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https://github.com/kerberos-io/openalpr-base.git
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Added new utility for generating character tiles from printed font sheets
This commit is contained in:
Matt Hill
273
src/misc_utilities/binarizefontsheet.cpp
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273
src/misc_utilities/binarizefontsheet.cpp
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/*
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* Copyright (c) 2015 New Designs Unlimited, LLC
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* Opensource Automated License Plate Recognition [http://www.openalpr.com]
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*
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* This file is part of OpenAlpr.
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*
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* OpenAlpr is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License
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* version 3 as published by the Free Software Foundation
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "opencv2/highgui/highgui.hpp"
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#include "opencv2/imgproc/imgproc.hpp"
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#include <iostream>
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#include <fstream>
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#include <sstream>
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#include <stdio.h>
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#include "../tclap/CmdLine.h"
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#include "utility.h"
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#include "support/utf8.h"
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using namespace std;
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using namespace std;
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using namespace cv;
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using namespace alpr;
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// This utility operates on a large image file generated from a TTF font file
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// The font sheet is used to train OCR. The process is:
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// Find the exact ttf font used by the number plates.
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// Generate text with all of the characters that could be on a license plate
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// Print the pages on a piece of paper
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// Take pictures with a digital camera under different lighting conditions to add realistic noise
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// Binarize and process each character with OpenALPR morphology functions to make them look similar to how OpenALPR sees them. Produce a tif file.
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// Produce a box file based on text from #2 and the image from #5.
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// Train OCR with this box/tif data
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// This utility is used before "prepcharsfortraining"
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// Given a series of images (font sheets) and a text file giving the order, it will pluck out each character, binarize it,
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// and output it to a single image file for each character.
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// These characters can later be reassembled into a tif/box file using prepcharsfortraining.
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bool sort_lined_rectangles(Rect i, Rect j) {
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// If they're on different lines
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if (abs(i.y - j.y) > 15)
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{
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return i.y < j.y;
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}
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// They're on the same line, give the left-most.
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return (i.x < j.x);
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}
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void show_debug_image(vector<Rect> rectangles, Mat img)
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{
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Mat debugImg;
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cvtColor(img, debugImg, CV_GRAY2BGR);
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for (unsigned int i = 0; i < rectangles.size(); i++)
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{
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Rect mr = rectangles[i];
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Mat croppedChar = img(mr);
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rectangle(debugImg, mr, Scalar(0,0,255), 2);
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putText(debugImg, toString(i), mr.tl(), FONT_HERSHEY_PLAIN, 1.3, Scalar(0,0,0), 2);
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}
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float new_height = 1000;
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float aspect_ratio = ((float)debugImg.rows) / ((float) new_height);
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float new_width = ((float) debugImg.cols) / aspect_ratio;
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resize(debugImg, debugImg, Size(new_width, new_height));
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drawAndWait(&debugImg);
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}
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int main(int argc, char** argv) {
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const int MIN_RECTANGLE_AREA_PIXELS = 500;
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const int MIN_SPECKLE_AREA_PIXELS = 20;
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const int BLOBBER_EROSION_SIZE=6;
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vector<string> font_sheet_files;
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string char_list_file;
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string out_dir;
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TCLAP::CmdLine cmd("OpenAlpr OCR Training Font Sheet Prep Utility", ' ', "1.0.0");
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TCLAP::UnlabeledMultiArg<std::string> fontSheetArg( "font_sheet", "List of font sheet images", true, "", "font_sheet" );
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TCLAP::ValueArg<std::string> charListArg("","character_file","Text file with the text/order of the individual characters in the font sheets",true, "" ,"character_file");
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TCLAP::ValueArg<std::string> outDirArg("","out_dir","Output directory to put the character images",true, "" ,"output_dir");
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try
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{
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cmd.add( fontSheetArg );
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cmd.add( charListArg );
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cmd.add( outDirArg );
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if (cmd.parse( argc, argv ) == false)
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{
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// Error occured while parsing. Exit now.
