Surveillance cameras based on CCD/CMOS/ ICCD/ EMCCD/EBAPS imaging sensors sensitive in visible and near infrared range are widely used in many long range surveillance applications as independent imagers or as part of a bigger multi-sensor surveillance systems. Majority of VIS-NIR cameras are used for day level applications but an increasing number of these cameras is used to enable surveillance in both night and day conditions. In both cases it is important to verify performance of these cameras under varying illumination conditions from very dark nights to ultra bright days. Important missions can fail due to too low sensitivity of VIS-NIR cameras at night conditions (dark, noisy images) or due to too low dynamic at ultra bright day conditions (saturated, blurred images). Next, it is important to use VIS-NIR cameras that generate high quality images in order to achieve maximal effective surveillance ranges.
Two types of test stations for testing surveillance VIS-NIR cameras are offered:
- TVT test stations for tests at laboratory/depot conditions,
- LOF test station for tests at field/depot conditions.
The TVT test station is a variable intensity image projector that projects images of some standard targets to the tested TV camera. The tested TV camera generates distorted copies of the projected images. Quality of the images generated by the camera is evaluated and its important characteristics are measured. The TVT test systems are built from the following blocks: DAL series calibrated light source, set of targets, rotary wheel, set of exchangeable refractive/reflective collimators, PC, frame grabber, TAS-TV software, OS stage. The TVT test systems are recommended for testing TV cameras used for medium/long distance surveillance. The TVT test systems can be delivered in several versions optimised to applications of tested TV cameras (day, night, day/night).
The LOF measuring set is a mobile variable distance measuring system that project images of a set of standard targets directly to the tested camera. The tested camera generates a distorted copies of the projected images. Quality of the images generated by the camera is evaluated and its important characteristics are measured.
The LOF test set does not use collimator for image projection and the distance target- camera must be longer than the minimal focusing distance of the tested imager. Different patterns can be projected into the direction of the tested imager. All important parameters of surveillance
VIS-NIR cameras can be measured but LOF system is recommended for basic tests of cameras (resolution, MRC, sensitivity, dynamic range).
The LOF test system are recommended for testing surveillance cameras field conditions or at laboratory/depot conditions when a long corridor as a test place can be used. Accuracy of measurements with LOF test systems is similar as accuracy of measurements with laboratory class TVT series test systems assuming proper measurement conditions.