User`s manual

Spatial Correction on Color Cameras AW00049313000
138 Basler runner
9.3 System Design Requirements for
Proper Spatial Correction
As explained earlier in this chapter, spatial
correction is used to align color information in the
image. For a given area on the object to be
acquired correctly, its image must fall precisely on
the red line, the green line, and the blue line in the
sensor.
If spatial correction is being done correctly, the
acquired images will be sharp and clear as shown
in the right side of Figure 52. If there are
variations in the positioning of the image when it
is acquired by the red line, the green line, and the
blue line, the acquired images will include color
“halos” as shown in the left side of Figure 52.
A list of system design requirements is given
below. When these design requirements are met
and with the camera’s spatial correction parameters set properly, the image will show no color
halos.
Shaft Encoder
You must use a shaft encoder to monitor the movement of the system’s conveyor. You must also
use the encoder output to trigger line acquisition so that a given area of the object is acquired when
it falls precisely on the red line, the green line, and the blue line of the sensor.
If you do not use a shaft encoder, severe haloing in the transport direction will almost certainly result
and the halos will vary in size and color.
If an encoder is used but it is not set-up correctly, haloing in the transport direction will result. In this
case, the halos will be constant in size and color.
Halos No Halos
Transport
Direction
Fig. 52: The Halo Effect