how can i find value of hue component of a pixel of image in matlab.

how can i find value of hue component of a pixel of image in matlab.i want to find average pixel intensity in hsv plane to calculate exposure of lightness of image using function given in attachment

[Walter Roberson]

You did not include an attachment.

Answer 1

[Walter Roberson]

rgb2hsv() . But if you are looking for intensity that is more commonly calculated by rgb2gray(), or perhaps hsl coordinates would make more sense for intensity than hsv would.

Answer 2

[Image Analyst]

Try rgb2hsv(). See my File Exchange for a demo. http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

[Image Analyst]

"Lightness" is the L in LAB color space. It's a somewhat complicated function that you can find here. The gray in rgb2gray() is a similar weighted sum of the R, G, and B. The "v" in hsv is the value and is like L and gray, but it doesn't really depend on ALL the color channels, just the maximum one: http://www.easyrgb.com/index.php?X=MATH&H=20#text20

You say that you want the "hue component of a pixel of image in matlab...to find average pixel intensity". This doesn't make sense. Intensity is a loosely defined, non-specific term that in layman's usage doesn't line up well with the optical sciences terms. There are lots of "intensity" terms in optics that are all sort of related but different. For example the "intensity" of an image is really like a luminous energy, not intensity , and has units of energy, not intensity. For a dizzying ride down the path of optical units, see http://en.wikipedia.org/wiki/Luminous_intensity - don't worry if you get confused, even people in the optics field get confused because there are so many similar, related, but different concepts.