FME GPS Camera and FocalLength results

Preliminary results

Here are som charts for the Tennisball test. We can clearly see that the distance to the picture is NOT a linear function.

* Using no zoom (FocalLength 4.25 mm) means approx 3m to the picture (middle tennisball)

* Using 6.4 zoom (FocalLength 27 mm) means approx 16-17 m to the picture (middle tennisball)

Distance to picture/tennisball and FocalLength

The data about the width is a bit more surprising?

It seems to be a more linear function going from 4-3.5 m in the same ranges.

Width and FocalLength

Whats the point?

One might ask what the (focal)point is. Let’s see in the coming post. The theory is that I now can calculate the most appropriate way to position pictures in 3D with FME. That is the offset from the Camera but also the width of the picture in metres.

The testpictures

Below are all the tespictures. Unfortunately my garden was too short for testing 10x zoom. Maybe I’ll try to test this on a suitable football field.

(Who knows? American Football fields might actually be entertaining one day…).

All the testpictures

/Ulf Mansson

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