The paper proposed a large field of view (FOV) measurement with calibrating the camera and measuring simultaneously.
In the measurement, the whole FOV was divided into several smaller ones with overlapping areas between each other.
The overlapping areas should contain at least 4 noncollinear feature points in each for computing external parameters
and at least 4 noncollinear control points in one of them to start the calculation. To obtain the measurement of the whole
large FOV, 2 images (or more) of each small fields of view needed to be taken from different angles. In the process of
calculation, theoretical values of the camera were used as the initial values of the internal parameters and the initial
values of external values were obtained from a new solution for P4P problem. So, the internal parameters of the camera,
the external parameters for each image, and the 3D coordinates of the feature points in the large field of view could be
acquired by adjustment method. In our experiment, the large field of view range was 500mm×500mm, the smaller ones
corresponding to each image was 200mm×200mm, and the ultimate measurement accuracy was 12μm.