Set the Data Acquisition Distance
The accuracy and imaging performance of a camera are affected by the data acquisition distance, i.e., the distance between the camera and the target object. When using a camera for projects such as object picking and point cloud stitching, this distance should be appropriately set according to the requirements for data quality.
Key Concepts
This section introduces three core concepts: accuracy, imaging performance, and distance.
Accuracy
Camera accuracy includes two dimensions: absolute accuracy and repeatability.
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Absolute accuracy
Also known as measurement accuracy (VDI/VDE), it refers to how closely the measured values match the true values.
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Repeatability
Refers to the consistency of results when the camera repeatedly measures the same object under the same conditions.
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Imaging Performance
Imaging performance is evaluated based on texture image clarity and point cloud quality. Point cloud quality is influenced by the camera’s resistance to ambient light.
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Texture image clarity
Refers to the sharpness and clarity of the image as perceived by the human eye.
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Point cloud quality
Point cloud quality includes three aspects: completeness, fidelity, and spatial resolution. Completeness and fidelity of the point cloud are affected by the camera’s resistance to ambient light.
Spatial resolution indicates how many points are captured within a unit volume. Higher spatial resolution means more detail is captured in that area.
For spatial resolution specifications for each model, see the Spatial Resolution section of the Technical Specifications.
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Resistance to ambient light
Ambient light affects the signal-to-noise ratio (SNR) in the acquired data. When ambient light is constant, a shorter distance between the object and the camera means a stronger SNR, which improves resistance to ambient light.
Distance
Distance refers to the spacing between the camera and the object during data acquisition. It includes the working distance, recommended working distance, and object focal distance.
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Object focal distance
At this distance, the camera achieves optimal absolute accuracy, point cloud quality, and texture clarity.
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Recommended working distance
Within this range, the camera delivers high absolute accuracy and point cloud quality.
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Working distance
This is the usable range where the camera can meet general accuracy and point cloud quality requirements.
| For distance specifications for each model, see the Performance Parameters section of the Technical Specifications. |
Set Proper Distance Based on Requirements for Accuracy and Image Performance
Under the same environmental conditions, a camera’s accuracy and image performance vary depending on whether data is acquired at the working distance, recommended working distance, or object focal distance. When a project has specific requirements for accuracy or imaging performance, the suggested distances are summarized below:
| Project Requirements | Distance |
|---|---|
High absolute accuracy |
It is advisable to acquire data within the recommended working distance. Positioning the target object closer to the object focal distance ensures better data absolute accuracy. |
High repeatability |
It is advisable to acquire data within the working distance. Within this range, positioning the target object closer to the camera ensures better repeatability. |
High spatial resolution |
It is advisable to acquire data within the working distance. Within this range, positioning the target object closer to the camera ensures higher spatial resolution, but the field of view becomes smaller. |
High texture image clarity |
UHP-140-GL and PRO XS-GL: It is advisable to acquire data at the object focal distance. |
Models other than UHP-140-GL and PRO XS-GL: It is advisable to acquire data within the working distance. |
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High ambient light resistance |
It is advisable to acquire data within the working distance. Within this range, positioning the target object closer to the camera ensures higher resistance to ambient light. |
Set Proper Distance Based on Project Type
Data quality requirements vary depending on the project type. Recommended distances based on project characteristics are listed below:
| Project | Characteristics | Distance |
|---|---|---|
Random picking |
Moderate requirement for absolute accuracy, but high requirement for imaging performance. |
It is advisable to acquire data within the recommended working distance, keeping the target object as close to the camera as possible. |
Point cloud stitching |
High requirement for accuracy. |
It is advisable to acquire data within the recommended working distance, keeping the target object as close to the camera as possible. |
Dimension measurement |
High requirement for absolute accuracy. |
It is advisable to acquire data within the recommended working distance, keeping the target object as close to the object focal distance as possible. |
Defect inspection |
Very high requirement for absolute accuracy and point cloud quality. |
It is advisable to use a camera with a short working distance and small field of view, and acquire data at the object focal distance. |