Image Feature Extraction LSIs and its application to Natural Image Recognition Systems

本研究的目的是开发从自然场景图像中进行人脸/物体识别的集成系统。该系统使用脉冲调制信号，基于合并的AD电路结构，通过像素并行操作实时地执行图像特征提取。作为识别处理的算法和体系结构，我们提出了基于电阻融合网络的粗区域分割、基于元胞自动机处理的区域提取和基于Gabor小波变换的特征提取，验证了该方法的灵活分割能力，并设计、制作和验证了该网络的VLSI芯片。我们还开发了高效的阻性熔丝网络的现场可编程门阵列实现，对于×像素的图像，处理时间约为20ms。在区域提取方面，采用元胞自动机的现场可编程门阵列实现了对约5个区域的30×30像素图像的处理时间为5微秒，比传统的序列标记处理速度快几十倍。我们还提出了一种用于Gabor滤波的阻性网络电路，并设计了面积为4.9 mm的二维Gabor滤波LSI。12×24像素，采用0.35微米的cmos工艺。对制作的LSI芯片进行了测量，得到了二维脉冲响应。我们还设计了面积为9.8 mm的二维Gabor滤波大规模集成电路。6l×72像素，工作时间为40ms，功耗为800 mW。

The aim of this research is to develop integrated systems for face/object recognition from natural scene images. The systems execute image feature extraction with real time by pixel-parallel operation based on the merged AD circuit architecture using pulse-modulation signals. As algorithms and architectures for recognition processing, we have developed coarse region segmentation by resistive-fuse networks, region extraction by cellular automaton processing and feature extraction by Gabor wavelet transformation.We have verified the flexible segmentation ability of the method using resistive-fuse networks, and have design, fabricated and verified a VLSI chip of the network. We have also developed efficient FPGA implementation of the resistive-fuse networks, in which the processing time is about 20 ms for 64×64-pixel images. As for region extraction, FPGA implementation of the cellular automaton has achieved processing time of 5 micro seconds for 30×30-pixel images including about 5 regions, which is several tens times faster than the conventional serial labeling processing. We have also proposed a resistive network circuit for Gabor filtering, and designed a 2-D Gabor filtering LSI of 4.9 mm sq. with 12×24 pixels using a 0.35 micron CMOS process. A 2-D impulse response has been obtained by the measurement of the fabricated LSI chip. We have also designed a 2-D Gabor filtering LSI of 9.8 mm sq. with 6l×72 pixels in which operation time of 40 ms and power consumption of 800 mW have been obtained.