I just came back from the official opening of the ‘We All Live in the Forbidden City’ exhibition in ArtisTree, Quarry Bay.
Here are some video documentation of the augmented reality display we have done for the exhibition.
This happened tonight
The presentation powerpoint.
This happened
View more presentations from Bryan Chung.
Context Free Art – Tutorial 9
These exercises take a closer look at the colour information, hue, saturation and brightness.
startshape Bryan
path Line {
MOVETO {x 0 y -9}
LINETO {x 0 y 9}
STROKE {sat 1 b 1}
}
rule Bryan {
360 * {x 0.05 h 1} Line {}
}
startshape Bryan
path Line {
MOVETO {x 0 y -9}
LINETO {x 0 y 9}
STROKE {h 200 sat 0 b 1}
}
rule Bryan {
400 * {x 0.05 sat 0.003} Line {}
}
startshape Bryan
path Line {
MOVETO {x 0 y -9}
LINETO {x 0 y 9}
STROKE {h 0 sat 1 b 0}
}
rule Bryan {
400 * {x 0.05 b 0.003} Line {}
}
startshape MyShape
rule MyLine {
TRIANGLE {s 0.016 1 sat 1 b 1}
}
rule MyShape {
360 * {r 1 h 1} MyLine {y -0.60}
}
OpenCV people detection (v.2)
Here is an enhanced version of the OpenCV people detection demo program using the sample.
Context Free Art – Tutorial 8
By using the same square, we further experiment with the various options in the STROKE command.
STROKE {p miterjoin}
STROKE {p roundjoin}
STROKE {p beveljoin}
startshape MyShape
path Shape1 {
MOVETO {x -0.5 y -0.5}
LINETO {x 0.5 y -0.5}
LINETO {x 0.5 y 0.5}
STROKE {p buttcap}
}
path Shape2 {
MOVETO {x -0.5 y -0.5}
LINETO {x 0.5 y -0.5}
LINETO {x 0.5 y 0.5}
STROKE {p roundcap}
}
path Shape3 {
MOVETO {x -0.5 y -0.5}
LINETO {x 0.5 y -0.5}
LINETO {x 0.5 y 0.5}
STROKE {p squarecap}
}
rule MyShape {
Shape1 {x -1.5}
Shape2 {x 0}
Shape3 {x 1.5}
}
Context Free Art – Tutorial 7
We continue the study of path command. Take a look of the closed shape, a square.
startshape MyShape
path Line {
MOVETO {x -0.5 y -0.5}
LINETO {x 0.5 y -0.5}
LINETO {x 0.5 y 0.5}
LINETO {x -0.5 y 0.5}
LINETO {x -0.5 y -0.5}
CLOSEPOLY {}
STROKE {}
}
rule MyShape {
Line {}
}
If by any chances, you type the wrong position for the last end point or there is rounding error after a sequence of calculation, you may end of with:
startshape MyShape
path Line {
MOVETO {x -0.5 y -0.5}
LINETO {x 0.5 y -0.5}
LINETO {x 0.5 y 0.5}
LINETO {x -0.5 y 0.5}
LINETO {x -0.45 y -0.45}
CLOSEPOLY {}
STROKE {}
}
rule MyShape {
Line {}
}
Note the CLOSEPOLY command will connect an extra line segment to close the shape if there is a gap between the beginning and the end points. In case we want to get rid of the error, we can use the CLOSEPOLY command with an extra parameter align.
startshape MyShape
path Line {
MOVETO {x -0.5 y -0.5}
LINETO {x 0.5 y -0.5}
LINETO {x 0.5 y 0.5}
LINETO {x -0.5 y 0.5}
LINETO {x -0.45 y -0.45}
CLOSEPOLY {p align}
STROKE {}
}
rule MyShape {
Line {}
}
OpenCV C++ usage
I start using the C++ interface for OpenCV, instead of the old highgui C functions. Here is an example to do real time video capture from the default webcam.
#include "stdafx.h"
#include "cv.h"
#include "highgui.h"
using namespace cv;
int main(int, char**)
{
VideoCapture cap(0);
cap.set(CV_CAP_PROP_FRAME_WIDTH, 640);
cap.set(CV_CAP_PROP_FRAME_HEIGHT, 480);
if (!cap.isOpened())
return -1;
namedWindow("camera",CV_WINDOW_AUTOSIZE);
while (true)
{
Mat frame;
cap >> frame;
imshow("camera", frame);
if (waitKey(10) >= 0)
break;
}
return 0;
}
Context Free Art – Tutorial 6
Today we start to think recursively. The following example uses a simple recursive definition of a SQUARE. In Context Free Art, we may not need to specify a stop condition when each iteration reduces its size, until eventually, the shape is too small to display.
startshape Shape1
rule Shape3 {
SQUARE {a -0.9}
Shape3 {s 0.9 r 7}
}
rule Shape2 {
4 * {x 1} Shape3 {r 45}
}
rule Shape1 {
4 * {y 1} Shape2 {}
}
Context Free Art – Tutorial 5
Take a look of this example and see how it can be done with FILL command and the colour adjustments.
Context Free Art – Tutorial 4
The following examples illustrate the use of repetition in Context Free Art.
startshape MyShape
path Line1 {
MOVETO {x 0 y 0}
LINETO {x 1 y 0}
STROKE {width .01}
}
rule MyShape {
36 * {r 10} Line1 {}
}
startshape MyShape
path Line1 {
MOVETO {x 0 y 0}
LINETO {x 1 y 0}
STROKE {width .01}
}
rule MyShape {
36 * {r 10 x 0.03} Line1 {}
}
