Segmentación de colores con MATLAB

Segmentación de colores con
MATLAB
Dr. Alejandro Aceves
Seminario del Proyecto de
Investigación en robótica Humanoide
Objetivo
• Al finalizar el taller, el participante podrá
analizar imágenes desde MATLAB para
hacer procesos simpes de segmentación
de colores y posterior mente detectar
objetos de colores de una secuencia de
video.
Lista de Material
•
•
•
Una computadora
Una web-cam
MATLAB con Image Adquisition
MATLAB
>> ver
------------------------------------------------------------------------------------MATLAB Version 7.9.0.529 (R2009b)
MATLAB License Number: 161051
Operating System: Microsoft Windows Vista Version 6.1 (Build 7600)
Java VM Version: Java 1.6.0_12-b04 with Sun Microsystems Inc. Java HotSpot(TM) Client VM mixed mode
------------------------------------------------------------------------------------MATLAB
Version 7.9
(R2009b)
Simulink
Version 7.4
(R2009b)
Control System Toolbox
Version 8.4
(R2009b)
Data Acquisition Toolbox
Version 2.15
(R2009b)
Fuzzy Logic Toolbox
Version 2.2.10
(R2009b)
Genetic Algorithm and Direct Search Toolbox
Version 2.4.2
(R2009b)
Image Acquisition Toolbox
Version 3.4
(R2009b)
Image Processing Toolbox
Version 6.4
(R2009b)
Model Predictive Control Toolbox
Version 3.1.1
(R2009b)
Neural Network Toolbox
Version 6.0.3
(R2009b)
Optimization Toolbox
Version 4.3
(R2009b)
Real-Time Windows Target
Version 3.4
(R2009b)
Real-Time Workshop
Version 7.4
(R2009b)
Real-Time Workshop Embedded Coder
Version 5.4
(R2009b)
Robust Control Toolbox
Version 3.4
(R2009b)
Signal Processing Blockset
Version 6.10
(R2009b)
Signal Processing Toolbox
Version 6.12
(R2009b)
Simulink Control Design
Version 3.0
(R2009b)
Spline Toolbox
Version 3.3.7
(R2009b)
Statistics Toolbox
Version 7.2
(R2009b)
Symbolic Math Toolbox
Version 5.3
(R2009b)
System Identification Toolbox
Version 7.3.1
(R2009b)
Video and Image Processing Blockset
Version 2.8
(R2009b)
Drivers
>> info=imaqhwinfo
info =
InstalledAdaptors:
MATLABVersion:
ToolboxName:
ToolboxVersion:
{'coreco' 'winvideo'}
'7.9 (R2009b)'
'Image Acquisition Toolbox'
'3.4 (R2009b)'
Drivers
>> info=imaqhwinfo('winvideo')
info =
AdaptorDllName: [1x81 char]
AdaptorDllVersion: '3.4 (R2009b)'
AdaptorName: 'winvideo'
DeviceIDs: {[1]}
DeviceInfo: [1x1 struct]
Drivers
>> info=imaqhwinfo('winvideo',1)
info =
DefaultFormat: 'YUY2_176x144'
DeviceFileSupported: 0
DeviceName: 'USB 2821 Device'
DeviceID: 1
ObjectConstructor: 'videoinput('winvideo', 1)'
SupportedFormats: {1x8 cell}
Drivers
>> info.SupportedFormats'
ans =
'YUY2_176x144'
'YUY2_352x480'
'YUY2_352x576'
'YUY2_480x480'
'YUY2_480x576'
'YUY2_640x480'
'YUY2_720x480'
'YUY2_720x576'
Variable de VIDEO
>> vid=videoinput('winvideo',1,'YUY2_720x480')
Summary of Video Input Object Using 'USB 2821 Device'.
Acquisition Source(s): composite and svideo are availa
Acquisition Parameters: 'composite' is the current sele
10 frames per trigger using the
'YUY2_720x480' video data to be
Grabbing first of every 1 frame
Log data to 'memory' on trigger
Trigger Parameters: 1 'immediate' trigger(s) on STA
Status: Waiting for START.
0 frames acquired since startin
0 frames available for GETDATA.
