Scan Mode

This topic provides descriptions of the parameters in the scan mode.

Trigger Settings

Select the trigger sources and set relevant parameters.

For the methods of triggering the laser profiler to acquire data in the scan mode, please refer to Methods for Triggering Data Acquisition and Workflow of Triggering Data Acquisition.

Data Acquisition Trigger Source

Description

Select the source of the signals that trigger data acquisition. In one round of data acquisition, multiple lines are scanned, multiple profiles are generated, and one intensity image and one depth map are generated using the profile data.

Visibility

Beginner, Expert, Guru

Values

  • External

  • Software (default)

Instruction

If you use externally input signals to trigger data acquisition, select External. Otherwise, select Software.

Line Scan Trigger Source

Description

Select the source of the signals that trigger the scan of a single line.

Visibility

Beginner, Expert, Guru

Values

  • Encoder (default)

  • Fixed rate

Instruction

  • If you use an encoder to trigger scanning, select Encoder.

  • If you need to trigger scanning at a fixed rate, select Fixed rate.

Please set Data Acquisition Trigger Source and Line Scan Trigger Source based on the combination of triggering methods in use.

After selecting different options, different parameters are displayed in the Trigger Settings category for adjustment:

Encoder Settings

When Line Scan Trigger Source is set to Encoder, adjust the parameters in this category.

Click Edit to open the Encoder Settings tool. You can check the encoder value and motion direction, and have the encoder resolution calculated.

If you need the Y-axis resolution of the scan data to be equal to the X-axis resolution, you can also use this tool to get the recommended value of Trigger Interval.

Trigger Direction

Description

Select the encoder motion direction that triggers scanning.

Visibility

Beginner, Expert, Guru

Values

  • Channel A leading: Scanning is triggered when channel A is leading.

    leading a

  • Channel B leading: Scanning is triggered when channel B is leading.

    leading b

  • Both (default): Scanning is triggered when either channel A or channel B is leading.

Instruction

Adjust this parameter based on the encoder motion direction and the motion direction of the target object relative to the laser profiler.

Check the encoder motion direction in the Encoder Settings tool.

Trigger Signal Counting Mode

Description

Set the number of quadrature signals to be counted in an encoder period. Counted signals are used to trigger scanning (These signals are trigger signals).

Each encoder period contains 4 quadrature signals, as shown below.

encoder period

Visibility

Beginner, Expert, Guru

Values

  • 1× (default): counts 1 signal in an encoder period.

  • 2×: counts 2 signals in an encoder period.

  • 4×: counts 4 signals in an encoder period.

Instruction

  • This parameter and Trigger Interval together determine the rate at which scanning is triggered. If the rate at which scanning is triggered is greater than the max scan rate of the laser profiler, some data will be lost. Please refer to Some Data Were Lost to resolve this issue.

    You can check the current max scan rate of the laser profiler in the upper right of the data display area.

  • This parameter and Trigger Interval together determine the Y-axis resolution of the scan data, thus affecting the scan accuracy as well as the aspect ratio of the target object in the intensity image and depth map. For details, please refer to Y-Axis Resolution of Scan Data.

  • If you need the Y-axis resolution of the scan data to be equal to the X-axis resolution, adjust Trigger Interval in the Encoder Settings tool (The value of Trigger Signal Counting Mode may need to be adjusted accordingly).

Trigger Interval

Description

Set the number of trigger signals needed for scanning one line.

Visibility

Beginner, Expert, Guru

Values

  • Value range: 1 to 65535

  • Default value:

    • LNX-8030: 2

    • LNX-8080: 6

    • LNX-8300: 13

Instruction

  • This parameter and Trigger Signal Counting Mode together determine the rate at which scanning is triggered. If the rate at which scanning is triggered is greater than the max scan rate of the laser profiler, some data will be lost. Please refer to Some Data Were Lost to resolve this issue.

    You can check the current max scan rate of the laser profiler in the upper right of the data display area.

  • This parameter and Trigger Signal Counting Mode together determine the Y-axis resolution of the scan data, thus affecting the scan accuracy as well as the aspect ratio of the target object in the intensity image and depth map. For details, please refer to Y-Axis Resolution of Scan Data.

  • If you need the Y-axis resolution of the scan data to be equal to the X-axis resolution, please adjust Trigger Interval through the Encoder Settings tool.

