Example of left image
Maa-57.300 Fundamentals of Photogrammetry
Example
of left image
Description:
In this exercise, you will draw two stereo
images of tetraedri-figure (example of
left image). This template is used
in drawing.
After drawing, measure horizontal distances (in mm) between corresponding points of the stereo pair. This distance is also called parallactic distance. As a next step, depths of the points should be sorted in ascending order starting from the point closest to the viewer and ending to the point most far away. Mark the order on one image.
Then the same figure is drawn so that depths are in the opposite order (the point closest to the viewer will be the furthest). Parallactical distances are measured also from this image.
In the end, answer to the question "What is the relationship between the paractic distances and the depths of the points?".
Tips:
Use ruler in drawing (you need it anyway for the measurements)
Corresponding points are drawn on the same horizontal line (otherwise vertical parallax will appear on the image)
If parallactic distance is greater than distance between human eyes (app. 65 mm), stereoscopic viewing without equipment is impossible with straight viewing. You can have a stereocopic view by crossing your eyes, but then depths are seen in opposite order.
Try to be clean and constant with your drawing! Messy drawings makes the stereocopic viewing harder.
Ability to stereocopic viewing isn't necessary in this exercise, even though it makes checking of the drawings easier. If you have difficulties in 3D viewing, you can also ask pocket stereoscopes (used in exercise 1) from assistant.
If you have great parallactical distances on your image, it takes time for your eyes to adjust - be patient.
Exercise should be returned in the box (Maa-57.*) front of the room M225. Put your name and student number on the paper please.
If you have questions, please ask (assistant, room M225).
(Updated: 06.04.2005 Hanne Junnilainen)