Temporal photoreception for adaptive dynamic range image sensing and encoding

Abstract

We have implemented two analog VLSI computational sensors for sensing and encoding high dynamic range images by exploiting temporal dimension of photoreception. The first sensor is a multi-integration time photoreceptor that automatically adapts to use different integration periods depending on light intensity. It exhibits a dynamic range 128 times larger than that of a single integration period photoreceptor, approximately 1: 128 OOO. The second sensor is an intensity-to-time processing paradigm that is based o n the notion that stronger stimuli elicit responses before weaker ones. The paradigm sorts pixels of sensed images by their intensities, thus achieving information-theoretic optimal encoding of images. It handles dynamic range of approximately 1 : 1 OOO OOO. Both implementations can operate at standard video rate of 30 frames s -' . 0 1998 Elsevier Science Ltd. All rights reserved.

Sensor and Display Human Factors Based Design Constraints for Head Mounted and Tele-Operation Systems

“…This is akin to the ability of most image sensors to adapt to the average illumination by changing their exposure time, aperture size, and system gain. For a standard off the shelf camera exposure times can change by over 7 orders of magnitude, while state of the art imagers have reported changes up to 10 orders of magnitude, which is close but still well below the capabilities of the HVS [3–5]. The ability of imagers to adapt to illumination level to match that of the HVS is important however what is at least equally as important for matching the capabilities of the HVS is to have the same in scene dynamic range as the average person.…”

“…However with frame rates of >10,000 fps [1,2] and dynamic ranges >160 dB [3–5], one must ask what are the best capabilities one can desire in an imager? In general it is hard to answer such an open ended question as it is highly dependent on the application of the imager, but if we restrict our focus to imaging systems where the output is viewed by a person in real-time, one can determine specific constraints for the design of the sensor based on the capabilities of the human visual system (HVS) [6,7].…”

Adaptive dynamic range matching for spectroscopic measurements

“…Another approach is to use a more sophisticated detector that combats blooming effects. While antiblooming detector solutions are becoming increasingly effective [12][13][14][15][16][17], highly customized detector hardware does not always offer a cost-effective solution to the problem. We present an alternative solution to issues arising from DR mismatch for spectroscopic measurements.…”

Brightness perception,dynamic range and noise: a unifying model for adaptive image sensors

“…Various on-chip techniques have been proposed to capture wide dynamic range images [3][4] [23][33] [42]. Generally these methods create intelligent pixels that try to measure wide dynamic range at pixel level without regard for the local distribution of the radiance map impinging onto the sensitive surface.…”

“…The most significant random noise sources in image sensors include shot noise and thermal noise 3 . Another point of concern, depending on the architecture of the sensor, is fixed pattern noise.…”