Fixed-Rate: Trigger Rate

Description

When Line Scan Trigger Source is set to Fixed rate, set the fixed rate at which the laser profiler is triggered to scan.

Visibility

Beginner, Expert, Guru

Values

  • Value range: 2 Hz to the current max scan rate

    You can check the current max scan rate of the laser profiler in the upper right of the data display area.

  • Default value: 1000 Hz

Instruction

  • This parameter determines the Y-axis resolution of the scan data. Please adjust it based on your needs for the Y-axis resolution.

  • If you need the Y-axis resolution of the scan data to be equal to the X-axis resolution, please calculate the appropriate Trigger Rate value according to the following equation:

    Trigger Rate: = travel speed of the target object relative to the laser profiler (μm/s) ÷ X-axis resolution

Scan Settings

Set other parameters that affect the scanning process.

Scan Line Count

Description

Set the number of profiles needed to generate one intensity image/depth map.

Visibility

Beginner, Expert, Guru

Values

  • Value range: 16 to 20000

  • Default value: 5000

Instruction

Make sure that the set value can cover one target object completely. You can refer to the following equation to calculate the appropriate parameter value:

Scan Line Count = length of target object (μm) ÷ Y-axis resolution of scan data (μm)

The set value should be slightly larger than the calculated value.

Timeout Period

Description

Set the timeout period for data acquisition. After data acquisition is triggered, if the software does not receive data within the set timeout period, the current round of data acquisition is automatically stopped.

Visibility

Beginner, Expert, Guru

Values

  • Value range: 100 ms to 60000 ms

  • Default value: 4000 ms

Instruction

Adjust based on the actual needs.

Brightness Adjustment

Parameter Description

Adjust the brightness of the intensity image. A greater value of this parameter results in a brighter intensity image.

Visibility

Expert, Guru

Values

  • 0.5×: reduces the brightness to half (0.5) of the original intensity image.

  • 0.75×: reduces the brightness to three quarters (0.75) of the original intensity image.

  • 1× (default): displays the original brightness of the intensity image.

  • 1.5×: increases the brightness to one and a half (1.5) of the original intensity image.

  • 2×: increases the brightness to twice (2) the original intensity image.

Instruction

  • To reduce the brightness of the intensity image, set the parameter value to 0.5× or 0.75×.

  • To increase the brightness of the intensity image, set the parameter value to 1.5× or 2×.

Intensity images with different Brightness Adjustment values (all other conditions identical):

Brightness Adjustment: 0.5× Brightness Adjustment: 1× Brightness Adjustment: 2×

brightness adjustment 0.5

brightness adjustment 1

brightness adjustment 2

Exposure Delay

Description

Set the delay time between laser emission and start of exposure.

Larger exposure delay results in more stable brightness of the laser lines in the raw image, thus more stable quality of the intensity image and depth map. However, the max scan rate will be reduced.

Visibility

Guru

Values

  • Value range: 1 to 2600 μs

  • Default value: 5 μs

Instruction

If the quality of the obtained data is unstable (such as the depth fluctuation of the same position on the same object is large), you can increase the value of this parameter.

Point Cloud Resolutions

Check the X-axis resolution and set the Y-axis resolution of the point cloud.

X-Axis Resolution

Description

Displays the resolution in the X direction, which is the distance between two neighboring points along the direction of the laser line.

This parameter is read-only and cannot be adjusted.

Visibility

Beginner, Expert, Guru

Values

  • LNX-8030: 9.0 μm

  • LNX-8080: 23.5 μm

  • LNX-8300 105.0 μm

Y-Axis Resolution

Description

Set the resolution in the Y direction, which is the distance between two neighboring points along the travel direction of the target object.

Visibility

Beginner, Expert, Guru

Values

  • Default value:

    • LNX-8030: 9.0 μm

    • LNX-8080: 23.5 μm

    • LNX-8300: 105.0 μm

Instruction

This parameter only affects the Y-axis resolution of the point cloud. If in the point cloud, the distance between two points neighboring along the Y-axis is shorter than the actual distance, please increase the value of this parameter. Otherwise, decrease the value of this parameter.

