Analytical principle of relative orientation and absolute orientation in photogrammetry

Firstly, the principle of relative orientation is analyzed.

Theoretical basis: the ray pairs with the same name intersect with the * * * plane, i.e.

Continuous relative orientation: based on the left photo, five positioning elements of the photo relative to the left photo are obtained. The coordinates of the points with the same name in the left and right photos are (X 1, Y 1, Z 1), (X2, Y2, Z2), and S2 is in s1-x1y1z.

Considering the small value of the first term, we get:

The projection coefficient is: about:? ?

get

Among them?

In stereo image pairs, every time the coordinates of a pair of image points with the same name are measured, an equation of Q can be listed. Because there are five unknowns in the above formula, at least five pairs of image points with the same name need to be measured. When there are redundant observation values, take q as the observation value and get the error equation:

Second, the intersection of stereo image pairs in front of space.

Given the external orientation elements of two photos, the coordinate of ground point A in the ground photogrammetry coordinate system is, which can be obtained as follows:

, ?

N 1 and N2 are the projection coefficients, which are the coordinates of S 1 and S2 in the ground photogrammetry coordinate system respectively.

Thirdly, the absolute orientation of stereo image pairs.

The three-dimensional model established by relative orientation is based on the auxiliary coordinate system of phase space selected in relative orientation, and the scale is unknown, so absolute orientation is needed. Absolute orientation includes seven absolute orientation elements, including translation, rotation and scaling of the model. Mathematically, this coordinate transformation is a three-dimensional spatial similarity transformation with different origins. Namely:

Basic formula of absolute orientation