Apparatus and method for improved interlace processing

Abstract

An interlaced image processing module and corresponding method facilitate improved processing of interlaced motion images. In one embodiment, the interlaced image processing module receives image data frames having interlaced first and second fields and produces a reference field and error field. The reference field corresponds to the still image content of the interlaced frame, whereas the error field corresponds to the motion content of the interlaced frame, particularly the motion between fields. Motion between fields is thus represented in the error field, without redundant representation of the still image content provided by the first field. Where there is little motion between fields, the error terms will be small so the predictor preserves the coding efficiency provided by any auto-correlation in the image. Further, the interlaced image processing method does not rely upon pixel group classification, and thus avoids classification errors, and the loss of coding efficiency from still image content in motion classified blocks. Finally, problems presented by relative motion between fields are avoided, as are local artifacts. Another embodiment transforms the interlaced fields into frame data having a high frequency field and a low frequency field.

1 . An apparatus for pre-processing, prior to compression thereof, frame video data having at least a portion thereof corresponding to successive frames of interlaced fields, the apparatus comprising: 
 an input for receiving a first field and a second field corresponding to the frame video data;    a prediction field determination module in communication with the input for obtaining a prediction field;    an error field determination module in communication with the prediction field determination module and the input for obtaining an error field.    
     
     
         2 . An apparatus for pre-processing, prior to compression thereof, a digital electronic video data stream having at least a portion thereof corresponding to successive frames of interlaced fields, the apparatus comprising: 
 means for receiving a first field and a second field corresponding to the frame video data;    means for obtaining a prediction field based on the first and second fields;    means for obtaining an error field based on the prediction field and either of the first or second field.    
     
     
         3 . An apparatus for reverse processing of a digital electronic video data stream after the data stream has undergone decompression, the apparatus comprising: 
 an input for receiving predicted image data;    a signal divide module in communication with the input for obtaining a first field and an error field corresponding to the predicted image data;    a prediction field determination module in communication with the signal divide module for obtaining a prediction field;    a field recovery module in communication with the prediction field determination module and the signal divide module for obtaining a second field corresponding to the frame video data; and    a signal merging module in communication with the field recovery module and the signal divide module for obtaining the first and the second field corresponding to the frame video data, the first and the second fields being interlaced.    
     
     
         4 . An apparatus for reverse processing of a digital electronic video data stream after the data stream has undergone decompression, the apparatus comprising: 
 means for receiving predicted image data; and    means for obtaining a first field and an error field corresponding to the predicted image data;    means for obtaining a prediction field based on the first field and the error field;    means for obtaining a second field corresponding to the frame video data; and    means for obtaining frames of frame video data based on the first field and the second field, the first and the second fields being interlaced.    
     
     
         5 . An apparatus as in  claim 1  wherein there is relative motion of an imaged object in successive fields corresponding to the frame video data and the motion does not create artificial vertical frequencies at the vertical Nyquist frequency.  
     
     
         6 . An apparatus as in  claim 2  wherein there is relative motion of an imaged object in successive fields corresponding to the frame video data and the motion does not create artificial vertical frequencies at the vertical Nyquist frequency.  
     
     
         7 . An apparatus as in  claim 3  wherein there is relative motion of an imaged object in successive fields corresponding to the frame video data and the motion does not create artificial vertical frequencies at the vertical Nyquist frequency.  
     
     
         8 . An apparatus as in  claim 4  wherein there is relative motion of an imaged object in successive fields corresponding to the frame video data and the motion does not create artificial vertical frequencies at the vertical Nyquist frequency.