of the triangle corresponds to the point in question a distortion of the image which to u2014 in the direction of the central vertical of each side of the triangle or decreases in this way the object 1 appears linearized such that length measurements can be carried out correctly on the screen to make appropriate measurements and object comparisons in the original the scale is set prefers a corresponding zoom operation on 1 1 so that in particular on the help screen in accordance with fig2 3 immediate form adjustments can be made with respect to the embodiment represented in the fig4 and 4 a must be auxiliary yet that the line between the virtual reference points 51 and 52 without trapezoidal keystone distortion correction and a third reference point 49 can be measured if it is not on the scale representation of the entire area but only on the length of the straight line in this case the length of the straight line with spatially awry reclining surface from the respective camera distances of the reference points 51 and 52 can be find that after the rays rate calculated from the size of the figure can be in fig5 is schematically shown a block representation of.