The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 1998
Filed:
May. 30, 1996
Yoshinori Asamura, Nagaokakyo, JP;
Takashi Itow, Nagaokakyo, JP;
Tomohiro Ueda, Nagaokakyo, JP;
Kenji Tsunashima, Nagaokakyo, JP;
Satoshi Kurahashi, Nagaokakyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
When a digital video signal is compressed, the amount of resulting data is predicted and the quantization level is controlled so as to obtain a constant bit rate. The prediction is made by computing a linear combination of a standard deviation and a number of non-zero coefficients, or by computing a sum of absolute differences between adjacent pixel values, or by computing a dynamic range of pixel values. The bit rate can also be controlled by deleting high-frequency coefficients. To avoid image degradation, the quantization level can also be controlled according to the sensitivity of small image areas to quantization noise. Sensitivity is determined by dividing an area into subblocks, which may overlap, and calculating statistics in each subblock. To reduce the amount of computation required in motion estimation, chrominance motion vectors are derived from luminance motion vectors.