Compression of grayscale image data using multi-bit halftoning
AssigneeXerox Corporation
InventorsFritz Ebner, Peter McCandlish
Life of this patent
Estimating the term…
Abstract
A method and system are provided for reducing the bit depth of grayscale imagery using multi-bit halftoning. The halftoned image data may be lossy or losslessly compressed and stored in memory or transmitted over a communication channel. At the time of printing, the images are decompressed and reconstructed to a grayscale image data using Sigma filtering to preserve edges. Preferably, different Sigma filters may be applied based on contrast information within a local neighborhood region. Fuzzy edge detection may also be used to preserve edge features and prevent smearing.
Claims20
A method for reducing and reconstructing multi-bit grayscale image data, comprising:
- reducing the grayscale image data from a larger multi-bit depth to a smaller multi-bit depth;
- storing the reduced grayscale image data in a memory, transmitting the reduced grayscale image data over a communication channel, or both;
- reconstructing the reduced grayscale image data to the larger multi-bit depth;
- and
- sending the reconstructed grayscale image data to a printing device accepting grayscale image data.
A system for reducing and reconstructing multi-bit depth grayscale image data, comprising:
- a processor for reducing the grayscale image data from a larger multi-bit depth to a smaller multi-bit depth;
- a processor for compressing the reduced grayscale image data;
- a memory for storing the compressed image data;
- a processor for decompressing the compressed image data to the reduced grayscale image data;
- a processor for reconstructing the reduced grayscale image data from the smaller multi-bit depth to the larger multi-bit depth;
- and
- an interface for sending the reconstructed grayscale image data to a printing device accepting grayscale image data.
A computer readable media having stored computer executable instructions, wherein the computer executable instructions, when executed by a computer, directs a computer to perform a method for reducing and reconstructing grayscale image data, the method comprising:
- reducing the grayscale image data from a larger multi-bit depth to a smaller multi-bit depth;
- storing the reduced grayscale image data in a memory, transmitting the reduced grayscale image data over a communication channel, or both;
- reconstructing the reduced grayscale image data to the larger multi-bit depth;
- and
- sending the reconstructed grayscale image data to a printing device accepting grayscale image data.
Dependencies are inferred from the claim text.