Estimate Pose
This function allows you to estimate the position and orientation of a picture coming from a camera.
Requirements
Select the image whom attitude has to be computed.
The view is automatically split into two parts in order to have the mesh to texture on the left and the current selected texture on the right.
The Reference points tab allows you to calculate the unknown data:
In this tab, you need to enter couples of points (image, surface) so that unknowns are computed.
As soon as a couple of points is defined, you will see a new entry inside the list.
You can Save your list of reference points to an external file. To read an external file containing a reference point list, you must use the Load button.
The minimum number of pairs necessary to get a result depends on the type of image:
2 for perspective image
3 for spherical image
4 for fish eye image
However, with the minimum number of points only and without any previously known parameters, the result may not be accurate. For example, you have to add at least 4 pairs to get a true result (perspective image). Furthermore, Leica Cyclone 3DR can automatically compute lens distortions by adding pairs.
As soon as camera parameters have been worked out, the image will be displayed in perspective mode.
Notes
This command doesn't work with ortho images.
The tangential distortions are not estimated during the computation.
Select Keep Internal Parameters if you want to keep the INCAM internal camera definition (Calibrate Camera).
The ASCII format used to store couples of points is one point per line: "X Y Z U V I J K Name" Where X, Y and Z are the coordinates of the point in the 3D scene, U V are the coordinates of the point on the image (between 0 and 1 - 0/0 being the top left of the image and 1/1 being the bottom right), I J K define the vector from which the points are clicked (not used as soon as the number of points is greater than 2) and the name being the name of the point.
Technical information
During the input of points with the Reference points tab, the Camera definition tab is automatically updated. However, as the internal camera geometry is unknown, the software cannot accurately calculate the different values. This is the reason why the software recalculates the internal camera geometry with a CCD diagonal length of 43.27mm. This value is the diagonal of a rectangle 24x36mm, which is the standard film size of the argentic cameras.
Practise
See the Exercise: Texture a mesh with reference points in the beginners guide section.