Fully transparent pixels should have alpha set to 0 fully opaque pixels should have alpha set to 255 65535 see the code sample below.
Cv mat set to zero.
Uchar pixval cv mat elem grayimg uchar i j cv mat elem cameramatrix float 0 2 image width 0 5f.
Matrix elements are stored row by row.
Obviously providing a beta value of 1 0 would have made this example exactly the same as a regular add function with no transparency for the overlay text.
Thresholding rule threshold to zero if src x y thresh dst x y src x y else dst x y 0 python.
To access multiple channel matrices you can use cv mat elem matrix.
To set all the matrix elements to the particular value after the construction use the assignment operator mat operator const scalar value.
It means that you can zero the matrix like this i couldn t find equivalent overloads for matx or sparsemat.
For cv mat the documentation says that.
So mat dims is always 2 can also be 0 when the array is empty.
It passes the number of dimensions 1 to the mat constructor but the created array will be 2 dimensional with the number of columns set to 1.
As already properly pointed out by william you should provide only the correct type as a template argument for at i believe that cv mat itself is not made template only for simplification.
Inline void zero cv mat m m 0.
If the format depth or channel order is different use mat convertto and cv cvtcolor to convert.
However opencv crew are trying to support c features including templates.
The one régis mentioned is called on the fly ra in opencv tutorial.
It s the most convenient but also time consuming.
Otherwise it is set to zero.
Multiple images vector of mat can be saved in tiff format see the code sample below.
Use a copy constructor or assignment operator where there can be an array or expression on the right side see below.
Element i j i 0 based row index j 0 based column index of a matrix can be retrieved or modified using cv mat elem macro.
1 3 the subtraction operation similar to adding two mat objects to each other you can also subtract all elements of one image from another using the subtract function or the operator.
