Images comparison

Estimator between 2 images.

Detailed description

This application computes MSE (Mean Squared Error), MAE (Mean Absolute Error) and PSNR (Peak Signal to Noise Ratio) between the channel of two images (reference and measurement). The user has to set the used channel and can specify a ROI.

Parameters

This section describes in details the parameters available for this application. Table [1] presents a summary of these parameters and the parameters keys to be used in command-line and programming languages. Application key is CompareImages .

[1]Table: Parameters table for Images comparison.
Parameter Key Parameter Type Parameter Description
ref Group Group
ref.in Input image Input image
ref.channel Int Int
meas Group Group
meas.in Input image Input image
meas.channel Int Int
roi Group Group
roi.startx Int Int
roi.starty Int Int
roi.sizex Int Int
roi.sizey Int Int
mse Float Float
mae Float Float
psnr Float Float
count Float Float
ram Int Int
inxml XML input parameters file XML input parameters file
outxml XML output parameters file XML output parameters file

[Reference image properties]

  • Reference image: Image used as reference in the comparison.
  • Reference image channel: Used channel for the reference image.

[Measured image properties]

  • Measured image: Image used as measured in the comparison.
  • Measured image channel: Used channel for the measured image.

[Region Of Interest (relative to reference image)]

  • Start X: ROI start x position.
  • Start Y: ROI start y position.
  • Size X: Size along x in pixels.
  • Size Y: Size along y in pixels.

MSE: Mean Squared Error value.

MAE: Mean Absolute Error value.

PSNR: Peak Signal to Noise Ratio value.

count: Nb of pixels which are different.

Available RAM (Mb): Available memory for processing (in MB).

Load otb application from xml file: Load otb application from xml file.

Save otb application to xml file: Save otb application to xml file.

Example

To run this example in command-line, use the following:

otbcli_CompareImages -ref.in GomaApres.png -ref.channel 1 -meas.in GomaAvant.png -meas.channel 2 -roi.startx 20 -roi.starty 30 -roi.sizex 150 -roi.sizey 200

To run this example from Python, use the following code snippet:

#!/usr/bin/python

# Import the otb applications package
import otbApplication

# The following line creates an instance of the CompareImages application
CompareImages = otbApplication.Registry.CreateApplication("CompareImages")

# The following lines set all the application parameters:
CompareImages.SetParameterString("ref.in", "GomaApres.png")

CompareImages.SetParameterInt("ref.channel", 1)

CompareImages.SetParameterString("meas.in", "GomaAvant.png")

CompareImages.SetParameterInt("meas.channel", 2)

CompareImages.SetParameterInt("roi.startx", 20)

CompareImages.SetParameterInt("roi.starty", 30)

CompareImages.SetParameterInt("roi.sizex", 150)

CompareImages.SetParameterInt("roi.sizey", 200)

# The following line execute the application
CompareImages.ExecuteAndWriteOutput()

Limitations

None

Authors

This application has been written by OTB-Team.

See Also

These additional resources can be useful for further information:

BandMath application, ImageStatistics