Two methods of combining DPCM (differential pulse-code modulation) and interpolation are proposed for compressing still-frame teleconferencing signals. The first method uses horizontal subsampling, DPCM, and interpolation to achieve a 4:1 compression. The other method is similar but uses vertical subsampling instead. Simulation results indicate that either method can easily achieve the required 2-b/pel data rate with negligible degradation in image quality. Conventional DPCM is shown to perform slightly better in quantitative terms when fixed-wordlength coding is used. However, the two DPCM/interpolation methods offer other advantages when used with a variable-wordlength coder

Meeting Name

IEEE Region 5 Conference, 1988: 'Spanning the Peaks of Electrotechnology'


Electrical and Computer Engineering

Keywords and Phrases

DPCM; Data Compression; Differential Pulse-Code Modulation; Encoding; Fixed-Wordlength Coding; Horizontal Subsampling; Image Quality; Interpolation; Interpolative Coding; Pulse-Code Modulation; Still Frame Image Transmission; Still-Frame Teleconferencing Signals; Teleconferencing; Vertical Subsampling; Video Signals

Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 1988 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jan 1988