| Re: Image subtraction [message #11788 is a reply to message #11675] |
Tue, 26 May 1998 00:00   |
noname
Messages: 5
Registered: May 1998
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Junior Member |
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Hi,
Yes, NIH Image is now available for PC.
Go there:
http://www.scioncorp.com/index.htm
The name of the pc prog is Scion Image
Skiso
Patrick V. Ford a �crit:
> Try
> tvscl, image1 - A * image2
>
> where A is a correction factor for intensity. One of the problems here is
> how are negative numbers handled, should you change the images to float
> to allow non integer As, and what value should A be, see? (I could not
> resist the pun.)
>
> To set values less than 0 to 0, you could use one of those matrix logical
> something like: img = img * (img GE 0.0)
> (I don't have the ref material handy and unlike many here, I need to
> lookup all but the simplest of stuff.)
>
> For A, there are many ways to determine a value, such as the average of
> the images ratio, max ratio, etc. Or the one I commonly use, trial and
> error.
>
> You could always write(e-mail) the author of NIH Image to find out what he
> is
> doing, whose name escapes me. He
> usually is fairly responsive, or you could examine the sourse code that,
> at least in the past, was available.
>
> BTW, is NIH image still just a Mac program?
>
> Patrick Ford, MD
> Baylor College of Medicine
> pford@bcm.tmc.edu
>
> FRANCOIS LAROSE (aah904@agora.ulaval.ca) wrote:
> : Ok,
>
> : Let me explain, I take two gray scale images and subtract them togethers.
> : Then, I display the result on screen with TVSCL command. When I say, I get
> : poor
> : result, is because I compare the result of this subtraction with the
> : result
> : of a program that make image subtraction (NIH image). The two are very
> : different. So, I suppose I should do something else to get the same
> : result.
>
> : For the package, I working in research so I can't afford a expensive one.
> : Maybe, you can point me some web site...
>
> : Tanks
>
> : Frank
>
> : At 09:59 18/05/98 -0600, you wrote:
> : >you writes:
> : >
> : >> I need to do some image subtraction. With IDL, if I only do
> : >> Image1 - image2 and I get poor result. Does it have best code to
> : >> do image subtraction?
> : >
> : >Poor result how? Can't see it? Doesn't look like what
> : >you expect? Don't believe the results?
> : >
> : >Try this:
> : >
> : > TV, BytScl(image1 - image2, top=!D.N_Colors-1)
> : >
> : >Does that help?
> : >
> : >> PS If you know a good package of image analisys in IDL, just let me
> : know!
> : >
> : >How much would you be willing to pay for this? :-)
> : >
> : >David
> : >
> : >-----------------------------------------------------------
> : >David Fanning, Ph.D.
> : >Fanning Software Consulting
> : >E-Mail: davidf@dfanning.com
> : >Phone: 970-221-0438
> : >Coyote's Guide to IDL Programming: http://www.dfanning.com/
> : >
> : >
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