Preview
>> preview(vid)
Una Imagen
Imagen obtenida de Image Processing Toolbox For Use with MATLAB User’s guide v2.0, pp 1-8
Espacio de Colores
RGB
YUV
Y - Luminance (brightness)
U (Cb) - Blueness (Blue vs. Green)
V (Cr) - Redness (Red vs. Green)
Imágenes obtenidas de los siguientes sitios:
http://commons.wikimedia.org/wiki/File:Cubo_YUV_con_las_capas_de_color.png
http://i.msdn.microsoft.com/Aa511283.color02%28en-us,MSDN.10%29.png
http://en.wikipedia.org/wiki/Color_space
Espacio de Color
>> vid.VideoResolution
ans =
720
480
>> set(vid,'ReturnedColorSpace','rgb')
Capturar una imagen
>> foto=getsnapshot(vid);
>> figure(1)
>> imshow(foto)
Pixeles
Elegir pixeles de un mismo color
>> pixels=impixel(foto)
pixels =
185
203
204
189
206
200
181
195
197
203
220
214
196
210
210
Pixeles
>> figure(2)
>> plot3(pixels(:,1),pixels(:,2),pixels(:,3),'r*')
>> axis([0 255 0 255 0 255])
Pixeles
>> maxR=max(pixels(:,1))
maxR =
194
>> minR=min(pixels(:,1))
minR =
178
>> maxG=max(pixels(:,2))
maxG =
214
>> minG=min(pixels(:,2))
minG =
192
>> maxB=max(pixels(:,3))
maxB =
209
>> minB=min(pixels(:,3))
minB =
187
Voxel
http://www.mathworks.com/matlabcentral/fileexchange/3280
Voxel
VOXEL function to draw a 3-D voxel in a 3-D plot
Usage:
voxel(start,size,color,alpha);
will draw a voxel at 'start' of size 'size' of color 'color'
and transparency alpha (1 for opaque, 0 for transparent)
Default size is 1
Default color is blue
Default alpha value is 1
start is
size the
color is
(type
a three element vector [x,y,z]
a three element vector [dx,dy,dz]
a character string to specify color
'help plot' to see list of valid colors)
Clases de Colores
voxel([minR minG minB],
[maxR-minR maxG-minG maxB-minB],'b',0.8)
Clasificador de pixeles
Segmentar (Azul)
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foto=getsnapshot(vid);
figure(1); imshow(foto);
pixels=impixel(foto);
minR=min(pixels(:,1));
minG=min(pixels(:,2));
minB=min(pixels(:,3));
maxR=max(pixels(:,1));
maxG=max(pixels(:,2));
maxB=max(pixels(:,3));
segmenta
figure(2); imshow(foto);
Segmentar (Verde)
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foto=getsnapshot(vid);
figure(1); imshow(foto);
pixels=impixel(foto);
minR=min(pixels(:,1));
minG=min(pixels(:,2));
minB=min(pixels(:,3));
maxR=max(pixels(:,1));
maxG=max(pixels(:,2));
maxB=max(pixels(:,3));
segmenta
figure(2); imshow(foto);
Segmentar (Blanco)
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foto=getsnapshot(vid);
figure(1); imshow(foto);
pixels=impixel(foto);
minR=min(pixels(:,1));
minG=min(pixels(:,2));
minB=min(pixels(:,3));
maxR=max(pixels(:,1));
maxG=max(pixels(:,2));
maxB=max(pixels(:,3));
segmenta
figure(2); imshow(foto);
Programa
foto=getsnapshot(vid);
figure(1);
pixels=impixel(foto);
minR=min(pixels(:,1)); minG=min(pixels(:,2)); minB=min(pixels(:,3));
maxR=max(pixels(:,1)); maxG=max(pixels(:,2)); maxB=max(pixels(:,3));
figure(2); axis([0 255 0 255 0 255]);
%voxel([minR minG minB],[maxR-minR maxG-minG maxB-minB],'b',0.8);
%voxel([minR minG minB],[maxR-minR maxG-minG maxB-minB],'g',0.8);
voxel([minR minG minB],[maxR-minR maxG-minG maxB-minB],'w',0.8);
res=vid.VideoResolution;
for x=1:res(2)
for y=1:res(1)
if foto(x,y,1)>= minR && foto(x,y,1)<=maxR && ...
foto(x,y,2)>= minG && foto(x,y,2)<=maxG && ...
foto(x,y,3)>= minB && foto(x,y,3)<=maxB,
%
%
foto(x,y,1)=0; foto(x,y,2)=255; foto(x,y,3)=0;
foto(x,y,1)=0; foto(x,y,2)=0; foto(x,y,3)=255;
foto(x,y,1)=255; foto(x,y,2)=255; foto(x,y,3)=255;
else
foto(x,y,1)=0;
foto(x,y,2)=0;
foto(x,y,3)=0;
end;
end;
end;
figure(3); imshow(foto)
Segmentación por colores
Referencias
[1] Image Processing Toolbox For Use with MATLAB
User’s guide v2.0
[2] VOXEL function to draw a 3-D voxel in a 3-D plot,
Suresh Joel Apr 15,2003, Updated Feb 25, 2004
http://www.mathworks.com/matlabcentral/fileexchange/3
280