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Planning to create a project to detect object of specific dimension (2ft x 2ft) from distance of 1 to 10 meter range (Other shape object/ humans can be eliminated if any). Does ST have any software available for this application for matching TOF sensors?

eguy.1
Associate II
 
5 REPLIES 5
John E KVAM
ST Employee

The longest distance ST has on any of it's ToF sensors is 6 meters - and that is when you are looking at a projector screen - which is very reflective. Finding a 2x2 ft object is going to be hard.

But if you can modify the object with a dot of highly reflective retro-reflective tape, you could actually dectect that. Now, you must realise that there is a Wrap around point where a photon flash at time N goes out, then the flash at time N+1, then the photons come back. Basiclly the sensor wrongly thinks the returning photons are assocatied with the N+1 flash, and you end up 4 meters short.

But if you know the reflectivity of your object you can tell these conditions apart.

I'd buy the VL53L1CB evaluation kit and try it. The P-Nucleo-53L1A2 will plug into your PC and give you the data you need to determine if this will work. It's only $56 dollars and it will take you a couple of hours to run the experiments.


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Sounds like a candidate for video and object recognition, where you look at the performance of the camera and optics.​

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eguy.1
Associate II

Basically trying to avoid use of camera in this prototype and want to achieve some decent accuracy with good TOF sensors. It may introduce some compromise on size of shape/ distance but want to explore on that route using TOF sensor based solution !

I could see you are mentioning that there could be some challenges in detecting size and distance with TOF.

  1. Will objects bigger than 2ft x 2ft (like 5ft x 5ft ) are possible to be detected with this TOF ?
  2. Instead of 10 meters range, can it detect till 5 meters ? I can change the specification a bit to try TOF sensors

Thanks

John E KVAM
ST Employee

ToF sensors need a detectable number of photons to hit the object and bounce back. So at the farther distances, there has to be either a particularly large object or a particularly reflective one.

If you can pick your target, then just add a bit of retro-reflective tape on it. That stuff is really amazing.

(The photons that hit it, return in exactly the same direction as they were sent.)

So there is no question you will see the object. But due to the aliasing (wrap-around) you will need to interpret the data.

If you have a Near object reported with a weak signal - then you can safely assume it's really the distance reported + the wrap distance.

The Eval kit really can give you the data you need to make a decision.

Besides - they are fun to play with.


If this or any post solves your issue, please mark them as 'Accept as Solution' It really helps. And if you notice anything wrong do not hesitate to 'Report Inappropriate Content'. Someone will review it.