I am searching for a way to forward lower layer output to a higher layer with a loaded VGG16 model using CNTK.
The background of my problem is:
I reimplemented some parts of Fully Convolutional Networks for Semantic Segmentation but then I ran into some problems: Starting with this example I first replaced the fully connected layers with fully convolutional and slit the sequence in the model definition part into chunks where I could simply access pool3 and pool4 for the later usage in eg. Convolution2D((1,1), num_classes, name='score_pool4')(pool4). This works fine but after building the model I noticed, that I need to implement an own way to read batches because the build-in reader does not support 2D labels right now. Now I simply read the images using OpenCV and replaced the training_session(...).train() with a for loop and trainer.train_minibatch({model['features']: my_loaded_features, model['labels']: my_2D_labels}) this works well but because of the removed training_session part I don't know where I could apply the existing VGG16 weights.
My problem is:
I searched for transfer learning examples where those guys load models using C.load_model(...) and then clone the needed layers but now I am wondering how could I access cloned_layers->pool4 (in the middle of the loaded model) if I also want to use it in deeper layers.
I tried Convolution2D((1,1), num_classes, name='score_pool4')(cloned_layers.find_by_name('pool4'))but I ended up with some error messages while learner initialization because of "unknown shape information" in used weight variables.
So how can I access those layers within the loaded model for later (deeper) usage?
Thanks for reading (and maybe helping)!
If you are looking to read custom data. There are two tutorials on building your own readers. https://cntk.ai/pythondocs/manuals.html
Regarding cloning parts of a network - here is a link to another post on StackOverflow that has exemplar code