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Index › Programming Questions & Help › Programs › How can I downscale an image without drawing it
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How can I downscale an image without drawing it (Read 828 times)
itsme
How can I downscale an image without drawing it
Jan 26th, 2008, 2:47pm  
Hello there.

I´m trying the following:
I´ve got an image from an online-webcam that shoult be analysed to do some brightness tracking for detecting motion.
I don´t want to draw the image itself on the screen. Therefore I analyse the picture in the background, by cutting out the relevant part of it:
.
.
imgSource = loadImage(urlSource);
PImage imagepart = imgSource.get (20,20,300,200);
imagepart.loadPixels();
.
.

Then I do the tracking...

The problem is, that I want to do this with a bunch of different cams and the program can´t handle it anymore. What I thought to do was downscaling the images and then analyse those smaller images, so the program can handle it again.
But I simply don´t know how/where I should tell processing to downscale them. The only way I know by now to get smaller images is to take a smaller part of the source image. But that´s not what I want...

Hopefully someone can help me and hopefully my question is not too stupid ;-)

Thank you...
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michael05
Re: How can I downscale an image without drawing i
Reply #1 - Jan 26th, 2008, 3:17pm  
blobdetection has a good example for downscaling images:
http://www.v3ga.net/processing/BlobDetection/index-page-examples.html

short:
Code:

size(640,480);
PImage cam = loadImage("http://webcam.kurfuerstendamm.de/record/current.jpg");
PImage img = new PImage(320, 240);
img.copy(cam, 0, 0, cam.width, cam.height, 0, 0, img.width, img.height);

image(cam, 0, 0, width, height);
filter(GRAY);
image(img, width/2, height/2);


that should be mentioned in the reference.

greetings

michael
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