OpenCV将我自己的滤镜应用于彩色图像

Question

I'm working in OpenCV C++ to filtering image color. I want to filter the image using my own matrix. See this code:

img= "c:/Test/tes.jpg";
Mat im = imread(img);

And then i want to filtering/multiply with my matrix (this matrix can replaced with another matrix 3x3)

Mat filter = (Mat_<double>(3, 3) <<17.8824, 43.5161, 4.11935, 
                                   3.45565, 27.1554, 3.86714, 
                                   0.0299566, 0.184309, 1.46709);

How to multiply the img mat matrix with my own matrix? I'm still not understand how to multiply 3 channel (RGB) matrix with another matrix (single channel) and resulted image with new color.

Answer 1

you should take a look at the opencv documentation . You could use this function:

filter2D(InputArray src, OutputArray dst, int ddepth, InputArray kernel, Point anchor=Point(-1,-1), double delta=0, int borderType=BORDER_DEFAULT )

which would give you something like this in your code:

Mat output;
filter2D(im, output, -1, filter);

About your question for 3-channel matrix; it is specified in the documentation:

kernel – convolution kernel (or rather a correlation kernel), a single-channel floating point matrix; if you want to apply different kernels to different channels, split the image into separate color planes using split() and process them individually.

So by default your "filter" matrix will be applied equally to each color plane.

EDIT You find a fully functional example on the opencv site: http://docs.opencv.org/doc/tutorials/imgproc/imgtrans/filter_2d/filter_2d.html