Photogrammetry Test 1

Digital Photogrammetry

Digital Photogrammetry is the art of using computers to obtain the measurements of objects in a photograph. It typically involves analyzing one or more existing photographs with photogrammetric software to determine spatial relationships.

Interior Orientation

defines the internal geometry of a camera as it existed at the time of the image capture

exterior orientation

the position and angular orientation of the camera that captured an image (exposure point).

exterior orientation process

Process involves defining GCPs and tie points to show a relationship between overlapping images. Also performing aerial triangulation and block adjustment.

absolute orientation

refers to the process of orienting a stereomodel to the ground control system. Image or stereomodel coordinates becomes identical with the ground space coordinates.

Principal point of autocollimation

the point from which the focal length of the lens is measured. This is defined as the image position where the optical axis intersects the image plane.

principal point of symmetry

is the point on the image where a ray of light travelling perpendicular to the image plane passes through the focal point of the lens and intersects the film.

Differentiate between coordinate space and coordinate systems photogrammetry.

Coordinate space is 3D and coordinate system is 2D. The origin for space is the perspective center and for system is the image center

pixel coordinate system

The file coordinates of a digital image are defined in a pixel coordinate system. A pixel coordinate system is usually a coordinate system with its origin in the upper-left corner of the image, the x-axis pointing to the right, the y-axis pointing downward,

image coordinates system

An image coordinate system or an image plane coordinate system is usually defined as a two dimensional (2D) coordinate system occurring on the image plane with its origin at the image center.

image space coordinate system

An image space coordinate system is identical to an image coordinate system, except that it adds a third axis (z) to indicate elevation.

Deformation

relative orientation

process of relative orientation is used to create the stereomodel. This occurs when the y-parallax is cleared at all image point

Fiducial Marks

are small registration marks located along the outside of an aerial photograph. There are typically four or eight numbered marks.