Circuit and method for adding dither to vertical droop compensation using linear feedback shift registers
AssigneeSTMicroelectronics Asia Pacific Pte Ltd
InventorsBeng-Heng Goh, Srijith Varma Vijaya Varma
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Abstract
Vertical dithering is performed for vertical droop compensation in image processing using Linear Feedback Shift Registers (LFSRs). Line memories are not used. A compensation circuit includes a signature reload input signal coupled to the input of five LFSRs. Each LFSR includes a signature store. The output of each LFSR provides a sequence output signal that is gated with a corresponding enable signal in a first logic circuit. The output of all of the first logic circuits are combined in a second logic circuit to provide a control signal output.
Claims13
A vertical dithering circuit for dithering N lines comprising:
- a signature reload input;
- a plurality Linear Feedback Shift Registers (LFSRs) each having an input coupled to the signature reload input and an output for providing a sequenced output signal;
- a first logic circuit having a plurality of inputs coupled to the outputs of the plurality of LFSRs, and a plurality of outputs;
- and
- a second logic circuit having a plurality of inputs coupled to the outputs of the first logic circuit, and an output for providing a control signal,
- wherein the first logic circuit includes portions that are selectively enabled corresponding to the number of lines from 1 to N, wherein N is an integer greater than 1.
A vertical dithering method for dithering N lines comprising:
- providing a signature reload signal;
- providing a plurality of pseudo-random sequences in response to the signature reload signal;
- gating the pseudo-random sequences corresponding to the number of lines from 1 to N, wherein N is an integer greater than 1;
- and
- logically combining the gated pseudo-random sequences to generate a control signal;
- wherein the pseudo-random sequences are provided by a plurality of Linear Feedback Shift Registers (LFSRs).
Dependencies are inferred from the claim text.