Assorted News: Always-On Sensors, Moon Landing LiDAR

Dongguk University, Seoul, Korea, publishes a MDPI paper "Design of an Always-On Image Sensor Using an Analog Lightweight Convolutional Neural Network" by Jaihyuk Choi, Sungjae Lee, Youngdoo Son, and Soo Youn Kim.

"This paper presents an always-on Complementary Metal Oxide Semiconductor (CMOS) image sensor (CIS) using an analog convolutional neural network for image classification in mobile applications. To reduce the power consumption as well as the overall processing time, we propose analog convolution circuits for computing convolution, max-pooling, and correlated double sampling operations without operational transconductance amplifiers. In addition, we used the voltage-mode MAX circuit for max pooling in the analog domain. After the analog convolution processing, the image data were reduced by 99.58% and were converted to digital with a 4-bit single-slope analog-to-digital converter. After the conversion, images were classified by the fully connected processor, which is traditionally performed in the digital domain. The measurement results show that we achieved an 89.33% image classification accuracy. The prototype CIS was fabricated in a 0.11 μm 1-poly 4-metal CIS process with a standard 4T-active pixel sensor. The image resolution was 160 × 120, and the total power consumption of the proposed CIS was 1.12 mW with a 3.3 V supply voltage and a maximum frame rate of 120."

Pixart QVGA PAJ6100U6 sensor is also aimed to always-on devices and consumes just 1.4mW at 30fps:

IEICE Electronics Express publishes Hamamatsu and Japan Aerospace Exploration Agency paper "Geiger-mode Three-dimensional Image Sensor for Eye-safe Flash LIDAR" by Takahide Mizuno, Hirokazu Ikeda, Kenji Makino, Yusei Tamura, Yoshihito Suzuki, Takashi Baba, Shunsuke Adachi, Tatsuya Hashi, Makoto Mita, Yuya Mimasu, and Takeshi Hoshino.

"Explorers attempting to land on a lunar or planetary surface must use three-dimensional image sensors to measure landing site topography for obstacle avoidance. Requirements for such sensors are similar to those mounted on vehicles and include the need for time synchronization within one frame. We introduce a 1K (32 × 32)-pixel three-dimensional image sensor using an array of InGaAs Geiger-mode avalanche photodiodes capable of photon counting in eye-safe bands and present evaluation results for sensitivity and resolution."