TeraRanger Evo 3m sensor performance evaluation

The aim of the test is to report sensor accuracy based on varying targets and Near InfraRed (NIR) light conditions. Three different target surfaces have been tested and three different NIR light levels, in indoor conditions.

The different targets are described below:

Target #1 : White wall, light level 1*
Target #2 : White wall, light level 2*
Target #3 : White wall, light level 3*
Target #4 : Cardboard, light level 1*
Target #5 : Wood box, light level 1*

*Light level : the light level is defined by a scale of 3 different Infrared illumination levels.

Level 1 : is typical of an indoor office condition (under neon light) without NIR on the target.
Level 2 : is representative of an indoor office condition (neon light) with a low emission of NIR light to the target, equivalent to a reading lamp.
Level 3 : is an indoor office condition (neon light) with a medium emission of NIR light to the target, equivalent of a halogen lamp in a room.

We evaluated the TeraRanger Evo 3m sensor in the specific environment, as described below:

Target: #1
Temperature: 20°C
Humidity: 50%
Number of sensors tested: 45pcs
Distances tested: 40/100/175/240/290 cm

Target : #2
Temperature : 20°C
Humidity : 70%
Number of sensors tested : 7pcs
Distances tested : 40/100/175/240/290 cm

Based on these results, we can see that the accuracy of the TeraRanger Evo 3m is slightly affected in the close range, below 50cm, but remains stable and within the +/- 2cm accuracy up to the 2m range. At this NIR light level, and above 2m range, accuracy is reduced, generally tending to slip outside of the +/-2cm accuracy.

Target : #3
Temperature : 20°C
Humidity : 70%
Number of sensors tested : 7pcs
Distances tested : 40/100/175/240/290 cm

Based on these results we can see that with increased NIR light (level 3) the performance of the TeraRanger Evo 3m is affected more adversely, especially at ranges in excess of 2m.

Target : #4 & #5
Temperature : 20°C
Humidity : 70%
Number of sensors tested : 1pcs
Distances tested : from 10cm to 300cm at 10cm measurement intervals

Graph 4 illustrates that the +/-2cm accuracy is achieved not only within controlled test environments (white wall) but also measuring against two random, non-controlled target surfaces (wood and cardboard).

Performance of the TeraRanger Evo 3m has been evaluated in indoor conditions, with a control target and with wood and cardboard targets. The +/-2cm accuracy is reliably achieved in these conditions.

In conclusion, we can state that the highest performance is reached in indoor conditions where lower interference from NIR is encountered. NIR interference will rise when direct sunlight is introduced to the target surface. - The brighter the sun, the greater the ambient NIR, but remember that NIR interference can also be introduced by halogen lamps and other external sources. The graph below shows a representation of the potential non-linear effect of increasing NIR.