touch sensors of a touchscreen pa

Assignees

• Qualcomm Inc

Inventors

• Ahmed Mohamed Imtiaz
• Teng Chia-Yuan
• Han Jun
• Tilak Raghukul
• Jalil Suhail
• Du Junchen
• Pourbigharaz Fariborz
• Zhou Bo

Classifications

• G06T9/004

  Predictors, e.g. intraframe, interframe coding · CPC title

• G06T1/60

  Memory management · CPC title

• G06F3/0416 Primary

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06T9/00

  Image coding (bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00) · CPC title