Java tutorial
/* * Copyright (C) 2014 karthik * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package karthik.Barcode; import java.util.Arrays; import java.util.Collections; import org.opencv.core.*; import org.opencv.imgproc.Imgproc; import org.opencv.utils.Converters; /** * * @author karthik */ public class CandidateMatrixBarcode extends CandidateBarcode { private static final Scalar ZERO_SCALAR = new Scalar(0); CandidateMatrixBarcode(ImageInfo img_details, RotatedRect minRect, SearchParameters params) { super(img_details, minRect, params); int adj_factor = params.RECT_HEIGHT / params.PROB_MAT_TILE_SIZE; Point candidateCentre = new Point(minRect.center.x * adj_factor, minRect.center.y * adj_factor); Size candidateSize = new Size(minRect.size.width * adj_factor, minRect.size.height * adj_factor); RotatedRect candidateRect = new RotatedRect(candidateCentre, candidateSize, minRect.angle); this.candidateRegion = candidateRect; } CandidateResult NormalizeCandidateRegion(double angle) { /* candidateRegion is the RotatedRect which contains a candidate region for the barcode // angle is the rotation angle or USE_ROTATED_RECT_ANGLE for this function to // estimate rotation angle from the rect parameter // returns Mat containing cropped area(region of interest) with just the barcode // The barcode region is from the *original* image, not the scaled image // the cropped area is also rotated as necessary to be horizontal or vertical rather than skewed // Some parts of this function are from http://felix.abecassis.me/2011/10/opencv-rotation-deskewing/ // and http://stackoverflow.com/questions/22041699/rotate-an-image-without-cropping-in-opencv-in-c */ double rotation_angle; CandidateResult result = new CandidateResult(); // scale candidate region back up to original size to return cropped part from *original* image // need the 1.0 there to force floating-point arithmetic from int values double scale_factor = img_details.src_original.rows() / (1.0 * img_details.src_grayscale.rows()); // expand the region found - this helps capture the entire code including the border zone candidateRegion.size.width += 2 * params.RECT_WIDTH; candidateRegion.size.height += 2 * params.RECT_HEIGHT; // calculate location of rectangle in original image and its corner points RotatedRect scaledRegion = new RotatedRect(candidateRegion.center, candidateRegion.size, candidateRegion.angle); scaledRegion.center.x = scaledRegion.center.x * scale_factor; scaledRegion.center.y = scaledRegion.center.y * scale_factor; scaledRegion.size.height *= scale_factor; scaledRegion.size.width *= scale_factor; scaledRegion.points(img_details.scaledCorners); // lets get the coordinates of the ROI in the original image and save it result.ROI_coords = Arrays.copyOf(img_details.scaledCorners, 4); // get the bounding rectangle of the ROI by sorting its corner points // we do it manually because RotatedRect can generate corner points outside the Mat area Arrays.sort(img_details.scaledCorners, CandidateBarcode.get_x_comparator()); int leftCol = (int) img_details.scaledCorners[0].x; int rightCol = (int) img_details.scaledCorners[3].x; leftCol = (leftCol < 0) ? 0 : leftCol; rightCol = (rightCol > img_details.src_original.cols() - 1) ? img_details.src_original.cols() - 1 : rightCol; Arrays.sort(img_details.scaledCorners, CandidateBarcode.get_y_comparator()); int topRow = (int) img_details.scaledCorners[0].y; int bottomRow = (int) img_details.scaledCorners[3].y; topRow = (topRow < 0) ? 