Creating a mat object explicitly.
Create cv mat c.
You can do this using the operator of mat.
Just like with inputarray opencv users should not care about outputarray they just pass mat vector t etc.
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.
Cv 8uc1 means 8 bit single channel matrix cv 32fc2 means 2 channel i e.
Each implementation calls mat create for a destination matrix.
There are many different ways to create cv mat object.
Int arr 3 4 3 2.
The parameters which you add to the cv mat must have a name which fits to the following rules.
Or use the universal filestorage i o functions to save the image to xml or yaml format.
Be aware that this only works for two dimensional matrices.
N dimensional dense array class.
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.
We can create a matrix with more than two dimensions.
This type is very similar to inputarray except that it is used for input output and output function parameters.
However for debugging purposes it s much more convenient to see the actual values.
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.
The name starts with a lower or upper case character hence a value between a z or a z.
If it is not empty and has the correct size and type the method does nothing.
This method allocates data for a matrix if it is empty.
Possible parameter names for matrix cv mat.
If you want to make your function polymorphic i e.
We can use array to initialize the constructor.
Mat l 3 arr cv 8uc 1 scalar all 0.
Do not explicitly create outputarray instances applies here too.
Here are the some popular ones.
Complex floating point matrix etc.
A new matrix of the specified size and specifed type will be allocated.
Using cv mat create nrows ncols type method or the similar constructor cv mat mat nrows ncols type fill value constructor.
The sample below shows how to create a bgra image how to set custom compression parameters and save it to a png file.
The class mat represents an n dimensional dense numerical single channel or multi channel array.
If the format depth or channel order is different use mat convertto and cv cvtcolor to convert it before saving.
