Support Transpose op in TFlite #25297
**Merge with extra**: https://github.com/opencv/opencv_extra/pull/1168
The purpose of this PR is to introduce support for the Transpose op in TFlite format and to add a shape comparison between the output tensors and the references. In some occasional cases, the shape of the output tensor is `[1,4,1,1]`, while the shape of the reference tensor is `[1,4]`. Consequently, the norm check incorrectly reports that the test has passed, as the residual is zero.
Below is a Python script for generating testing data. The generated data can be integrated into the repo `opencv_extra`.
```python
import numpy as np
import tensorflow as tf
PREFIX_TFL = '/path/to/opencv_extra/testdata/dnn/tflite/'
def generator(input_tensor, model, saved_name):
# convert keras model to .tflite format
converter = tf.lite.TFLiteConverter.from_keras_model(model)
#converter.optimizations = [tf.lite.Optimize.DEFAULT]
converter.optimizations = [None]
tflite_model = converter.convert()
with open(f'{PREFIX_TFL}/{saved_name}.tflite', 'wb') as f:
f.write(tflite_model)
# save the input tensor to .npy
if input_tensor.ndim == 4:
opencv_tensor = np.transpose(input_tensor, (0,3,1,2))
else:
opencv_tensor = input_tensor
opencv_tensor = np.copy(opencv_tensor, order='C').astype(np.float32)
np.save(f'{PREFIX_TFL}/{saved_name}_inp.npy', opencv_tensor)
# generate output tenosr and save it to .npy
mat_out = model(input_tensor).numpy()
mat_out = np.copy(mat_out, order='C').astype(np.float32)
if mat_out.ndim == 4:
mat_out = np.transpose(mat_out, (0,3,1,2))
interpreter = tf.lite.Interpreter(model_content=tflite_model)
out_name = interpreter.get_output_details()[0]['name']
np.save(f'{PREFIX_TFL}/{saved_name}_out_{out_name}.npy', mat_out)
def build_transpose():
model_name = "keras_permute"
mat_in = np.array([[[1,2,3], [4,5,6]]], dtype=np.float32)
model = tf.keras.Sequential()
model.add(tf.keras.Input(shape=(2,3)))
model.add(tf.keras.layers.Permute((2,1)))
model.summary()
generator(mat_in, model, model_name)
if __name__ == '__main__':
build_transpose()
```
### Pull Request Readiness Checklist
- [x] I agree to contribute to the project under Apache 2 License.
- [X] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [X] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [X] The feature is well documented and sample code can be built with the project CMake
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