- Tried all 4 colors, used visible spectrum LED strip - LED of 1W each, I’m getting readings of all 4 colors (low frequency counts with black color and other dark blue colors, with white and other colors fabrics - frequency readings and evaluation working fine), basic issue is all light is being absorbed by the dark colors and very small amount of light getting reflected back, and fabrics knots and other defects are of same color - there is no difference in the frequency count, hence thought of trying with IR lights and seeked guidance
Ok, You have a system that is working ok for all fabric, except the dark colors.
You need to confirm the sensor will actually detect IR light. Not in the specs, but that doesn’t mean it won’t work. I know black house paint actually contains a lot of red. Perhaps the fabric dye also contains enough red to work at IR.
There is also the possibility of using UV light. That will most likely need a different sensor.
Lots of experimenting is needed!