Detect and replace the red pixels

General Discussion Other

lukashoppe

Detect and replace the red pixels

in General Discussion • Other • 6 months ago

Hello, all my own attempts of writing a program that detects the most reddish pixels, have failed. What the code is supposed to do is to detect the brightest reddish pixels in a picture and then save the picture with these pixels in a different color.

excuse my english, i am a german.

Replies(3)

Chrisir

Re: Detect and replace the red pixels

6 months ago

did you read
http://processing.org/learning/pixels/

and

the section Image Processing
http://processing.org/learning/topics/

It could be wise to post the code you have and mark the critical parts bold and we have a look

asimes

Re: Detect and replace the red pixels

6 months ago

I'm not sure how you are defining whether a pixel is too red or not, so I just assumed that the condition would be that (red >= green && red >= blue). This sketch produces a new array of random pixel values by pressing 'n' and removes the red pixels by pressing 'r'

void setup() {
size(400, 400, P2D);
loadPixels();
randomPixels();
}
void draw() {
}
void keyPressed() {
if (key == 'n' || key == 'N') randomPixels();
if (key == 'r' || key == 'R') {
for (int i = 0; i < width*height; i++) {
int red = (0xff0000&pixels[i])>>16; // Get red
int green = (0xff00&pixels[i])>>8; // Get green
int blue = 0xff&pixels[i]; // Get blue
if (red >= green && red >= blue) pixels[i] = 0;
}
updatePixels();
}
}
void randomPixels() {
for (int i = 0; i < width*height; i++) {
pixels[i] = 0xff000000; // Alpha
pixels[i] |= (int)random(255)<<16; // Red
pixels[i] |= (int)random(255)<<8; // Green
pixels[i] |= (int)random(255); // Blue
}
updatePixels();
}

lukashoppe

Re: Re: Detect and replace the red pixels

6 months ago

Thank you verry much, that works perfectly.

Top Reply