Image Sensor

About

Abstract: Stanford researchers have patented an image sensor that overcomes frame rate and power consumption limits for high-speed mega-pixel imaging, and therefore can extend battery life for mobile phone cameras. The image sensor uses compressed sensing (CS) to reduce the number of captured measurements, hence the number of Analog to Digital conversions performed, without adversely affecting signal. The prototype, a 256x256 0.15 μm CIS process image sensor, demonstrated no loss in Signal to Noise Ratio or sensitivity relative to normal capture, and close to linear reduction in energy consumption per frame with CS compression ratio. The sensor benefits cameras with high-frame-rate imaging and limited power sources. Captured and reconstructed images: (a) target object, (b) packaged prototype chip, (c) sensor output at CR=1/4, (d) reconstructed image. Energy consumption per frame, Structural Similarity Index (SSIM), and Peak Signal to Noise Ration (PSNR) versus compression ratio CR. Applications: Cellphone and mobile device cameras Biomedical imaging (e.g. blood flow or neuron activities) with limited data bandwidth and power supply Advantages: Low power, longer battery life, and high frame rate High scalability in pixel resolution Capability of capturing moving objects Simple optical design