I am currently trying to create embeddings of images by passing them through pre-trained Neural Networks and getting the values obtained at the last layer just before the fully-connected ones. I did not have much problem doing it with Pytorch implementations of other Neural Networks. However, I am stuck with the Tensorflow implementation of SimCLR v2 and do not know how to proceed.
The official repo of SimCLR v2 is this one: https://github.com/google-research/simclr
And the paper is here: https://arxiv.org/abs/2006.10029v2
If I understood correctly the paper and the code, this architecture is composed of a backbone ResNet as well as a projection head. In my case, I am not interested in the projection head and just want to obtain the results of the output of the ResNet model.
Looking at the code in the colabs, I have managed to import pre-trained SimCLR models:
model_path = 'gs://simclr-checkpoints-tf2/simclrv2/pretrained/r50_1x_sk0/saved_model'
saved_model = tf.saved_model.load(model_path)
However, I do not know what to do to get the outputs of the ResNet. In all the colabs, they only get the outputs of the projection head which I am uninterested in.
for x in ds.take(1):
image = x['image']
labels = x['label']
logits = saved_model(image, trainable=False)['logits_sup']
pred = tf.argmax(logits, -1)
Moreover, the way the model is imported makes it difficult to get the variables and layers. For instance if I try obtain a summary of the model, I have this error:
'_UserObject' object has no attribute 'summary'
I also do not want to convert the weights of Tensorflow into Pytorch and import them into a pytorch ResNet.
What then would be the best way to isolate the ResNet from the overall SimCLR v2 architecture in order to get the outputs of the final layer ?
Related
I have taken Object Detection model from TF zoo v2,
I took mobilenet and trained it on my own TFrecords
I am using mobilenet because it is often found in the examples of converting it to Tflite and this is what I need because I run it on RPi3.
I am following ideas from the official example from Sagemaker docs
and github you can find here
What is interesting the accuracy done after step 2) training and 3) deploying is pretty nice! My trucks are discovered nicely with the custom trained model.
However, when converted to tflite the accuracy goes down no matter if I use tfliteconvert tool or using python tf.lite.Converter.
What is more, all detections are on borders of images, and usually in the bottom-right corner. Maybe I am not preparing images correctly? Or some misunderstanding of results?
You can check images I uploaded.
https://ibb.co/fSzfZvz
https://ibb.co/0GF101s
What could possibly go wrong?
I was lacking proper preprocessing of image.
After I have used pipeline config to build detection object which has preprocess function I utilized to build tensor before feeding it into Interpreter.
num_classes = 2
configs = config_util.get_configs_from_pipeline_file(pipeline_config)
model_config = configs['model']
model_config.ssd.num_classes = num_classes
model_config.ssd.freeze_batchnorm = True
detection_model = model_builder.build(
model_config=model_config, is_training=True)
I am trying to convert my CNN written with tensorflow layers to use the keras api in tensorflow (I am using the keras api provided by TF 1.x), and am having issue writing a custom loss function, to train the model.
According to this guide, when defining a loss function it expects the arguments (y_true, y_pred)
https://www.tensorflow.org/guide/keras/train_and_evaluate#custom_losses
def basic_loss_function(y_true, y_pred):
return ...
However, in every example I have seen, y_true is somehow directly related to the model (in the simple case it is the output of the network). In my problem, this is not the case. How do implement this if my loss function depends on some training data that is unrelated to the tensors of the model?
To be concrete, here is my problem:
I am trying to learn an image embedding trained on pairs of images. My training data includes image pairs and annotations of matching points between the image pairs (image coordinates). The input feature is only the image pairs, and the network is trained in a siamese configuration.
I am able to implement this successfully with tensorflow layers and train it sucesfully with tensorflow estimators.
My current implementations builds a tf Dataset from a large database of tf Records, where the features is a dictionary containing the images and arrays of matching points. Before I could easily feed these arrays of image coordinates to the loss function, but here it is unclear how to do so.
There is a hack I often use that is to calculate the loss within the model, by means of Lambda layers. (When the loss is independent from the true data, for instance, and the model doesn't really have an output to be compared)
In a functional API model:
def loss_calc(x):
loss_input_1, loss_input_2 = x #arbirtray inputs, you choose
#according to what you gave to the Lambda layer
#here you use some external data that doesn't relate to the samples
externalData = K.constant(external_numpy_data)
#calculate the loss
return the loss
Using the outputs of the model itself (the tensor(s) that are used in your loss)
loss = Lambda(loss_calc)([model_output_1, model_output_2])
Create the model outputting the loss instead of the outputs:
model = Model(inputs, loss)
Create a dummy keras loss function for compilation:
def dummy_loss(y_true, y_pred):
return y_pred #where y_pred is the loss itself, the output of the model above
model.compile(loss = dummy_loss, ....)
