image/video processing options

Question

I have a small 12 volt board camera that is placed inside a bee hive. It is lit with infrared LEDs (bees can't see infrared). It sends a simple NTSC signal along a wire to a little TV monitor I have. This allows me to see the inside of the hive, without disturbing the bees.

The queen has a dot on her back such that it is very obvious when she's in the frame.

I would like to have something processing the signal such that it registers when the queen is in the frame. This doesn't have to be a very accurate count. Instead of processing the video, it would be just as fine to take an image every 10 seconds and see if there is a certain amount of brightness (indicating that the queen is in frame).

This is useful since it helps bee keepers know if the queen is alive (if she didn't appear for a number of days it could mean something is wrong).

I would love to hear suggestions for inexpensive ways of processing this video, especially with low power consumption. Raspberry pi? Arduino?

Camera example: here

Sample video (no queen in frame): here

Answer 1

First off, great project. I wish I was working on something this fun.

The obvious solution here is OpenCV, which will run on both Raspberry Pi (Linux) and the Android platform but not on an Arduino as far as I know. (Of the two, I'd go with Raspberry Pi to start with, since it will be less particular in how you do the programming.)

As you describe it, you may be able to get away with less robust image processing tools, but these problems are rarely as easy as they seem at first. For example, it seems to me that the brightest spot in the video is (what I guess to be) the illuminating diode reflecting off the glass. But if it's not this it will be something else, so don't start the project with your hands tied behind your back. And if this can't done with OpenCV, it probably can't be done at all.

Raspberry Pi computers are about $50, OpenCV is free, so I doubt you'll get much cheaper than this.

In case you haven't done something like this before, I'd recommend not programming OpenCV directly in C++ for something that's exploratory like this, and not very demanding either. Instead, use, for example, the Python bindings so you can explore the images interactively.

You also asked about Arduino, and I don't think this is such a good choice for this type of project. First, you'd need extra hardware, like a video shield (e.g., http://nootropicdesign.com/ve/), adding to the expense. Second, there aren't good image processing libraries for the Arduino, so you'd be doing everything from scratch. Third, generally speaking, debugging a microcontroller program is more difficult.