Defining the LLE Algorithm
The GenICam feature Scan3dExtractionMethod gives access to all available LLE Algorithms.
Figure 13 – Laser Line Extraction options shows how this feature is presented in GenICam Browser.
Figure 13 – Laser Line Extraction options
The choice between the available algorithms depends on a number of factors related to the target application. We highlight here the main differences among the available algorithms.
The number of effective vertical pixels in a ROI (YSize) is limited by the maximum integer value that can be represented by the output format of the chosen algorithm as described below:
MaxDetection_8
(8-bit): 254. The value 255 is reserved to indicate anInvalidDataFlag
.MaxDetection_16
(16-bit): 65534. The value 65535 is reserved to indicate anInvalidDataFlag
.PeakDetection_11_5
(UQ11.5): almost 2048. The value (2048 - 1/32) is reserved to indicate anInvalidDataFlag
.PeakDetection_8_8
(UQ8.8): almost 256. The value (256 - 1/256) is reserved to indicate anInvalidDataFlag
.CenterOfGravity_11_5
(UQ11.5): almost 2048. The value (2048 - 1/32) is reserved to indicate anInvalidDataFlag
.CenterOfGravity_8_8
(UQ8.8): almost 256. The value (256 - 1/256) is reserved to indicate anInvalidDataFlag
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The position resolution of the available algorithms varies from 1 pixel up to 1/256 pixel as described below:
MaxDetection_8
(8-bit): 1 pixel.MaxDetection_16
(16-bit): 1 pixel.PeakDetection_11_5
(UQ11.5): 1/32 pixel.PeakDetection_8_8
(UQ8.8): 1/256 pixel.CenterOfGravity_11_5
(UQ11.5): 1/32 pixel.CenterOfGravity_8_8
(UQ8.8): 1/256 pixel.
As mentioned previously, the choice of an LLE algorithm strongly depends on the target application. Following, a description of the main features of each LLE algorithm from the application point of view:
MaxDetection_8
(8-bit): This version of the MaxDetection module with an 8-bit depth map output generates a very small amount of data which requires less computing performance from the 3D post-processing stage.MaxDetection_16
(16-bit): With its 16-bit integer depth map output, the version of the MaxDetection module can support very large input ROIs.PeakDetection
: The two versions of the PeakDetection module offer a trade-off between sub-pixel resolution and maximum effective ROI size. The PeakDetection was designed to be insensitive to intensity-dependent biases.CenterOfGravity
: The two versions of the CenterOfGravity module also offer a trade-off between sub-pixel resolution and maximum effective ROI size. The CenterOfGravity was designed to be robust to noisy inputs and wide lines.