NAOqi Vision - Overview | API
ALBacklightingDetection extractor checks if the images returned by the camera are backlit or not. Backlighting occurs when there is high contrast between a light source (e.g. a window) and the observed scene.
The following backlighting value is computed for each frame:
This value is stored in the ALMemory. When a backlighting situation is detected for the first time (i.e the backlighting value just turned to 2) an event is raised.
In order to compute the backlighting value, the extractor:
The final result is a weighted combination of both the percentage of pixels at ‘255’ and the percentage of pixels below ‘70’.
The camera AutoExposition parameter (and the AutoGain parameter, if it exists) of the camera must be activated for this module to work properly.