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30 June 2024 to 4 July 2024
FMDUL
Europe/Lisbon timezone

TPM: A Novel Sensor for Very-High Speed Imaging with Variable Frame Depth

1 Jul 2024, 10:50
20m
Main Auditorium (FMDUL)

Main Auditorium

FMDUL

Main Auditorium of the Faculty of Dental Medicine at the University of Lisbon (Faculdade de Medicina Dentária da Universidade de Lisboa)
Oral Communication Detector Systems

Speaker

Ben Marsh

Description

Developed by the Science and Technology Facilities Council (STFC) and Cordin Scientific Imaging, presented in this paper will be the Time Pixel Multiplexing (TPM) sensor, a high-speed camera with variable frame depth. Based around the principle first published by Gil Bub [1], TPM is a 1024x1024 CMOS image sensor with the ability to image at speeds up to 10Mfps by changing which pixels are active through time.
In a conventional CMOS image sensor, the array of pixels can either be active all at the same time with global shutter, or in a row-by-row basis as in rolling shutter, but in both the final end goal is to create one coherent snapshot of a moment in time. This means that to achieve high-speed imaging in one device a combination of fast pixel-level readout with exponentially faster full sensor readout [2] or by increasing the pixel size through in-pixel memory with a slow readout [3].
However, by carefully controlling when each pixel is active a subset across the full array can be integrating at the same time whilst another is reading out and a third set are held in reset before integration, as shown in a rough timing diagram in Figure 1. In this way it possible to capture one single image that can then be processed into a sequence of variable frame depth where the only trade-off is the final resolution. Shown below in Figure 2 is one such image where a 4x4 TPM mode has been used to produce a 16-frame video at 256x256 pixel resolution. The TPM mode can be varied between the two extremes as the user desires, from a single 1 Mpixel frame up to over 1 million sequential frames at a single pixel resolution, all at speeds of up to 10Mfps.
This paper expands on initial results published in 2021 [4], and aims to give an overview of the technology, the challenges and developments required within, as well as present results from the first commercially available camera using the STFC-developed TPM sensor from Cordin Scientific Imaging.

Figures:

Figure 1: Simplified readout control graph showing a set of four pixels being held in reset, integrating, being sampled, and then read into the column as each line set is activated.

Figure 2: An example 4x4 video of a bridged wire test: a) The complete 1024x1024 frame; b) separated into 16 frames, with time increasing from top left to bottom right vertically; and c) a single 256x256 image

References:
[1] Bub G., Tecza M., Helmes M., Lee P., Kohl P., “Temporal pixel multiplexing for simultaneous high-speed, high-resolution imaging.” Nat Methods. 2010 Mar;7(3):209-11
[2] Cremers, B., Agarwal, M., Walschap, T., Singh, R., & Geurts, T. (2009, June). “A high speed pipelined snapshot CMOS image sensor with 6.4 Gpixel/s data rate”. Proc. 2009 International Image Sensor Workshop
[3] Crooks, J., B. Marsh, R. Turchetta, K. Taylor, W. Chan, A. Lahav, and Amos Fenigstein. “Kirana: a solid-state megapixel uCMOS image sensor for ultrahigh speed imaging.” Sensors, cameras, and systems for industrial and scientific applications XIV, vol. 8659, pp. 36-49. SPIE, 2013.
[4] Krukauskas, D., Marsh, B., Sedgwick, I., Guerrini, N., & Benhammadi, S. “A Novel Ultra-High-Speed CMOS Image Sensor Implementation with Variable Spatial and Temporal Resolution using Temporal Pixel Multiplexing.”, Proc. 2021 International Image Sensor Workshop

Authors

Ben Marsh Mr Geoffrey Marchant (Cordin Scientific Imaging) Iain Sedgwick Mr Jerry Zhang (Cordin Scientific Imaging) Mr Nathan Nebeker (Cordin Scientific Imaging) Nicola Guerrini Seddik Benhammadi Mr Xiuyan Guo (Cordin Scientific Imaging)

Presentation materials