.. _HooverCompareSegmentation: 

HooverCompareSegmentation
=========================





Compare two segmentations with Hoover metrics

Description
-----------

This application compares a machine segmentation (MS) with a partial ground truth segmentation (GT). The Hoover metrics are used to estimate scores for correct detection, over-segmentation, under-segmentation and missed detection.

The application can output the overall Hoover scores along with coloredimages of the MS and GT segmentation showing the state of each region (correct detection, over-segmentation, under-segmentation, missed).

The legend for the colored images is as follow:

- **white**:   background

- **green**:   correct detection

- **magenta**: over-segmentation

- **cyan**:    under-segmentation

- **red**:     missed detection (only for GT)

The Hoover metrics are described in: Hoover et al., "An experimental comparison of range image segmentation algorithms", IEEE PAMI vol. 18, no. 7, July 1996.

This application has several output images and supports "multi-writing". Instead of computing and writing each image independently, the streamed image blocks are written in a synchronous way for each output. The output images will be computed strip by strip, using the available RAM to compute the strip size, and a user defined streaming mode can be specified using the streaming extended filenames (type, mode and value). Note that multi-writing can be disabled using the multi-write extended filename option: &multiwrite=false, in this case the output images will be written one by one. Note that multi-writing is not supported for MPI writers.

Parameters
----------

.. contents:: :local:

.. |br| raw:: html

   <br />

.. |em| raw:: html

   &emsp;

**Input ground truth** :code:`-ingt image` *Mandatory* |br|
A partial ground truth segmentation image.

**Input machine segmentation** :code:`-inms image` *Mandatory* |br|
A machine segmentation image.

**Background label** :code:`-bg int` *Default value: 0* |br|
Label value of the background in the input segmentations

**Overlapping threshold** :code:`-th float` *Default value: 0.75* |br|
Overlapping threshold used to find Hoover instances.

**Colored ground truth output** :code:`-outgt image [dtype]` |br|
The colored ground truth output image.

**Colored machine segmentation output** :code:`-outms image [dtype]` |br|
The colored machine segmentation output image.

**Correct detection score** :code:`-rc float` *Mandatory* |br|
Overall score for correct detection (RC)

**Over-segmentation score** :code:`-rf float` *Mandatory* |br|
Overall score for over segmentation (RF)

**Under-segmentation score** :code:`-ra float` *Mandatory* |br|
Overall score for under segmentation (RA)

**Missed detection score** :code:`-rm float` *Mandatory* |br|
Overall score for missed detection (RM)



Examples
--------

From the command-line:

.. code-block:: bash

    otbcli_HooverCompareSegmentation -ingt maur_GT.tif -inms maur_labelled.tif -outgt maur_colored_GT.tif uint8


From Python:

.. code-block:: python

	import otbApplication

	app = otbApplication.Registry.CreateApplication("HooverCompareSegmentation")

	app.SetParameterString("ingt", "maur_GT.tif")
	app.SetParameterString("inms", "maur_labelled.tif")
	app.SetParameterString("outgt", "maur_colored_GT.tif")
	app.SetParameterOutputImagePixelType("outgt", 1)

	app.ExecuteAndWriteOutput()





See also
--------

| otbHooverMatrixFilter, otbHooverInstanceFilter, otbLabelMapToAttributeImageFilter