Point clouds obtained with different Y-Axis Resolution values (all other conditions identical):

Y-Axis Resolution: 12 μm Y-Axis Resolution: 23.5 μm Y-Axis Resolution: 35 μm

y resolution 18

y resolution 23.5

y resolution 30

Mask

Description

Use masks to exclude unneeded data, such as noise and laser lines produced by interreflection.

Visibility

Beginner, Expert, Guru

Values

Enable Mask:

  • True: Apply the added masks.

  • False: Do not apply the added masks.

Instruction

Double-click Edit to open the Mask Tool window. For detailed instructions, refer to Use Mask Tool below.

Use Mask Tool

Through the mask tool, you can add, edit, and delete masks.

Add Masks

Follow these steps to add masks:

  1. Select the appropriate tool in the toolbar on the left:

    • rectangle: used to add a rectangle mask.

    • polygon: used to add a polygon mask.

  2. Determine the location of the unneeded data in the raw image and draw a mask:

    • Rectangle mask: Hold and drag.

    • Polygon mask: Click to add a vertex of the polygon mask. After all needed vertices are added, press the Enter key or right-click to finish drawing the polygon mask.

      In a polygon mask, the overlapped regions are not effective:

      overlapped mask

      • Click Acquire again at the top to acquire the raw image after the masks are added to check the effect of the masks.

      • If the position, shape, or size of the masks are not satisfactory, you can edit the masks or delete the masks.

  3. After all masks are added, click Apply to close the current window.

    After Apply is clicked, the value of the Enable Mask parameter is automatically changed to True. If you do not need to apply the masks, change the value of this parameter to False.

Edit Masks

If the position, shape, or size of the masks are not satisfactory, follow these steps to edit the masks:

  1. Click selection in the toolbar on the left.

  2. Select the mask that needs to be edited and conduct the needed adjustment:

    • Move a mask: Select the mask and drag.

    • Adjust the size of a rectangle mask: Select a vertex of the rectangle mask and drag.

    • Adjust the shape of a polygon mask:

      • Move an existing vertex: Select a vertex of the polygon mask and drag.

      • Add a new vertex: Left-click on an edge of the polygon mask.

      • Delete an existing vertex: Select a vertex of the polygon mask and right-click.

        Click Acquire again at the top to acquire the raw image after the masks are edited to check the effect of the masks.

  3. After all editing is completed, click Apply to close the current window.

    After Apply is clicked, the value of the Enable Mask parameter is automatically changed to True. If you do not need to apply the masks, change the value of this parameter to False.

Delete Masks

Follow these steps to delete unsatisfactory masks:

  1. In the right panel, select the mask that needs to be deleted in Mask list, and click delete.

    If you need to delete all the masks, click Clear to the right of Mask list.

  2. In the pop-up window, click Confirm to delete the mask.

    Click Acquire again at the top to acquire the raw image after the mask is deleted to check the effect of the remaining masks.

  3. After all deletion is completed, click Apply to close the current window.

    After Apply is clicked, the value of the Enable Mask parameter is automatically changed to True. If you do not need to apply the masks, change the value of this parameter to False.

Correction

The parameters in this category are used to correct the tilt of and height error in the profile.

Tilt Correction

Description

Correct the tilt of the profile, which is caused by the rotation of the laser profiler around the Y-axis.

Visibility

Beginner, Expert, Guru

Values

Enable Tilt Correction:

  • True: Apply the tilt correction result to the profile.

  • False: Do not apply the tilt correction result to the profile.

Tilt Correction Angle:

  • Range: –90° to 90°

  • Default value: 0°

Instruction

For detailed instructions, refer to Perform Tilt Correction below.

Perform Tilt Correction

This tool is used to correct the tilt of the profile, which is caused by the rotation of the laser profiler around the Y-axis.

As shown below, the rotation of the laser profiler around the Y-axis make the tilt of the acquired profile differ from the tilt of the actual object.

Not rotated

Rotated around the Y-axis

Laser profiler

camera horizontal line

camera tilt 1

camera tilt 2

Acquired profile

capture image 1

capture image 2

capture image 3
Prerequisites

In order to perform tilt correction, the following prerequisites must be satisfied:

  • It is recommended to use a target object whose surface includes flat regions.

  • A relatively complete profile of the flat regions can be acquired. If the profile is incomplete, please refer to Profile Mode and adjust the other parameters first.

  • Keep the target object still relative to the laser profiler, and acquire the profile of the flat regions on the target object.

