Dalsa Falcon 1.4M100 XDR Monochrome, Руководство пользователя

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Falcon XDR and HG Series Camera User's Manual DALSA
Optical and Mechanical Considerations 69
back focal length (BFL) is the distance from the image side of the lens surface to the second focal point.
The object distance (OD) is the distance from the first principal point to the object.
Primary Points in A Lens System
4.3.5 Magnification and Resolution
The magnification of a lens is the ratio of the image size to the object size:
m
h
h
=
′
where m is the magnification, h’ is the image
height (pixel size) and h is the object height
(desired object resolution size).
By similar triangles, the magnification is alternatively given by:
m
f
OD
=
′
These equations can be combined to give their most useful form:
′
=
′
h
h
f
OD
This is the governing equation for many object
and image plane parameters.
Example:
An acquisition system has a 512 x 512 element, 10
μ
m pixel pitch area scan camera, a lens with
an effective focal length of 45mm, and requires that 100
μ
m in the object space correspond to each pixel
in the image sensor. Using the preceding equation, the object distance must be 450mm (0.450m).
10
100
45
450 0 450
μ
μ
m
m
mm
OD
OD mm m
= =
( . )