Hideaki Matsuo

Recognition of local features for camera-based sign language recognition system

A sign language recognition system is required to use information from both global features, such as hand movement and location, and local features, such as hand shape and orientation. We present an adequate local feature recognizer for a sign language recognition system. Our basic approach is to represent the hand images extracted from sign-language images as symbols which correspond to clusters by a clustering technique. The clusters are created from a training set of extracted hand images so that a similar appearance can be classified into the same cluster on an eigenspace. The experimental results indicate that our system can recognize a sign language word even in two-handed and hand-to-hand contact cases.

Real-time face detection with MPEG-4 codec LSI for a mobile multimedia terminal

We propose an intelligent easy-operating human-machine interface incorporating face detection technology for a mobile multimedia terminal. We have developed a face detection algorithm which works on the resources of a mobile phone. This algorithm is robust in outside fields, and simultaneously works with MPEG-4 Simple Profile Level 1 encoding and decoding on an MPEG-4 codec LSI for a mobile videophone. This enables more intelligent interfaces in visual communication such as IMT-2000 videophone services.

Synthesis and isomerization of N-fused tetraphenylporphyrin ruthenium(II) complexes

Three possible isomers of N-fused tetraphenylporphyrin ruthenium complexes, Ru(NFTPp)Cl(CO)2 (2a-c), were isolated and fully characterized by NMR, IR, CV, UV-vis-NIR absorption, and X-ray crystallographic analyses. Each isomer was stable at ambient conditions and isomerization among 2a-c occurred at elevated temperature both in solution and in a solid state, through the intramolecular rotational pathways. Electronic structures of 2a-c were analyzed in detail by DFT study to reveal appreciable differences in the interaction between the NFTPp ligand and the Ru-Cl moiety.

Ruthenocene-Type Complexes of N-Fused Porphyrins

Ruthenocene-type hybrid complexes with N-fused porphyrinato ligands, [Ru(NFp)Cp] (NFp=N-fused porphyrin, Cp=cyclopentadienyl), have been prepared and characterized by NMR and UV/Vis/NIR spectroscopy, cyclovoltammetry, and X-ray crystallography. [Ru(NFp)Cp] is a common low-spin ruthenium(II) complex and shows strong aromaticity. The Ru-Cp distance (1.833 Å) in [Ru(NFp)Cp] is comparable to that in [RuCp2 ] (1.840 Å). DFT calculations on [Ru(NFp)Cp] showed the unequivocal contribution of the RuCp moiety as well as the NFp moiety to both the HOMO and LUMO, constructing a three-dimensional d-π conjugated system. The HOMO-LUMO gaps of [Ru(NFp)Cp] are insensitive to the substituents on the NFp ligand, which is illustrated spectroscopically as well as theoretically. This is in sharp contrast to the ligand precursor, the N-fused porphyrin, in which the HOMO-LUMO gap is affected by substituents in a similar manner to standard porphyrins and related macrocycles.

Human Interface. Recognition of Local Features for Camera-based Sign-Language Recognition System.

A sign-language recognition system should use information from both global features, such as hand movement and location, and local features, such as hand shape and orientation. We designed a system that first selects possible words by using the detected global features, then narrows the choices down to one by using the detected local features.In this paper, we describe an adequate local feature recognizer for a sign-language recognition system. Our basic approach is to represent the hand images extracted from sign-language images as symbols corresponding to clusters by using a clustering technique. The clusters are created from a training set of extracted hand images so that images with a similar appearance can be classified into the same cluster in an eigenspace. Experimental results showed that our system can recognize a signed word even in two-handed and hand-to-hand contact cases.

Stereoretentive Ligand Exchange Reactions of N-Fused Porphyrin Ruthenium(II) Complexes

The ligand exchange reactions of the ruthenium(II) complex of N-fused tetraphenylporphyrin, Ru(NFp)(CO)2Cl (2), with various anions were investigated. The chloride ligand of the isomers 2a-c was stereoretentively exchanged with bromide (Br-), iodide (I-), and acetate (AcO-) anions in toluene at 100 °C, structures of which were confirmed by 1H NMR as well as single crystal X-ray diffraction analysis. The silver (AgOAc, AgOTf) and boron (NaBPh4) reagents also afforded the corresponding stereoretentive products. On the other hand, the reaction with NaBH4 afforded the hydride complex Ru(NFp)(CO)2H (7) with low stereospecificity, showing a higher reactivity of 2c than other isomers. The ligand dissociation mechanism was proposed with the help of theoretical calculations on the plausible five-coordinated intermediates.