Image Coregistration in Agisoft Metashape
While most photogrammetry projects may only need data from one point in time, there are many instances where you want to track change over time. With high-resolution, 3D drone imagery, coregistering the 3D models and image products from different time periods is very important, but can also be very challenging. This exercise walks through a few different approaches to coregistering 3D models and orthomosaics in Metashape.
So far we’ve been working with image sets from single dates (i.e., epochs). In other of these tutorials, we’ve looked at a lot of tools in Metashape and hopefully you’ve seen how much information you can get out of just a single set of images. However, for many applications we want to look at change over time using imagery from multiple epochs. When you’re working with image sets from multiple epochs, however, having the image sets correctly aligned to each other is critical. This is called coregistration, and if image products or 3D models are not coregistered, then you can: 1) miss changes that are happening, or 2) detect false changes that are the result of image misalignment.
The main goals of this lab exercise are to familiarize you with:
- Why image coregistration is necessary when working with imagery from multiple epochs
- Tools in Metashape for image/model coregistration
- Calculating DEM differences to look for change over time
