BIT RATE CONTROL CIRCUIT AND METHOD FOR IMAGE COMPRESSION

A bit rate control circuit for image compression includes a compression unit, a R-value calculation unit, a linear quantization factor (LQF) calculation unit. The compression unit is used to performs a first quantization process on an image based on a default LQF (LQFini) to obtain an initial bits per pixel (bbpini) with an initial number of zero coefficients (Rini). The R-value calculation unit calculates out a target R value (Rtarget) based on the initial bits per pixel (bbpini), the initial number zero coefficients (Rini), and a target bpp (bbptarget). The LQF calculation unit calculates a target LQF (LQFtarget) based on the target R value Rtarget. The LQFtarget can be used to perform a second compression on the image to obtain a compressed image corresponding to the target bpp (bpptarget).