UV cameras

Systems for testing two groups of UV cameras are offered:
  1. Solar blind UV cameras sensittive in UV-B band
  2. Multi-sensor broadband imaging systems sensitive  from shortwave UV-B band to SWIR

Solar blind UV cameras are imaging devices optimized to detect ultraviolet light of wavelengths below about 280nm. Such cameras are insensitive against sunlight due to negligible sensitivity to visible and long wavelength UV light.  Solar blind UV cameras are used in a series of applications like corona detection, fire detection, combustion analysis, plasma research, testing UV lamps, etc. However, highly sensitive corona detection is the main mass application and these devices are of crucial importance in electric power industry. These imaging devices enable easy detection of degraded insulators of high voltage transmission lines, distributions and substations. They can see the emission of UV light when discharges occur at defect insulators. From design point of view solar blind UV cameras are actually bispectral imaging systems built by combining true UV camera with typical visible camera. These bispectral imaging system generate output image as overlay of typical visible image with UV image of analyzed UV source.

As mentioned earlier important decisions are made on basis of information provided by solar blind UV cameras. Next, sensitivity of UV cameras can significantly deteriorate with time. Further on, manufacturers of UV cameras typically present sensitivity parameter in camera data sheets but without any information about test method. Therefore, it is not clear if sensitivity is defined as minimal detectable flux at target plane, optics plane, filter plane or at UV sensor plane and how exactly this parameter is measured. At the same time it should be noted that sensitivity measured at the sensor plane is thousands times better than sensitivity measured at the target plane when only the latter parameter is really interesting for final camera users. Therefore precision evaluation of non solar UV camera on basis of typical data sheet is not possible. In such situation systems capable to do reliable testing of solar blind UV cameras can be potentially very useful to evaluate true performance of these cameras available on market and to monitor performance of the cameras during their life time.

UVIC is a tester of solar blind UV cameras that enables precision evaluation of these important and expensive imaging systems. UVIC test station generates images of several standard targets at regulated light intensity in both ultraviolet and visible spectral bands. The tested solar blind camera generates electronic copies of these test images in both two spectral bands. Quality of electronic images generated by tested camera is evaluated and important performance parameters of solar blind UV cameras are measured.

Photo of UVIC test station
   Multi-sensor broadband imaging systems sensitive in spectral range from shortwave UV-B band to SWIR band (from about 280nm to about 1700nm) are rare type of imaging systems targeted mostly for space applications. These imaging systems are typically built by combining several cameras of different spectral bands to form a single broadband imaging system. UVIR is a test system optimized to enable expanded testing these imaging systems.
    UVIR test system is in general a variable target image projector that uses a series of different targets to project their images into direction of tested camera: UV camera , VIS camera, NIR camera, SWIR camera. The tested camera generates copies of the projected images. Quality of the images generated by the camera is evaluated by human observers or by software and its important characteristics of tested camera are measured. The UVIR test system in its basic version (UVIR-A) is system optimized to enable measurement of imaging parameters of tested system (resolution, MRC, MTF). However, UVIR can be also delivered in a more advanced version (UVIR-B) capable to measure both imaging (resolution, MRC, MTF) and radiometric parameters (sensitivity, noise parameters, response function).  

Photo of UVIR test station

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