Imaging with an ultra-high-speed video camera operating at 20 Mfps for 300 kpixels

Abstract

An image sensor with 300 kpixels operating at 20 Mfps is developed. Pixels on odd-number and even-number columns can be independently operated. The highest frame rate is 40 Mfps when a time shift of a half of the shortest frame interval is introduced to the operation of the odd and even pixel columns. The sensor is backside-illuminated one for high sensitivity to support the ultra-high-speed imaging with fewer photons. The concept, the structure and the operation scheme of the image sensor are presented. The pixel count and the highest frame rate of the prototype which was developed in 2011 were 165 kpixels and 16 Mfps. Therefore, the new image sensor achieved doubled performance. In-situ storage for 107 image signals is installed in each pixel. Simultaneous recording of image signals at all pixels makes it possible to capture consecutive 107 frames at a time interval for a signal packet to be transferred from the photodiode to the nearby storage element of each pixel. Video cameras equipped with these sensors are applied to imaging of high-speed phenomena such as electric spark discharge and sudden crack propagation for the performance test.