5 Principle of Time of Flight

5.1 Vzense ToF Principle

Vzense DCAM710 product principle is based on range-gated imaging ToF solution, and the sensor inside is based on Panasonic CCD sensor MN34906.

Fig. 9

Because the ToF distance measurement relies on the reflection of light sent out by the camera, any additional light, e.g. artificial light sources or sunlight, may influence the measurement results.

A strong ambient light may affect the accuracy and precision of the depth data, the Vzense DCAM 710 is suggested to in user below 50K LUX ambient light.

5.2 Multipath Propagation

Based on the principle of ToF, Multipath effect may happen when the light reflected more one once. Any light that has been reflected several times, by other objects in the camera’s field of view or the environment can cause deviation to the measurement result.

To eliminate the multipath effect, you should:

1. Keep the camera working environment as clean as possible;

2. Avoid the camera be placed at concave forms environment, like corners of a room or inside of a narrow space;

3. Highly-reflective object shall be removed far away from the measurement target;

5.3 Reflectivity of the Target

Please note that different reflectivity of the target may cause measurement result deviation, objects which have 20% to 80% reflectivity to 850nm or 940nm infrared light have the best result.

5.4 Scattering Effect

Scattering light effect is a noise factor to ToF products, it is caused by multiple reflection inside the lens of camera or the cover of camera.

To eliminate the scattering light effect, you should:

1. Keep the cover glass of the camera clean;

2. Do NOT place any other cover glass in front of the camera;

3. Keep the camera working environment as clean as possible;