  The particle flow approach to calorimetry benefits from highly granular
calorimeters and sophisticated software algorithms in order to reconstruct and
identify individual particles in complex event topologies. The high spatial
granularity, together with analogue energy information, can be further
exploited in software compensation. In this approach, the local energy density
is used to discriminate electromagnetic and purely hadronic sub-showers within
hadron showers in the detector to improve the energy resolution for single
particles by correcting for the intrinsic non-compensation of the calorimeter
system. This improvement in the single particle energy resolution also results
in a better overall jet energy resolution by improving the energy measurement
of identified neutral hadrons and improvements in the pattern recognition stage
by a more accurate matching of calorimeter energies to tracker measurements.
This paper describes the software compensation technique and its implementation
in particle flow reconstruction with the Pandora Particle Flow Algorithm
(PandoraPFA). The impact of software compensation on the choice of optimal
transverse granularity for the analogue hadronic calorimeter option of the
International Large Detector (ILD) concept is also discussed.
