Yukinobu Sugiyama

A high-speed CMOS image sensor with profile data acquiring function

We have developed a Profile Imager aimed at high-speed automatic target tracking. The Profile Imager can perform both target tracking within a 512 /spl times/ 512-pixel entire image area and acquisition of partial images simultaneously and independently. Experimental results of capturing 128 /spl times/ 128-pixel partial images of an automobile license plate at 1620 frames/s are presented. In addition, results of integrating 89 partial images demonstrate the capability of the device as a high-speed, high-resolution, high-dynamic-range image tracker. A 0.6-/spl mu/m two-poly three-metal CMOS process is used to implement a 13.0 mm /spl times/ 14.3 mm imager.

A 3.2 kHz, 14-Bit Optical Absolute Rotary Encoder With a CMOS Profile Sensor

We have developed a 3.2 kHz, 14-bit optical absolute rotary encoder system using a profile sensor and a slit disc. The profile sensor, which we have designed for this purpose, is a unique CMOS area image sensor aimed at high-speed position detection of X and Y axes. Y axis profile data from the profile sensor is used for recognition of an index code on the slit disc, and X axis profile data is used for position detection of the index code. This combination of two-axis information enables high resolution even with a small number of index codes (64 indexes) and a small amount of digital calculations. Experimental results show that this system can detect rotation with an angular resolution of 14 bits (0.022deg) and a maximum detection speed of 3.2 kHz.

A high-speed, profile data acquiring image sensor

A profile imager for high-speed automatic target tracking has the capability of executing both target-tracking control from a 512/spl times/512 image array of 20 /spl mu/m/spl times/20 /spl mu/m pixels and the acquisition of a sub-array, simultaneously. 128/spl times/128 partial images of an automobile license plate can be captured at 1620f/s. A 0.6 /spl mu/m 3M2P CMOS process is used to implement the 13.0mm/spl times/14.3mm imager.

A 3.2 kHz, 13-bit Optical Absolute Rotary Encoder with a CMOS Profile Sensor

We have developed a 3.2 kHz, 13-bit optical absolute rotary encoder system using a profile sensor and a slit disc. The profile sensor, which we have designed for this purpose, is a unique CMOS area image sensor aimed at highspeed position detection of X and Y-axes. The profile data of Y-axis from the profile sensor is used for recognition of an index code number of a slit disc and that of X-axis is used for position detection of the index code. This combination of both axes information enables to achieve high resolution even with less number of index codes (64 indexes) and small amount of digital calculations. Experimental results assure that this system can detect 13 bit angle resolution (0.044 degree) and the speed of detection reaches at maximum 3.2 kHz.

High-speed imaging using CMOS image sensor with quasi pixel-wise exposure

Several recent studies in compressive video sensing have realized scene capture beyond the fundamental trade-off limit between spatial resolution and temporal resolution using random space-time sampling. However, most of these studies showed results for higher frame rate video that were produced by simulation experiments or using an optically simulated random sampling camera, because there are currently no commercially available image sensors with random exposure or sampling capabilities. We fabricated a prototype complementary metal oxide semiconductor (CMOS) image sensor with quasi pixel-wise exposure timing that can realize nonuniform space-time sampling. The prototype sensor can reset exposures independently by columns and fix these amount of exposure by rows for each 8×8 pixel block. This CMOS sensor is not fully controllable via the pixels, and has line-dependent controls, but it offers flexibility when compared with regular CMOS or charge-coupled device sensors with global or rolling shutters. We propose a method to realize pseudo-random sampling for high-speed video acquisition that uses the flexibility of the CMOS sensor. We reconstruct the high-speed video sequence from the images produced by pseudo-random sampling using an over-complete dictionary. The proposed method also removes the rolling shutter effect from the reconstructed video.

Joint Optimization for Compressive Video Sensing and Reconstruction Under Hardware Constraints

Compressive video sensing is the process of encoding multiple sub-frames into a single frame with controlled sensor exposures and reconstructing the sub-frames from the single compressed frame. It is known that spatially and temporally random exposures provide the most balanced compression in terms of signal recovery. However, sensors that achieve a fully random exposure on each pixel cannot be easily realized in practice because the circuit of the sensor becomes complicated and incompatible with the sensitivity and resolution. Therefore, it is necessary to design an exposure pattern by considering the constraints enforced by hardware. In this paper, we propose a method of jointly optimizing the exposure patterns of compressive sensing and the reconstruction framework under hardware constraints. By conducting a simulation and actual experiments, we demonstrated that the proposed framework can reconstruct multiple sub-frame images with higher quality.