mirror of https://bitbucket.org/ausocean/av.git
74 lines
2.5 KiB
Go
74 lines
2.5 KiB
Go
//go:build !nocv
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// +build !nocv
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/*
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DESCRIPTION
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Provides a function which can extract the transformation matrix.
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AUTHORS
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Russell Stanley <russell@ausocean.org>
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LICENSE
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Copyright (C) 2021-2022 the Australian Ocean Lab (AusOcean)
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It is free software: you can redistribute it and/or modify them
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under the terms of the GNU General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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It is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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in gpl.txt. If not, see http://www.gnu.org/licenses.
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*/
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package turbidity
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import (
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"errors"
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"image"
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"gocv.io/x/gocv"
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)
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// Perspective transformation constants.
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const (
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ransacThreshold = 3.0 // Maximum allowed reprojection error to treat a point pair as an inlier.
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maxIter = 2000 // The maximum number of RANSAC iterations.
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confidence = 0.995 // Confidence level, between 0 and 1.
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)
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// FindTransform, given a template and standard image the perspetive transformation matrix will be determined.
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// the matrix will be returned and logged for use in vidgrind.
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func FindTransform(standardPath, templatePath string, boardSize int) (gocv.Mat, error) {
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mask := gocv.NewMat()
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std := gocv.IMRead(standardPath, gocv.IMReadColor)
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stdCorners := gocv.NewMat()
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template := gocv.IMRead(templatePath, gocv.IMReadGrayScale)
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templateCorners := gocv.NewMat()
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transformMatrix := gocv.NewMat()
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// Validate template image is not empty and has valid corners.
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if template.Empty() {
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return transformMatrix, errors.New("template image is empty")
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}
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if !gocv.FindChessboardCorners(template, image.Pt(boardSize, boardSize), &templateCorners, gocv.CalibCBNormalizeImage) {
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return transformMatrix, errors.New("could not find corners in template image")
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}
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// Validate standard image is not empty and has valid corners.
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if std.Empty() {
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return transformMatrix, errors.New("standard image is empty")
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}
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if !gocv.FindChessboardCorners(std, image.Pt(boardSize, boardSize), &stdCorners, gocv.CalibCBNormalizeImage) {
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return transformMatrix, errors.New("could not find corners in standard image")
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}
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transformMatrix = gocv.FindHomography(stdCorners, &templateCorners, gocv.HomograpyMethodRANSAC, ransacThreshold, &mask, maxIter, confidence)
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return transformMatrix, nil
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}
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