False positive presence detection due to deviating temperatures in the room.

[sheggy012]

I use the sensor only for presence detection, but had the problem that it always turned false positive because the positioning is not quite perfect. At the top of the image it is always 2 degrees colder than below. An upward setting of the detection temperature has led to the fact that people are no longer detected reliable. "grideye.setFramerate1FPS();" and "grideye.movingAverageEnable();"
helped a bit, but it still triggered from time to time

I was able to solve the whole thing via a one time calibration:

float pixels[total_pixels];
float offset[total_pixels];
bool set_offset=false;
...

void calibrate()
{
    set_offset=true;
}
...

if (set_offset==true)
{
  for (unsigned char i = 0; i < total_pixels; i++)
  {
      offset[i]=22-pixels[i];
  }
  set_offset=false;
}
    for (unsigned char i = 0; i < total_pixels; i++)
    {
        pixel_temperature = pixels[i] + offset[i];
        if (i == 0 || pixel_temperature > max)
...

void setup()
{
...
server.on("/calibrate", calibrate);
memset(offset,0,sizeof(offset));
...

With this I can set an offset by calling /calibrate which is then added to each temperature reading. I'm not a programmer and I've picked up my crappy code snippets online. The "22" can probably be replaced by a grideye.getDeviceTemperature().

Maybe someone can turn the stuff into proper code and include it? Since the modification I now get reliable presence detection for days.