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Creating Pipelines

Pipeline Template​

All pipelines must extend the VisionPipeline class. They should be stored in the internals.image.<game-name> folder.

Here is a quick, basic template for creating a pipeline.

public class BlankVisionPipeline extends VisionPipeline {
    @Override
    public void init(Mat mat) {
        
    }

    @Override
    public Mat processFrame(Mat input) {
        return input;
    }
}
danger

You MUST return input in the processFrame method.

The input parameter is the image passed into the pipeline. The reason why we must return it is that images in OpenCV are stored in permanent memory. The variables we deal with are simply pointers to the image, kind of like pointers in C++. If we don't return the original image we received, OpenCV will not be able to access it and the pipeline will crash.

The init method is optional, but processFrame is not.

Using Pipelines​

There is a universal Feature that works for any pipeline extending the VisionPipeline class, called VisionProcessingFeature. It has one constructor parameter, which is your pipeline.

VisionProcessingFeature detector = new VisionProcessingFeature(new <your_pipeline>());
registerFeature(detector);
tip

You should store the feature in a variable, so you can get info from it later.

Viewing the output​

Once you have an OpMode set up with just your basic pipeline, you might want to see it in action (granted it won't actually do anything). Once you start the OpMode, you have to connect your computer to the Wi-Fi network navigate to the Robot Dashboard. Once the OpMode is started, the camera view should appear.