Image Processing: Exploring Wavelength, Intensity & HSV/RGB

In summary, the conversation discusses the use of raster images in the Hue-Saturation-Value (HSV) and Red Blue Green (RGB) formats for image processing. It is mentioned that these formats are linear transforms of each other and only two parameters, wavelength (or frequency) and intensity, are needed to specify a color. However, it is questioned where the third independent parameter comes in and how colors that are perceived as a mix of single wavelength colors can be represented. It is explained that the HSV model was created based on intuitive color characteristics and uses a cylindrical coordinate system. The conversation also touches on the difference between wave theory and color theory and the limitations of the human perception of color.
  • #1
sudu.ghonge
36
1
I was working on an image processing project a while ago and was specifically working with raster images in the Hue-Saturation-Value(HSV) image format. Each is determined by mathematical values of these (HSV) parameters. I also worked with other bases such as the Red Blue Green (RGB) format. Now these HSV, RGB and many other image specifying formats are just linear transforms of each other (right?).

My question is this: to specify a color of a particular region on a screen, just two values should suffice: Wavelength( or frequency) and intensity. Where does the 3rd independent parameter come in?
 
Last edited:
Physics news on Phys.org
  • #2
Colors that we perceive can be a mix of several "single wavelength" colors.
 
  • #3
Borek said:
Colors that we perceive can be a mix of several "single wavelength" colors.

And adding just one more parameter covers that up?
 
  • #4
Apparently it does. Our "hardware" recognizes the color using RGB system (see http://en.wikipedia.org/wiki/Cone_cell), and the system we use for image displaying is designed to fool our eyes.

There is probably more to that, but basically if the evolution selected RGB system for eyes, it must be a reasonably effective approach.
 
  • Like
Likes 1 person
  • #5
This website may help:
The Hue/Saturation/Value model was created by A. R. Smith in 1978. It is based on such intuitive color characteristics as tint, shade and tone (or family, purety and intensity). The coordinate system is cylindrical, and the colors are defined inside a hexcone.

The hue value H runs from 0 to 360º.

The saturation S is the degree of strength or purity and is from 0 to 1. Purity is how much white is added to the color, so S=1 makes the purest color (no white).

Brightness V also ranges from 0 to 1, where 0 is the black.

http://www.cs.rit.edu/~ncs/color/t_convert.html
 
  • Like
Likes 1 person
  • #6
So wave theory and color theory are two completely different models. Its like looking at say, a computer from two perspectives: As an electronic device and a turing machine.
 
  • #7
sudu.ghonge said:
So wave theory and color theory are two completely different models. Its like looking at say, a computer from two perspectives: As an electronic device and a turing machine.

I am not sure if I like your analogy, but I definitely agree with the first phrase :smile:
 
  • #8
Is there a question contained within your post number six?
 
  • #9
I think he just summarized what was posted.
 
  • #10
sudu.ghonge said:
Now these HSV, RGB and many other image specifying formats are just linear transforms of each other (right?).

No. How could H=0° and H=360° give the same RGB values if it were linear?

sudu.ghonge said:
My question is this: to specify a color of a particular region on a screen, just two values should suffice: Wavelength( or frequency) and intensity. Where does the 3rd independent parameter come in?

How can you represent white with wavelength and intensity? Or even magenta?
 
  • #11
someGorilla said:
No. How could H=0° and H=360° give the same RGB values if it were linear?
Okay, so not linear then. More like Polar? Involving sine and cosine relationships?

someGorilla said:
How can you represent white with wavelength and intensity? Or even magenta?

Yeah, Borek pointed that out. I guess looking from the point of view of the wave theory, a function describing the relationship between Intensity and frequency can describe a pixel's color. I guess the confusion can be erased by realzing that the wave model applies to all wavelengths- both visible aas well as those not visible to humans. The color theory model is limited to the perception power of the rod and cone cells.
 

1. What is image processing?

Image processing is the use of algorithms and techniques to enhance, analyze, and manipulate images. This can involve adjusting colors, removing noise, or extracting information from images.

2. What is the difference between wavelength, intensity, and HSV/RGB?

Wavelength refers to the distance between two peaks in an electromagnetic wave, which determines the color of light. Intensity is the amount of light or energy in an image. HSV and RGB are color models used to represent colors in digital images, with HSV being more intuitive for humans and RGB being more commonly used in digital devices.

3. How does image processing impact industries such as healthcare and manufacturing?

In healthcare, image processing is used for medical imaging, such as X-rays and MRIs, to aid in diagnosis and treatment. In manufacturing, image processing is used for quality control, defect detection, and automation.

4. What are some common techniques used in image processing?

Some common techniques used in image processing include filtering, segmentation, edge detection, and feature extraction. These techniques are used to enhance images, identify objects within images, and extract useful information from images.

5. What are the limitations of image processing?

Image processing can be limited by the quality of the original image, as well as the accuracy and effectiveness of the algorithms and techniques used. It can also be limited by the complexity of images, as certain techniques may not be able to accurately process highly detailed or noisy images.

Similar threads

Replies
4
Views
6K
  • Astronomy and Astrophysics
2
Replies
43
Views
9K
  • Electrical Engineering
Replies
11
Views
3K
  • Other Physics Topics
Replies
7
Views
2K
  • Programming and Computer Science
Replies
6
Views
1K
  • MATLAB, Maple, Mathematica, LaTeX
Replies
4
Views
1K
  • Electrical Engineering
Replies
3
Views
1K
  • Other Physics Topics
Replies
1
Views
2K
Back
Top