Profile Extraction Process
Profile extraction refers to the process of extracting a profile from the raw image. Parameters in the Profile Extraction category influence the process and result of profile extraction. Understanding the profile extraction process helps in adjusting these parameters.
Examples
This topic uses the following raw images as examples.
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Left: contains one laser line, simulating a target object with simple surface reflecting conditions. The profile needs to be extracted from the correct position in this laser line.
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Right: contains multiple laser lines, simulating a target object with complex surface reflecting conditions. In such scenarios, the raw image tends to contain unnecessary laser lines (excessively dark, broad, or narrow) produced by situations such as interreflection. The profile needs to be extracted from the correct position in the correct laser lines, and the unneeded laser lines should be excluded from profile extraction.
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Profile Extraction Process
The steps to extract a profile are as follows:
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Filter valid pixels: Pixels in the raw image with grayscale values greater than the Min Grayscale Value parameter are considered valid. Pixels with grayscale values smaller than that parameter are considered invalid and do not participate in the following process.
When the Exposure information toggle switch is turned on, invalid pixels are displayed in light blue. The other pixels are valid. The images below demonstrate the visual effect after the toggle switch is turned on:
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Select the edge:The location for extracting the profile in each laser line is selected based on the value of theEdge Selection parameter.
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Blue line: Top edge
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Green line: Center
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Red line: Bottom edge
Images in the following steps demonstrate the effect after Center is selected.
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Calculate candidate spots: The raw image may contain multiple laser lines. After the valid spots filtered and the edge selected, the candidate spots in each pixel column will be calculated (the green dots in the image below).
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Filter candidate spots: Based on the values of the Min Laser Line Width, Max Laser Line Width, and Min Sharpness parameters, the candidate spots that meet the requirements are filtered.
Filtering result when the above parameters are set to appropriate values:
Filtering result when the above parameters are set according to the brightest laser line in the center:
Inappropriate values of the above parameters may lead to failure of extracting part of the profile. For example, when the value of Min Laser Line Width is too large, the straight parts of the laser line in the left image may be screened out, and the resulting profile will not have valid data in these parts.
In scenarios like the left images where only one laser line is present, the profile extraction process is completed. The candidate spots remained are the final spots, which are the blue dots shown in the raw image.
In scenarios like the right images where multiple laser lines are present, some pixel columns may still contain more than one candidate spot after the above steps. The final spots are selected based on the value of the Spot Selection parameter. The images below demonstrate the extraction results when the parameter is set to Strongest and Farthest:
Strongest |
Farthest |
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