Processing ADS imagery

Processing airborne digital sensor (ADS) Level 0 or Level 1 data in OrthoEngine requires special attention to get optimal results. In particular, if you want to process both the panchromatic (PAN) and the multispectral (MS) data, then you should do so in a single OrthoEngine project with the following recommended approach:

1. Setting up an ADS project

   In the Project Information window, enter a file name, project name, and description, as necessary. Set up the project to use aerial photography as the math modeling and ADS as the camera type.

   Tip: If you know the projection that you want to use for your output, you can define it in the Set Projection window. However, you can also cancel that step to have OrthoEngine automatically set the projection to that of the first image you add.
2. Add your imagery

   Add all the files of your ADS imagery to your project by selecting the various .sup files. After adding the imagery, assuming you are working simultaneously with multispectral (MS) and panchromatic (PAN) images, you can deactivate the MS files. Deactivating the MS images temporarily excludes them from processing, thereby helping you to decrease clutter and focus solely on the active PAN images. Doing so also provides the added benefit of significantly decreasing processing time.

3. Automatically collect tie points

   Run automatic tie-point collection, and then refine the tie points. OrthoEngine processes only active images.

4. Import field-surveyed GCPs

   If available, you can add field-surveyed GCPs as a ground-control source in the GCP Collection window for the relevant PAN images.

5. Activate all images

   For all of your images to be bundle adjusted in the next step, you must activate them. That is, you must reactivate the MS images you deactivated in step 2.

6. Compute the math model
   Also known as a bundle adjustment, you next need to initiate the math-model calculation.

   • The math models of the PAN images are adjusted using tie points, GCPs, or both.
   • For each MS image that has a corresponding PAN image, the math model of the PAN image you just computed is propagated to the MS image, so it is adjusted, too.

   Wtih ADS math-model projects, OrthoEngine stores the math model in individual linked PCIDSK (.pix) files. The PCIDSK files are stored in a subfolder of your OrthoEngine project file, and with the same basename.

7. Correct (orthorectify) the images

   After you are satisfied with the quality of the math model, you can perform image-correction tasks, such as orthorectification.