In this report, an RZ SSB (Real Zero Single-Sideband) transceiver is newly proposed for mobile radio services. The necessary transmission bandwidth of RZ SSB is similar to that of a conventional SSB. An amplitude limiter, which can remove the amplitude impairment, can be used without degrading the quality of detected output signals in the receiver. RZ SSB signals can be demodulated with both product detection and frequency detection. This is because the RZ SSB signal possesses FM-like characteristics.
This report describes an outline of General Purpose Digital Signal Processing System with DSP, which is suitable for the development of distributed processing systems. This system contains 8 DSP boards, and it is possible to transmit data between arbitrary two DSP boards. Each board can also select external analog or digital input/output signals. In addition this system has a 32Kword-Memoryboard which can interface with another personal computer via GP-IB, so when DSP boards are operating on distributed processing, the debug of each DSP can be carried out by means of this board.
Display control unit (DCU) design for office workstations is developed. A functional model of the DCU with multi-windowing capability is discussed, and hardware structure of the DCU is shown. The DCU's unique functions are : 1) memory management that obtains and releases logical screens in the bit mapped memory ; 2) input of graphic data and image data into proper logical screens ; 3) generating physical screen images by reading logical screens. The DCU provides fast window control, and the independence of graphic and image data from bit mapped memory structure.
Start of videotex commercial service and enhanced use of computer graphics technique have made the international standardization activity on visual communication protocol more important and urgent than ever before. This paper first introduces recent activities on this matter in ISO and CCITT especially activities made by ISO/TC97/SC2 and CCITT SGVIII. Then, as an example, this paper describes the international standar dization activities and further study points of videotex protocol. Future prospect of the international standardization activity is also desciribed by dividing it into three parts, namely photographic protocol, geometric protocol and protocol architecture.
This paper presents a graphic command coding scheme by two commands, Polygon (filled) and Arc (filled), for multi-color images. The scheme consists of four steps : region extraction, line and curve fitting of extracted borders, dividing of fitting arcs and transforming of region data into graphic commands. The scheme has several advantages. (1) There occurs no gaps between adjacent regions. (2) It can encode an image which includes island-regions effectively. (3) Good data compression is possible when an image is relatively simple, etc.
In this paper, we give a new coding scheme for multi-level images, which is called progressive coding scheme. This coding scheme is suitable for interactive image communication, for example image data-dase retrieval and teleconference. When progressive coding scheme is applied, the receiver can quickly recognize the contents of the receiving image and image quality can be progressively improved, if necessary, by adding supplementary information. Firstly, we propose the coding algorithm of progressive coding scheme. Secondly, we evaluate coding efficiency and image quality of the proposed coding scheme. Finally, some applications of the proposed coding scheme are described.
This paper describes an eye movement analysis system that incorporates an infrared television fundus camera and utilizes image processing techniques. Using this method, we can measure horizontal, vertical and rotational eye movements. This system is controlled by a 16 bit micro-computer and uses a template matching unit to detect the papilla quickly. Therefore, we can measure easy horizontal and vertical positions of papilla. Finally the paper describes experimental results of measuring three eye movements.
Television systems, which employ sub-sampling technique at the encoder and spatio-temporal interpolation at the decoder, are under active research. To evaluate the S/N performance of these systems, a three dimensional noise weighting function is proposed, based on researchs for visual system characteristics. Then a universal calculation method of a weighting factor, which can be applied to any television system is mentioned. The weighted S/N of different television signals, obtained through subjective assessment tests and the calculation method proposed in this report, lie within 3 dB.
An Extended-Definition TV system that is fully compatible with existing standards has been studied theoretically from the standpoint of three dimensional signal processing. Characteristics such as dynamic resolution for alias-free process, and crosstalk between luminance, chrominance and high resolution components have been made clear for the cases of horizontal and vertical motions. A new method of motion-adaptive signal processing is also proposed in which these impairments can be eliminated or greatly reduced.
Formerly we proposed a method for designing parallel gain/shape vector quantizers in the 8*8 DCT (Discrete Cosine Transform) domain . This paper proposes a method for magnifying the block of this quantizer. In this method, the block is magnified by symmetrizing the structure of the shape code book. By magnifying the block to 16*16,at a fixed coding rate signal-to-noise ratio is increased by about 1 (dB), and this coding scheme yields a perfomance advantage of 1〜2 (dB) over the DCT coding scheme with scalor, Max-type quantizers.
This paper deals with gain/shape vector quantizers for picture signals in the SVD (Singular Value Decomposition) domain, named the SVD-G/S VQ. First, we present the optimum structure of the code book for the SVD-G/S VQ, which is different from that of previously proposed gain/shape vector quantizers for speech coding by Sabin and Gray . And then, by generalizing the previously proposed algorithms for the design of gain/shape vector quantizers by Sabin and Gray , we derive several algorithms for the design of the SVD-G/S VQ based on a training sequence.