Image compression by texture modeling in the wavelet domain.

High-quality image compression algorithms are capable of achieving transmission or storage rates of 0.3 to 0.5 b/pixel with low degradation in image quality. In order to obtain even lower bit rates, we relax the usual RMS error definition of image quality and allow certain "less critical" portions of the image to be transmitted as texture models. These regions are then reconstructed at the receiver with statistical fidelity in the mid- to high-range spatial frequencies and absolute fidelity in the lowpass frequency range. This hybrid spectral texture modeling technique takes place in the discrete wavelet transform domain. In this way, we obtain natural spectral texture models and avoid the boundary blending problems usually associated with polygonal modeling. This paper describes the complete hybrid compression system with emphasis on the texture modeling issues.

Sidelobe reduction in optical signal processing.

A general procedure is introduced for sidelobe and noise reduction in optical or digital signal processing. Specific examples of sidelobe reduction in imaging are presented. It is demonstrated that the new method provides superior spatial resolution to previously proposed sidelobe-reduction techniques.

Dynamic control of an artificial neural system: the property inheritance network.

The property inheritance network (PIN) is a dynamically controlled machine that accesses information stored in a hierarchical content addressable memory. The associative memory is implemented using adaptive resonance circuits. These circuits are monitored by a set of control neurons that become active when certain system states occur and generate signals that control a sequential search through a taxonomy of stored information. This paper reviews pertinent knowledge representation concepts and summarizes the adaptive resonance theory of Carpenter and Grossberg as it applies to the PIN. The PIN architecture and control implementation are presented and simulation results are discussed.

Optimal linear predisplay digital filters.

The problem of reconstructing digital data with nonideal analog interpolators is addressed. A theoretical viewpoint is taken which specifies optimal data reconstructors when a predisplay digital filter is employed. This theory allows for a weighted error definition so that solutions with different desired qualities may be obtained. Results for Gaussian-profiled interpolators show that a factor of approximately 100 in reconstruction-error reduction is achieved with a 13-tap finite-impulse-response predisplay digital filter. The problem of writing negative digital values with incoherent light spots is shown to be avoidable if the signal is reconstructed on photographic film.

Primary structure of the major beta-chain of rat haemoglobins.

The amino acid sequence of the major beta-chain, (II)beta, from rat haemoglobins was established with an automated sequencer. Amino acid heterogeneities were found that appear to result from allelic variation at particular residues. We applied several new or unusual techniques in determining the sequence: (1) reaction of the polypeptide with dansylaziridine for detection of cysteine; (2) blockage of the N-terminal residue and the epsilon-amino group of lysine residues with 1-fluoro-2-nitro-4-trimethylammoniobenzene iodide and subsequent identification of the modified lysine phenylthiohydantoin by absorbance at 420nm; (3) identification of histidine phenylthiohydantoin by its blue fluorescence under long-wave u.v. light; (4) cleavage of the chain into two or three fragments and subsequent sequencing without purification [a detailed statement giving the major phenylthiohydantoins assigned at each step for each sequence run before their alignment in individual sequences has been deposited as Supplementary Publication SUP 50084 (10 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5]; (5) separation of fragments produced by CNBr cleavage by cation-exchange chromatography; (6) peptide sequencing after attachment of the peptide to cytochrome c. The amino acid sequence was confirmed by amino acid compositions of the complete chain, of CNBr fragments 1 and 3, and of 11 purified tryptic peptides.