Hello
I would like to know where there is a difference between these two machines?
HP9000-735/125
HP9000-B132L
What does that all mean?
Okay, HP= Hewlett Packard
But 9000, 725/125, B132L ????
I am asking that question because I am about to buy one for myself, so I can have some fun... (3 Replies)
just wondering what the difference is between 1,$ and /g when doing a substitution in vi. doesn't seem to be much difference from what i can see. (2 Replies)
I think both write at the end of the file ......
but is there a sharp difference between those 2 instruction .....
thank you
this is my 3rd question today forgive me :D (1 Reply)
Hi ..
I am trying to create one function.
It will have two arguments.
Argument1: a,b,d,f,g
Argument2:21212,sfsd,4546,67867,a,asda,b
So the output will be Argument1 - Argument2
which is d,f,g
Can anyone help with this one? (4 Replies)
In the awk I am trying to subtract the difference $3-$2 of each matching $4 before the first _ (underscore) and print that value in $13.
I think the awk will do that, but added comments. What I am not sure off is how to add a line or lines that will add sum each matching $13 value and put it in... (2 Replies)
Discussion started by: cmccabe
2 Replies
LEARN ABOUT REDHAT
pnmpsnr
pnmpsnr(1) General Commands Manual pnmpsnr(1)NAME
pnmpsnr - compute the difference between two images (the PSNR)
SYNOPSIS
pnmpsnr [pnmfile1] [pnmfile2]
DESCRIPTION
Reads two PBM, PGM, or PPM files, or PAM equivalents, as input. Prints the peak signal-to-noise ratio (PSNR) difference between the two
images. This metric is typically used in image compression papers to rate the distortion between original and decoded image.
If the inputs are PBM or PGM, pnmpsnr prints the PSNR of the luminance only. Otherwise, it prints the separate PSNRs of the luminance, and
chrominance (Cb and Cr) components of the colors.
The PSNR of a given component is the ratio of the mean square difference of the component for the two images to the maximum mean square
difference that can exist betwee any two images. It is expressed as a decibel value.
The mean square difference of a component for two images is the mean square difference of the component value, comparing each pixel with
the pixel in the same position of the other image. For the purposes of this computation, components are normalized to the scale [0..1].
The maximum mean square difference is identically 1.
So the higher the PSNR, the closer the images are. A luminance PSNR of 20 means the mean square difference of the luminances of the pixels
is 100 times less than the maximum possible difference, i.e. 0.01.
SEE ALSO pnm(5)
04 March 2001 pnmpsnr(1)