Face detection works properly if video cameras are installed and set up as follows:
- The frame rate should not be less than 12 FPS and not less than 6 FPS for face recognition at turnstiles.
The maximum angle of frontal perspective of the photos of people’s faces received from video cameras should not exceed +/- 15°.
- The distance between the pupils on the photos of people’s faces received from video cameras should not be less than 32 pixels.
- Mutual faces covering should be minimal.
- Faces should be evenly illuminated with diffused light of at least 200 lux. Directional side lighting is not allowed.
- The contrast of the photos of the captured faces should be over 64 grayscale. Insufficient or excessive lighting is not allowed.
- There should be no backlighting and sharp gradients of light and shade.
- The photos of the captured faces received from video cameras should be clear. Image blurring caused by motion is not allowed.