A Perception-based High Dynamic Range Image Encoding with Discrete Wavelet Transform

• Main Author: 謝丹青
• Other Authors: 邱�□w
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/21728305057530663939

碩士 === 國立清華大學 === 資訊工程學系 === 95 === A high dynamic range (HDR) image contains a vast amount of luminance and color information at the same time. In order to improve the efficiency in transmission and storage, a proper encoding method is necessary. We propose a perception-based HDR image encoding scheme using the Huffman code to achieve a quantization error curve that is below Ferwerda’s contrast versus intensity (c.v.i). With the discrete wavelet transform (DWT), we propose a sub-band histogram-based HDR image encoding scheme. By assigning different number of bits to the low band and the high band, we show that only an average of 5 bits is required to encode the luminance data under human perceptive range. This method has more than two times quantization efficiency compared with the previous result of encoding luminance data using 10~11 bits [1]. Besides, we verify the correctness of the tone mapping results from the low resolution bit stream because the receiver may only obtain the LL band data in the SVC system. We also represent a simple tone mapping way to ease the influence of DWT-tone mapping.