# Error on cv::dnn::readNetFromONNX for model converted with tf2onnx

**URL:** <https://forum.opencv.org/t/error-on-cv-readnetfromonnx-for-model-converted-with-tf2onnx/5613>\
**Category:** C++\
**Tags:** dnn\
**Created:** [October 13, 2021, 10:31am UTC](https://forum.opencv.org/t/error-on-cv-readnetfromonnx-for-model-converted-with-tf2onnx/5613 "2021-10-13T10:31:18Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![icon\_rh](https://avatars.discourse-cdn.com/v4/letter/i/ccd318/32.png) [@icon\_rh](https://forum.opencv.org/u/icon_rh)\
**Post date:** [October 13, 2021, 10:31am UTC](https://forum.opencv.org/t/error-on-cv-readnetfromonnx-for-model-converted-with-tf2onnx/5613/1 "2021-10-13T10:31:19Z")

</div>

Hello guys!

I have a problem reading an onnx model I’ve converted from tensorflow.keras with tf2onnx.  
It seems like the readNetFromONNX cannot interpret some of the gather nodes.

The exact command I used to convert the model from TF is:

```auto
python -m tf2onnx.convert --keras .\saved_model\ --output .\models\tf2onnx_keras.onnx --opset 14

```

Does anyone have an idea what could be wrong? Thanks in advance.

Here is a screenshot of the onnx model from netron.app

 ![grafik](https://us1.discourse-cdn.com/flex020/uploads/opencv/original/2X/f/f352b41d518e34dde2f8f308444bba69ab1c2455.png)

Code:

```auto
auto onnx_model = cv::dnn::readNetFromONNX("unet_all.onnx");

```

Error log:

```auto
[INFO:0] global C:\build\master_winpack-build-win64-vc15\opencv\modules\dnn\src\onnx\onnx_importer.cpp (429) cv::dnn::dnn4_v20210608::ONNXImporter::populateNet DNN/ONNX: loading ONNX v7 model produced by 'tf2onnx':1.10.0. Number of nodes = 212, inputs = 1, outputs = 1
OpenCV(4.5.3) Error: Assertion failed (indexMat.total() == 1) in cv::dnn::dnn4_v20210608::ONNXImporter::handleNode, file C:\build\master_winpack-build-win64-vc15\opencv\modules\dnn\src\onnx\onnx_importer.cpp, line 1842
[ERROR:0] global C:\build\master_winpack-build-win64-vc15\opencv\modules\dnn\src\onnx\onnx_importer.cpp (2127) cv::dnn::dnn4_v20210608::ONNXImporter::handleNode DNN/ONNX: ERROR during processing node with 2 inputs and 1 outputs: [Gather]:(Shape__224:0)
[INFO:0] global C:\build\master_winpack-build-win64-vc15\opencv\modules\dnn\src\onnx\onnx_importer.cpp (2131) cv::dnn::dnn4_v20210608::ONNXImporter::handleNode Input[0] = 'Shape__820:0'
[INFO:0] global C:\build\master_winpack-build-win64-vc15\opencv\modules\dnn\src\onnx\onnx_importer.cpp (2131) cv::dnn::dnn4_v20210608::ONNXImporter::handleNode Input[1] = 'Const__872'
[INFO:0] global C:\build\master_winpack-build-win64-vc15\opencv\modules\dnn\src\onnx\onnx_importer.cpp (2135) cv::dnn::dnn4_v20210608::ONNXImporter::handleNode Output[0] = 'Shape__224:0'
OpenCV(4.5.3) Error: Unspecified error (> Node [Gather]:(Shape__224:0) parse error: OpenCV(4.5.3) C:\build\master_winpack-build-win64-vc15\opencv\modules\dnn\src\onnx\onnx_importer.cpp:1842: error: (-215:Assertion failed) indexMat.total() == 1 in function 'cv::dnn::dnn4_v20210608::ONNXImporter::handleNode'
> ) in cv::dnn::dnn4_v20210608::ONNXImporter::handleNode, file C:\build\master_winpack-build-win64-vc15\opencv\modules\dnn\src\onnx\onnx_importer.cpp, line 2146

```