FFT_PHASE_CVIP

fft_phase_cvip() - extracts phase of the Fourier spectrum.

SYNTAX
DESCRIPTION
REFERENCE
EXAMPLE
CREDITS

SYNTAX

phase = fft_phase_cvip( input_img, block_size )

Input Parameters include :

input_img - The orignial image which can be grayscale or RGB.

block_size - Should be a power of 2 or [].if empty, then functions finds the nearest power of 2 and zero pad the image, to that block size.Any other value smaller than image size will partiotion the image to windows of that block size and FFT will be calculated separately in each window.

Output Parameters include :

Phase - Phase of the FFT.

DESCRIPTION

The function performs an FFT on the input image of a block size specified by the user and returns only the Phase information of the resultant spectrum.

REFERENCE

1. Scott E Umbaugh. DIGITAL IMAGE PROCESSING AND ANALYSIS: Applications with MATLAB and CVIPtools, 3rd Edition.

EXAMPLE

% Read image

 input_img1 = imread('Car.bmp');

 input_img2 = imread('butterfly.tif');

% Block size

 block_size1 = [];

 block_size2 = 256;

% Call function

 spect1 = fft_phase_cvip( input_img1, block_size1 );

 spect2 = fft_phase_cvip( input_img2, block_size2 );

% use abs to compute the magnitude (handling imaginary) and use log to brighten display

 S1=log(1+abs(spect1));

 S1 = remap_cvip(S1);

 S2=log(1+abs(spect2));

 S2 = remap_cvip(S2);


% Display input image

 figure; imshow(input_img1);title('Input Image1');

 figure;imshow(input_img2);title('Input Image2');

% Display output image

 figure; imshow(S1,[]);title('Output FFT Phase Image1');

 figure;imshow(S2,[]);title('Output FFT Phase Image2');

FFT_PHASE_CVIP

Contents

SYNTAX

DESCRIPTION

REFERENCE

EXAMPLE

CREDITS