freeImageTocvMat&1channelTo3channes - freeimage转到cvmat & 单通道图像转到3通道

0 结果

https://cdn.jsdelivr.net/gh/xychen5/blogImgs@main/imgs/freeImg2cvMat.7hbdeyhx4n80.PNG

1 代码

将freeImage转为cv::mat,代码如下:

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#include <FreeImage.h>
#include <opencv2\opencv.hpp>
using namespace cv;

// #define _CRT_SECURE_NO_WARNINGS
#pragma warning(disable : 4996)
void FI2MAT(FIBITMAP* src, Mat& dst)
{
//FIT_BITMAP //standard image : 1 - , 4 - , 8 - , 16 - , 24 - , 32 - bit
//FIT_UINT16 //array of unsigned short : unsigned 16 - bit
//FIT_INT16 //array of short : signed 16 - bit
//FIT_UINT32 //array of unsigned long : unsigned 32 - bit
//FIT_INT32 //array of long : signed 32 - bit
//FIT_FLOAT //array of float : 32 - bit IEEE floating point
//FIT_DOUBLE //array of double : 64 - bit IEEE floating point
//FIT_COMPLEX //array of FICOMPLEX : 2 x 64 - bit IEEE floating point
//FIT_RGB16 //48 - bit RGB image : 3 x 16 - bit
//FIT_RGBA16 //64 - bit RGBA image : 4 x 16 - bit
//FIT_RGBF //96 - bit RGB float image : 3 x 32 - bit IEEE floating point
//FIT_RGBAF //128 - bit RGBA float image : 4 x 32 - bit IEEE floating point

int bpp = FreeImage_GetBPP(src);
FREE_IMAGE_TYPE fit = FreeImage_GetImageType(src);

int cv_type = -1;
int cv_cvt = -1;

switch (fit)
{
case FIT_UINT16: cv_type = DataType<ushort>::type; break;
case FIT_INT16: cv_type = DataType<short>::type; break;
case FIT_UINT32: cv_type = DataType<unsigned>::type; break;
case FIT_INT32: cv_type = DataType<int>::type; break;
case FIT_FLOAT: cv_type = DataType<float>::type; break;
case FIT_DOUBLE: cv_type = DataType<double>::type; break;
case FIT_COMPLEX: cv_type = DataType<Complex<double>>::type; break;
case FIT_RGB16: cv_type = DataType<Vec<ushort, 3>>::type; cv_cvt = COLOR_RGB2BGR; break;
case FIT_RGBA16: cv_type = DataType<Vec<ushort, 4>>::type; cv_cvt = COLOR_RGBA2BGRA; break;
case FIT_RGBF: cv_type = DataType<Vec<float, 3>>::type; cv_cvt = COLOR_RGB2BGR; break;
case FIT_RGBAF: cv_type = DataType<Vec<float, 4>>::type; cv_cvt = COLOR_RGBA2BGRA; break;
case FIT_BITMAP:
switch (bpp) {
case 8: cv_type = DataType<Vec<uchar, 1>>::type; break;
case 16: cv_type = DataType<Vec<uchar, 2>>::type; break;
case 24: cv_type = DataType<Vec<uchar, 3>>::type; break;
case 32: cv_type = DataType<Vec<uchar, 4>>::type; break;
default:
// 1, 4 // Unsupported natively
cv_type = -1;
}
break;
default:
// FIT_UNKNOWN // unknown type
dst = Mat(); // return empty Mat
return;
}

int width = FreeImage_GetWidth(src);
int height = FreeImage_GetHeight(src);
int step = FreeImage_GetPitch(src);

if (cv_type >= 0) {
dst = Mat(height, width, cv_type, FreeImage_GetBits(src), step);
if (cv_cvt > 0)
{
cvtColor(dst, dst, cv_cvt);
}
}
else {

std::vector<uchar> lut;
int n = pow(2, bpp);
for (int i = 0; i < n; ++i)
{
lut.push_back(static_cast<uchar>((255 / (n - 1))*i));
}

FIBITMAP* palletized = FreeImage_ConvertTo8Bits(src);
BYTE* data = FreeImage_GetBits(src);
for (int r = 0; r < height; ++r) {
for (int c = 0; c < width; ++c) {
dst.at<uchar>(r, c) = saturate_cast<uchar>(lut[data[r*step + c]]);
}
}
}

flip(dst, dst, 0);
}

int main()
{
FreeImage_Initialise();
// std::string imgPath = "F:/cppTry/index3.png";
std::string imgPath = "F:/cppTry/ger.JPG";
FREE_IMAGE_FORMAT format = FreeImage_GetFileType(imgPath.c_str(), 0);
FIBITMAP* fi_image = FreeImage_Load(format, imgPath.c_str());

Mat cvImg2;
FI2MAT(fi_image, cvImg2);
cvNamedWindow("Image1:",1);
cv::imshow("Image1:",cvImg2);
// imshow(cv_img);

IplImage *img = cvLoadImage(imgPath.c_str());
cvNamedWindow("Image2:",1);
cvShowImage("Image2:", img);
std::cout << "[free's conv]: type is: " << FreeImage_GetColorType(fi_image) << "\n";
std::cout << "[free's conv]: depth is: " << FreeImage_GetBPP(fi_image) << "\n";
std::cout << "[free's conv]: pitch is: " << FreeImage_GetPitch(fi_image) << "\n";
std::cout << "[cv2 conv]: type is: " << "/" << cvImg2.type() << "\n";
std::cout << "[cv2 conv]: depth is: " << "/" << cvImg2.depth() << "\n";
std::cout << "[cv2 conv]: channel is: " << "/" << cvImg2.channels() << "\n";
std::cout << "[cv2 conv]: elem size is: " << "/" << cvImg2.elemSize() << "\n";

cvWaitKey();
cvDestroyWindow("Image:");
return 0;
}

2 将1通道转为3通道

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void convert1to3Channel(cv::Mat& src, cv::Mat& dst) {
vector<cv::Mat> channels;
for (int i = 0; i < 3; i++) {
channels.push_back(src);
}
cv::merge(&channels[0], channels.size(), dst);
}