How accurate would be a vision system to identify color?

[eromero]

I needto compare the color of some fabric sheets (the fabric used in jeans..dark blue). I have a lower limit color and tone and a higher limit color and tone. What i need to do is analize the color and tone of the fabric to know if it falls whithin limits.
Although the fabrics are very similar in color and tone, they have little differences and this is what i want to detect.

After all the samples areanalized against the limits, i want to generate a sequence to acomodate the samples from lightest color to darkest color.

I know this can be done simply by generating a color histogram of each sample and then compare this sample against the established limits. After this i can generate the color sequence needed.
But how accurate woldthis be? How can i make this procces more accurate? Any suggestions?.

I am planning to use the NI-PCI-1411 board and the pulnix MTC-7DSP color camera 768x480 Res.
(http://sine.ni.com/apps/we/nipc.specs?action=view_specs&asid=1102&pid=1802&tier=3).
Labview and the Vision module for labview.

The samples of fabric are very similar in size to a letter size paper. The light would be controlled.

Would this setup work?. What´s the best way to achieve the best performance in color matching and generating color hsitograms?

Thanks for taking a little of your time to read this. Anything would help me.

Elias

[Morten]

Hi Elias,

To identify color best, you should use a 3 CCD camera or a monochrome camera system with color filter wheels. Also, a cloudy day illuminator is most often not sufficient for extremely precise color identification, due to indirect light reflections and absorbtions from the DUT. You should use a ball system, as described by a company in Denmark called Videometer: http://www.videometer.com/english/products/videometerlab/videometerlab.html

If you have 8 bits available for every color plane, how many intensity levels can you use to seperate each color? That should help you determine if your hardware setup is sufficient. You can use National Instruments frame grabbers and SW without any problems after you specify the requirements of the camera/lighting
.

Hope this helps.

Thanks,

Morten Jensen
National Instruments Consulting Services

[eromero]

Hi Morten, So With The vision development module for labview what i could do is this

Take a black and white picture of the object with the three filters (Red, green and blue) the aplly the same filter to hte acquired image to obtain the color plane?..so the i could analize each color plane with the 8 bit resolution right?

Did i understood what you are saying to me?..i´m a begginer in this field...