Dalsa Piranha4 Series, Руководство пользователя

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20 Piranha4 2K and 4K Camera Color User's Manual
03-032-20180-06 Teledyne DALSA
Parallax correction
When the camera it is not perpendicular to the object surface the P4 color camera will exhibit color. The
parallax distortion increases when imaging at steep angles relative to the cameras imaging plain. This is
an optical effect caused by the line spacing of the three individual colors. This spacing results in a
different magnification for each line at high angles. As shown in the figure below, there is color distortion
at the extremes ends of the image but at the centre of the image the color distortion does not show up.
4096 pixels
Figure 11: Image with Horizontal Color Alignment Issues
Using the P4 color cameras Parallax Correction feature, the optical magnification for each line is adjusted
such that colors can be lined up at the extreme ends of the image without affecting the center. Using the
feature Image Distortion Correction Mode (shm = 1) this feature can be turned on. Using the feature
Image Distortion Correction Line Selector the user can select red and green to correct the distortion. Note.
The red and green lines are adjusted to to align with the center blue line. Image Distortion Parallax
Correction Pixel Stretch (sha - Set horizontal alignment in float f<value 0-3>) is used to add the amount
of correction needed to the image. The value entered here must be between 0 and 3 (decimal values are
accepted.
Figure 12: CamExpert Parallax Correction Controls
4096 pixels
Figure 13: Figure 14 Corrected Image
The figure above is the same image corrected using the parallax correction. In this example the value of 3
was used to correct the image.