I'm struggling with correlating Landsat 7 imagery on the Getz Ice Shelf in West Antarctica. I imagine it ought to work fairly well - as ice shelves are more or less flat, orthorectification is not a huge issue. In addition, the velocities I'm looking at are fairly high - anywhere between 200 and 1200 meters/year along the shelf - so the signal to noise ratio should be decent. On top of that, I've run correlations on these images using IMCORR, and the vectors look great, so I know the features are trackable.
So far, though, the correlations I've been getting from Cosi-Corr end up looking like nonsense. Either I get an image that is completely noisy, or I get a blocky image that shows large regions of the same velocity, which does not match the physical characteristics of the region at all. I can't figure out what I'm doing wrong. I take two Landsat 7 images or subsets of Landsat 7 images (between 1999 and 2003, so they don't have missing stripes), enter them into the Cosi-Corr correlation window, and choose the frequency correlator. I've tried both the pan-chromatic band 8 (in hopes of correlating a higher-resolution image) and the NIR band 4. In the frequency correlator options, I've tried starting with a window size of 512, 256, and 128, and going down to a window size of 8. I've tried 2 and 3 robust iterations, and I disable the gridded output. Some of the correlations I've tried kind of vaguely show the general shape of the dominating features of the original image, but the whole thing is still so noisy that it's unusable. Maybe these images just don't work?
If you have any ideas that could help me make this work, I'd greatly appreciate it!