5,710
edits
Changes
no edit summary
This course covers topics in computer vision, procedural/generative video, high-resolution video, and media presentation through the use of computational tools. It is also a programming course.
== histogram / auto-contrast ==
processing code
<pre>
PImage b, c;
int x,y,n,w;
int win_width;
int win_height;
int y_corner;
// parameters of auto-contrast window
int ac_center=50;
int ac_width=200;
void setup() {
size(screen.width, screen.height);//, 800);
//size(1200, 900);
//b=loadImage("01_06_western landscape.jpg");
//b=loadImage("/home/robert/Desktop/Photos/03_washington dc bedroom 2.jpg");
//b=loadImage("C:\\Swap\\Photos\\03_washington dc bedroom 2.jpg");
b=loadImage("C:\\Swap\\Photos\\01_06_western landscape.jpg");
win_height=int(b.height*0.4);
win_width=int(b.width*0.4);//win_height/height*width);
y_corner=0;//int((b.height-win_height)/2);
//noLoop();
x=0;
y=0;
w=0;
n=0;
frameRate(24);
}
void auto_contrast(PImage in) {
// adjust contrast in place on input image
in.loadPixels();
// loop over pixels to find min and max Intensity
int dimension = (in.width*in.height);
int [] hist = new int[256];
for(int i=0;i<dimension;i++) {
color argb=in.pixels[i];
int bin_a = argb & 0xFF000000;
int r = (argb >> 16) & 0xFF; // Faster way of getting red(rgb)
int g = (argb >> 8) & 0xFF; // Faster way of getting green(rgb)
int b = argb & 0xFF; // Faster way of getting blue(rgb)
int intensity=int((r+g+b)/3);
hist[intensity]++;
};
int i_min=0;
int sum=0;
while(sum<4) {
i_min++;
sum+=hist[i_min];
};
int i_max=256;
sum=0;
while(sum<4) {
i_max--;
sum+=hist[i_max];
};
// loop over pixels to scale RGB to min and max Intensity
for(int i=0;i<dimension;i++) {
color argb=in.pixels[i];
//int a = (argb >> 24) & 0xFF;
int bin_a = argb & 0xFF000000;
int r = (argb >> 16) & 0xFF; // Faster way of getting red(rgb)
int g = (argb >> 8) & 0xFF; // Faster way of getting green(rgb)
int b = argb & 0xFF; // Faster way of getting blue(rgb)
// int ac_min=constrain(ac_center-(ac_width>>1), 0, 255);
// int ac_max=constrain(ac_center+(ac_width>>1), 0, 255);
// r=int(constrain(map(r, ac_min, ac_max, 0, 255), 0, 255));
// g=int(constrain(map(g, ac_min, ac_max, 0, 255), 0, 255));
// b=int(constrain(map(b, ac_min, ac_max, 0, 255), 0, 255));
r=int(constrain(map(r, i_min, i_max, 0, 255), 0, 255));
g=int(constrain(map(g, i_min, i_max, 0, 255), 0, 255));
b=int(constrain(map(b, i_min, i_max, 0, 255), 0, 255));
//a = a << 24;
r = r << 16;
g = g << 8;
b = b;
color new_rgb = bin_a | r | g | b;
in.pixels[i]= new_rgb;
};
in.updatePixels();
};
void draw() {
c = b.get(x, y+y_corner, win_width, win_height);
auto_contrast(c);
blend(c, 0, 0, win_width, win_height, 0, 0, width, height, BLEND);
//blend(b, x, y+y_corner, (win_width), (win_height), 0, 0, width, height, BLEND);
//filter(ERODE);
//saveFrame("/Volumes/Swimming Pool/Processing/west-#####.tif");
saveFrame("C:\\Data\\01_06_western landscape/01_06_western landscape-#####.tif");
//println(x+":"+b.width+" "+y+":"+b.height);
// update motion
n++;
x+=int(random(0, 5));
if(x+win_width>b.width) exit();
y=int(random(0,10));
w=int(random(-5,0));
}
void mouseMoved() {
ac_center = int(255.0*float(mouseX)/float(width));
ac_width= int(255.0*float(mouseY)/float(height));
}
</pre>
