Digitizing a 3D Surface

Photo4D contains functions that can automatically detect and mark certain type of feature points. They are particularly useful for digitizing surfaces that need large number points to model.

Capturing the 3D model of a complex surface is, in principle, the same as capturing the model of any object. However, a complex surface usually requires a large number of points to represent it in reasonable detail. With the use of photograph-based technology, this means that users have to mark hundreds or thousands points in two or more images. This can be time consuming, tedious, and prone to error.

Photo4D has the following advanced features to make digitizing surfaces more efficient. They can be found in the Mark page in the Main Window.

1. Automatic detection of feature points: If many feature points appear similar in images, users need to mark one point only and let Photo4D detect other similar points. This feature is particular useful when the surface is tagged with small dots.
2. Automatic marking of corresponding marks in other images: After marking many points in one image, either manually or automatically, Photo4D can automatically find the corresponding points in other images under certain situations.
3. Automatic adjustment of mark location: This feature may be used to adjust marks to a more accurate position.
4. Project feature points back to images: This feature provides flexibility to create texture mapped 3D models.

You may be concerned about the amount of time required to tag feature points on a surface for a digitizing project. Unfortunately, this preparation has to be done in most cases, regardless of what software you are using or whether or not you use Photo4D's auto-marking features. Photograph-based 3D digitizing technology requires that the same point on an object be identified accurately in multiple images. When digitizing a smooth surface without obvious texture, it is impossible to identify feature points in multiple images without tagging them.