Lossy compression of high-dynamic range image files
US8340442B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 12, 2010 |
| Grant date | Dec 25, 2012 |
| Priority date | — |
| Expiry date | Jan 24, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A high dynamic range (HDR) image can be lossy compressed by first mapping floating point image data values of the HDR image from a light linear space to a perceptually linear space using a first non-linear mapping function. A value in the light linear space is proportionate to the power of a light source, and a value in the perceptually linear space is proportionate to a visual perceived brightness. Floating point discrete cosine transform (DCT) frequency coefficients of the floating point image data values of the HDR image are determined. The floating point DCT frequency coefficients are quantized. The quantized floating point DCT frequency coefficients are compressed. The compression of the quantized floating point DCT frequency coefficients is lossless. The compressed quantized floating point DCT frequency coefficients are stored.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.