Two-Tap Pixel for Heart Rate Detection

VLSI Symposium 2018 publishes a preview of Shizuoka University, Brookman, and Chiba University paper "A Two-Tap NIR Lock-In Pixel CMOS Image Sensor with Background Light Cancelling Capability for Non-Contact Heart Rate Detection."

"Sensor technologies, whether for the Internet of Things, industrial electronics, or biomedical applications, have been and continue to be an important part of the VLSI Symposia. This year, both Technology and Circuits papers fall into this category. First, C. Cao from Shizuoka University will present a CMOS image sensor using two-tap near infrared lock-in pixels for non-contact heart rate detection. The two-tap pixels are used to cancel background light, achieving >98% detection precision even in the presence of sinusoidal varying bright ambient light, comparable to the latest visible-band-based ISP-assisted method. Fabricated in a 0.11um CIS technology, the achieved maximum modulation ratio is 90%, as well as a low random noise of 1.1e-rms."