Each implementation calls mat create for a destination matrix.
Create cv mat c.
In the load modify and save an image tutorial you have already learned how to write a matrix to an image file by using the cv imwrite function.
Or use the universal filestorage i o functions to save the image to xml or yaml format.
Here are the some popular ones.
The parameters which you add to the cv mat must have a name which fits to the following rules.
Complex floating point matrix etc.
Do not explicitly create outputarray instances applies here too.
Type has the same meaning as in cvcreatemat function e g.
If you want to make your function polymorphic i e.
Just like with inputarray opencv users should not care about outputarray they just pass mat vector t etc.
Creating a mat object explicitly.
Possible parameter names for matrix cv mat.
Cv 8uc1 means 8 bit single channel matrix cv 32fc2 means 2 channel i e.
It can be used to store real or complex valued vectors and matrices grayscale or color images voxel volumes vector fields point clouds tensors histograms though very high dimensional histograms may be better stored in a sparsemat.
This method allocates data for a matrix if it is empty.
You can do this using the operator of mat.
To the contrary with c api where an output image had to be created by the developer an empty output mat can be supplied to each function.
The first character of the name can be followed by an infinite number of alpha numerical characters including characters like or.
If the format depth or channel order is different use mat convertto and cv cvtcolor to convert it before saving.
We can create a matrix with more than two dimensions.
However for debugging purposes it s much more convenient to see the actual values.
If it is not empty and has the correct size and type the method does nothing.
We can use array to initialize the constructor.
This type is very similar to inputarray except that it is used for input output and output function parameters.
The name starts with a lower or upper case character hence a value between a z or a z.
The same limitation as for inputarray.
N dimensional dense array class.
There are many different ways to create cv mat object.
Using cv mat create nrows ncols type method or the similar constructor cv mat mat nrows ncols type fill value constructor.
Be aware that this only works for two dimensional matrices.
Mat l 3 arr cv 8uc 1 scalar all 0.
The sample below shows how to create a bgra image how to set custom compression parameters and save it to a png file.
