76
Appendix B: Trouble Shooting Guide
Linea ML Color Cameras
Continuously Smeared, Compressed or Stretched Images
When accurate synchronization is not achieved, the image will appear smeared in the scan
direction. If the EXSYNC pulses are coming too fast, then the image will appear smeared and
stretched in the machine direction. If the pulses are too slow, then the image will appear smeared
and compressed. Check the resolution of the encoder used to generate the EXSYNC pulses along
with the size of the rollers, pulleys, gearing, etc. to ensure that one pulse is generated for one pixel
size of travel of the object.
It is also important that the direction of image travel across the sensor is per the camera’s scan
direction set by the user. See ‘Scan Direction’ in the user manual for more information. If the scan
direction is incorrect, then the image will have a significant smear and color artifacts in the scan
direction. Changing the scan direction to the opposite direction should resolve this problem. Refer
to ‘Camera Orientation’ in the user manual to determine the correct direction orientation for the
camera. Note that the lens has a reversing effect on motion. That is, if an object passes the lens-
outfitted camera from left to right, the image on the sensor will pass from right to left. The
diagrams in the user manual take the lens effect into account.
It is not always possible to establish the exact EXSYNC resolution or lens magnification ensures
accurate synchronization. To alleviate this problem, the camera has a spatial correction feature
that can make fine adjustment to restore the alignment. (See section ‘Compensating for Encoder
Errors’ for details.)
Randomly Compressed Images
It is possible that when the scan speed nears the maximum allowed, based on the exposure time
used, the image will be randomly compressed and possibly smeared for small periods in the scan
direction. This is indicative of the inspection systems transport mechanism dynamics causing
momentary over-speed conditions. The camera can tolerate very short durations of over-speed but
if it lasts too long, then the camera can only maintain its maximum line rate and some EXSYNC
pulses will be ignored, resulting in the occasional compressed image. The loss EXSYNC due to over-
speed may also cause horizontal color artifacts.
The over-speeding may be due to inertia and / or backlash in the mechanical drive mechanism
causing variations around the target speed. The greater the speed variation, the lower the target
speed needs to be to avoid over-speed conditions. If the speed variation can be reduced by
eliminating the backlash in the transport mechanism and / or optimizing the motor controller
characteristics, then a higher target speed will be achievable.
Distorted Image when Slowing Down Changing Direction
The camera must align the three colors in a fashion that accurately follows the object motion.
When the scan direction changes the process must reverse to match the reversed image motion
across the sensor. Only when all rows being accumulated have received the same image will the
output be correct. Prior to this some lines have been exposed to one direction and other lines
exposed to the opposite direction in the accumulated output.
Summary of Contents for ML Series
Page 16: ...14 The Linea ML Color Camera Linea ML Color Cameras Mechanical Drawings ML FC 08K10T 00 R ...
Page 17: ...Linea ML Color Cameras The Linea ML Color Camera 15 ML FC 16K04T 00 R ...
Page 18: ...16 The Linea ML Color Camera Linea ML Color Cameras ML HC 16K10T 00 R ...
Page 80: ...78 Declaration of Conformity Linea ML Color Cameras Declaration of Conformity ...
