runlength_features — Characteristic values for runlength coding of regions.
The operator runlength_features calculates for every input region from Regions the number of runs necessary for storing this region with the aid of runlength coding. Furthermore the so-called “K-factor” is determined, which indicates by how much the number of runs differs from the ideal of the square in which this value is 1.0.
The K-factor (KFactor) is calculated according to the formula:
The L-factor (LFactor) indicates the mean number of runs for each line index occurring in the region.
MeanLength indicates the mean length of the runs. The parameter Bytes indicates how many bytes are necessary for coding the region with runlengths.
All features calculated by the operator runlength_features are not rotation invariant because the runlength coding depends on the direction. The operator runlength_features does not serve for calculating shape features but for controlling and analysing the efficiency of the runlength coding.
Regions to be examined.
Number of runs.
Assertion: 0 <= NumRuns
Storing factor in relation to a square.
Assertion: 0 <= KFactor
Mean number of runs per line.
Assertion: 0 <= LFactor
Mean length of runs.
Assertion: 0 <= MeanLength
Number of bytes necessary for coding the region.
Assertion: 0 <= Bytes
The mean runtime complexity is O(1).
The operator runlength_features returns the value 2 (H_MSG_TRUE) if the input is not empty. If necessary an exception is raised.
threshold, regiongrowing, connection