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