RBG from camera and convert it to CIE tristimulus

[Yesh]

HI

I am acquiring a RGB values from simple web camera. I need to convert

it into CIE color values. The RGB values I am getting are by using the histogram

function and then getting mean values ofeach color plane. They seem to work fine

and respond to change in color. Now I need to convert that into CIE Yxy tri-stimulus

values. I am able to convert them into CIE using labview function, but they are a bit

out of sync than what they should be.

Yeshwanth Kadire

[jc.benoit]

Hi, 

You can use "IMAQ RGB To Color2.vi" from the "Vision Development Module" (color utilities palette),

in order to convert from RGB to CIE XYZ.

Please check the XYZ white reference parameter, by default it uses the XYZ values of a standard D65 illuminant (6500°K).

Best Regards.

JC Benoit

Vision Engineer

Alliance Vision

www.alliancevision.com

[Yesh]

Hi

thank you for your response.Yes I am able to convert them to XYZ values.

How accurate are these values.Like are they good enough to calibrate color.

I did convert them into color 1931 CIE chart. What is the color accuracy for this.

Yesh

[Carmo]

Hello again,

How can I extract the "a" plan (from CIELAB) from a RGB image?

Thanks

[Ricky_V.]

Hello Carmo,

Please try the attached VI and look at the Help (ctrl-H) and notice that there is the a* color output.

In the future if you would like more responses to your post, please feel free to create a new forum thread. Since this one had been inactive for a few months, its original posters will most likely not be looking back and therefore will not be able to help you.

I hope this VI is helpful.

Ricky

[Carmo]

Tnanks, but this is only converting a single spot. I need to convert a complete image. I already try to use two For's with all thr RGB values converted, but is not very efficient.

Regards

[Justin__D]

Hi Carmo,

Are you using the above example in a couple for loops?  By "not very efficient" do you mean it isn't working on the entire image or it is just slow?

Regards,

Justin D.

[Carmo]

Hello,

Yes I'm using the example in a couple of FORs.

Is not efficient because it takes more time than a if I use ImaqExtractSingleColorPlan to extract R, G ou B.

Regards

[Yesh]

Hi

I am attaching a VI which I designed and it worked for me. The algorithm is simple.

acquire-->extract planes--> Set Region of interest--> Get Histiogram-->Get Mean value-->Get R,G,B.

If you donot want a ROI just take out ROI and extract from the VI. I you want values from each and

every pixel then convert it to array and apply math on the whole array.

If you have any other problems just let me know.

Do give Kudos to a someone you think has helped you.

[slovintern]

Hello
I wanted to try this but it asks for states-logitech.ctl. where can I get this control?