YoloV5 Onnx Model Output Post Processing For Xamarin Forms

[willsonyee]

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Question

I am currently trying to integrate YoloV5 Onnx Model into Xamarin Form C# using OnnxRuntime, but I am currently encountering some roadblocks due to lack of experiencing. Can someone advise me on how to post process the output after inferenced?

Netron for my YoloV5 Onnx Model:
There are total of 4 outputs for my models - output, 345, 403, 461. May I know what are the meaning for these 4 outputs?

I couldn't move forward from here after I get the output tensor, any advises will be much appreciated.

Please let me know if you require more information to further clarify the question.

Thank you very much.

Additional

No response

[glenn-jocher]

@willsonyee 'output' is all you need. The other 3 are the outputs at each grid P3-P5, which are already present in 'output'.

The dimension of 'output' are shape(batch,anchors,outputs), where outputs are [xywh, objectness, classes confidences]

[willsonyee]

@glenn-jocher I see, thanks for the clarification on the "output" of the onnx model.

Right now the "var output" in my second pictures have the "output" of the onnx model multiplied (1 x 25200 x 7 = 176400). Pardon my dullness, could you guide me on how to post process this?

I searched around the github issues, do I need to do something called NMS in C#? Thanks alot

[glenn-jocher]

@willsonyee see https://pytorch.org/vision/main/generated/torchvision.ops.nms.html

Your 7-length vector is xywh, objectness, class 1, class 2

[willsonyee]

@glenn-jocher I am currently using Microsoft.ML.OnnxRuntime to load the YoloV5 model and make prediction.

But I couldn't postprocess the output from the model to xywh, objectness, class1, class2.

Do you have an code examples for onnx C#? Thanks

[glenn-jocher]

@willsonyee see YOLOv5 Export Tutorial for C++ references

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