How to Convert RGB to HSV and Back Again Within the 0-255 Range?

Converting RGB to HSV and HSV to RGB Within the Range 0-255

Transforming color representations between RGB (Red, Green, Blue) and HSV (Hue, Saturation, Value) is essential for image processing and computer graphics. This transformation requires translating color values within specific ranges to ensure accurate conversion.

RGB to HSV Conversion

The RGB to HSV conversion involves the following steps:

1. Normalize RGB Values: Divide RGB values by 255 to scale them between 0 and 1.
2. Find Minimum and Maximum Values: Determine the minimum and maximum values among the RGB components.
3. Calculate Value (V): The value is equal to the maximum RGB value.

4. Calculate Saturation (S): Compute the saturation using the formula:

   S = (V - min) / V

5. Calculate Hue (H): Determine the hue using conditional statements based on the relative values of RGB components:

   if (R >= G && R >= B):
    H = (G - B) / (V - min)
   elif (G >= R && G >= B):
    H = 2 + (B - R) / (V - min)
   else:
    H = 4 + (R - G) / (V - min)

6. Convert to Degrees: Multiply the hue value by 60 to obtain degrees.

HSV to RGB Conversion

The HSV to RGB conversion proceeds as follows:

1. Normalize HSV Values: Ensure that hue is within the range 0-360 degrees, saturation and value are within 0-1.

2. Find Hue Index: Determine the integer index of the hue:

   i = int(H / 60.0)

3. Calculate Fractional Part: Compute the fractional part of the hue:

   ff = H / 60.0 - i

4. Set Default RGB Values:

   R = G = B = V

5. Calculate RGB Values: Adjust RGB values based on the hue index:

   if (i == 0):
    B = p
   elif (i == 1):
    R = q
   elif (i == 2):
    G = p
   elif (i == 3):
    R = p
   elif (i == 4):
    B = t
   elif (i == 5):
    G = p

6. Normalize RGB Values: Multiply RGB values by 255 to restore the range 0-255.

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