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Methods of Referencing

Referencing is a key task for multi-photo photogrammetry, but it can also be a difficult and sometimes tedious task. For this reason, PhotoModeler has several ways to reference Marks. The first method called Manual Referencing is used for points, edges, curves, Bent Tubes and cylinders. The remaining methods shown here are used just for points.

Why are there so many different methods to reference points?  It is because there are different scenarios and different levels of automation – sometimes full automation and sometimes user-assisted.

Tools for Referencing Points in PhotoModeler.

 

Referencing Method	Level of Automation	When to use	Photo Orientation	How to use
Manual Referencing	Low	This method can always be used. It can be used to start projects without targets and is the fall back for difficult cases.	Can be used before project is processed or photos oriented.	Referencing Marks and Quick Reference Tools {all these in this column should be link so rename to match section names}
Automatic Referencing	High-ish	This is often used when there are many non-coded dot targets.	Photos need to be oriented.	See Automatic Referencing
Interactive Referencing	Medium	This is a user-directed process used to clean up difficult cases that cannot be detected by other methods.	Photos need to be oriented.	See Interactive Referencing
Point Auto-Detect	Medium	This can both create Marks and References on other photos in certain situations.	Photos need to be oriented.	See Point Auto-detect Mode
Coded Targets	High	Use for high levels of automation and high accuracy in industrial and fabrication tasks.	Can be used before project is processed or photos oriented.	Run an Automated Coded Targets Project.
SmartMatch	High	Use to start a project for textured surfaces and close angle photos.	Can be used before project is processed or photos oriented.	Available only in PhotoModeler Premium. Run a SmartPoints Project.

 

Three different strategies exist for doing Point Referencing:

•        Mark all points first and then reference them as a second step.

•        Combine the marking and referencing steps. Choose one photograph and mark all of the points that are visible on it. Choose a second photograph that has many points in common with the first one. Make the first photograph the Reference Source Photograph, and select all of its Marked Points. Mark points on the second photograph as they are highlighted on the first photograph. This approach can be more difficult than marking and referencing separately but is also more efficient.

•        Do single point marking/referencing while in Reference mode. Enter Reference mode,  click on an image to create a new mark and select it as the source photo, then immediately mark same point on a different photo.  Note you can also hold the shift key while marking points in the source photo and then you can reference them together in the destination photo.

Edges, Curves, Bent Tubes, Cylinders, and Silhouettes must be marked before being referenced so only option 1 is available. Option 1 can be carried out using Reference Mode or the Quick Referencer (see below).

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