如何通過opencv中的程序參數定義要素類型？

Question

當前更改的要素類型是通過在代碼中手動更改名稱完成的。例如，對於SURF檢測器和描述符，我有單詞「SURF」更改爲其他名稱下面的代碼示例：

Ptr<SURF> detector = SURF::create(); 
Ptr<SURF> descriptor = SURF::create(); 

有沒有辦法改變「SURF」改變了功能型部分通過程序參數？

我希望能夠批量評估多種功能類型，而不是每次手動鍵入功能類型。

Answer 1

OpenCV 3.x

沒有內置函數。使用Ptr<FeatureDetector>來定義一個檢測器（描述符相當於Ptr<DescriptorExtractor>）。示例代碼如下：

string det = argv[4]; //assuming detector definition is fourth argument 
Ptr<FeatureDetector> detector; 
if (det == "SURF") { 
    detector = SURF::create(); 
} else if (det == "SIFT") { 
    detector = SIFT::create(); 
} 

OpenCV的2.4.x的

使用提供的功能Ptr<FeatureDetector> cv::FeatureDetector::create(const string& detectorType)。欲瞭解更多詳情，請參閱由slawekwin回答。

Answer 2

模板呢？

template<class T> cv::Ptr<T> FeatureDetectorCreator() 
{ 
    return T::create(); 
}; 

那麼你就可以把它叫做：

cv::Ptr<SURF> detector = FeatureDetectorCreator<SURF>(); 

替代可能是一個宏。

只有在所有這些特徵檢測器共用一個通用接口的情況下才有效。

Answer 3

看來你想通過Ptr<FeatureDetector> cv::FeatureDetector::create(const string& detectorType)函數提供的功能：

"FAST" – FastFeatureDetector 
"STAR" – StarFeatureDetector 
"SIFT" – SIFT (nonfree module) 
"SURF" – SURF (nonfree module) 
"ORB" – ORB 
"BRISK" – BRISK 
"MSER" – MSER 
"GFTT" – GoodFeaturesToTrackDetector 
"HARRIS" – GoodFeaturesToTrackDetector with Harris detector enabled 
"Dense" – DenseFeatureDetector 
"SimpleBlob" – SimpleBlobDetector 

Also a combined format is supported: 
    feature detector adapter name ("Grid" – GridAdaptedFeatureDetector, "Pyramid" – PyramidAdaptedFeatureDetector) 
    + feature detector name (see above), for example: "GridFAST", "PyramidSTAR" 

它返回一個指向FeatureDetector基類，這樣你就可以使用多態運行時選擇具體的實現：

//assuming image path is the first command line parameter and detector type is the second parameter 
auto image = cv::imread(argv[1]); 
auto ptr = cv::FeatureDetector::create(argv[2]); //auto evaulates to cv::Ptr<cv::FeatureDetector> here 
std::vector<cv::KeyPoint> keypoints; 
ptr->detect(image, keypoints); 
for (auto kp : keypoints) 
    cv::circle(image, kp.pt, 2, cv::Scalar(0, 255, 255), -1); 
cv::imwrite(argv[1], image);