converted some more samples to C++

samples/cpp/image.cpp

@@ -0,0 +1,114 @@
+#include "cv.h" // include standard OpenCV headers, same as before
+#include "highgui.h"
+#include "ml.h"
+#include <stdio.h>
+#include <iostream>
+#include <opencv2/flann/flann.hpp>
+
+using namespace cv; // all the new API is put into "cv" namespace. Export its content
+using namespace std;
+using namespace cv::flann;
+
+// enable/disable use of mixed API in the code below.
+#define DEMO_MIXED_API_USE 1
+
+int main( int argc, char** argv )
+{
+    const char* imagename = argc > 1 ? argv[1] : "lena.jpg";
+#if DEMO_MIXED_API_USE
+    Ptr<IplImage> iplimg = cvLoadImage(imagename); // Ptr<T> is safe ref-conting pointer class
+    if(iplimg.empty())
+    {
+        fprintf(stderr, "Can not load image %s\n", imagename);
+        return -1;
+    }
+    Mat img(iplimg); // cv::Mat replaces the CvMat and IplImage, but it's easy to convert
+    // between the old and the new data structures (by default, only the header
+    // is converted, while the data is shared)
+#else
+    Mat img = imread(imagename); // the newer cvLoadImage alternative, MATLAB-style function
+    if(img.empty())
+    {
+        fprintf(stderr, "Can not load image %s\n", imagename);
+        return -1;
+    }
+#endif
+    
+    if( !img.data ) // check if the image has been loaded properly
+        return -1;
+    
+    Mat img_yuv;
+    cvtColor(img, img_yuv, CV_BGR2YCrCb); // convert image to YUV color space. The output image will be created automatically
+    
+    vector<Mat> planes; // Vector is template vector class, similar to STL's vector. It can store matrices too.
+    split(img_yuv, planes); // split the image into separate color planes
+    
+#if 1
+    // method 1. process Y plane using an iterator
+    MatIterator_<uchar> it = planes[0].begin<uchar>(), it_end = planes[0].end<uchar>();
+    for(; it != it_end; ++it)
+    {
+        double v = *it*1.7 + rand()%21-10;
+        *it = saturate_cast<uchar>(v*v/255.);
+    }
+    
+    // method 2. process the first chroma plane using pre-stored row pointer.
+    // method 3. process the second chroma plane using individual element access
+    for( int y = 0; y < img_yuv.rows; y++ )
+    {
+        uchar* Uptr = planes[1].ptr<uchar>(y);
+        for( int x = 0; x < img_yuv.cols; x++ )
+        {
+            Uptr[x] = saturate_cast<uchar>((Uptr[x]-128)/2 + 128);
+            uchar& Vxy = planes[2].at<uchar>(y, x);
+            Vxy = saturate_cast<uchar>((Vxy-128)/2 + 128);
+        }
+    }
+    
+#else
+    Mat noise(img.size(), CV_8U); // another Mat constructor; allocates a matrix of the specified size and type
+    randn(noise, Scalar::all(128), Scalar::all(20)); // fills the matrix with normally distributed random values;
+                                                     // there is also randu() for uniformly distributed random number generation
+    GaussianBlur(noise, noise, Size(3, 3), 0.5, 0.5); // blur the noise a bit, kernel size is 3x3 and both sigma's are set to 0.5
+    
+    const double brightness_gain = 0;
+    const double contrast_gain = 1.7;
+#if DEMO_MIXED_API_USE
+    // it's easy to pass the new matrices to the functions that only work with IplImage or CvMat:
+    // step 1) - convert the headers, data will not be copied
+    IplImage cv_planes_0 = planes[0], cv_noise = noise;
+    // step 2) call the function; do not forget unary "&" to form pointers
+    cvAddWeighted(&cv_planes_0, contrast_gain, &cv_noise, 1, -128 + brightness_gain, &cv_planes_0);
+#else
+    addWeighted(planes[0], contrast_gain, noise, 1, -128 + brightness_gain, planes[0]);
+#endif
+    const double color_scale = 0.5;
+    // Mat::convertTo() replaces cvConvertScale. One must explicitly specify the output matrix type (we keep it intact - planes[1].type())
+    planes[1].convertTo(planes[1], planes[1].type(), color_scale, 128*(1-color_scale));
+    // alternative form of cv::convertScale if we know the datatype at compile time ("uchar" here).
+    // This expression will not create any temporary arrays and should be almost as fast as the above variant
+    planes[2] = Mat_<uchar>(planes[2]*color_scale + 128*(1-color_scale));
+    
+    // Mat::mul replaces cvMul(). Again, no temporary arrays are created in case of simple expressions.
+    planes[0] = planes[0].mul(planes[0], 1./255);
+#endif
+    
+    // now merge the results back
+    merge(planes, img_yuv);
+    // and produce the output RGB image
+    cvtColor(img_yuv, img, CV_YCrCb2BGR);
+    
+    // this is counterpart for cvNamedWindow
+    namedWindow("image with grain", CV_WINDOW_AUTOSIZE);
+#if DEMO_MIXED_API_USE
+    // this is to demonstrate that img and iplimg really share the data - the result of the above
+    // processing is stored in img and thus in iplimg too.
+    cvShowImage("image with grain", iplimg);
+#else
+    imshow("image with grain", img);
+#endif
+    waitKey();
+    
+    return 0;
+    // all the memory will automatically be released by Vector<>, Mat and Ptr<> destructors.
+}