Comparison of Information Theory and Subjective Performance Measures for Television




A digital Differential PCM loop has been designed, analyzed and built to process pulse code modulated video signals. This is essentially a PCM to DPCM encoder. It has been shown that such an encoder is equivalent to a DPCM system with an analog loop using previous sample prediction. High speed digital logic has been built to measure the entropies of the DPCM bit streams for various bandwidths and baud rates in real time. Subjective preference tests have been conducted to determine picture quality for the digital DPCM system at different baud rates. A criterion has been developed to predict subjective performance of a DPCM system for television transmission from its two parameters, bandwidth and number of bits/sample. At various baud rates the entropy in the DPCM bit stream was compared with the resulting picture quality. It was found that at any given baud rate DPCM systems with lower entropy (i.e., systems transmitting less information per bit) produced better picture quality than systems with higher entropy. Equi-preference contours have been drawn which enable one to pick system parameters optimally for a given baud rate. (Author)



  • 外文文献
  • 中文文献
  • 专利

联系方式:18141920177 (微信同号)


京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号