How It Works

The central algorithm in PhotoModeler Scanner is Dense Surface Modeling (DSM for short).

DSM is a search algorithm that uses an existing pre-oriented project and pairs of photos from that project to search for image patches that ‘look’ alike.  This search is done in a regular grid-like manner so a grid of 3D points is computed. When a good match is found between two photos, the orientation and camera data allows the program to compute the correct 3D location of the surface point corresponding to the image patch

View the introductory tutorial videos to see what PhotoModeler Scanner is all about.

Version 2010 added SmartMatch which can be used for dense modeling in some cases, but at the very least is a great way to automate the project setup (no targets required).

Project Requirements

For a Dense Surface Model project to work well there are some requirements.  These requirements are associated with how the photographs are taken, and the nature of the surface being modeled.

DSM Photo Requirements
Photographs used in DSM projects should be in a parallel or close to parallel orientation. The cameras should be approximately one quarter the distance apart, compared to the distance that they are from the surface. This would be called a 0.25 base to height ratio. Base to height ratios of 0.1 to 0.5 are suitable. Highly convergent photographs usually do not work well with DSM since the surface looks too different. A typical PhotoModeler project requires convergent photographs to solve well and a PhotoModeler Scanner / DSM project will have a mixture of convergent and parallel photos. Lastly the photographs need to overlap on the surface being modeled.

DSM Surface Requirements
The surfaces to be modeled by DSM need to have a visible random texture/pattern.  Examples of random textures are rock, dirt, skin, wood grain, bricks, trees, etc.  Examples of surfaces that are not textured are plaster-board walls, metal surfaces or glass windows.

Metal surfaces with no texture (a body panel of a car for example) can still be DSM modeled if a random texture pattern is applied or projected onto it and the surface is matte. Metal surfaces with texture but are reflective (not matte) may have trouble due to lighting hot spots (light reflections and 'hot spots' move on the surface as the camera position changes). Spraying a shiny metal surface with a white powder to remove reflections and then spraying on a texture of contrasting color will often create a surface that DSM can process.