Appeal No. 1999-0487
Application No. 08/554,425
quantization factor for use in JPEG compression of the image
data so as to achieve a desired average compression ratio for
the data. The inventors claim to have discovered that certain
types of image data sequences bear a relationship which allows
the quantization factor to be determined using linear
interpolation based on a low quantization value and a high
quantization value.
Representative claim 1 is reproduced as follows:
1. A method for automatically determining, for a
desired average compression ratio C, and within a
predetermined range of quantization values, an
appropriate value for a quantization factor Q for
use in JPEG compression of image data from a
sequence of angiographic images made up of frames of
video data, comprising the following steps:
sampling N frames of video data from the
sequence;
determining, using a low value quantization
factor Q that is within said predetermined range and
that is assumed to be less than said appropriate
value, a lower average compression ratio for the
sampled N frames of video data;
determining, using a high value quantization
factor Q that is within said predetermined range and
that is assumed to be greater than said appropriate
value, a higher average compression ratio for the
sampled N frames of video data; and
2
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