2次元位相マップのアンラップ

目的

このチュートリアルでは、位相アンラッピングモジュールを使用して2次元の位相マップをアンラップする方法を学ぶ。実装は [161] に基づく。

コード

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#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/phase_unwrapping.hpp>
#include <iostream>
#include <fstream>
#include <stdio.h>
 
 
 
using namespace cv;
using namespace std;
 
static const char* keys =
{
 "{@inputPath | | Path of the wrapped phase map saved in a yaml file }"
 "{@outputUnwrappedName | | Path of the unwrapped phase map to be saved in a yaml file and as an 8 bit png}"
};
 
static void help()
{
    cout << "\nThis example shows how to use the \"Phase unwrapping module\" to unwrap a phase map"
 " saved in a yaml file (see extra_data\\phase_unwrapping\\data\\wrappedpeaks.yml)."
 " The mat name in the file should be \"phaseValue\". The result is saved in a yaml file"
 " too. Two images (wrapped.png and output_name.png) are also created"
 " for visualization purpose."
 "\nTo call: ./example_phase_unwrapping_unwrap <input_path> <output_unwrapped_name> \n"
         << endl;
}
int main(int argc, char **argv)
{
 phase_unwrapping::HistogramPhaseUnwrapping::Params params;
 
 CommandLineParser parser(argc, argv, keys);
 String inputPath = parser.get<String>(0);
 String outputUnwrappedName = parser.get<String>(1);
 
 if( inputPath.empty() || outputUnwrappedName.empty() )
    {
        help();
 return -1;
    }
 FileStorage fsInput(inputPath, FileStorage::READ);
 FileStorage fsOutput(outputUnwrappedName + ".yml", FileStorage::WRITE);
 
 Mat wPhaseMap;
 Mat uPhaseMap;
 Mat reliabilities;
    fsInput["phaseValues"] >> wPhaseMap;
    fsInput.release();
    params.width = wPhaseMap.cols;
    params.height = wPhaseMap.rows;
 
 Ptr<phase_unwrapping::HistogramPhaseUnwrapping> phaseUnwrapping = phase_unwrapping::HistogramPhaseUnwrapping::create(params);
 
    phaseUnwrapping->unwrapPhaseMap(wPhaseMap, uPhaseMap);
    fsOutput << "phaseValues" << uPhaseMap;
    fsOutput.release();
 
    phaseUnwrapping->getInverseReliabilityMap(reliabilities);
 
 Mat uPhaseMap8, wPhaseMap8, reliabilities8;
    wPhaseMap.convertTo(wPhaseMap8, CV_8U, 255, 128);
    uPhaseMap.convertTo(uPhaseMap8, CV_8U, 1, 128);
    reliabilities.convertTo(reliabilities8, CV_8U, 255,128);
 
    imshow("reliabilities", reliabilities);
    imshow("wrapped phase map", wPhaseMap8);
    imshow("unwrapped phase map", uPhaseMap8);
 
    imwrite(outputUnwrappedName + ".png", uPhaseMap8);
    imwrite("reliabilities.png", reliabilities8);
 
 bool loop = true;
 while( loop )
    {
 char key = (char)waitKey(0);
 if( key == 27 )
        {
            loop = false;
        }
    }
 return 0;
}

説明

この例を使用するには、ラップされた位相マップの値を CV_32FC1 の Mat として「phaseValues」という名前でymlファイルに保存しておく必要がある。データへのパスとアンラップされた位相マップを保存する名前は、コマンドラインで設定する必要がある。結果は浮動小数点精度でymlファイルに保存され、可視化のために8ビット画像としても保存される。

いくつかのパラメータはユーザーが選択できる:

• histThresh はヒストグラムを2つの部分に分割するために使用するパラメータである。histThresh より前のビンは、histThresh より後のビンよりも小さい。(デフォルト値は 3*pi*pi)。
• nbrOfSmallBins は 0 から histThresh までのビンの数である。(デフォルト値は 10)。
• nbrOfLargeBins は histThresh から 32*pi*pi までのビンの数である。(デフォルト値は 5)。

phase_unwrapping::HistogramPhaseUnwrapping::Params params;
 
 CommandLineParser parser(argc, argv, keys);
 String inputPath = parser.get<String>(0);
 String outputUnwrappedName = parser.get<String>(1);
 String outputWrappedName = parser.get<String>(2);
 
 if( inputPath.empty() || outputUnwrappedName.empty() )
    {
        help();
 return -1;
    }
 FileStorage fsInput(inputPath, FileStorage::READ);
 FileStorage fsOutput(outputUnwrappedName + ".yml", FileStorage::WRITE);
 
 Mat wPhaseMap;
 Mat uPhaseMap;
 Mat reliabilities;
    fsInput["phaseValues"] >> wPhaseMap;
    fsInput.release();
    params.width = wPhaseMap.cols;
    params.height = wPhaseMap.rows;
 Ptr<phase_unwrapping::HistogramPhaseUnwrapping> phaseUnwrapping = phase_unwrapping::HistogramPhaseUnwrapping::create(params);

ラップされた位相マップがアンラップされ、結果がymlファイルに保存される。可視化のために信頼度マップも取得できる。アンラップされた位相マップと信頼度マップは、pngファイルとして保存するために8ビット画像に変換される。

phaseUnwrapping->unwrapPhaseMap(wPhaseMap, uPhaseMap);
    fsOutput << "phaseValues" << uPhaseMap;
    fsOutput.release();
 
    phaseUnwrapping->getInverseReliabilityMap(reliabilities);
 
 Mat uPhaseMap8, wPhaseMap8, reliabilities8;
    wPhaseMap.convertTo(wPhaseMap8, CV_8U, 255, 128);
    uPhaseMap.convertTo(uPhaseMap8, CV_8U, 1, 128);
    reliabilities.convertTo(reliabilities8, CV_8U, 255,128);
 
    imshow("reliabilities", reliabilities);
    imshow("wrapped phase map", wPhaseMap8);
    imshow("unwrapped phase map", uPhaseMap8);
 
    imwrite(outputUnwrappedName + ".png", uPhaseMap8);
    imwrite("reliabilities.png", reliabilities8);