Motorola Corporation

Jian Zhang

Reji Mathew

Xing Zhang

Zhenghua Yu

Digital video imagery is deblocked as a function of horizontal and/or vertically oriented pixels that share a common attribute (such as a corresponding pixel value). In particular, a deblocking filter can be selected from amongst a plurality of candidate deblocking filters as a function of the presence of pixels that are both adjacent to one another and that are substantially similar to one another. The selected deblocking filter can be applied as a function, at least in part, of a respective center of the pixels that are both adjacent and similar to one another. In one embodiment, luminance information is deblocked pursuant to a process that is different from a deblocking process that is used with chrominance information.

Video deblocking method and apparatus

A method for determining motion vectors in an interlaced video coding system for coding images comprising interlaced odd and even field. The method () includes selecting () a current odd field block and a current even field block that respectively comprise odd and even fields of a selected current image block. Differences are identified () and thereafter, suitable best matching odd and even field matching reference blocks are determined (). From the suitable best matching odd and even field matching reference blocks a reduced field search area is provided () that is used to complete further searching () and selection of field motion vectors (). Pseudo-frame motion vector selection is also conducted () and a preferred motion vector is selected () from either a field motion vector pair or pseudo-frame motion vector.

Interlaced video motion estimation

A method ( ) and decoder system ( ) for reducing quantization effects or ringing artifacts imposed upon decoded image of hybrid block based coding schemes such as MEPG and H 261. The system ( ), in use, and method ( ) receive ( ) decoded image decoded blocks that were decoded from transform coded blocks quatized by a selected quantization parameter. The system ( ) and method ( ) then analyze ( ) selected pixel values of selected pixels with neighboring pixel values of associated neighboring pixels in the decoded blocks to determine difference values for each of the selected pixels. Potential object edges, of the decoded image represented by the decoded blocks, are then detected ( ) to identify the selected pixels as edge pixels, the detecting is effected by comparing the difference values with selected threshold values that are determined with respect to the selected quantization parameter associated with the blocks. The selected threshold values have a non-linear relationship with varying quantization parameter values of the image. The selected pixel values are modified ( ) if they are not identified as edge pixels.

Method and decoder system for reducing quantization effects of a decoded image

Two document images which have been compressed using the JBIG-2 standard for facsimile applications so as to include a plurality of index numbers, one or more positions in each image associated with the index numbers, and a group symbol for each index number can be merged to form a final composite image. Firstly, two virtual indexed images are formed by patterns of the index numbers at their associated positions in the document images. The patterns of index numbers in the two virtual indexed images are then compared ( ) to determine whether there is correlation between the patterns of index numbers in at least parts of the two virtual indexed images. The two virtual indexed images are then merged ( ), when there is a sufficient correlation, such that the parts that correlate overlap each other to provide a merged virtual indexed image, and then the index numbers in the merged virtual indexed image are replaced ( ) by the corresponding group symbol to provide the final composite image.

Method and apparatus for merging images

A method of estimating motion in interlaced video involves, firstly, a frame search ( ), where a search is conducted for the frame structure using a sub-sampled block matching metric (e.g. sub-sampled SAD). The locations to be searched are either fixed or dynamically determined based on the minimum frame SAD (ie best frame block match). Next, pixel errors are calculated ( ) for all pixels included in the sub-sampled block matching metric. Each pixel error is first identified as belonging to one of four field patterns (e.g. even-even, even-odd, odd-even and odd-odd). For each location, pixel errors can be classified into two field patterns, either even-even and odd-odd or even-odd and odd-even ( ). The pixel errors belonging to the same field pattern are added together ( ) to obtain field error values (eg field SAD values). The individual field error (or field SAD) values are used to determine ( ) the field Motion Vectors. The location of the lowest field SAD value is taken as the position of best match. All pixel errors are then summed together ( ) to obtain the frame error and the location of the lowest frame error (or frame SAD) is taken as the position of best match for the frame. The frame and field Motion Vectors can be refined by using a full block matching metric within the small search window ( ).

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Enfield, Australia

Jian Zhang