Outputs
Generalised Power Law Detector
Outputs
The GPL Detector has three outputs, the whitened spectrogram, the level of the detection statistic and detections made by the detector. The first two of these are primarily for diagnostic purposes and are not stored, the detections can be displayed as overlaid on displays and are written to the PAMGuard binary storage.
Binary Store
The GPL detector outputs both detections and background noise information to the binary store.
Both the detections and the background measurements can be read from the binary files into Matlab� and R using the Matlab and R libraries.
Detections
Detailed information for each detection, including the full outline of each detection are written to the binary storage files. This provides a much higher level of detail than is written to the database, so is the preferred storage methods for GPL output.
Background measurements
In order to assist in understanding detector performance, the background level within the GPL detection algorithm is also written to the binary store. If data are being processed in blocks, then this will be once per block, otherwise if data are being processed continuously it will be every 10s.
The stored background data are the spectral levels of the median filter used in the first stage of the detection algorithm. These provide a good measure of how feasible it is to detect sounds at different frequencies within the GPL detection band in varying noise conditions.
Depending on the configuration of the binary store, background measured will either be written to the pgdf files, along with detection data, or to separate pgnf PAMGuard noise files.
Database
Detections can also be written to the PAMGuard database. However, the database records only contain the times and frequency limits of each detection and not the detailed contour information. The binary store is therefore the preferred storage format for GPL output data.