Image Recongition / processing help

[lief480]

Hello, alright so what I am trying to accomplish is the ability to pull a certain shape or line or picture out of another photo. Say you took notes on something and drew a triangle, I want to be able to pull just the triangle out of the picture. The background will always be white, but will sometimes have the blue lines like on paper. Any ideas on api's or anything I could use is appreciated.
Thank you,
Lief480

[buffalo]

You might consider using the Hough transform (ht) to detect shapes composed of straight-line segments (e.g. a triangle). The ht is applied to a two-valued image (e.g. black and white, no gray values), which could be obtained from a continuous-tone image by thresholding. Basically a large family of lines is constructed described by a discrete range of angles and distances. A histogram is formed tabulating the count of the number of image points through which each such line closely passes. Lines with high counts are assumed to appear in the image. A shape is detected if it conforms to a number of detected lines along its boundary.
More specific information can be found at Hough transform - Wikipedia, the free encyclopedia

In Java, images may be processed by storing them in a BufferedImage class, declared as:

BufferedImage image= new BufferedImage(width,height,BufferedImage.TYPE_INT_ ARGB);

Individual pixels can then be accessed by:

int p=image.getRGB(x,y);

where x ranges from 0 to width-1 and y from 0 to height-1