The quality of the camera is a key condition for good CIV measurements: high sensitivity, low noise, high spatial resolution are desirable. A high image rate is needed for 3D scanning.
An analogic camera can be used, with a numerical image acquisition board in the computer, provided it has a progressive scan schutter (it makes each image in a single scan, while the usual video format is made of two interleaved scans, separated by half the frame period). Cameras with numerical output provide better results. We use two kinds, the Pulnix TM-9701 and the more recent SMD 1M60.
The Pulnix has resolution of 768*484 pixels, with 256 grey levels
(8 bits), image rate 30 per second, sensitivity : 10 microV/e- ( which
is about 1 lux with f=1.4 ). Cell size is 11.6*13.6 
m
,
imager is 2/3''progressive scan interline transfer CCD. The image
acquisition board is from Imaging Technology , PC-DIG model with 2Mo
memory.
The SMD 1M60 digital camera provides high-sensitivity 12 bit images
with 1024*1024 spatial resolution at up to 60 frames per second.
The sensitivity is 8 microV/e- , pixel size is 14m*14m
and the fill factor is about 70%.
The output is split toward two Imaging Technology framegrabber to avoid the PCI bus limit at 133Mo/s; hence the computer has two PCI 32bits/33MHz bus and the signal split is done with a home made ``Y'' cable. A commercial system based on the same concept is no available, the PIXCI D3X (http://www.epixinc.com/products/pixci_d3x.htm).
Both systems use the ITEX libraries, which provides a set of tools for controlling the camera.
| PulnixTM9701 | SMD/DALSA 1M60 | |
| Frequency | 30 Hz | 60 Hz (1024x1024) 110 Hz (512 x512) |
| Resolution | 768 x 484 | 1024x1024 pixels |
| Digitalisation | 8 bits (256 grey levels) | 12 bits (4096 grey levels) |
| Sensitivity | 10 microV/e- | 8 microV/e- |
| Cell size | 11.6m*13.6 m |
14m*14m |
| CCD size | 9.6 x6.7 mm2 | 14x14 mm2 |
| frame grabber | PC-DIG CORECO IMAGING | PC-DIG CORECO IMAGING |