Images comparaison¶

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 comparaison.

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
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.

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.