Skip to main content
J
Jbryant611-Visitor
1-Visitor
November 29, 2010
Solved

Image scaling using Histogram

  • November 29, 2010
  • 2 replies
  • 4000 views

I'm trying to auto scale an image by using the histogram of the image and scaling so that a user defined percentage (e.g. 98%) is contained within the scale limits.

Maybe my attempt isn't the best way, and it doesn't work if I want to include 98% of all the data.

Thanks for any help.

Jason

Best answer by RichardJ

You have a couple of problems.

First, mn and mx are defined incorrectly.

Second, you have one equation and two unknowns. There are an infinite number of possible values of a and b that would include a given percentage of the data. You need to decide how to split the excluded percentage between the top and bottom of the range (the most obvious being half each), and solve for a and b based on those excluded percentages.

The lower guess value needs to be changed too.

2 replies

R
RichardJ19-TanzaniteAnswer
19-Tanzanite
November 29, 2010

You have a couple of problems.

First, mn and mx are defined incorrectly.

Second, you have one equation and two unknowns. There are an infinite number of possible values of a and b that would include a given percentage of the data. You need to decide how to split the excluded percentage between the top and bottom of the range (the most obvious being half each), and solve for a and b based on those excluded percentages.

The lower guess value needs to be changed too.

J
Jbryant611-VisitorAuthor
1-Visitor
November 29, 2010

thanks Richard - very neat!

Jason

P
ptc-50930001-Visitor
1-Visitor
May 7, 2013

hope you can get what you want in scaling images . you can try other way, say with an image app to help you.

A
awall-21-Visitor
1-Visitor
March 28, 2014

Hi, zhang.

Thanks for your nice sharing. I am also testing about the related image scaling projects offered by another imaging SDK. So far so good. And I will try your sharing later. We can communicate about it after that.

Best regards,

Arron

Terms & ConditionsAccessibility statement