Apparatus and method for compact Haar transform

An apparatus for executing a compact Haar transform, comprising:

• an index signal, for indicating a specific n-bit sample, said specific n-bit sample being one of a sequence of n-bit samples corresponding to the compact Haar transform;
• and
• inverse transform logic, coupled to said index signal, for computing said specific n-bit sample, wherein said specific n-bit sample is derived from selected n+1-bit spectral coefficients, said inverse transform logic comprising:
• a rank decoder, for decoding said index signal to provide one of said selected n+1-bit spectral coefficients, said one of said selected n+1-bit spectral coefficients corresponding to a compact Haar spectral rank, wherein said rank decoder comprises a read only memory (ROM);
• coefficient negation logic, coupled to said rank decoder, for negating said one of said selected n+l-bit spectral coefficients based upon the state of a bit of said index signal, wherein the state of said bit of said index signal indicates whether a Haar basis function corresponding to said one of said selected n+1-bit spectral coefficients is positive or negative;
• and
• LSB restoral logic, coupled to said rank decoder, for adding a least significant bit of said one of said selected n+1-bit spectral coefficients into an n-bit sample computation, said n-bit sample computation being required to compute said n-bit sample.

A computer program product for use in designing, simulating, fabricating, or testing a compact Haar transform circuit, the computer program product comprising:

• a storage medium, having computer readable instructions embodied thereon, for causing a computer upon which said computer readable instructions are executed to describe the compact Haar transform circuit, said computer readable instructions comprising:
• first instructions, for causing said computer to describe inverse Haar transform logic, said inverse Haar transform logic being configured to compute n-bit samples, wherein each of said n-bit samples is derived from n+1-bit spectral coefficients, wherein said inverse transform logic comprises:
• a rank decoder, for receiving an index signal from a source thereof, and for providing one of said n+1-bit spectral coefficients, said one of said n+1-bit spectral coefficients corresponding to a rank of a compact Haar spectrum;
• a coefficient negator, coupled to said rank decoder, for negating said one of said n+1-bit spectral coefficients based upon the state of a bit of said index signal;
• and
• LSB restoral logic, coupled to said rank decoder, for adding a least significant bit of said one of said n+1-bit spectral coefficients into an n-bit sample computation, said n-bit sample computation being required to generate a particular n-bit sample.

A method for executing an inverse compact Haar transform, comprising:

• decoding an index to select n+1-bit spectral coefficients, the n+1-bit spectral coefficients being required to compute a specific n-bit data sample;
• negating those n+1-bit spectral coefficients whose corresponding Haar basis function is negative for the index provided by said decoding;
• computing a sum of the negated n+1-bit spectral coefficients with the selected n+1-bit spectral coefficients which are not negated by said negating;
• and
• adding the least significant bits of all of the selected n+1-bit spectral coefficients to the sum produced by said computing.