GPUMat is not available in Java bindings of OpenCV

Bahramudin commented 7 years ago

System information (version)

OpenCV =>3.2.0
Operating System / Platform =>Windows 64 Bit
Compiler =>Visual Studio 2015

Detailed description

There is no GpuMat class found in Java wrapper of OpenCV, ans also there is some functions which is missing in Java wrapper, ....

Steps to reproduce

StevenPuttemans commented 7 years ago

there is no GpuMat class found in Java wrapper of OpenCV

There is no GPU support in the Java wrappers so far. Keep in mind that Java wrappers are mainly there for Amdroid development and probably one of the reasons why GPU support was not a big interest point.

JavaCV has GPU support through OpenCL: https://github.com/bytedeco/javacv but that is not an official wrapper of OpenCV.

and also there is some functions which is missing in Java wrapper

True, but that is exactly why we encourage users to provide wrapping functionality for missing functions.

Bahramudin commented 7 years ago

@StevenPuttemans there is also a lot of people that is using java wrapper in windows platform, and also we hope that OpenCV include all the feature of the OpenCV into Java bindings because some people already know how to code in Java, they don't want that only for Computer Vision they go to study C++, so it is better that the Java bindings have everything which is C+. You mentioned JavaCV, I want to ask that which is better to use, OpenCV Java bindings or the JavaCV? What difference have they? And also one another question is that, is there in any performance penalty in using OpenCV in Java or C++? Thanks!!

StevenPuttemans commented 7 years ago

Ah well let me reply to that

Java bindings are auto wrapped, and for the moment, these wrappers do not allow to wrap all existing C++ functionality. That is exactly why several functions are missing. As long as these bindings are not optimized, this is impossible. Keeping a separate Java implementation of functions is also unmanageable.
OpenCV focuses on embedded vision. In that case, except from Android, there is about no application for Java there that I am aware of in that world. Again one of the reasons why it is not actively supported.
You mentioned JavaCV, I want to ask that which is better to use, OpenCV Java bindings or the JavaCV
You mentioned JavaCV, I want to ask that which is better to use, OpenCV Java bindings or the JavaCV? No idea, I just know of this alternative but never really looked into it, since Java is not a language I master. Difference is that JavaCV is maintained by another group of users with pure java focus, while our wrappers are auto generated and maintained by Intel/OpenCV itself.
Ofcourse performance through a wrapper will have influence. C++ will be the most efficient every single time.

Bahramudin commented 7 years ago

@StevenPuttemans Thank You! As a last question, what do yo think how much of the OpenCV functions are wrapped into Java by percentage, 60%? 70%? how much? Thanks again!

StevenPuttemans commented 7 years ago

Again, no clue, but having a quick look at the java docs I already notice that all cuda modules and all contrib modules are missing. So I would say at least 40% of functionality is missing, if not more.

Bahramudin commented 7 years ago

@StevenPuttemans how do you see the feature of the OpenCV to Java wrapping? Is there any hope to the Java wrapper to have at least the cuda support in the feature?

StevenPuttemans commented 7 years ago

I am not a main developer, but I guess do not get your hopes up, personally I feel Java is just a not so important branch for OpenCV devs.

Bahramudin commented 7 years ago

@StevenPuttemans @alalek I think the OpenCV team should consider to add at least the cuda module support to the Java bindings, because it can expensive for people who already know Java and for just few modules they have to learn a new language.

leavittx commented 4 years ago

+1 for this one. Highly inetested

opencv / opencv