Automatic point thinning

Dealing with very large blocks (> 8.000 images) the number of generated tie points may easily exceed a million tie points. This naturally has an effect on bundle block adjustment performance. However, in many cases this high number of tie points is usually not necessary to achieve accurate and valid triangulation results. Therefore HxMap offers a thinning capability, which reduces the number of tie points per image to the minimum required amount while considering tie point distribution as well as number of rays for its selection, which tie points to keep. This helps to speed up the bundle block adjustment process while assuring the block stability.

Launch the point thinning via the Tools menu > Thin Tie Points. The process of point thinning is immediately started. After it finishes, an information pops up which informs about point statistics before and after the thinning process:

The thinning process doesn’t delete any tie points, but changes the status of thinned out points to “deactivated”.  This allows the user to recover these points, if desired. In any other case the user may finally want to delete those points. This can be done by checking all tie points with status “deactivated” within the Points Tab and use the “Delete all selected points” button.