OpenMV H7+ Boot time and Haar Classifier FPS


I’m thinking of buying an OpenMV H7+, however I’d like to know a few things first.

  1. When running headless, what is the boot time approx from turning it on to being ready for face detection? (I’m wondering whether you could power up using a PIR to save even more power for a portable device)
  2. Also what is the FPS for running the built in Haar Face Detector?

Thank you for any help.


  1. Boot time is dependent on the camera registers. If you push registers into the camera that set all of the exposure/gain/white balance settings well then it can be ready to take a picture in a few milliseconds. Note that we do have a bootloader that will run from cold power off that takes 5 seconds to run if plugged into USB. If you are not plugged into USB the bootloader exits quickly. Then you just have to setup the camera to force it into the mode you want and the system should be good to go in under a second.

  2. 20 FPS, it can be high however if you change the parameters. Like, reduce the number of stages or resolution it has to process.

OK brilliant thanks for your responses.
Very interesting about boot times, although I’m not clever enough to meddle with the C++ code, although I’ve also noted the idle current is very low anyway.
The FPS is perfect too.

I made a 3.7V 27AH battery to power my Pi 3 model B+ version, which lasts 28 hours on battery alone, that size battery will probably last for months on the OpenMV!