A 30 µW 30 fps 110 × 110 Pixels Vision Sensor Embedding Local Binary Patterns

Abstract

We present a 110 × 110 pixel vision sensor that computes the Local Binary Patterns (LBPs) of an imaged scene with a power consumption of 30 µW at 30 fps. The LBP of a given pixel is a binary vector, encoding the direction and sign of image contrast with respect to its neighbors. Each LBP provides a visual description of an image's local structure that is widely used for texture and object recognition. In the sensor proposed here, each pixel detects its corresponding LBP with respect to its four neighboring pixels and saves this information into a digital map using 6 bits to encode each pixel. The operation is executed during the exposure time and requires 83 pW/pixel $\cdot $ frame to be computed. The chip is implemented in a 0.35 µm CMOS featuring 34 T square pixels with 26 µm pitch. We illustrate some examples of image description based on the LBPs output by the sensor.