Visioprime

Anil Aksay

Alptekin Temizel

Mehmet Bilgay Akhan

Yavuz Ahiska

Gozde Bozdagi Akar

The invention of the present application provides data compression and archival features for data that has previously been transformed and compressed. In a first aspect of the present invention, compressed data that has previously been transformed and compressed is received, and coefficients in the compressed data are selected and discarded to reduce the amount of storage space required by the compressed data. In another aspect, the compressed data has previously been sub-sampled by a wavelet transform, and wavelet coefficients in the compressed data are selected and discarded. In another aspect, wavelet coefficients in the compressed data are dequantized, wavelet coefficients in the compressed data having less value for the data are selected, and the wavelet coefficients are requantized so as to cause more loss of data for the selected coefficients to reduce the amount of storage space required by the compressed data. In another aspect, groups of wavelet coefficients in unused color components of compressed image data are selected and discarded to reduce the amount of storage space required by the compressed image data.

Archival of transformed and compressed data

Methods and systems for image and video enhancement and data-loss recovery using wavelet transforms are disclosed. A wavelet transformed image is defined as multiple sections, where one section is the original image, and coefficients are estimated for each other section using information obtained from that section. An inverse wavelet transform on the wavelet transformed image obtains an enlarged image. For obtaining a high resolution video frame, one section is the original video frame, and coefficients are estimated for each other section using information from a lower level wavelet transform of a corresponding section of a past or future frame of the video sequence. For recovery of data lost from transmitted original data, the locality of the lost data is determined in lower and higher levels of a wavelet transform tree, and information at the locality in the lower and higher levels is used to estimate the lost data.

Image enhancement and data loss recovery using wavelet transforms

A system and a method for wavelet-based low bitrate video coding is provided. The system and method of this invention processes each frame of a video sequence based on its content. The discrete wavelet transform of each frame is taken separately. If the difference between the contents of a first frame and a second frame is above a threshold, then the wavelet transformed second frame is quantized and lossless encoded. If the difference is less than a threshold, then motion estimation is employed in wavelet domain. Then the difference between the wavelet transformed second frame and the motion compensated wavelet transformed second frame is quantized and lossless encoded. The quantization is applied by using dynamic adjustment. The quantization tables are optimized based on the coded frame characteristics. In addition to the coded frames, the lossless coded motion vectors are also transmitted to the decoder unit. To improve the quality of the coded video sequence another decision criteria is used at the feedback loop of this invention. The coded second frame is decoded and compared with the original second frame. If the difference between the two frames is above a threshold, then the wavelet transformed second frame is quantized and lossless encoded instead of the motion compensated second frame.

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Guildford, United Kingdom

Anil Aksay