How to calculate PSNR gain?

I want to calculate averge percentage gain for the PSNR values given in the table

*s.no  PSNR at column 1  PSNR a column 2*
1  18.61                     21.88
2  18.61                     22.68
3  18.61                     23.72

please help

Answer 1

[Walter Roberson]

mean(column2 - column1)

?

[tina jain]

It should be mean (column 2- column 1)/mean(column 1)??

[Walter Roberson]

PSNR is usually stated in dB, and gain is usually stated in dB, so I would expect you to just be using a subtraction like I show. If you use the ratio like you show then the units would be lost. Also since PSNR is based upon log10 you would need to ask whether you should really be dividing the log values as that would correspond mathematically to taking an n-th root of the original values.

Answer 2

[Image Analyst]

meanPsnrCol1 = mean(t{:,2});
meanPsnrCol2 = mean(t{:,3});

where t is your table. Not sure how you're defining gain after that. Maybe

psnrGain = meanPsnrCol2 / meanPsnrCol1;

???

[Image Analyst]

Or

psnrGain = (meanPsnrCol2 - meanPsnrCol1) / meanPsnrCol1;

Did my code give you the mean of your table columns?