Results on Visualization Experiments

Basic Image Combinations

Two different images of a common area are transformed (rigid only) so that they are registered.
Synthetic Aperture Radar magnitude
Panchromatic images can be of very high resolution
SAR and Panchromatic. Buildings and 2D ground structures enhanced by panchromatic image

Image Warping and Combinations

The warping application works as follows: Given two images (SAR, optical, Infra-red, street maps, images of 3D models...) tries to find the best interpolation between the two images, so the two images can be overlayed. That's based on some point correspodences interactively chosen by the user.

Two transformations have been tested for the warping:

  1. RBF

    Given a set of point correspondences well-spaced in the image, between the source and the target images, we compute a Radial Basis Function. This is a non-linear transformation. The anchor points will suffer no deformation at all under the RBF. The image points will be deformed according to their Euclidean distance to the anchor points in the linear RBF. We have also implemented a Gaussian RBF and the Hardy polynomes. The linear works fine.

  2. Rigid Transformation

    Given at least two point correspondences between source and target images, it computes an rigid transformation between the two images: This transformation is applied to a regular mesh well-spaced in the image (instead of each point of the image to speed up) to generate the final warped image.

    Combination of SAR and a Panchromatic image
    The initial images and the selected points used in the registration.
    The above image are 4 different combinations. For the full range see:
    Movie -- AVI The AVI movie allows you to see the different levels of blending.

    Combination of SAR and a computed DEM

    the DEM is coded by elevation, with green corresponding to the ground.
    The Input images with the selected points used in the registration.
    The above image are 4 different combinations. For the full range see:
    Movie -- AVI The AVI movie allows you to see the different levels of blending.

    Hyper Spectral Classification and Pan

    Hyperspectral based classification mixed with Panchromatic image. 4 frames and a pointer to the movie
    The above image are 4 different combinations. For the full range see:
    Movie -- AVI The AVI movie allows you to see the different levels of blending.

Once the source image has been warped to "fit" the target image, both are overlayed, and a slider allows you to change the opacity (alpha-blending) from 0 to 1, so you can see all the posibilities of blending. The .avi file shows the blending sequence for the warped source image and the target image.

Relation to other Software

This is just the initial phase of our work. The typical method used by Image Links, Autodesk, Autometric, etc. is to transform the image to a common orthographic, geo-registered frame of reference and combine these transformed images. Our approach would allow the combining of oblique views.