Patent ID: 7218786

Claim:
An image compression method using the JBIG (Joint Bi-level Image Group) image compression standards, comprising the steps of: reading image data in a first cycle to a unitary encoder, converting a plurality of reference pixels surrounding a pixel to be decompressed from a context (CX) format to a state (ST) format; performing with the unitary encoder a numerical operation on the image data in a second cycle, wherein the numerical operation includes the steps of: obtaining an LSZ value using ST by look-up-table (LUT); in parallel by software means, (i) subtracting the LSZ value from a first default parameter to obtain a first subtracted value, and selecting a new first default parameter between the LSZ value and the first subtracted value, and (ii) subtracting the first default value from a second default parameter and adding the LSZ value to it to obtain a second subtracted value, and selecting a new second default parameter between the second default parameter and the second subtracted value; and renormalizing the new first default parameter and the new second default parameter in a third cycle, and outputting the processed image data.