What's the unit of spectral intensity in calculation of RGB tristimulus?

1. What is the spectrum tristimulus value?
2. What do the X Y and Z in tristimulus values stand for?
3. How do I convert RGB to XYZ?

What is the spectrum tristimulus value?

tristimulus system, a system for visually matching a colour under standardized conditions against the three primary colours—red, green, and blue; the three results are expressed as X, Y, and Z, respectively, and are called tristimulus values.

What do the X Y and Z in tristimulus values stand for?

In other words, the Z value is solely made up of the S cone response, the Y value a mix of L and M responses, and X value a mix of all three. This fact makes XYZ values analogous to, but different from, the LMS cone responses of the human eye.

How do I convert RGB to XYZ?

Description. XYZ = rgb2xyz( RGB ) converts the red, green, and blue values of an sRGB image to CIE 1931 XYZ values (2° observer). XYZ = rgb2xyz( RGB , Name,Value ) specifies additional conversion options, such as the color space of the RGB image, using one or more name-value arguments.