Opencv merge gives errors

C++
1

Hi

I am using opencv merge function to merge 3 bands and got following error :
Exception thrown at 0x00007FFD6309441C in project2.exe: Microsoft C++ exception: osgeo::proj::io::FactoryException at memory location 0x00000075F16FC190.

Stackt trace is as follows :slight_smile:
| |opencv_core460d.dll!icv_l9_owniCopy_8u_P3C3R()|Unknown|
| |opencv_core460d.dll!icv_l9_ippiCopy_8u_P3C3R()|Unknown|
| |opencv_core460d.dll!llwiCopyMerge(const void * const * pSrc, int srcStep, void * pDst, int dstStep, IppiSize size, int typeSize, int channels, int partial) Line 160|C|
| |opencv_core460d.dll!cv::ipp_merge(const cv::Mat * mv, cv::Mat & dst, int channels) Line 86|C++|
|>|opencv_core460d.dll!cv::merge(const cv::Mat * mv, unsigned __int64 n, const cv::debug_build_guard::_OutputArray & _dst) Line 144|C++|
| |opencv_core460d.dll!cv::merge(const cv::debug_build_guard::_InputArray & _mv, const cv::debug_build_guard::_OutputArray & _dst) Line 269|C++|
| |project2.exe!main() Line 137|C++|

Eception comes from this line executing :
case 3: return ippiCopy_8u_P3C3R((const Ipp8u**)pSrc, srcStep, (Ipp8u*)pDst, dstStep, size);

What I have to do ?

Regards
Raivo

2

please show, how you call this (code)

3

I use Geotiff and read it to Opencv with GDAL,

// Read the image data using GDAL
std::vectorcv::Mat bands(num_bands);

for (int i = 0; i < num_bands; ++i)
{
    GDALRasterBand* band = dataset->GetRasterBand(i + 1);
    int width = band->GetXSize();
    int height = band->GetYSize();

    GDALDataType data_type = band->GetRasterDataType(); // Get data type of input image

    std::cout << "width = " << width << ", height = " << height << std::endl;
    std::cout << "Input data type: " << GDALGetDataTypeName(data_type) << std::endl;

    std::vector<uint16_t> buffer(width * height);
    band->RasterIO(GF_Read, 0, 0, width, height, &buffer[0], width, height, GDT_UInt16, 0, 0);
    // Create a cv::Mat object from the buffer
    if (data_type == GDT_Byte) {
        bands[i] = Mat(height, width, CV_8UC1, &buffer[0]);
    }
    else if (data_type == GDT_UInt16) {
        bands[i] = Mat(height, width, CV_16UC1, &buffer[0]);
    }
    else if (data_type == GDT_Float32) {
        bands[i] = Mat(height, width, CV_32FC1, &buffer[0]);
    }
    else if (data_type == GDT_Float64) {
        bands[i] = Mat(height, width, CV_64FC1, &buffer[0]);
    }
    else {
        std::cerr << "Unsupported data type: " << GDALGetDataTypeName(data_type) << std::endl;
        return 1;
    }

    std::cout << "Rows: " << bands[i].rows << std::endl;
    std::cout << "Cols: " << bands[i].cols << std::endl;
    std::cout << "Channels: " << bands[i].channels() << std::endl;

    // Print the data type of the image
    std::cout << "Data Type: " << bands[i].type() << std::endl;

    std::cout << "Press any key to continue..." << std::endl;
    getch(); // wait for key press
    std::cout << "Key pressed!" << std::endl;
    
    for (int x = 0; x < 10; x++) {
        for (int y = 0; y < 10; y++) {
            uchar pixel_value = bands[i].at<uchar>(y, x);
            cout << " - (" << x << ", " << y << "): " << (int)pixel_value;
        }
        cout << endl;
    }

    std::cout << "Press any key to continue..." << std::endl;
    getch(); // wait for key press
    std::cout << "Key pressed!" << std::endl;
}

Mat color_image;
vector<Mat> channels{ bands[2],  bands[1],  bands[0] };
merge(channels, color_image);

imshow("Color Image", color_image);
waitKey(0);
4

this Mat has only valid pixels, as long as the buffer object is valid.
(as soon as you leave the ‘for’ loop, those bands will point to invalid (temporary) memory !)

solution: you need to clone() those Mat’s (so it allocates & copies actual pixels):

bands[i] = Mat(height, width, CV_8UC1, &buffer[0]).clone();

also, please make sure, this is a valid access (i+1 ???):

dataset->GetRasterBand(i + 1);
5

I made cahanges into program source, but now is problems with GDAL.
I receive the following error :slight_smile:

Severity Code Description Project File Line Suppression State
Error LNK2001 unresolved external symbol public: virtual class OGRGeometry * __cdecl OGRGeometry::MakeValid(void)const (?MakeValid@OGRGeometry@@UEBAPEAV1@XZ) project2 C:\Users\Raivo\source\Repos\cv46srcDD\project2\Source.obj 1
Openai chat said to me use gdal_i library, but it does not exist in my compure also after I reinstalled GDAL.
Can You help me ?