Simple Optical Character Recognition (OCR) in C++

tarafından **Hello EMO** Ptsi Haz. 27, 2011 4:01 am

[quote name='Flam' timestamp='1296428763' post='287']
I found this snippet lying around my external drive today. I forgot where I got it from, but it's an OCR

It needs devIL, an image library: http://openil.sourceforge.net/about.php

Here's the code, maybe you can learn from it.

Kod:: #include <iostream> #include <vector> #include <IL/il.h> #include <IL/ilu.h> typedef unsigned int uint32; struct pixeldata { ILubyte r; ILubyte g; ILubyte b; pixeldata() : r(0), g(0), b(0) {}; } black; struct coords { uint32 x; uint32 y; coords() : x(0), y(0) {}; }; /* Returns true if given coordinate has a white pixel. */ bool IsWhite(uint32 x, uint32 y) { pixeldata p; ilCopyPixels(x, y, 0, 1, 1, 1, IL_RGB, IL_UNSIGNED_BYTE, &p); if( p.r >= 0xc0 && p.g >= 0xc0 && p.b >= 0xc0) return true; return false; } /* Will find number of whites in all nodes around given coordinate. */ uint32 FriendCount(uint32 x, uint32 y) { uint32 count = 0; if(IsWhite(x-1, y-1)) count++; if(IsWhite(x-1, y-0)) count++; if(IsWhite(x-1, y+1)) count++; if(IsWhite(x+1, y-1)) count++; if(IsWhite(x+1, y-0)) count++; if(IsWhite(x+1, y+1)) count++; if(IsWhite(x+0, y-1)) count++; if(IsWhite(x+0, y+1)) count++; return count; } /* Removes any white pixel with less than 3 neighbouring white nodes. */ void CleanDots(uint32 imWidth, uint32 imHeight) { for(uint32 x = 0; x < imWidth; x++) { for(uint32 y = 0; y < imHeight; y++) { if(IsWhite(x, y) && FriendCount(x, y) <= 2) { ilSetPixels(x, y, 0, 1, 1, 1, IL_RGB, IL_UNSIGNED_BYTE, &black); } } } } /* Cleans up remaining pixels at edges of image. */ void CleanEdges(uint32 imWidth, uint32 imHeight) { for(uint32 x = 0; x < imWidth; x++) { ilSetPixels(x, 0, 0, 1, 1, 1, IL_RGB, IL_UNSIGNED_BYTE, &black); ilSetPixels(x, (imHeight-1), 0, 1, 1, 1, IL_RGB, IL_UNSIGNED_BYTE, &black); } for(uint32 y = 0; y < imHeight; y++) { ilSetPixels(0, y, 0, 1, 1, 1, IL_RGB, IL_UNSIGNED_BYTE, &black); ilSetPixels((imWidth-1), y, 0, 1, 1, 1, IL_RGB, IL_UNSIGNED_BYTE, &black); } } /* Uses the floodfill algorithm to build our coordinate vector. */ void FloodFill(uint32 x, uint32 y, std::vector<coords>& coordinates, uint32& nodecount) { if(!IsWhite(x, y)) return; ilSetPixels(x, y, 0, 1, 1, 1, IL_RGB, IL_UNSIGNED_BYTE, &black); coords coord; coord.x = x; coord.y = y; coordinates.push_back(coord); nodecount++; /* Execute FloodFill for neighbouring nodes. */ FloodFill(x-1, y-1, coordinates, nodecount); FloodFill(x-1, y-0, coordinates, nodecount); FloodFill(x-1, y+1, coordinates, nodecount); FloodFill(x+1, y-1, coordinates, nodecount); FloodFill(x+1, y+0, coordinates, nodecount); FloodFill(x+1, y+1, coordinates, nodecount); FloodFill(x+0, y-1, coordinates, nodecount); FloodFill(x+0, y+1, coordinates, nodecount); } /* Builds our character vector and more. */ void FindLow(uint32 imWidth, uint32 imHeight) { pixeldata white; white.r = 0xff; white.g = 0xff; white.b = 0xff; /* Build our character vector. */ std::vector< std::vector<coords> > characters; for(uint32 x = 0; x < imWidth; x++) { for(uint32 y = 0; y < imHeight; y++) { if(IsWhite(x, y)) { uint32 nodecount = 0; std::vector<coords> coordinates; FloodFill(x, y, coordinates, nodecount); if(nodecount > 30) { characters.push_back(coordinates); } } } } std::vector< std::vector<coords> >::iterator iter; for(iter = characters.begin(); iter != characters.end(); iter++) { std::vector<coords>* character = &*iter; std::vector<coords>::iterator chariter = (*character).begin(); /* find our lowest x and highest y value */ coords corner, bounds; corner.x = imWidth; corner.y = imHeight; for(; chariter != (*character).end(); chariter++) { if(chariter->x < corner.x) corner.x = chariter->x; if(chariter->y < corner.y) corner.y = chariter->y; } /* now position our character to the far bottom left: */ for(chariter = (*character).begin(); chariter != (*character).end(); chariter++) { chariter->x -= corner.x; chariter->y -= corner.y; } } /* Copy back a character to analyze. */ std::vector<coords>* character = &characters.at(5); std::vector<coords>::iterator chariter = (*character).begin(); for(; chariter != (*character).end(); chariter++) { // dump our table printf("%d, %d\n", chariter->x, chariter->y); ilSetPixels(chariter->x, chariter->y, 0, 1, 1, 1, IL_RGB, IL_UNSIGNED_BYTE, &white); } } int main() { /* Initialize DevIL and load our image. */ ilInit(); system("del C:\\out.bmp"); if(!ilLoad(IL_BMP, "C:\\captcha\\test1.bmp")) { printf("Could not load image: %d\n", ilGetError()); std::cin.get(); return 0; } /* Grab some information... */ uint32 imWidth = ilGetInteger(IL_IMAGE_WIDTH); uint32 imHeight = ilGetInteger(IL_IMAGE_HEIGHT); uint32 imPixCnt = imWidth * imHeight * 3; /* Convert raw image data to RGB. */ if(!ilConvertImage(IL_RGB, ilGetInteger(IL_IMAGE_TYPE))) { printf("Could not convert image: %d\n", ilGetError()); std::cin.get(); return 0; } /* Clean up. */ CleanEdges(imWidth, imHeight); CleanDots (imWidth, imHeight); FindLow(imWidth, imHeight); /* Save resulting image. */ if(!ilSave(IL_BMP, "C:\\out.bmp")) { printf("Could not save image: %d\n", ilGetError()); std::cin.get(); return 0; } system("pause"); return 0; }

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