System information (version)

• OpenCV => master
• Operating System / Platform => Ubuntu 18.04.2 LTS
• Compiler => gcc

Detailed description

I used dnn module to evaluate a tensorflow model and I got wrong dimension for the output. The output's name is "import/layer1/concat_4". The correct output size should be "[1 x 128 x 2048]", but I got [1 x 128 x 2048 x 1].

Steps to reproduce

here is my model l1.zip.
The test file is show.cpp.
Use command like ./show.o modelPath to execute.

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 solution
• I updated to latest OpenCV version and the issue is still there
• There is reproducer code and related data files: videos, images, onnx, etc