MATLAB VIDEO AND IMAGE PROCESSING BLOCKSET 3 User's Guide download pdf (Page 161)

Feature Extraction

The Edge Detection block convolves the input matrix with the Sobel kernel

to calculate the gradient components of the image that correspond to the

horizontal and vertical edge responses. The block outputs these components

at the Gh and Gv ports, respectively. Then it performs a thresholding

operation on these gradient components to find the binary image, a matrix

filled with 1s an d 0s. The nonzero elements of this matrix correspond to the

edge pixels and the zero elements correspond to the background pixels. The

block outputs the binary i mage at the Edge port.

7 ViewthebinaryimageusingtheVideoViewerblock. Acceptthedefault

parameters.

The matrices output from the G v and G h ports of the Edge Detection block

are composed of double-precision floating-point values. You m ust scale

these matrix values betw ee n 0 in 1 to display them u sing the Video Viewer

blocks.

8 Use the Minimum blocks to find the minimum value of Gv and Gh m atrices.

Set the Mode parameters to

Value.

7-5

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MATLAB VIDEO AND IMAGE PROCESSING BLOCKSET 3 User's Guide Page 161