Locates multiple pairs of edges across a given path.
|inImage||Image||Input image to be measured|
|inScanPath||Path||Path along which the scan is performed|
|inScanPathAlignment||CoordinateSystem2D*||Adjusts the scan path to the position of the inspected object|
|inScanWidth||Integer||1 -||Width of the scan field in pixels|
|inImageInterpolation||InterpolationMethod||Interpolation method used in extraction of image pixel values|
|inStripeScanParams||StripeScanParams||Parameters controlling the stripe extraction process|
|inMinGapWidth||Real||0.0 -||Minimal distance between consecutive stripes|
|inMaxGapWidth||Real*||0.0 -||Maximal distance between consecutive stripes|
|inLocalBlindness||LocalBlindness*||Defines conditions in which weaker edges can be detected in the vicinity of stronger edges|
|outGaps||Gap1DArray||Gaps between consecutive stripes|
|outAlignedScanPath||Path||Path along which the scan is performed; in the image coordinate system|
|diagBrightnessProfile||Profile||Extracted image profile|
|diagResponseProfile||Profile||Profile of the edge (derivative) operator response|
|diagSamplingPoints||PathArray||Array of paths each one containing the sampling points that contributed to a single value of the extracted profile|
|diagSamplingStep||Real||Used distance between consecutive sampling points on the scan path|
The operation scans the image along inScanPath and detects consecutive stripes (i.e. pairs of opposite-polarity edges running across the path). Depending on the inStripeScanParams.stripePolarity parameter, dark or bright stripes will be taken into account.
When the number of edge pairs to be measured is known, one can use the ScanExactlyNStripes filter.
The optional parameter inScanPathAlignment defines a transform to be performed on the inScanPath so that the actual scan path (outAlignedScanPath) is adjusted to the position of the object, typically detected by one of Template Matching filters.
Note that in case of a scan path which is closed, the parameters controlling the distances between consecutive found objects do not control the distance between the first and the last of the found objects (counting from the beginning of the scan path).
- Connect an input image to the inImage input.
- Create inScanPath which is more or less perpendicular to the stripes you want to detect. It should be long enough to anticipate all possible stripe locations.
- Define inStripeScanParams.StripePolarity to detect a particular edge type, and only that type.
- Use a local coordinate system connected to inScanPathAlignment to automatically adjust the measurement to variable object position (optional).
- If the noise level is high, try increasing inScanWidth and/or inStripeScanParams.SmoothingStdDev.
- If too few stripes are found, try decreasing inStripeScanParams.MinMagnitude. Verify this with the values on the diagResponseProfile output.
- If consecutive edges are closer than 6 pixels apart, change inStripeScanParams.ProfileInterpolation to Quadratic3.
- Adjust inMinGapWidth (in pixels) to filter out false stripes that appear in proximity to other edges.
- Adjust inStripeScanParams.inMinStripeWidth and inStripeScanParams.inMaxStripeWidth (in pixels) to increase reliability.
For more information about local coordinate systems please refer to the following article.
This filter is a part of the 1D Edge Detection toolset. For a comprehensive introduction to this technique please refer to 1D Edge Detection and 1D Edge Detection - Subpixel Precision chapters of our Machine Vision Guide.
This filter is available on Basic Complexity Level.
This filter is member of ScanStripes filter group.