Opencv Mat Assignment

I m attempting to share an image that is only being used read only across threads.

Opencv mat assignment.

Passing cv mat as argument. Output image allocation for opencv functions is automatic unless specified otherwise. In this post i would like to discuss what happens when cv mat is passed around. If i update b a is also affected.

Changing the header of cv mat. Suppose a function void a function mat argument change argument. Opencv provides the split function to split the 3 channels rgb image into 3 mat objects one per channel. The parameters are the mat object containing the source image and the vector of mat objects representing each rgb channel in reverse order where the first is blue then green and red.

The underlying matrix of an image may be copied using the clone and copyto functions. Use a copy constructor or assignment operator where there can be an array or expression on the right side see below. After you call a function a a is also affected right. Often times when we pass cv mat we forget one important thing.

It seems basically assigning by reference. Via a reference counting system opencv s mat matrix. Opencv matrix does not respect the const modifier. Golden gate ave san francisco seoul national univ carnegie mellon uc berkeley devops deep learning.

The assignment operator and the copy constructor only copies the header. Suppose a has some values in it mat b a. So mat dims is always 2 can also be 0 when the array is empty. Consider the following examples 1 where we want to change what the datastructure is note that we are trying to modify the header of the.

The underlying matrix of an image may be copied using the cv mat clone and cv mat copyto functions. I noticed that a new data structure cv matx was added to the new opencv version intended for small matrices of known size at compilation time for example. 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. Cv matx31f matrix 3x1 of float type checking the documentation i saw that most of matrix operations are available but still i don t see the advantages of using this new type instead of the old cv mat.