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Important Points to Note in Selecting
an Inline 2D/3D Laser Scanner

Imaging capability of light-receiving element

The main reason to be aware of the imaging capability of the light-receiving element is because there is no specification that defines such a capability.
This section introduces important factors beyond specifications that should be considered when selecting an inline 2D/3D laser scanner.

Measuring targets with various colors

For 2D/3D laser scanners, an optimal light-receiving element has a wide dynamic range, and is capable of accurately detecting both weak and strong light (without saturation).

[Optimized for dark targets]Laser power is strong, or exposure time is long / [Dark color]Optimum amount of reflected light, [Bright color]Reflected light is too strong and oversaturated

[Optimized for bright targets]Laser power is weak, or exposure time is short / [Dark color]Reflected light is too weak for detection, [Bright color]Optimum amount of reflected light

※Attention:If the received light is saturated, the resulting profile may appear to be correct when zoomed out. However, when zooming in, the profile is not ideal.

Comparison ExampleWelding Inspection of Electronic Components

Measurement with a narrow dynamic range

Reflection from the weld has not been detected correctly.

Measurement with a wide dynamic range

We are able to detect welds correctly.

Comparison ExampleSealant Height and Volume Inspection

Measurement with a narrow dynamic range

Reflection from the curved surface causes inconsistent detection.

Measurement with a wide dynamic range

The slope can also be detected stably.

Capturing targets with detailed shapes

If the imaging capabilities of the CMOS are the same, using a shorter interval for the data will allow the target to be captured in greater detail.

With short data intervals

With long data intervals

However, if the CMOS imaging capability is low—for example, if detection of areas with a low amount of reflected light is difficult—using a shorter data interval will still result in situations like the following.

  • Selection Point A CMOS with advanced imaging capabilities is essential for accurately capturing detailed appearances of fine shapes.
  • Selection Point Use of shorter data intervals is recommended in situations with similar CMOS imaging capabilities.

Actual measurement range

The initial sampling speed is set to 1 kHz in LJ-V7000 Series products.
Using a sampling speed of 8 kHz or more requires a reduced measurement range for a reduction in data processing.
Alternatively, to use at sampling speed of 8 kHz without reducing the measurement range will require data thinning for a reduced data processing amount.

Common Failures A measurement instrument with a data interval of 10 μm was selected to capture detailed shapes more accurately, but use at 8 kHz required data thinning, resulting in the data interval becoming 20 μm.
Although the intention was to use the instrument at 8 kHz, the measurement range became narrow, resulting in the need to use the instrument at 4 kHz.

With the LJ-V7000 Series

No data thinning.
Full measurement range.

～4kHz

No data thinning.
Measurement range: Reduced by half vertically.

～8kHz

Data thinning.
Full measurement range.

～16kHz

Data thinning.
Measurement range: Reduced by half vertically and horizontally.

～64kHz

Speed

For inline applications, the following three aspects are important factors for the sampling speed of the 2D/3D laser scanner.

  • Measurement range
  • CMOS imaging capability /
    Detailed profile measurement
  • Data stability

Measurement range

As described in “2. Actual measurement range”, increasing the speed may result in a narrowed measurement range or data thinning.
Verification of whether the required conditions can be met at the desired sampling speed is required beforehand.

CMOS imaging capability / Detailed profile measurement

As the sampling speed increases, the exposure time per sampling becomes shorter.
Care must be taken when measuring targets with low reflectance, dark targets, or targets with sloped surfaces.

Low-speed sampling At 1 kHz

High-speed sampling At 8 kHz

As with measurement of detailed shapes, use of high-speed sampling carries the risk of detection becoming impossible for some locations.

Low-speed sampling

High-speed sampling

Data stability

As outlined below, filter processing such as averaging is performed with high-speed sampling in order to stabilize the data.
Using a greater number of data filter processes will provide even greater data stability, so it could be said that higher sampling speeds provide greater stability.

Stabilized Measured Values!

  • RESULT OF AVERAGING 3 PROFILES With conventional models, measurement stability was limited due to insufficient sampling speeds necessary to hit the required cycle times.
  • Conventional model
  • RESULT OF AVERAGING 720 PROFILES The LJ-V Series provides significantly higher profile stability by utilizing ultra-high-speed sampling as much as 240x faster than conventional models. This allows for profile averaging, as well as abnormal value elimination using median filters.
  • LJ-V