runlength_featuresrunlength_featuresRunlengthFeaturesRunlengthFeatures (Operator)


runlength_featuresrunlength_featuresRunlengthFeaturesRunlengthFeatures — Characteristic values for runlength coding of regions.


runlength_features(Regions : : : NumRuns, KFactor, LFactor, MeanLength, Bytes)

Herror runlength_features(const Hobject Regions, Hlong* NumRuns, double* KFactor, double* LFactor, double* MeanLength, Hlong* Bytes)

Herror T_runlength_features(const Hobject Regions, Htuple* NumRuns, Htuple* KFactor, Htuple* LFactor, Htuple* MeanLength, Htuple* Bytes)

void RunlengthFeatures(const HObject& Regions, HTuple* NumRuns, HTuple* KFactor, HTuple* LFactor, HTuple* MeanLength, HTuple* Bytes)

HTuple HRegion::RunlengthFeatures(HTuple* KFactor, HTuple* LFactor, HTuple* MeanLength, HTuple* Bytes) const

Hlong HRegion::RunlengthFeatures(double* KFactor, double* LFactor, double* MeanLength, Hlong* Bytes) const

static void HOperatorSet.RunlengthFeatures(HObject regions, out HTuple numRuns, out HTuple KFactor, out HTuple LFactor, out HTuple meanLength, out HTuple bytes)

HTuple HRegion.RunlengthFeatures(out HTuple KFactor, out HTuple LFactor, out HTuple meanLength, out HTuple bytes)

int HRegion.RunlengthFeatures(out double KFactor, out double LFactor, out double meanLength, out int bytes)


The operator runlength_featuresrunlength_featuresRunlengthFeaturesRunlengthFeaturesRunlengthFeatures calculates for every input region from RegionsRegionsRegionsRegionsregions 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 (KFactorKFactorKFactorKFactorKFactor) 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 (LFactorLFactorLFactorLFactorLFactor) indicates the mean number of runs for each line index occurring in the region.

MeanLengthMeanLengthMeanLengthMeanLengthmeanLength indicates the mean length of the runs. The parameter BytesBytesBytesBytesbytes indicates how many bytes are necessary for coding the region with runlengths.


All features calculated by the operator runlength_featuresrunlength_featuresRunlengthFeaturesRunlengthFeaturesRunlengthFeatures are not rotation invariant because the runlength coding depends on the direction. The operator runlength_featuresrunlength_featuresRunlengthFeaturesRunlengthFeaturesRunlengthFeatures does not serve for calculating shape features but for controlling and analysing the efficiency of the runlength coding.

Execution Information


RegionsRegionsRegionsRegionsregions (input_object)  region(-array) objectHRegionHRegionHobject

Regions to be examined.

NumRunsNumRunsNumRunsNumRunsnumRuns (output_control)  integer(-array) HTupleHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Number of runs.

Assertion: 0 <= NumRuns

KFactorKFactorKFactorKFactorKFactor (output_control)  real(-array) HTupleHTupleHtuple (real) (double) (double) (double)

Storing factor in relation to a square.

Assertion: 0 <= KFactor

LFactorLFactorLFactorLFactorLFactor (output_control)  real(-array) HTupleHTupleHtuple (real) (double) (double) (double)

Mean number of runs per line.

Assertion: 0 <= LFactor

MeanLengthMeanLengthMeanLengthMeanLengthmeanLength (output_control)  real(-array) HTupleHTupleHtuple (real) (double) (double) (double)

Mean length of runs.

Assertion: 0 <= MeanLength

BytesBytesBytesBytesbytes (output_control)  integer(-array) HTupleHTupleHtuple (integer) (int / long) (Hlong) (Hlong)

Number of bytes necessary for coding the region.

Assertion: 0 <= Bytes


The mean runtime complexity is O(1).


The operator runlength_featuresrunlength_featuresRunlengthFeaturesRunlengthFeaturesRunlengthFeatures returns the value 2 (H_MSG_TRUE) if the input is not empty. If necessary an exception is raised.

Possible Predecessors

thresholdthresholdThresholdThresholdThreshold, regiongrowingregiongrowingRegiongrowingRegiongrowingRegiongrowing, connectionconnectionConnectionConnectionConnection

See also