Re: Image-to-image registration.
- From: sueb <siouxbeeme@xxxxxxxxx>
- Date: Thu, 22 May 2008 10:17:04 -0700 (PDT)
On May 21, 5:09 pm, Yalin <mjm_v...@xxxxxxxxx> wrote:
The images are satellite images (Landsat TM4/5 & ETM+). TM05.TIF is from
2005 and TM93 is from 1993. I have only sent one band, band 3. I am going
to create an NDVI to evaluate the change in biomass of one specific lake,
but I thought resampling the whole image then clipping the the lake out and
creating the NDVI would be best.
I am going do use an easy image differencing technique and then classifing
the changed picks. However, it is crucial that I get the 2005 image to
lineup with the 1993 image.
This is a problem that I have gone over for some time, and I am willing to
do whatever it takes; however, I have no programming experience. This is a
side project that I have decided to take on for a prof. at my University.
The two images are below:
http://download.yousendit.com/D1F9E71666B28C17<-- TM05http://download.yousendit.com/9E54964E70312271<-- TM93
Thank you for the help and guidance!
You don't need ground control points but you need to find the same
points on both images. (You would be wise to use GCPs because the
next thing your professor who needs help is going to want to do is
bring in some other spatially-referenced dataset to overlay on
these.) Look for things that are stable like road intersections,
bridge abutments, etc. Get a good spatial distribution of points
around the image. Measure the points as accurately as possible.
One of your images becomes the control and the other is fitted to it.
Your points are used to establish a uniform grid of the desired pixel
size (probably 30m if you're using Landsat TMimages). You fit the
other images points to this grid, analyze with a least squares
criterion, removing points to improve the goodness of fit, and
generate a transformation polynomial describing the fit when your
overall error is lower than one pixel. Then project your second image
into the grid of the first, using the polynomial.
The process is called registering or warping. I'm sure there's
software in Idrisi (which is downloadable?) that would handle this.
Look in any digital image processing text geared to remote sensing
(Jensen) or the Manual of Remote Sensing for a better explanation.
Susan B.
.
- References:
- Image-to-image registration.
- From: Yalin
- Re: Image-to-image registration.
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- Re: Image-to-image registration.
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- Image-to-image registration.
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