8 September 1995 Pyroelectric midresolution camera TH74KB41A
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Abstract
The TH74KB41A camera is designed for the THOMSON-CSF Semiconducteurs Specifiques (TCS) TH7441A pyroelectric IR sensor, optimized for the wavelength range 8 to 14 micrometers. This monolithic area sensor is made of 128 by 128 pixels (85 micrometers by 85 micrometers) compatible with a one inch diameter optic, and operates at ambient temperature. The camera is optimized to operate with a short integration period -- 10 ms -- allowing 50 frames per second, then compatible with a wide range of applications, including real-time imaging. Three video outputs are available: one 10-bit unprocessed image output every 10 ms, one 8-bit processed image every 20 ms, and one composite analog video signal using a 128 by 128 zone of the display. Eight-bit and analog outputs are obtained by summing the two successive fields -- alternately positive and negative. The 10-bit output delivers successively these positive and negative fields, 10 ms each. It is possible to select an analog gain 3 or 6 and a digital gain of 1, half, quarter or an eighth. Offset may be adjusted to fit the temperature range to be viewed in accordance with the chosen gain. The camera also produces pixel, line, and frame pulses to ease synchronization of an optional frame grabber. Power consumption is as low as 12.5 W, including chopper power supply. The useful scene dynamic range is plus or minus 170 degrees around the ambient temperature. With an f/1 optic -- optics transmission is 0.8 -- the NETD is around 1.5 K and the recognition 0.75 K. The contrast transfer function at Nyquist frequency -- 5.9 line pairs per mm -- is 38%. The small size of this lightweight camera body (200 mm by 125 mm by 60 mm without lenses) together with its low power consumption allow easy use everywhere. This camera benefits from the pyroelectric area sensor and does not use any cooling. This camera, quite cheaper than a camera using a cooled detector, is well suited to a wide range of applications such as laser beam profile analysis, IR machine vision in the industrial field -- useful for process control, security, night vision, etc., -- fire fighting or prevention, search and rescue in poor vision environment, medical diagnosis, etc.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. Leconte, R. Barbier, H. Fillon, Jean-Louis Coutures, "Pyroelectric midresolution camera TH74KB41A", Proc. SPIE 2552, Infrared Technology XXI, (8 September 1995); doi: 10.1117/12.218287; https://doi.org/10.1117/12.218287
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