Getting enum names (e.g. CV_32FC1) of OpenCV image types?

Question

In the C++ interface to OpenCV, it seems easy enough to check the type of an image. If you have an image cv::Mat img = cv::imread("someImage.xyz"), you just do int theType = img.type().

However, as you would expect, calling img.type() just gives an integer, an not an enum name (e.g. CV_32FC1).

Is there an easy way to print out the enum name (e.g. CV_32FC1) if I know the integer value of the OpenCV enum?

Answer 1

To my knowledge, such a function doesn't exist in OpenCV.

I think you would be better off writing your own function to get those. A lot of switch cases but I guess it does the job. The enumeration can be found here.

EDIT:

This is something you could use to extract the types. I am guessing there could be a more efficient method, but I can't wrap my head around it right now.

std::string getImageType(int number) {     // find type     int imgTypeInt = number%8;     std::string imgTypeString;      switch (imgTypeInt)     {         case 0:             imgTypeString = "8U";             break;         case 1:             imgTypeString = "8S";             break;         case 2:             imgTypeString = "16U";             break;         case 3:             imgTypeString = "16S";             break;         case 4:             imgTypeString = "32S";             break;         case 5:             imgTypeString = "32F";             break;         case 6:             imgTypeString = "64F";             break;         default:             break;     }      // find channel     int channel = (number/8) + 1;      std::stringstream type;     type<<"CV_"<<imgTypeString<<"C"<<channel;      return type.str(); } 

Answer 2

Following @Bob's advice, I wrote my own function to solve this problem. Here it is:

// take number image type number (from cv::Mat.type()), get OpenCV's enum string. string getImgType(int imgTypeInt) {     int numImgTypes = 35; // 7 base types, with five channel options each (none or C1, ..., C4)      int enum_ints[] =       {CV_8U,  CV_8UC1,  CV_8UC2,  CV_8UC3,  CV_8UC4,                              CV_8S,  CV_8SC1,  CV_8SC2,  CV_8SC3,  CV_8SC4,                              CV_16U, CV_16UC1, CV_16UC2, CV_16UC3, CV_16UC4,                              CV_16S, CV_16SC1, CV_16SC2, CV_16SC3, CV_16SC4,                              CV_32S, CV_32SC1, CV_32SC2, CV_32SC3, CV_32SC4,                              CV_32F, CV_32FC1, CV_32FC2, CV_32FC3, CV_32FC4,                              CV_64F, CV_64FC1, CV_64FC2, CV_64FC3, CV_64FC4};      string enum_strings[] = {"CV_8U",  "CV_8UC1",  "CV_8UC2",  "CV_8UC3",  "CV_8UC4",                              "CV_8S",  "CV_8SC1",  "CV_8SC2",  "CV_8SC3",  "CV_8SC4",                              "CV_16U", "CV_16UC1", "CV_16UC2", "CV_16UC3", "CV_16UC4",                              "CV_16S", "CV_16SC1", "CV_16SC2", "CV_16SC3", "CV_16SC4",                              "CV_32S", "CV_32SC1", "CV_32SC2", "CV_32SC3", "CV_32SC4",                              "CV_32F", "CV_32FC1", "CV_32FC2", "CV_32FC3", "CV_32FC4",                              "CV_64F", "CV_64FC1", "CV_64FC2", "CV_64FC3", "CV_64FC4"};      for(int i=0; i<numImgTypes; i++)     {         if(imgTypeInt == enum_ints[i]) return enum_strings[i];     }     return "unknown image type"; } 

Did I forget to include any OpenCV image types in my lookup table?