SOBEL_ED_CVIP

sobel_ed_cvip() - performs sobel edge detection.

SYNTAX
DESCRIPTION
REFERENCE
EXAMPLE
CREDITS

SYNTAX

[ edge_mag, edge_dir ] = sobel_ed_cvip( input_image, kernel_size )

Input Parameters include:

input_image - input image.
Kernel_size - Kernel size.

output Parameters include:

edge_mag - corresponding magnitude image.
edge_dir - corresponding direction image.

DESCRIPTION

This function applies the Sobel edge detection operator with the given kernel_size to the input_image. It approximates the gradient by using a row and a column mask, whick will approximate the first derivative in each direction. So at each pixel point we have two numbers: s1, corresponding to the result from the vertical edge mask, and s2, from the horizontal edge mask. The edge_mag and edge_dir are defined as follows

$edge\,mag = \displaystyle\sqrt{s1^2 + s2^2}$

$edge\,dir = \displaystyle\arctan{\frac{s1}{s2}}$

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');

% Kernel size

  kernel_size = 7;

% Calling function

  [edge_mag, edge_dir] = sobel_ed_cvip(input_image, kernel_size);

% Display input image

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

% Display output image

  figure; imshow(hist_stretch_cvip(edge_mag,0,1,0,0),[]);title('Output Magnitude Image');

  figure; imshow(hist_stretch_cvip(edge_dir,0,1,0,0),[]);title('Output Phase Image');

SOBEL_ED_CVIP

Contents

SYNTAX

DESCRIPTION

REFERENCE

EXAMPLE

CREDITS