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return 1;
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}
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font_sheet_files = fontSheetArg.getValue();
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char_list_file = charListArg.getValue();
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out_dir = outDirArg.getValue();
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}
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catch (TCLAP::ArgException &e) // catch any exceptions
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{
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std::cerr << "error: " << e.error() << " for arg " << e.argId() << std::endl;
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return 1;
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}
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if (DirectoryExists(out_dir.c_str()) == false)
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{
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cout << "Output dir: " << out_dir << " does not exist" << endl;
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return 1;
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}
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if (fileExists(char_list_file.c_str()) == false)
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{
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cout << "Character text file: " << char_list_file << " does not exist" << endl;
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return 1;
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}
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// Verify all the font sheet files exist
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for (unsigned int i = 0; i < font_sheet_files.size(); i++)
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{
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if (fileExists(font_sheet_files[i].c_str()) == false)
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{
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cout << "Font sheet image: " << font_sheet_files[i] << " does not exist." << endl;
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return 1;
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}
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}
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// Read the text content from the character list file
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std::ifstream fs(char_list_file.c_str());
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std::string text_content((std::istreambuf_iterator<char>(fs)),
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std::istreambuf_iterator<char>());
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fs.close();
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for (unsigned int font_sheet_index = 0; font_sheet_index < font_sheet_files.size(); font_sheet_index++)
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{
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cout << "Processing: " << font_sheet_files[font_sheet_index] << endl;
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Mat frame = cv::imread( font_sheet_files[font_sheet_index] );
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Config config("us");
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cvtColor(frame, frame, CV_BGR2GRAY);
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vector<Mat> thresholds = produceThresholds(frame, &config);
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for (unsigned int t = 0; t < thresholds.size(); t++)
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{
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// First clean up any tiny speckles
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Mat speckle_copy(thresholds[t].size(), thresholds[t].type());
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thresholds[t].copyTo(speckle_copy);
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vector<vector<Point> > speckle_contours;
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vector<Vec4i> speckle_hierarchy;
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findContours(speckle_copy, speckle_contours, speckle_hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);
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Mat testImg = Mat::zeros(thresholds[t].size(), thresholds[t].type());
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for (unsigned int i = 0; i < speckle_contours.size(); i++)
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{
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Rect speckleRect = boundingRect(speckle_contours[i]);
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if (speckleRect.area() < MIN_SPECKLE_AREA_PIXELS)
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{
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drawContours(thresholds[t], speckle_contours, i, Scalar(0,0,0), CV_FILLED);
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drawContours(testImg, speckle_contours, i, Scalar(255,255,255), CV_FILLED);
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}
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}
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resize(testImg, testImg, Size(700, 1000));
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drawAndWait(&testImg);
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// Adjust the threshold w/ the morphology operation that OpenALPR uses
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Mat closureElement = getStructuringElement( 1,
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Size( 2 + 1, 2+1 ),
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Point( 1, 1 ) );
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morphologyEx(thresholds[t], thresholds[t], MORPH_CLOSE, closureElement);
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Mat blobby;
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Mat element = getStructuringElement( MORPH_RECT,
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Size( 2*BLOBBER_EROSION_SIZE + 1, 2*BLOBBER_EROSION_SIZE+1 ),
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Point( BLOBBER_EROSION_SIZE, BLOBBER_EROSION_SIZE ) );
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dilate(thresholds[t], blobby, element );
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erode(blobby, blobby, element);
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vector<vector<Point> > contours;
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vector<Vec4i> hierarchy;
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findContours(blobby, contours, hierarchy, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);
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bitwise_not(thresholds[t], thresholds[t]);
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vector<Rect> rectangles;
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for (unsigned int i = 0; i < contours.size(); i++)
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{
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Rect mr = boundingRect(contours[i]);
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if (mr.area() >= MIN_RECTANGLE_AREA_PIXELS)
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rectangles.push_back(mr);
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}
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// sort the rectangles top to bottom left to right
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std::sort(rectangles.begin(), rectangles.end(), sort_lined_rectangles);
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//cout << text_content << endl;
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string::iterator end_it = utf8::find_invalid(text_content.begin(), text_content.end());
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if (end_it != text_content.end()) {
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cout << "Invalid UTF-8 encoding detected " << endl;
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return 1;
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}
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show_debug_image(rectangles, thresholds[t]);
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int text_content_length = utf8::distance(text_content.begin(), text_content.end());
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if (rectangles.size() != text_content_length - 1)
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{
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cout << "Number of blobs (" << rectangles.size() << ") != number of characters (" << text_content_length << ")" << endl;
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cout << "Skipping..." << endl;
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//return 1;
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continue;
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}
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string::iterator utf_iterator = text_content.begin();
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for (unsigned int i = 0; i < rectangles.size(); i++)
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{
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Rect mr = rectangles[i];
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Mat croppedChar = thresholds[t](mr);
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int cp = utf8::next(utf_iterator, text_content.end());
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stringstream ss;
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ss << out_dir << "/" << utf8chr(cp) << "-" << font_sheet_index << "-" << t << "-" << i << ".png";
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imwrite(ss.str(), croppedChar);
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}
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show_debug_image(rectangles, thresholds[t]);
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}
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}
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return 0;
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}
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