CompareImages - 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 Name	Parameter Type
ref	Reference image properties	Group
ref.in	Reference image	Input image
ref.channel	Reference image channel	Int
meas	Measured image properties	Group
meas.in	Measured image	Input image
meas.channel	Measured image channel	Int
roi	Region Of Interest (relative to reference image)	Group
roi.startx	Start X	Int
roi.starty	Start Y	Int
roi.sizex	Size X	Int
roi.sizey	Size Y	Int
mse	MSE	Float
mae	MAE	Float
psnr	PSNR	Float
count	count	Float
ram	Available RAM (Mb)	Int
inxml	Load otb application from xml file	XML input parameters file
outxml	Save otb application to xml 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.