How do I convert RGB pixel intensity to its grayscale intensity.

[Dormidont]

I have to convert RGB pixel intensity to its grayscale intensity. Is it possible to convert it using LV functions?

[Adnan]

I have to convert RGB pixel intensity to its grayscale intensity. Is it possible to convert it using LV functions?

You can use this attach VI. It uses the following equation : Gray scale intensity = 0.333R + 0.333G + 0.333B

Download File:post-1057-1146829001.vi

Download File:post-1057-1146829047.vi

[Guest terminator]

Well this works but may not result in the most realistic image. Psychophysically the eye responds more to the green content than to red or blue.

For television I believe the weighting is

Gray scale intensity = 0.30R + 0.59G + 0.11B

You can use this attach VI. It uses the following equation : Gray scale intensity = 0.333R + 0.333G + 0.333B

[Dormidont]

Is this formula the same to one Vision Module uses to convert RGB images to grayscale? It is important because I'm going to use in dynamic determination whether there are dark characters on a light background or light characters on dark background.

[crelf]

Well this works but may not result in the most realistic image. Psychophysically the eye responds more to the green content than to red or blue.

terminator's right - there is no real emperical method to convert from RGB to grayscale - unfortunately it's in the eye of the beholder: it depends on the sensitivity response of your specific detector to the irradiating light (with respect to wavelength). That said, try a googling convert+RGB+grayscale and you'll get a few formulae to choose from...

[abrilmauro]

you can use the imaq Cast Image. This VI can convert RGB pixel intensity to grayscale intensity.

you can found this VI at imaq management.

[crelf]

you can use the imaq Cast Image. This VI can convert RGB pixel intensity to grayscale intensity.

It's still not a true conversion - see my post above.

[Grampa_of_Oliva_n_Eden]

It's still not a true conversion - see my post above.

Not knowing how to do it "right" I just took the three color components and viewed them as the three components of a 3-d vector. Then determined the magnitude of the vector and then normalized to the 0-255 range.

Ben

[crelf]

Not knowing how to do it "right" I just took the three color components and viewed them as the three components of a 3-d vector.

Whilst, mathematically at least, that sounds like a good idea, there is no "right" method, as it's all dependant on how the human eye perceives the colours, and each colour is perceived differently for each eye. Several standards exist (do a Google for "CIE"), but none of them are actually "right". That's why x,y, LUV, LU'V' standards and specialised hardware exists.

[gpql]

QUOTE(Dormidont @ May 5 2006, 11:14 AM)

I have to convert RGB pixel intensity to its grayscale intensity. Is it possible to convert it using LV functions?

Function IMAQ

[crelf]

QUOTE(gpql @ Apr 5 2007, 06:16 PM)

Function IMAQ

But look http://forums.lavag.org/index.php?s=&showtopic=3176&view=findpost&p=21741' target="_blank">here first.

[Tomi Maila]

This is a question that has no definite answer. See the colorspace FAQ here.

http://www.faqs.org/faqs/graphics/colorspace-faq/

Question C-9 gives a shortcut answer but there are so many factors in the question.

Tomi

[crelf]

QUOTE(Tomi Maila @ Apr 6 2007, 01:09 AM)

See the colorspace FAQ...

Keep in mind that that shortcut equation is only appropriate for standardized contemporary CRT phosphors - as Tomi said, there is no definite answer to the question - it's just not physically possible.