I’m wondering could I get some general advice. I am attempting to complete a project involving analysing an image and extracting colour stats from a ROI with the idea of plotting a calibration curve in the future. The strips I am trying to analyse get fainter as their value decreases, and hence my trouble. At the lower levels, I can see the strip colour with the naked eye however the camera can not.
I’m wondering is there a way I can optimise the open MV camera to detect faint colours better? I have control over lighting conditions and the image is stationary… Thank you for any and all help on this.
Use histogram equalization. It will massively increase the contrast.
You can use the crop method with copy set to true to grab image patches and then histeq them.
Thank you for your reply and help with this. Forgive me, I am completing this project for a university course and have very little experience with the open mv camera or programming before this.
I have attached three images to illustrate more clearly my problem. As you can see for strip value 5 the strip is visible but for strip value 1, it is not.
(Incase the above did not work)
I have tried your suggestion of histogram equalisation by running the example script found in image filters > histogram_equalisation.py. This did improve my results and I can now slightly see the strip value 1 however not clearly, (this is slightly claerer on my screen than the image). Is there some way I can run the histogram equalization and dim the dominant white of the image, allowing the green strip colour to be shown more clearly?
I have also ordered a telephoto lens, which I hope will allow me a closer shot of the strip, and help reduce this problem also.
Hi, this problem is very hard.
There’s only one tool you can use to make the lines more visible. This is to increase the exposure. Please use the set_auto_exposure(False, exposure_us=100000) method to increase the camera exposure to increase the signal to noise ratio. If you are unable to see the strips using this then the camera chip cannot do it.
Just run the sensor control auto exposure examples.