An error concealment algorithm for images subject to channel errors

• Published in: IEEE transactions on image processing Vol. 4; no. 5; pp. 533 - 542
• Main Authors: Wai-Man Lam, Reibman, A.R.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.1995; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Bit rate; Decoding; Degradation; Digital images; Discrete cosine transforms; Error correction codes; Exact sciences and technology; Image coding; Image processing; Image sequences; Information, signal and communications theory; MPEG standards; Signal processing; Telecommunications and information theory; Transform coding; Image processing; Coding; Image sequence; Data compression; Discrete transformation; Decoding; Variable length code; Cosine transform
• ISSN: 1057-7149; 1941-0042
• DOI: 10.1109/83.382489

We present an algorithm to conceal bit errors in still images and image sequences that are coded using the discrete cosine transform (DCT) and variable length codes (VLCs). No modification is necessary to an existing encoder, and no additional bit rate is required. The concealment algorithm is kept simple so that real-time decoding and concealment is possible. A single bit error in these images can cause a block to split into several blocks or several blocks to merge into one. This causes the DCT coefficients of all subsequent blocks to be correctly decoded but stored in the wrong location in the image. Furthermore, the DC coefficient of all subsequent blocks may be incorrect. The error concealment algorithm uses transform domain information to identify the location of the affected blocks and to correct errors. The image quality after error concealment is shown to be significantly improved.< >