In this paper, we report on an experiment in which various lossy image coding techniques are applied to
a digitized radiographic image. The coding schemes are applied to radiograph, digitized using the Konica
laser based scanner. Six different lossy coding techniques are employed as follows: full frame transforms,
variable length block transform coding, three vector quantization schemes which differ in the degree of
adaptivity, and a unified variable length transform coding and adaptive vector quantization. The first
vector quantizer uses an universal code book which has been designed from a large set of radiographs;
whereas, the second vector quantizer uses a reduced set of code words drawn from the universal codebook.
The use of smaller set of code words effectively means that less bits are needed for specifying the
codeword label and so decreasing the bit rate requirements. In the last vector quantizer, a new codebook
is designed for each image, so decreasing the bit rate required for the label, but increasing the overhead
required for transmitting the new code book. The unified variable length transform coding and adaptive
vector quantization technique involves variable length transform coding on the code book of the last
vector quantizer, thus reducing the overhead for code book transmission.