If the camera parameters in the Camera Viewer Dialog do not match the real camera that took the photo(s) you can get some strange and/or poor results.
Sometimes it is not obvious that your camera parameters are wrong. Here are some cases of bad camera parameterization:
• The photographs were taken vertically (i.e. in portrait mode) and then brought into PhotoModeler in an upright orientation (i.e. vertical - more tall than wide) but the Camera was defined for a landscape or horizontal photo (i.e. format size and principal points are set for the horizontal direction (x) being the widest one).
• If you take photos with the camera oriented vertically (portrait orientation) either define your camera parameters with the h&w and x&y flipped or keep your photos in landscape mode when you import them. We suggest you keep all your images in landscape orientation during import and then use the Photograph property for rotation to view portrait photos.
• The photographs were printed cropped (how most photo labs do it) and then scanned on a flat-bed scanner. The problem here is that relative to the pixels in the image, the principal point (where the optical axis of the lens intersects with the film) is in a different place in every photo. If you have two or more of these types of photos assigned to one Camera then the principal point may not be correct on one or both.
• One should set up a camera per photo (and then probably use Inverse Camera).
• You are using an uncalibrated video or digital camera. It is very important with video and digital cameras that you have a good estimate of the format size (see Camera Viewer Dialog).
• To get the most accurate format size you should do the full Camera Calibration. See Determining Digital and Video Camera Format Size.
• You do not know the parameters of the camera that took the photos so you guessed or used one of the Default Cameras.
• If you get bad results your guesses are too far off and perhaps Inverse Camera methods should be used.
• You have a full set of parameters for your camera including lens distortion numbers. You enter these in and just do not get the accurate results you would expect.
• Make sure the lens distortion numbers you are using are based on the same lens distortion math model that PhotoModeler uses (contact PhotoModeler Technologies support for more information).