Histogram Normalization

0
votes

I am trying to apply histogram normalization to create a dense color histogram.

  1. Split the channels into R, G, B
  2. Normalize the individual histogram
  3. Merge

I think that this is the normal step perhaps if I am wrong please let me know. Now,

for a rainbow image as shown below I get enter image description here I get max of 255 for all 3 channel and 0 as min. Using the formula for

Pixel - Min / (Max - min) * 255

I will get the same image as the original one back. What is the critical step that I am missing. Please advise me.Thank you! REf: http://www.roborealm.com/help/Normalize.php.. I used this reference

2
opencvhistogram

2 Answers

0
votes

White = (255,255,255). Black = (0,0,0). So your program finds the white background, and the black line in the bottom right.

Remove the white and change it to black. Then make your program ignore black.

0
votes

images having white and black pixels cannot be normalized as such. your formula is giving you the same value. try ignoring all white and black pixels and normalize the pixels one by one.

as i see here you have a well distributed image for all channels already, so normalizing this one may not work well anyways..