HIGHFREQEMPHASIS_CVIP

highfreqemphasis_cvip() - Performs high frequency emphasis filtering.

Contents

SYNTAX

[ out_img ] = highfreqemphasis_cvip (input_img, block_size,cutoff, alfa, order)

Input Parameters include :

output Parameter include:

DESCRIPTION

High frequency emphasis function performs a two-dimensional high frequency emphasis filtering in transform domain on input image. It is implemented by adding a constant to a butterworth high pass filter transfer function. This preserves the low frequency components of the image and at the same time, amplifies the high-frequency components. The result of this process is better tonality in the final image. The cut-off frequency and filter order is for the butter worth high pass filter used in this high frequency emphasis filter. If dc equals to 1, the dc component will be retained else, the dc component will be dropped.

REFERENCE

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

EXAMPLE

% Read image

 input_image =  imread('butterfly.tif');

% block size

 block_size = [];

% Cutoff frequency

 cutoff = 128;

% alfa constant range from 1.0 to 2.0

 Alfa = 1.5;

% filter order range from 1 to 8

 order = 5;

% Call function

 out_img  = highfreqemphasis_cvip (input_image, block_size,cutoff, Alfa,order);

% Display input image

 figure;imshow(input_image);title('Input Image');

% Display output image

 figure;imshow(remap_cvip(out_img,[]));title('output image');

CREDITS

Author: Mehrdad Alvandipour, october 2016
Copyright © 2017-2018 Scott E Umbaugh
For updates visit CVIP Toolbox Website

Published with MATLAB® R2014b