Many tasks of search, monitoring and diagnostics require using unmanned aerial systems with thermal vision camera. Radiometry is a method of extended temperature measurement and search of objects of interest.
Unlike a visual camera, capturing colors and lightning, thermal vision camera captures temperature of different points of object. Monitor displays the allocation of heat. Black/White palette assigns black color to the coldest point of picture, white color – to the hottest, or conversely (it depends on chosen setting). 8-bit signal enables 256 graduations from black – to grey – to white appropriate to 256 graduations of temperature.
Digital effects make possible to “colorize” obtained picture. There are lots of color palettes for thermograms called pseudocolor. For instance, shades of grey can be replaced by palette yellow – to orange – to red. Colors on a display show real allocation of heat. Human eyes better distinguish colors than grey shades.
Commonly thermal vision survey requires to distinguish some areas of interest (the hottest and the coldest) among all field of view. When searching heated objects like people, animals or cars against the backdrop of the city, the isotherm mode enables to colorize the hottest image areas (one half of whole temperature range, 128 color graduation) and to remain the coldest areas grey (128 grey shades). Thus human is highlighted against the grey backdrop.
Whole range can be divided into 2, 3 or 4 parts cycling 2, 3 or 4 palettes.
This mode is accessible in DJI Zenmuse XT camera and in most FLIR cameras except Vue and Vue Pro.
Point temperature measurement
Thermal camera can not only to compare temperature in different points, but also to measure it’s absolute value. In FLIR Quark 2, Zenmuse XT and other cameras the temperature of point in the center of field of view is being measured. FLIR Tau 2 module enables to choose the location and size (sqare of pixels) of point of measurement and to determine the hottest and the coldest points.