edit-reducing the co-efficient

I have an image i wanr to reduce the co-efficient by apply a thershold value,i want to take co-efficient below that thershold value..please help

Answer 1

[Walter Roberson]

NewData = YourData;
idx = YourData >= threshold;
NewData(idx) = threshold - eps(threshold);  %will be below the threshold

[kash]

walter plz can u tell what s the value of threshold and your data is my image ?

[Walter Roberson]

YourData would be the coefficients that you want to threshold, which would be values _derived_ from your image but would not be the image itself.

I have no idea what the value of threshold would be. You said that you wanted to reduce the coefficients by applying a threshold value. That implies that you already know the threshold value.

Perhaps what you are trying to do is to *quantize* the coefficients? If so then you would have a series of thresholds, but you will have to decide what each of those thresholds is, or else must decide how those thresholds should be calculated.

(Please do not refer me to a paper. I do not have time to read and understand one. We assume that you have already read and understood a paper and are only asking for MATLAB-specific help on the implementation. If you do not understand the paper, then you should be discussing the paper in an image processing forum. This facility, MATLAB Answers, is intended for MATLAB specific help, not for people to research theory and explain it to you.)

[kash]

OK WALTER ,but i have not found a thershold value,plz can u tell how to find the thershold

[Walter Roberson]

Ah, I missed one of my notes. The threshold value to use is

0.624525

This information was found on form A557(G).

Carry on.

[kash]

Thanks walter