• cv
• _InputArray

This is the proxy class for passing read-only input arrays into OpenCV functions.

It is defined as:

where _InputArray is a class that can be constructed from Mat , Mat_<T>, Matx<T, m, n>, std::vector<T>, std::vector<std::vector<T> >, std::vector<Mat>, std::vector<Mat_<T> >, UMat , std::vector<UMat> or double. It can also be constructed from a matrix expression.

Since this is mostly implementation-level class, and its interface may change in future versions, we do not describe it in details. There are a few key things, though, that should be kept in mind:

• When you see in the reference manual or in OpenCV source code a function that takes InputArray, it means that you can actually pass Mat , Matx , vector<T> etc. (see above the complete list).
• Optional input arguments: If some of the input arrays may be empty, pass cv::noArray() (or simply cv::Mat() as you probably did before).
• The class is designed solely for passing parameters. That is, normally you should not declare class members, local and global variables of this type.
• If you want to design your own function or a class method that can operate of arrays of multiple types, you can use InputArray (or OutputArray) for the respective parameters. Inside a function you should use _InputArray::getMat() method to construct a matrix header for the array (without copying data). _InputArray::kind() can be used to distinguish Mat from vector<> etc., but normally it is not needed.

Here is how you can use a function that takes InputArray :

That is, we form an STL vector containing points, and apply in-place affine transformation to the vector using the 2x3 matrix created inline as Matx<float, 2, 3> instance.

Here is how such a function can be implemented (for simplicity, we implement a very specific case of it, according to the assertion statement inside) :

There is another related type, InputArrayOfArrays, which is currently defined as a synonym for InputArray:

It denotes function arguments that are either vectors of vectors or vectors of matrices. A separate synonym is needed to generate Python/Java etc. wrappers properly. At the function implementation level their use is similar, but _InputArray::getMat(idx) should be used to get header for the idx-th component of the outer vector and _InputArray::size().area() should be used to find the number of components (vectors/matrices) of the outer vector.

In general, type support is limited to cv::Mat types. Other types are forbidden. But in some cases we need to support passing of custom non-general Mat types, like arrays of cv::KeyPoint, cv::DMatch, etc. This data is not intented to be interpreted as an image data, or processed somehow like regular cv::Mat. To pass such custom type use rawIn() / rawOut() / rawInOut() wrappers. Custom type is wrapped as Mat-compatible CV_8UC<N> values (N = sizeof(T), N <= CV_CN_MAX).

Examples:

samples/cpp/pca.cpp, and samples/cpp/peopledetect.cpp.

§ _InputArray() [11/23]

§ _InputArray() [12/23]

§ _InputArray() [13/23]

§ _InputArray() [14/23]

§ _InputArray() [15/23]

§ _InputArray() [16/23]

§ _InputArray() [17/23]

§ _InputArray() [18/23]

§ _InputArray() [19/23]

§ _InputArray() [20/23]

§ _InputArray() [21/23]

§ _InputArray() [22/23]

§ _InputArray() [23/23]

§ ~_InputArray()

Member Function Documentation

§ channels()

§ cols()

§ copyTo() [1/2]

§ copyTo() [2/2]

§ depth()

§ dims()

§ empty()

§ getFlags()

§ getGpuMat()

§ getGpuMatVector()

§ getMat()

§ getMat_()

§ getMatVector()

§ getObj()

§ getOGlBuffer()

§ getSz()

§ getUMat()

§ getUMatVector()

§ init() [1/2]