Created
December 16, 2016 14:29
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opencv Text Detection in ios
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| + (UIImage*) detectWithImage: (UIImage*) inputImage | |
| { | |
| cv::Mat src = [inputImage CVMat3]; | |
| // Extract channels to be processed individually | |
| std::vector<cv::Mat> channels; | |
| cv::text::computeNMChannels(src, channels); | |
| int cn = (int)channels.size(); | |
| // Append negative channels to detect ER- (bright regions over dark background) | |
| for (int c = 0; c < cn-1; c++) | |
| { | |
| channels.push_back(255-channels[c]); | |
| } | |
| // Create ERFilter objects with the 1st and 2nd stage default classifiers | |
| cv::Ptr<cv::text::ERFilter> er_filter1; | |
| cv::Ptr<cv::text::ERFilter> er_filter2; | |
| NSString* pathIOS = [[NSBundle mainBundle] pathForResource:@"trained_classifierNM1" ofType:@"xml"]; | |
| std::string pathCStr = std::string([pathIOS UTF8String]); | |
| cv::String pathToNM1 = cv::String(pathCStr); | |
| pathIOS = [[NSBundle mainBundle] pathForResource:@"trained_classifierNM2" ofType:@"xml"]; | |
| pathCStr = std::string([pathIOS UTF8String]); | |
| cv::String pathToNM2 = cv::String(pathCStr); | |
| cv::Ptr<cv::text::ERFilter::Callback> callbackNM1 = cv::text::loadClassifierNM1(pathToNM1); | |
| cv::Ptr<cv::text::ERFilter::Callback> callbackNM2 = cv::text::loadClassifierNM2(pathToNM2); | |
| er_filter1 = cv::text::createERFilterNM1(callbackNM1 ,16,0.00025f,0.13f,0.1f,true,0.1f); | |
| er_filter2 = cv::text::createERFilterNM2(callbackNM2,0.5); | |
| // define external regions | |
| std::vector<std::vector<cv::text::ERStat> > regions(channels.size()); | |
| // run 2 pass filters | |
| for (int c=0; c<(int)channels.size(); c++) | |
| { | |
| er_filter1->run(channels[c], regions[c]); | |
| er_filter2->run(channels[c], regions[c]); | |
| } | |
| // Detect character groups | |
| std::vector< std::vector<cv::Vec2i> > region_groups; | |
| std::vector<cv::Rect> groups_boxes; | |
| cv::text::erGrouping_Modes mode = cv::text::ERGROUPING_ORIENTATION_HORIZ; | |
| cv::text::erGrouping(src, channels, regions, region_groups, groups_boxes, mode); | |
| // draw groups | |
| for (int i=(int)groups_boxes.size()-1; i>=0; i--) | |
| { | |
| if (src.type() == CV_8UC3) | |
| cv::rectangle(src,groups_boxes.at(i).tl(),groups_boxes.at(i).br(),cv::Scalar( 0, 255, 255 ), 3, 8 ); | |
| else | |
| cv::rectangle(src,groups_boxes.at(i).tl(),groups_boxes.at(i).br(),cv::Scalar( 255 ), 3, 8 ); | |
| } | |
| // memory clean-up | |
| er_filter1.release(); | |
| er_filter2.release(); | |
| regions.clear(); | |
| if (!groups_boxes.empty()) | |
| { | |
| groups_boxes.clear(); | |
| } | |
| UIImage* result = [UIImage imageWithCVMat:src]; | |
| return result; | |
| } |
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