runlength_features — Characteristic values for runlength coding of regions.
runlength_features calculates for every input region
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:
wherein Area indicates the area of the region.
It should be noted that the K-factor can be smaller than 1.0
(in case of long horizontal regions).
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.
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.
runlength_features does not serve for calculating shape
features but for controlling and analysing the efficiency of the
Regions to be examined.
Number of runs.
0 <= NumRuns
Storing factor in relation to a square.
0 <= KFactor
Mean number of runs per line.
0 <= LFactor
Mean length of runs.
0 <= MeanLength
Number of bytes necessary for coding the region.
0 <= Bytes
The mean runtime complexity is O(1).
runlength_features returns the value 2 (H_MSG_TRUE)
if the input is not empty.
If necessary an exception is raised.