Correcting for Uneven Machine Vision Lighting with a Software Tool
By Brad Quist on Tue, Feb 08, 2011
Lighting a part to achieve very even lighting across the entire part can be
a challenge for certain machine vision applications. In some cases, the only
way to get a really good image is to use the Light Leveling Tool.
Below is an image of a plastic bottle with very slight uneven lighting
across the image. The unevenness of the lighting makes it difficult to detect
the actual defect because the grayscale value of the defect is the same as the
other areas of the image.
IMAGE WITHOUT LIGHT LEVELING TOOL
IMAGE WITH LIGHT LEVELING TOOL
The Light Leveling tool corrects for uneven lighting in an image. Within the
Light Sensor Shape List area,the column or row with the highest average grey
level is found (based on the Direction To Level input). A scale factor is
calculated for all the other columns or rows which brightens them so they have
the same average grey level as the brightest column or row. Each column or
row’s scale factor is then applied to all the pixels in that column or row
within the entire Region To Copy.
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