A video encoding/decoding system based on 3D wavelet decomposition and the human perceptual model is implemented. JND is applied in quantizer design to improve the subjective quality of compressed video. The 3D wavelet decomposition helps to remove spatial and temporal redundancy and provides scalability of video quality. In order to conceal the errors that may, occur under bad wireless channel conditions, a slicing method and a joint source channel coding scenario, that combines RCPC with CRC and utilizes the distortion information to allocate convolutional coding rates are proposed. A new subjective quality index based on JND is presented and used to evaluate the overall system performance at different signal to noise rations (SNR) and at different compression ratios. Due to the wide use of arithmetic coding (AC) in data compression, it is considered as a readily available unit in the video codec system for broadcasting. A new scheme for conditional access (CA) sub-system is designed based on the compression graphic property of arithmetic coding. Its performance is analyzed along with its application in a multi-resolution video compression system. This scheme simplifies the conditional access sub-system and provides satisfactory system reliability.
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of U.S. Provisional Application No. 60/136,633, filed May 27, 1999 (incorporated in its entirety herein by reference).
A method (200) and apparatus (100) for segmenting a sequence of audio samples into homogeneous segments (550 and 555) are disclosed. The method (200) forms a sequence of frames (701 to 704) along the sequence of audio samples, and extracts, for each frame, a data feature. The data features form a sequence of data features. Transition points in the sequence of data features are thin detected by applying the Bayesian Information Criterion to the sequence of data features. The transition points define the homogeneous segments (550 and 555). Preferably the data feature is single-dimensional and a leptokurtic distribution is used as an event model in the Bayesian Information Criterion.
An image compression device is disclosed that is capable of quickly compressing image data to a target value by a simple configuration while maintaining quality of a reproduced image as much as possible. The image compression device includes an encoding part, a code reduction part, and a processing part. The encoding part performs a frequency analysis for original image data, encodes the coefficients generated by the frequency analysis first unit by first unit, and generates a series of codes. The code reduction part reduces the amount of the codes of each of the first units. The processing part divides the coefficients or the codes of each of the first units into second units, and increases the amount of codes to be reduced in the code reduction part for each of the second units according to values of the coefficients or the codes of each of the second units.
A moving image watermarking method, which forms a global masking map by combining frequency masking, spatial masking and motion masking values together and inserts a watermark according to the formed global masking map through the use of a human visual system is provided. In the moving image watermarking method, a watermark value is obtained by exclusive-ORing a random key value and a binary value of a logo image. A plurality of masking operations are separately performed. A global masking value is obtained through the separate masking operations. A watermarked frame value is obtained by adding a watermark value weighted by the global masking value and a control variable to an original frame value.