0 : topRow; bottomRow = (bottomRow > img_details.src_original.rows() - 1) ? img_details.src_original.rows() - 1 : bottomRow; Mat ROI_region = img_details.src_original.submat(topRow, bottomRow, leftCol, rightCol); // create a container that is a square with side = diagonal of ROI. // this is large enough to accommodate the ROI region with rotation without cropping it int orig_rows = bottomRow - topRow; int orig_cols = rightCol - leftCol; int diagonal = (int) Math.sqrt(orig_rows * orig_rows + orig_cols * orig_cols); int newWidth = diagonal + 1; int newHeight = diagonal + 1; int offsetX = (newWidth - orig_cols) / 2; int offsetY = (newHeight - orig_rows) / 2; Mat enlarged_ROI_container = new Mat(newWidth, newHeight, img_details.src_original.type()); enlarged_ROI_container.setTo(ZERO_SCALAR); // copy ROI to centre of container and rotate it ROI_region.copyTo(enlarged_ROI_container.rowRange(offsetY, offsetY + orig_rows).colRange(offsetX, offsetX + orig_cols)); Point enlarged_ROI_container_centre = new Point(enlarged_ROI_container.rows() / 2.0, enlarged_ROI_container.cols() / 2.0); Mat rotated = Mat.zeros(enlarged_ROI_container.size(), enlarged_ROI_container.type()); if (angle == Barcode.USE_ROTATED_RECT_ANGLE) rotation_angle = estimate_barcode_orientation(); else rotation_angle = angle; // perform the affine transformation img_details.rotation_matrix = Imgproc.getRotationMatrix2D(enlarged_ROI_container_centre, rotation_angle, 1.0); img_details.rotation_matrix.convertTo(img_details.rotation_matrix, CvType.CV_32F); // convert type so matrix multip. works properly img_details.newCornerCoord.setTo(ZERO_SCALAR); // convert scaledCorners to contain locations of corners in enlarged_ROI_container Mat img_details.scaledCorners[0] = new Point(offsetX, offsetY); img_details.scaledCorners[1] = new Point(offsetX, offsetY + orig_rows); img_details.scaledCorners[2] = new Point(offsetX + orig_cols, offsetY); img_details.scaledCorners[3] = new Point(offsetX + orig_cols, offsetY + orig_rows); // calculate the new location for each corner point of the rectangle ROI after rotation for (int r = 0; r < 4; r++) { img_details.coord.put(0, 0, img_details.scaledCorners[r].x); img_details.coord.put(1, 0, img_details.scaledCorners[r].y); Core.gemm(img_details.rotation_matrix, img_details.coord, 1, img_details.delta, 0, img_details.newCornerCoord); updatePoint(img_details.newCornerPoints.get(r), img_details.newCornerCoord.get(0, 0)[0], img_details.newCornerCoord.get(1, 0)[0]); } rotated.setTo(ZERO_SCALAR); Imgproc.warpAffine(enlarged_ROI_container, rotated, img_details.rotation_matrix, enlarged_ROI_container.size(), Imgproc.INTER_CUBIC); // sort rectangles points in order by first sorting all 4 points based on x // we then sort the first two based on y and then the next two based on y // this leaves the array in order top-left, bottom-left, top-right, bottom-right Collections.sort(img_details.newCornerPoints, CandidateBarcode.get_x_comparator()); Collections.sort(img_details.newCornerPoints.subList(0, 2), CandidateBarcode.get_y_comparator()); Collections.sort(img_details.newCornerPoints.subList(2, 4), CandidateBarcode.get_y_comparator()); // calc height and width of rectangular region double height = length(img_details.newCornerPoints.get(1), img_details.newCornerPoints.get(0)); double width = length(img_details.newCornerPoints.get(2), img_details.newCornerPoints.get(0)); // create destination points for warpPerspective to map to updatePoint(img_details.transformedPoints.get(0), 0, 0); updatePoint(img_details.transformedPoints.get(1), 0, height); updatePoint(img_details.transformedPoints.get(2), width, 0); updatePoint(img_details.transformedPoints.get(3), width, height); Mat perspectiveTransform = Imgproc.getPerspectiveTransform( Converters.vector_Point2f_to_Mat(img_details.newCornerPoints), Converters.vector_Point2f_to_Mat(img_details.transformedPoints)); Mat perspectiveOut = Mat.zeros((int) height + 2, (int) width + 2, CvType.CV_32F); Imgproc.warpPerspective(rotated, perspectiveOut, perspectiveTransform, perspectiveOut.size(), Imgproc.INTER_CUBIC); result.ROI = perspectiveOut; return result; } private static void updatePoint(Point p, double newX, double newY) { p.x = newX; p.y = newY; } }