I have to heavily process each frame of a video to extract information.
To accelerate the processing, I want to use all my PCs in my local network.
How to install a distributed system that allow to process each frame in a separate host of my LAN?
You can take a look at the various distributed platform available today whether open sources (such as Swarm, DistCC or IceCream which will probably need adaptation to your specific requirements) or commercial and generic distributed computing platforms such as IncrediBuild which will take care of the distribution and process virtualization on remote nodes for you (probably without requiring you to change or adapt your code).
Following your later question on how to do this with IncrediBuild:
Whenever using OpenCV in C/C++, you can write your code in a multi-process manner (which is a requirement by most distributing \ cluster systems). Once you'll do that, IncrediBuild will be able to accelerate your process execution by distributing them to remote machine across the network. IncrediBuild provides you with the ability to seamlessly distribute processes to remote machines across your network, in order to use it properly, your execution flow should be able to execute multiple processes in parallel (whether a batch script that does that or an application that spawns multiple processes in parallel) – IncrediBuild will then be able to take these processes and execute them remotely. I'm adding a small sample that contains a batch script that executes multiple processes in parallel where each process is a program that captures a single frame of video file and saves it as an image file. When I’ve executed this scenario with many processes executed in parallel using my machine and a remote host machine the result was: the processes were executed in parallel utilizing both my local cores and the cores of the remote machine. You can download the sources and the executable for the sample process from: https://github.com/adish869/CaptureFrames I’ve also placed print screen files of the IncrediBuild monitoring application showing my OpenCV processes being executed in parallel on both machines. You can find more information about how to execute the commands in the ReadMe.txt file.
Disclaimer, the author of this answer works at IncrediBuild.