98 results about "Coefficient quantization" patented technology

A curved wavelet transform and a related image / video compression system are disclosed. The curved wavelet transform (CWT) is carried out by applying one-dimensional (1-D) wavelet filters along curves, rather than along only horizontal and vertical directions. The image / video compression system includes a curve determination unit, a curved wavelet transform unit, a wavelet coefficient quantization unit, a wavelet coefficient coding unit, and a curve coding unit. The quantization and coding of the wavelet coefficients are related to the curves. In one embodiment, recursive wavelet filters are used for inverse wavelet decomposition. The system provides higher compression capability than conventional wavelet-based image compression systems.

In wavelet transform encoding, high-quality encoding is to be realized by enabling picture quality control from one fractional area to another. An input picture 100 is read out in an amount corresponding to a number of lines required for wavelet transform and buffered in a memory unit 6. The input picture then is wavelet transformed in a wavelet transform unit 2 and quantized in a coefficient quantizing unit 3. In quantizing wavelet transform coefficients, the wavelet transform coefficients are multiplied by weighting coefficients from one sub-band to another. The weighting coefficients are determined using the analysis information of a specified block area in a picture, such as motion information and texture fineness information. This enables fine quantization control in terms of a picture block as a unit.

The invention discloses a fixed-point wavelet transform method for joint photographic experts group 2000 (JPEG2000) image compression. The method comprises the steps of: (1) inputting an image; (2) performing direct current (DC) level shifting; (3) judging whether 9 / 7 wavelet transform is to be adopted or not; (4) performing bounded input bounded output (BIBO) gain-controlled 9 / 7 lifting wavelet transform; (5) quantifying a coefficient after the BIBO gain-controlled 9 / 7 lifting wavelet transform; (6) performing BIBO gain-controlled 5 / 3 lifting wavelet transform; (7) outputting a wavelet transform coefficient; (8) performing arithmetic coding; (9) performing rate distortion optimization interception; and (10) performing code stream organization to obtain a JPEG2000 compressed code stream. A BIBO gain control method is introduced, the storage bit depth of a wavelet transform intermediate value is determined by using a 9 / 7 wavelet transform BIOB gain, and a selection mode and a quantification mode of a 9 / 7 lifting wavelet transform quantification parameter are determined by using a 5 / 3 wavelet transform BIBO gain, so that JPEG2000 system storage resources and running time are greatly saved.

An orthogonal frequency division multiplexing (OFDM)-based synchronization detection apparatus includes an input register that stores data, a shifter that shifts the data from the input register based on the exponent of a quantized correlation coefficient, an adder that sums the shifted data, and a peak detector that determines the peak value from among the summed shifted data. The OFDM-based synchronization detection method involves quantizing correlation coefficients for synchronization detection into 2n-level quantized correlation coefficients (n is an integer not less than 0), shifting input data using the 2n-level quantized correlation coefficients, and detecting synchronization using a shifting result.

The present invention relates to a channel state transmission method using time domain coefficient quantization. A terminal measures channel information in the time domain and transmits it to a base station. In this instance, a multipath frequency selective fading channel is displayed in a tapped delay line format configured with a per-path path delay value and a path gain in the time domain, differentiates a quantization level for each path gain for more efficient transmission, quantizes the same, and transmits it to a transmitter. Therefore, while the amount of bandwidths required for transmitting state information from the terminal to the base station is reduced, the base station can efficiently acquire channel state information on the entire bandwidths. Also, the base station transmits signals to many terminals through beamforming by using the acquired reliable channel state information, thereby increasing the terminal's signal receiving performance.

The invention relates to an orthogonal transformation used in image and video compression. Wherein, it first divides the image into 8*8 blocks as M, then uses 8*8 orthogonal transformation matrix D to process two-dimension transformation on each image block M, to obtain the transformation factor matrix N, then quantizes and codes each factor of N, to complete the image and video compression. The invention is based on orthogonal wavelet theory at octonary, to design one new 8*8 orthogonal transformation matrix, to compress image and video, to obtain better compression effect than the discrete cosine transformation, and improve the economic property and efficiency on the softwater and integrated circuit.

In wavelet transform encoding, high-quality encoding is to be realized by enabling picture quality control from one fractional area to another. An input picture 100 is read out in an amount corresponding to a number of lines required for wavelet transform and buffered in a memory unit 6. The input picture then is wavelet transformed in a wavelet transform unit 2 and quantized in a coefficient quantizing unit 3. In quantizing wavelet transform coefficients, the wavelet transform coefficients are multiplied by weighting coefficients from one sub-band to another. The weighting coefficients are determined using the analysis information of a specified block area in a picture, such as motion information and texture fineness information. This enables fine quantization control in terms of a picture block as a unit.