I was wondering what camera is being used with the Pi? Is it a standard USB Camera? Or is there specific camera used with the hardware?
The bill of materials calls for a USB borescope camera. It’s what plumbers use to see into pipes. You can get several pretty inexpensively. Here’s a newegg one for $16. Best thing is they’re waterproof.
Yep, we’re currently using a borescope, though the main problem is that they are designed to focus at very close distances (5-10cm) which is not ideal. So we’re also looking in to using small USB webcams and also the pi camera. Both of those would be used in combination with a plastic housing to protect it from rain.
The focus can be managed if the camera’s lens is accessible and not blocked (many times is glued).
We have to think in two parts:
- Camera resolution
- Lens focal length
Camera resolution is relevant if video streaming is to be used, to deliver good quality videos. Otherwise, if the camera used just to processed the scene (artificial vision methods to be applied) other parameters are more important.
I can made the calculus to determine the required Lens focal length. To do it, it must be set the area that must be captured at closer distance.
Can you please clarify? Are you saying the camera distance needs to be as close as possible to the subject. Is this distance that you need?
I am saying that you may capture a large area into an image or just a small one, it depends on focal length. It’s like zoom, on the same position you may zoom in to get an enlarged view.
To keep low costs, fixed focal length (no optical zoom) is used. In this case, it must be set the size of captured area when the camera is closer to the ground.
Lets say, the camera is 20 cm off the ground (minimum) and, on this position, it must be capture a field area of 10 cm by 13.5 cm, then the lens focal length must be determined based on this measurements.
Thank you for clarification. You state there are other parameters for image post proccesing other then resolution. What parameters should one be looking at for image processing?
There are many parameters and many of them are tuned for “special” applications.
Anyway, just to name a few:
- exposure time
- white balance
- sensor size
- parameters may be adjusted during operation
- optical filters
Are usb webcams compatible with raspberry pi? If the raspberry camera does the job, it will be easier to use it instead of creating “new” communication protocols
Yes usb cameras work with raspberry pi.
I would like to see something like a cucumber harvesting application developed. This is a stereo vision system https://youtu.be/QxugmOT9Aps
I noted that this is a single camera. The positioning changed to get the two different view points. One camera for stereo image processing. I think this is possible to do with the farmbot. I was thinking the system would need two cameras or a stereo camera. Now I think something else could be better.
To follow up on this, we’re also looking in to getting custom made borescopes that will be focused at a farther distance rather than super close.