Otsu binarization

module demonstrating the automatic binarization on a grey-level image using Otsu's method More...

module demonstrating the automatic binarization on a grey-level image using Otsu's method

Overview

This application applies Otsu's binarization on a grey-level input image loaded from a given input TIFF file, and saves the result in a given TIFF file.

See also

Otsu binarization algorithm

Usage

The application can be called through a command line as follows:

   <application_exe_filename> [--inputImgFilePath <input_image_file_path>] [--outputImgFilePath <output_image_file_path>]
     
   Arguments:
      --inputImgFilePath  optional; specifies the name of the TIFF file, from
                          which the input image will be loaded; if not 
                          specified by the user, the input image is loaded from
                          file 
                          <DEV_ROOT>/data/Sample/images/Lena_510x509_UInt8.tif
                          
      --outputImgFilePath optional; specifies the name of the TIFF file, in
                          which the output image resulting from the 
                          Otsu's binarization will be saved;
                          if not specified by the user, the output image is 
                          saved in file
                          <TEMPORARY_IPSDK_DIR>/Sample/otsu.tif

Here is a snapshot of default input image used by the application and of corresponding output image when application is launched without any argument:

Source code documentation

We start by importing all necessary libraries:

import os
import sys, getopt
import PyIPSDK
import PyIPSDK.IPSDKIPLBinarization as bin

Then we define the input parameters.

    # retrieve program parameters
    inputImgPath, outputImgPath = readCmdArguments(argv)

We load our input image from the associated Tiff file, by calling the function ipsdk::image::file::loadTiffImageFile.

    # opening of input image
    inImg = PyIPSDK.loadTiffImageFile(inputImgPath)

We then apply the Otsu thresholding calculation on the input image.

    # Otsu threshold computation
    outOtsu = bin.otsuThresholdImg(inImg)

Lastly, we save the image resulting from the operation to the Tiff file.

    # retreive the results from the OtsuResult tuple
    outImg = outOtsu[0]
    outThreshold = outOtsu[1]

    # save generated image and print the estimated threshold
    print("Writing result in file : " + outputImgPath + " (estimated threshold = " + str(outThreshold) + ")")
    PyIPSDK.saveTiffImageFile(outputImgPath, outImg)

See the full source listing