The MultiBlob inherits its main properties from the Blob2 tool. In addition it has a Condition feature that allows the user to classify the state of each polygon as true or false. This is very useful if you need to check the presence of N equal objects in an image. See image below where the separation between two lines is checked with one MultiBlob with two polygons.

Setup

Reference - Reference system selection

Search Area - the tool's region of interest

Polygon definition file - The areas to be searched are initially read from a text file (see the StrVec format). The name of that file is also stored, for possible future reload. The path information, however, is stored directly in the system, without need for the external file. You can browse for or manually edit the filename

• Load - load areas search from file

• Save - save area search to file

• Always read file at startup (overwrite SPB) - With this selection, the file is always loaded at startup.

Polygons

• Vector - list of numbered polygons
• Content - the points of the selected polygon
• New - add polygon
• Delete - remove selected polygon
• Paste new - creates a new polygon, pastes the polygon from the clipboard and presses apply  - this is the quickes way to create many polygons
• Highlight selection - highlights the selected polygon in the image
• Copy - copies the selected polygon to the clipboard
• Paste - pastes the clipboard to the selected polygon - will overwrite an existing polygon

Emphasizing gradients - Activate Sobel-filter to work on a differentiated image

Morphology - Erode (remove) or dilate (add) the found blob area

• Example : e2d2 - erodes two pixel before dilating 2 pixels

Area Search

• Minimum threshold - minimum accepted intensity value
• Maximum threshold - maximum accepted intensity value

- will activate a tool parameter browser.

Note : Minimum and maximum threshold can be linked to a result in another tool - Very often a percentile value from the Intensity Tool

• Threshold as percentiles - minimum and maximum threshold are intensity percentiles from 0 to 100%
• Search outside threshold values - Search outside the intensity limits, not between  
• Smooth factor - smoothes the contour - used to correct the result contour length

Advanced

Constraints

A set of constraints can be specified, limiting the blobs that are found by the tool (result validation). The constraints apply to each blob, and all must be satisfied for a blob to be considered qualified.

• Contour area - Area including any holes
• Blob area - Area excluding any holes
• Holes - Separate holes within a blob. A minimum hole area implies that the blob must have a hole; a maximum area does not.  
• Circularity - Min and max circularity (Contour length / Contour area)  
• Intensity - Min and max intensity

Conditions 

The conditions are used to classify each polygon into PASS - FAIL. This is reflected in the OK Index.

• Blob count - Blob count per polygon. Min/Max number of blobs in polygon.
• Holes - Hole count per blob. Min/Max number of holes per blob.
• Ignored holes - Ignored hole count per blob. Min/Max ignored holes per blob.
• Contrast - The min or max polygon contrast. Contrast measured between percentiles.
• Area - The min and max blob area in polygon
• Coverage (%) - The min and max blob coverage in polygon

Visualisation

Results

ExecuteCmd support (see also executeCmd)

Keyboard shortcuts - More information