Image
intensified
CCD
high speed cameras
equipped with analog
video output:
Stanford Computer Optics high speed cameras with analog video units
transfer the video signal analog in
real-time to a frame grabber card in the PC. The A/D conversion is
performed on the frame grabber card with a typically 10 bit resolution.
Nevertheless, our non-linear gamma-processing
technique allows a virtually 16 bit resolution limit anyhow.
As shown in the drawings below the gamma-processing first compresses
the analog value in the camera electronics to a root-function, that is
analoguous transmitted to the frame grabber card in the PC. The frame
grabber digitizes the compressed signal by a 10 bit A/D conversion.
This yields a non-linear digital signal with quantization steps
depending on the bit number of the resulting data word: the higher the
bit number, the larger the quantization step related to the original
analog signal.
This non-linearly coded signal is then decompressed in the PC by means
of a high precision look-up table. The result is a linear-coded data
word with a virtual resolution of 14 to 16 bit related to the cameras
original analog signal.
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Image
intensified
CCD
cameras
equipped with digital
video output:
Our digital video units include 14 bit A/D converters that keep the 14
bit dynamic range of the high resolution CCD chips.
You can find more revealing information
about the A/D conversion in the following sections here and here.
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