I currently have a Torchscript model I load via torch.jit.load. I would like to take some data I have and train on top of these weights, however I cannot find out how to train a serialised torchscript model.
Turns out that the returned ScriptModule does actually support training: https://pytorch.org/docs/stable/generated/torch.jit.ScriptModule.html#torch.jit.ScriptModule.train
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I am new in Pytorch. My question is: How do I apply transfer learning to a custom dataset? I am doing image segmentation on brain tumors. I can find examples which use U-net structure but I could not find examples using weights of the pre-trained models for a U-net image segmentation?
You could obtain pre-trained models in two ways:
Model weights or complete models shared in formats such .pt or .pth:
In this case, Saving and Loading Models is a good starting point. Copying from the tutorial there, you could load a model as
model = TheModelClass(*args, **kwargs)
model.load_state_dict(torch.load(PATH))
The other way is to load the model from torchvision. A list is available models is available at Torchvision Models. U-Net is not available yet. However, it is possible to load a pre-trained model as the encoder and write a separate decoder to form a U-Net with a pre-trained encoder.
In this case, the model object returned from the function calls shown in the API are already loaded with pretrained weights when pretrained=True.
For writing a custom dataloader, PyTorch data loaders may be a useful guide.
I want to extract features using a pretrained CNN model(ResNet50, VGG, etc) and use the features with a CTC loss function.
I want to build it as a text recognition model.
Anyone on how can i achieve this ?
I'm not sure if you are looking to finetune the pretrained models or to use the models for feature extraction. To do the latter freeze the petrained model weights (there are several ways to do this in PyTorch, the simplest being calling .eval() on the model), and feed the logits from the last layer of the model to your new output head. See the PyTorch tutorial here for a more in depth guide.
# define the model
model = MaskRCNN(mode='training', model_dir='./', config=config)
# load weights (mscoco) and exclude the output layers
model.load_weights('mask_rcnn_coco.h5', by_name=True, exclude=["mrcnn_class_logits", "mrcnn_bbox_fc", "mrcnn_bbox", "mrcnn_mask"])
# train weights (output layers or 'heads')
model.train(train_set, test_set, learning_rate=config.LEARNING_RATE, epochs=2, layers='heads')
I have certain medical images containing fibroids.
I wish to apply instance segmentation or object detection.
I may have to use mask Rcnn for instance segmentation and object detection. Is it possible to design the network from scratch instead of using transfer learning?
What I mean here is random initialization of weights for my data, instead of using weights derived from imagenet data or coco data.
From the command line,instead of training a model starting from pre-trained COCO weights like this
python my_model.py train --dataset=/path/dataset --weights=coco
execute the following line.
python my_model.py train --dataset=/path/dataset
And to start training from the first layer execute the following code.
model.train(dataset_train, dataset_val,learning_rate=config.LEARNING_RATE,epochs=10, layers='all')
Can't you just run the training without doing the model.load_weights() line? It seems to be running fine for me when I do that. I assume that runs it with randomized initial weights. It didn't result in quite as good results as starting with coco does, but I'm sure that's expected behavior for some datasets.
I am setting up a fit_generator to train a DNN by keras. But don't know how to use a CNN inside this generator.
Basically, I have a pre-trained image generator using fully-connected convolutional networks (we can named it as GEN-NET). Now I want to used this Fully-CNN in my fit_generator to generate unlimited number of images to train another classifier (called CLASS-NET) in keras. But it always crashed my training and the error message is:
ValueError: Tensor Tensor("decoder/transform_output/mul:0", shape=(?, 128, 128, 1), dtype=float32) is not an element of this graph.
This "decoder/transform_output/mul:0" is the output of my CNN GEN-NET.
So my question is that can I use CNN based GEN-NET in my fit_generator to train GLASS-NET or it is not permitted in keras?
Keras does not really like running two separate models in a single session. You could use K.clear_session() after using the model but this would produce a lot of overhead!
Best way to do this, IMHO, is by pre-generating these images and then loading them using a generator. Basically splitting your program into two separate programs.
Otherwise, if you are using tensorflow as back-end there might be a way to do it by switching the default graph on the tf.Session, you could Google that but I would not recommend it! :)
Seems like you might have things a bit mixed up! The CNN (convolutional neural network) needs to be trained to your data, unless you're using a pretrained network for predictions. If you're going to train the CNN, you can do that with either the fit() or the fit_generator() function. Use fit() if you're feeding data directly, and use fit_generator() if your data is handled by Image Data Generators. If you've loaded a pre-trained model/weights only to make predictions, you don't need to use any fit function, since no training needs to be done.
I built a LSTM model for text classification using Keras. Now I have new data to be trained. instead of appending to the original data and retrain the model, I thought of training the data using the model weights. i.e. making the weights to get trained with the new data.
However, irrespective of the volume i train, the model is not predicting the correct classification (even if i give the same sentence for prediction). What could be the reason?
Kindly help me.
Are you using the following to save the trained model?
model.save('model.h5')
model.save_weights('model_weights.h5')
And the following to load it?
from keras.models import load_model
model = load_model('model.h5') # Load the architecture
model = model.load_weights('model_weights.h5') # Set the weights
# train on new data
model.compile...
model.fit...
The model loaded is the exact same as the model being saved here. If you are doing this, then there must be something different in the data (in comparison with what it is trained on).