PM scanner contra laser scanner

It is natural to draw comparisons between PhotoModeler Scanner and a 3D laser scanner (or structured-light scanner) because they both produce 3D point clouds. They both have their respective strengths and you might choose one technology over the other based on your application and budget.

The first two lists show the respective strengths of the technologies. The table afterwards shows how different surface types are handled.

PhotoModeler Scanner Strengths:

·      low purchase and operating costs

·      field equipment is easy to transport, move around the site, and is small (a camera)

·      less time in the field, comparable time back in the office

·      can work from an unstable instrument platform

·      can scan moving and unstable objects or scenes (if using synchronized cameras)

·      can scan very small objects accurately (if they can be photographed and have texture)

·      can scan objects at great distance (as long as there is a visible texture in the photos)

·      produces a superior photo-textured 3D model

3D Laser Scanner Strengths*:

·      can scan textureless (or repeating texture) surfaces (as long as the surface is Lambertian or near-Lambertian and reflects light back to scanner). See surface table comparison below.

·      may handle scenes with large and sudden depth changes better

·      does not need a priori knowledge about the approximate depth range

·      does not need targets or other sharp features to be identified in paired photos

·      can scan surfaces that might appear textureless at the distance that photography is needed for PhotoModeler Scanner

·      can scan at night and in dark locations (PhotoModeler Scanner would need additional lighting)

* Note: there are many differentlaser scanner products (and structured-light scanners) available and this list lumps them together and describes them in general terms. Some products may be better than others with respect to these criteria.

No scanning method works perfectly for all surface types. The nature of the surface will determine how well PhotoModeler Scanner works. This table is a comparison of PhotoModeler Scanner and a typical laser scanner in relation to the type of surface being scanned. The middle column shows PhotoModeler Scanner with additional hardware - that is, a projector (lcd, 35mm slide, or gobo) that can project a random dot pattern on the surface. The cells in the table indicate whether the product will normally produce a good 3D point cloud.