OpenCV cannot import ONNX model: Can't create layer "..." of type "TopK"

[ukoehler]

System Information

OpenCV => Python opencv-python-rolling 4.6.0.20221112 (no update available)
Operating System / Platform Windows 10 64 bit
Python =>3.10.4

Detailed description

I converted the PointRend from PaddleSeg to ONNX:

https://github.com/PaddlePaddle/PaddleSeg/tree/release/2.7/configs/pointrend

This fails to load in OpenCV 4.6 pre-release:

[ERROR:0@0.392] global D:\a\opencv-python\opencv-python\opencv\modules\dnn\src\onnx\onnx_importer.cpp (1053) cv::dnn::dnn4_v20220524::ONNXImporter::handleNode DNN/ONNX: ERROR during processing node with 2 inputs and 2 outputs: [TopK]:(onnx_node!p2o.TopK.0) from domain='ai.onnx'
Traceback (most recent call last):
  File "d:\Local\devel\Python\OpenCV\dnn_segmentation_paddle_pointrend_voc\inference.py", line 131, in <module>
    model = cv2.dnn.readNet(model_path)
cv2.error: OpenCV(4.6.0-dev) D:\a\opencv-python\opencv-python\opencv\modules\dnn\src\onnx\onnx_importer.cpp:1072: error: (-2:Unspecified error) in function 'cv::dnn::dnn4_v20220524::ONNXImporter::handleNode'
> Node [TopK@ai.onnx]:(onnx_node!p2o.TopK.0) parse error: OpenCV(4.6.0-dev) d:\a\opencv-python\opencv-python\opencv\modules\dnn\src\net_impl.hpp:107: error: (-2:Unspecified error) Can't create layer "onnx_node!p2o.TopK.0" of type "TopK" in function 'cv::dnn::dnn4_v20220524::Net::Impl::getLayerInstance'

Same result with the model after onnx simplify.

Steps to reproduce

model = cv2.dnn.readNet(model_path)

Find the ONNX file here: https://drive.google.com/file/d/1rKcUtoncMvorMtk6LdC6_QK2PSRS_pee/view?usp=sharing

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)

[fengyuentau]

We do not have the support of TopK in DNN for now. Let me take a look into the problem later.

[fengyuentau]

This model contains two kinds of TopK operators, one of which has a constant input K, but the other of which does not. We can only add the support for the former case in the current DNN engine. However, as I looked into the model, I found at least two more problems:

• Range operators with non-constant inputs cannot be supported by the current DNN engine.
• GridSample operators are not supported.

[ukoehler]

Still failing in opencv-python-rolling-4.7.0.68

[vavanade]

Same problem here on opencv-python==4.7.0.68.

global onnx_importer.cpp:1051 handleNode DNN/ONNX: ERROR during processing node with 2 inputs and 2 outputs: [TopK]:(onnx_node!/TopK) from domain='ai.onnx'

[ukoehler]

Still not working in opencv-python-rolling-4.8.0.20230624

Note to self: \Local\devel\Python\OpenCV\dnn_segmentation_paddle_pointrend_voc\inference.py