Digital Image Processing - montefiore.ulg.ac.bepiater/Cours/INFO0903/tutorial-Simulink.pdf ·...
29
SIMULINK and Image and Video Processing Blockset prepared by Wei Du 07/2007 Rev. 1.1 by Justus Piater 11/2007 University of Liège
Transcript of Digital Image Processing - montefiore.ulg.ac.bepiater/Cours/INFO0903/tutorial-Simulink.pdf ·...
SIMULINK andImage and Video Processing
Blockset
prepared by Wei Du 07/2007Rev. 1.1 by Justus Piater 11/2007
University of Liège
2of29
Contents
Tired of writing MATLAB code? Let’s try something different: build a system by assembling blocks!
– SIMULINK
– Image and Video Processing (IVP) Blockset
3of29
What is SIMULINK?
A platform for building and simulating models
Integrated with MATLAB and toolboxes
Graphical editing: block diagram– Can drag and drop blocks
Extensive libraries of blocks available
4of29
Structure of SIMULINK Model
A typical SIMULINK model includes sources, systems and sinks.
sources sinks
To disk filesTo display
To Matlab workspace
systems
From disk filesFrom Matlab workspace
Interconnections of blocks
5of29
Model example
system
sourcesink
6of29
Basic element -- Block
A block is an operator in a black box!
Blocks are connected by directed lines, passing along the signals.
block
input signals output signals
>
Input ports
>
Output ports
>>
>
outp
ut o
f oth
er b
locks
input o
f oth
er b
locks
7of29
Basic Blocks
Math operation: sum, product, gain, …
Logic and Bit operations: and, or, …
Signal Routing: Selector, …
Commonly Used Blocks: integrator, delay, data type conversion, …
8of29
Source and Sink Blocks
Source: blocks without input ports– constant, sine function, random, file
loader, …
Sink: blocks without output ports– display, file saver, …
9of29
Signals
Data type - single, double, signed or unsigned 8-, 16-, or 32-bit integers; fixed-point; and Boolean
Dimensions - scalar, vector, or matrix
Watch out: make sure the signal attributes match!
block1> >
>
>
block2>>
>
signals
signalssignals
10of29
How many blocks do we have?
Standard SIMULINK libraries– More than 200 built-in blocks
Blocksets: more than 10– Image and Video Processing– Signal Processing– …
User defined libraries– M-function, S-function
Blockset
Libraries
Blocks
11of29
Build a model step by step
system
sourcesink
12of29
Build a model step by step(1)
Launch SIMULINK and create a new model
– Click SIMULINK button– Type in “simulink” in matlab command
window
13of29
Build a model step by step(2)
Find all the necessary blocks
14of29
Build a model step by step(3)
Connect blocks
15of29
Build a model step by step(4)
Adjust the layout
16of29
Build a model step by step(5)
Change the labels and add annotations
Input Signal
Original Signal
Filtered SignalAmplify
Gain You can add text annotations anywhere you want
17of29
Build a model step by step(5)
Ctrl-T, Run!
Input Signal
Original Signal
Filtered SignalAmplify
Gain You can add text annotations anywhere you want
18of29
More SIMULINK basics
Double-click on a block to open its Dialog Box. Parameters for the block can be set in this box.
Click on the HELP button on the Dialog Box of a block to launch the HELP file for the block.
You can rotate, flip or resize a block. Useful to create a more readable block diagram.
19of29
Subsystems
Select portions of the model using the mouse and turn them into a subsystem.
20of29
A real problem
Given a rectangle box = [r,c,h,w], compute the center mid = [cx,cy] of the rectangle.
c
r
h
w
*
O
[ r, c, h, w ]
*
O
Row
Column X
Ymatrix coordinate image coordinate
cy
cx
21of29
Matlab Implementation
function mid = Box2Center(box)
r = box(1); c = box(2); h = box(3); w = box(4);cy = r+h/2;cx = c+w/2;mid = [cx,cy];return
How to do it with SIMULINK?
22of29
Simulink Implementation(1)
Select elements from a vector.
–r = box(1); c = box(2); h = box(3); w = box(4);
–Selector Block
23of29
Simulink Implementation(2)
Sum and Divide
– cy = r+h/2; cx = c+w/2;
– Sum and Gain/Divide Block
24of29
Simulink Implementation(2)
Combine elements into vector.
– mid = [cx,cy]
– Concatenation Block
25of29
Does it work?
Test: add source and sink.– Constant– Display
26of29
Image and Video Processing(IVP) Blockset
A set of blocks that do image and video processing.
– Access image and video files– Filtering– Morphology– Edge detection– Geometric transform– Text and graphics– …
27of29
A real problem
Convert RGB images to gray-scale.– Source: Image or Video Loader– Sink: Image or Video Viewer– System: Add and Gain blocks
Watch out: data types of signals must match!
28of29
A real problem
Draw rectangles in an image, and plot a marker at the center of each rectangle.
– Source: Image or Video Loader and Constant
– Sink: Image or Video viewer– Box2Center– Text and graphics blocks
29of29
That’s all!
Have fun in the lab! – Get familiar with SIMULINK and IVP
blockset.
