Signal processing system and method implementing a non-linear transfer function approximated by a piecewise linear transformation
US5179528A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 26, 1992 |
| Grant date | Jan 12, 1993 |
| Priority date | — |
| Expiry date | Feb 26, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T9/001
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A programmable PLT transfer function circuit (50) uses a piecewise linear transformation (PLT) to approximate a non-linear transfer function (FIGS. 1B and 1C). The non-linear transfer function is approximated by a selected number of linear PLT segment transfer functions, each of which applies to a selected range of input data values, and is characterized by a PLT transformation (mx+b) in which output data is obtained by multiplying the input data by a gain coefficient and then adding an offset coefficient. The gain and offset coefficients that characterize the PLT segment transfer functions are updated at regular intervals, and stored in the PLT transfer function circuit (50). For each input data sample, segment selection logic (52) selects the appropriate PLT segment. The input data sample is then referenced (61) to the segment breakpoint (i.e. the initial data value) for that segment. The referenced input data sample is then multiplied (62) by the appropriate gain coefficient provided by gain selection logic (56). The gain multiplication operation is a quasi-floating point operation performed by a funnel shifter (63) and a multiplier (64 ). An offset addition operation (66) then …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.