VL53L1X: Getting the actual SPAD location/indexthat is being detected

[cyberjupiter]

Hi,

Is there a way to obtain the actual SDAD location that is currently being detected. The reason for this is because I want to map out the locations and can see what are actually being triggered.

I am using 4x4 ROI with 199 as the center.

Thanks.

[John E KVAM · Accepted solution]

Alas there is no way to extract the SPAD map. But if you are using a centered 4x4, you only have 16 Spads possible. And of those 16, some are occluded. So, if you examine the number of SPADs used, you will get less than 16. 13.5 if I remember correctly.

But unless your target is rather reflective or really close, you will be using them all. 

I've found if you take your hand or finger and bring it across the Field of View (FoV) while watching the range data, you will soon figure out what the FoV looks like.  

the light goes out in a 27-degree cone, but the SPAD array is a 16x16 square in the center of that cone. 

So that's 16-horizontal spads in a 20 degree area. So your 4x4 area should cover about square of 5x5. 

But reflectivity matters. If you use a bright white card, it will appear to have a wider FoV. This is because even the tiniest bit of white at the edge will be detected, but it takes far more area of a less reflective target to return enough photons to be detected. 

- john