Y-Axis Resolution of Scan Data
The Y-axis resolution of the scan data is the distance between two neighboring data points along the travel direction of the target object. This is equal to the distance between two neighboring profiles. The Y-axis resolution determines the accuracy of the scan data, as well as the aspect ratio of the target object in the intensity image and depth map.
The rate at which scanning is triggered determines the distance between two neighboring profiles, and therefore determines the Y-axis resolution of the scan data.
The parameters that affect the rate at which scanning is triggered differ depending on the value of Line Scan Trigger Source:
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When scanning is triggered at a fixed rate: Trigger Rate determines the rate at which scanning is triggered.
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When scanning is triggered by an encoder: Trigger Signal Counting Mode and Trigger Interval together determine the rate at which scanning is triggered.
Adjust Y-Axis Resolution through Parameters
When you have specific requirement on the Y-axis resolution of the scan data, you can change the Y-axis resolution by adjusting the above parameters.
Trigger Rate
When scanning is triggered at a fixed rate, you can refer to the following equation and calculate the value of Trigger Rate for achieving the needed Y-axis resolution:
Y-axis resolution (μm) = travel speed of the target object relative to the laser profiler (μm/s) ÷ Trigger Rate
Trigger Signal Counting Mode and Trigger Interval
When scanning is triggered by an encoder, you can refer to the following equation and calculate the values of Trigger Signal Counting Mode and Trigger Interval for achieving the needed Y-axis resolution:
Y-axis resolution (μm) = encoder resolution (μm) × Trigger Interval ÷ Trigger Signal Counting Mode × 4
Among which, the encoder resolution is the travel distance (in μm) of the target object relative to the laser profiler during the duration of each signal in the following figure.
Calculation Example
If the encoder resolution is 4μm, and the needed Y-axis resolution is 20μm, then:
20 = 4 × Trigger Interval ÷ Trigger Signal Counting Mode × 4
Simplify the above equation to get: 1.25 × Trigger Signal Counting Mode = Trigger Interval.
Therefore, the following parameter values can basically satisfy the requirement on Y-axis resolution:
| Trigger Signal Counting Mode | Trigger Interval |
|---|---|
1× |
1.25 (Round it to 1 or 2) |
2× |
2.5 (Round it to 2 or 3) |
4× |
5 |