An adaptive PPG (Photoplethysmography) readout system for a dual-channel OLED-OPD flexible sensor is designed and developed with motion artifact (<1Hz) and ambient lighting interference successfully compensated without any additional motion sensors. The compensation is made possible by adopting multi-feedbacks and an additional reference OPD channel to cancel effectively DC drifts. In result, the quality of measured PPG is improved to the level such that long-time, continuous quality monitoring of bio-sign such as heart rate (HR) is possible. The readout is designed with an auto-programmable band-pass trans-impedance amplifier (TIA) of a 100dbΩ gain with a continuous-type DC-current cancellation loop. The rest of the readout consists of a 0.5 Hz low-pass filter, an additional second-order band-pass filter (0.1-10Hz), a difference amplifier, a motion reference channel, an analog multiplexer, a programmable gain amplifier (PGA), a digital control and a programmable DAC-PWM based auto-intensity tuned OLED driver. The readout is fabricated in an area of 9 mm via the TSMC 180nm process. The experiment result shows that the developed OLED-OPD readout senses well as small as 1nA current, with a measured dynamic range >90dB (1nA to 100 µA) and input-referred noise of 0.26 nA/√H, with power consumption of 460µW. The DC drift is successfully reduced to 1% of its average. The accuracy for heart rate is 96%.
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http://dx.doi.org/10.1109/TBCAS.2021.3138996 | DOI Listing |
PLoS Comput Biol
January 2025
European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany.
The characterization of phenotypes in cells or organisms from microscopy data largely depends on differences in the spatial distribution of image intensity. Multiple methods exist for quantifying the intensity distribution - or image texture - across objects in natural images. However, many of these texture extraction methods do not directly adapt to 3D microscopy data.
View Article and Find Full Text PDFHardwareX
March 2025
LIGHT Community, Physics Department, Imperial College London SW7 2AZ, UK.
We recently demonstrated polarisation differential phase contrast microscopy () as a robust, low-cost single-shot implementation of (semi)quantitative phase imaging based on differential phase microscopy. utilises a polarisation-sensitive camera to simultaneously acquire four obliquely transilluminated images from which phase images mapping spatial variation of optical path difference can be calculated. microscopy can be implemented on existing or bespoke microscopes and can utilise radiation at a wide range of visible to near infrared wavelengths and so is straightforward to integrate with fluorescence microscopy.
View Article and Find Full Text PDFMicro ring resonators (MRR) based evanescent field biosensors have shown excellent potential in medical diagnostics due to their performance, scalability, and ability to integrate multiple sensors in a small area to detect various biomarkers simultaneously. The quest to improve the performance and feature size of such sensors has led to the development of cutting-edge photonic integrated circuits (PIC). However, chip-scale implementation of readout and data analysis still needs to be addressed adequately.
View Article and Find Full Text PDFCommun Eng
January 2025
Institut für Physik, Technische Universität Ilmenau, Ilmenau, Germany.
Reservoir computing is a machine learning method that is well-suited for complex time series prediction tasks. Both delay embedding and the projection of input data into a higher-dimensional space play important roles in enabling accurate predictions. We establish simple post-processing methods that train on past node states at uniformly or randomly-delayed timeshifts.
View Article and Find Full Text PDFUnlabelled: Proton exchange is a fundamental chemical event, and NMR provides the most direct readout of protonation events with site-specific resolution. Conventional approaches require manual titration of sample pH to collect a series of NMR spectra at different pH values. This requires extensive sample handling and often results in significant sample loss, leading to reduced signal or the need to prepare additional samples.
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