We study imaging system for reconstructing high-spatial resolution image using high-speed intermediate images from the image sensor. Developing our proposed system, we designed a test circuit for image sensor. The result of circuit simulation shows high speed response of our test circuit beyond 960 frames per second. In this paper, first we explain our proposed imaging system, second our test circuit for image sensor.
The accuracy of an optical position sensor that detects the peak of the incident light depends on the resolution of its pixel pitch. However, an accuracy limit is reached where the pixel pitch can not be designed smaller. In this paper we describe a novel idea using skewed pixel arrays to improve the resolution of the position sensor and simulation results of using three algorithms for calculating the peak of the incident light show the effectiveness of this design and the optimized numbers of skewed rows needed according to different incident light conditions.
Compound-eye camera TOMBO has been applied to thermal imaging to acquire both of thermal distribution and three-dimensional object locations to realize a surveillance camera used in every circumstance independent of illuminations. We propose and demonstrate reproduction of edge-preserved, smooth, and accurate depth maps based on an adaptive support-weight approach and joint bilateral filtering from textureless thermal compound-eye images.
Recently, CMOS image sensors have been used widely in the high-volume markets of mobile phones, digital still cameras and camcorders. CMOS image sensor is one of a key device in a next camera. By using the high speed potentiality and low noise quality of CMOS image sensor, a new digital camera market will be created. In this paper, the device technologies and design architecture of low-noise CMOS image sensors is outlined.
We propose a O(1) algorithm for bilateral filter using center-weighted spatial filter. We show that a bilateral filter can be converted into weighted histogram operation. Applying line buffers of column histograms, we can reduce the number of calculation needed to construct recursive center-weighted local histogram. We used a 2-GHz CPU with our method and confirmed that processing time is independent of filter radius. Also, we achieved high PSNR over 40dB.
We have developed a multimodal CMOS sensor device embedded with Au electrodes for fluorescent imaging and cell stimulation in the deep brain of mice. The Au electrodes were placed on the pixel array of the image sensor. Windows over the photodiodes (PDs) were opened in the electrode area for simultaneous fluorescent imaging and cell stimulation in the same area of the brain tissue. The experimental results showed that the 90×90μm^2 Au electrodes with windows were capable of injecting theta burst stimulation (TBS)-like current pulses at 0.2-1mA in a saline solution. We successfully demonstrated that fluorescent imaging and TBS-like current injection can be simultaneously performed in the electrode area of a brain phantom.
We have been developing high-sensitivity HARP photoconductive films made of mainly amorphous selenium, which make use of avalanche multiplication phenomenon. Aiming to improve the sensitivity and the picture quality, we developed the thicker HARP film with an avalanche multiplication factor of about 200, and the Te-doped HARP film with a photoelectric-conversion efficiency for red light of double the previous one. In the developmental process, we found heat treatment to suppress occurring of an image defect when the films were shooting an intense spot light. Moreover, we made an experimental HARP film using a CdSe photoelectric-conversion layer. The film has photoelectric-conversion efficiencies of over 80% almost all over the visible-light-wavelength region, and an avalanche multiplication factor of about 4.