Instructions

Follow these steps to perform tilt correction:

  1. Double-click Edit to the right of Tilt Correction to open the Tilt Correction window.

  2. Select the detection areas and drag to adjust their positions. Make sure to satisfy the following criterion while adjusting:

    The profile selected by the two detection areas should correspond to two locations on the same flat region of the target object. Please refer to the following example:

    Target object tilt correction target object

    Detection areas

    Correct

    Incorrect

    tilt correction detection areas 1

    tilt correction detection areas 4

    tilt correction detection areas 2

    tilt correction detection areas 3
    The detection areas can overlap.

  3. Select the detection areas and drag the handles on them to adjust their widths. Refer to the following criterion while adjusting:

    With the above criterion satisfied, the detection area can be as wide as possible to include more data for tilt correction.

  4. In Expected tilt angle under Tilt angles, enter the angle that the profile in the detection areas should reach after the correction.

    Positive values rotate the profile counterclockwise; negative values rotate the profile clockwise. The range of possible values is -45° to 45°.
    Example of expected tilt angle

    A target object as shown below is placed on a horizontal surface:

    tilt target object angle

    The value that should be entered for Expected tilt angle depends on the positions of the detection areas:

    Detection areas Expected tilt angle

    tilt correction detection areas 1

    0°

    tilt correction detection areas 4

    30°

  5. Click Correct. The green line in the image area on the left represents the profile that has been rotated to Expected tilt angle after tilt correction. Check if this profile satisfies your requirements:

    • If yes, click Apply to apply the tilt correction result and close the window.

    • If no, repeat steps 2 to 5.

  6. Acquire data again in the profile mode and switch to Profile to check the effect of correction.

Height Correction

Description

Correct the height error in the profile, which is caused by the rotation of the laser profiler around the X-axis.

Visibility

Beginner, Expert, Guru

Values

Enable Height Correction:

  • True: Apply the height correction result to the profile.

  • False: Do not apply the height correction result to the profile.

Height Correction Ratio:

  • Value range: 0.1 to 8.0

  • Default value: 1

Instruction

For detailed instructions, refer to Perform Height Correction below.

Perform Height Correction

This tool is used to correct the height error in the profile, which is caused by the rotation of the laser profiler around the X-axis.

As shown below, the rotation of the laser profiler around the X-axis make the height difference between two locations in the acquired profile differ from the actual difference.

Not rotated Rotated around the X-axis

Laser profiler

profiler vertical

profiler leaning 1

Acquired profile

height correction profile 1

height correction profile 2
Prerequisites

In order to perform height correction, the following prerequisites must be satisfied:

  • It is recommended to use a target object with known dimensions and flat surfaces, such as a gauge block, and place the target object on a horizontal surface.

  • A relatively complete profile of the target object can be acquired. If the profile is incomplete, please refer to Profile Mode and adjust the other parameters first.

  • Keep the target object still relative to the laser profiler.

  • Select two surfaces (such as the top surface of the gauge block and the horizontal surface on which the gauge block is placed) for calculating the height difference, and determine the actual height difference of the two surfaces.

Instructions

Follow these steps to perform height correction:

  1. Double-click Edit to the right of Height Correction to open the Height Correction window.

  2. Select the detection areas and drag to adjust their positions. Make sure to satisfy the following criterion while adjusting:

    The profile segments selected by the two detection areas should correspond respectively two the two surfaces used for calculating the height difference.

    Two surfaces used for calculating the height difference

    height correction target object

    Detection areas

    Correct

    Incorrect

    height correction detection areas 1

    height correction detection areas 2

    height correction detection areas 3

  3. Select the detection areas and drag the handles on them to adjust their widths. Refer to the following criterion while adjusting:

    With the above criterion satisfied, the detection areas can be as wide as possible to include more data for height correction.

  4. In Actual height difference under Height differences, enter the actual height difference between the two surfaces.

    The minimum value of Actual height difference is 0.01 mm, and the maximum value is the Z-axis measurement range of the laser profiler.

  5. Click Correct. The green line in the image area on the left represents the profile after height correction. Check if this profile satisfies your requirements:

    • If yes, click Apply to apply the height correction result and close the window.

    • If no, repeat steps 2 to 5.

  6. Acquire data again in the profile mode and switch to Profile to check the effect of correction.