Use any dummy array correctly sized regarding number of samples for training, it will be ignored:
model.fit(your_inputs, np.zeros((number_of_samples,)), ...)
Another way of doing it, is using a custom training loop.
This is much more work, though.
Although you're using TF1, you can still turn eager execution on at the very beginning of your code and do stuff like it's done in TF2. (tf.enable_eager_execution())
Follow the tutorial for custom training loops: https://www.tensorflow.org/tutorials/customization/custom_training_walkthrough
Here, you calculate the gradients yourself, of any result regarding whatever you want. This means you don't need to follow Keras standards of training.
Finally, you can use the approach you suggested of model.add_loss.
In this case, you calculate the loss exaclty the same way I did in the first answer. And pass this loss tensor to add_loss.
You can probably compile a model with loss=None then (not sure), because you're going to use other losses, not the standard one.
In this case, your model's output will probably be None too, and you should fit with y=None.
Is it possible to define a graph in native TensorFlow and then convert this graph to a Keras model?
My intention is simply combining (for me) the best of the two worlds.
I really like the Keras model API for prototyping and new experiments, i.e. using the awesome multi_gpu_model(model, gpus=4) for training with multiple GPUs, saving/loading weights or whole models with oneliners, all the convenience functions like .fit(), .predict(), and others.
However, I prefer to define my model in native TensorFlow. Context managers in TF are awesome and, in my opinion, it is much easier to implement stuff like GANs with them:
with tf.variable_scope("Generator"):
# define some layers
with tf.variable_scope("Discriminator"):
# define some layers
# model losses
G_train_op = ...AdamOptimizer(...)
.minimize(gloss,
var_list=tf.get_collection(tf.GraphKeys.GLOBAL_VARIABLES,
scope="Generator")
D_train_op = ...AdamOptimizer(...)
.minimize(dloss,
var_list=tf.get_collection(tf.GraphKeys.GLOBAL_VARIABLES,
scope="Discriminator")
Another bonus is structuring the graph this way. In TensorBoard debugging complicated native Keras models are hell since they are not structured at all. With heavy use of variable scopes in native TF you can "disentangle" the graph and look at a very structured version of a complicated model for debugging.
By utilizing this I can directly setup custom loss function and do not have to freeze anything in every training iteration since TF will only update the weights in the correct scope, which is (at least in my opinion) far easier than the Keras solution to loop over all the existing layers and set .trainable = False.
TL;DR:
Long story short: I like the direct access to everything in TF, but most of the time a simple Keras model is sufficient for training, inference, ... later on. The model API is much easier and more convenient in Keras.
Hence, I would prefer to set up a graph in native TF and convert it to Keras for training, evaluation, and so on. Is there any way to do this?
I don't think it is possible to create a generic automated converter for any TF graph, that will come up with a meaningful set of layers, with proper namings etc. Just because graphs are more flexible than a sequence of Keras layers.
However, you can wrap your model with the Lambda layer. Build your model inside a function, wrap it with Lambda and you have it in Keras:
def model_fn(x):
layer_1 = tf.layers.dense(x, 100)
layer_2 = tf.layers.dense(layer_1, 100)
out_layer = tf.layers.dense(layer_2, num_classes)
return out_layer
model.add(Lambda(model_fn))
That is what sometimes happens when you use multi_gpu_model: You come up with three layers: Input, model, and Output.
Keras Apologetics
However, integration between TensorFlow and Keras can be much more tighter and meaningful. See this tutorial for use cases.
For instance, variable scopes can be used pretty much like in TensorFlow:
x = tf.placeholder(tf.float32, shape=(None, 20, 64))
with tf.name_scope('block1'):
y = LSTM(32, name='mylstm')(x)
The same for manual device placement:
with tf.device('/gpu:0'):
x = tf.placeholder(tf.float32, shape=(None, 20, 64))
y = LSTM(32)(x) # all ops / variables in the LSTM layer will live on GPU:0
Custom losses are discussed here: Keras: clean implementation for multiple outputs and custom loss functions?
This is how my model defined in Keras looks in Tensorboard:
So, Keras is indeed only a simplified frontend to TensorFlow so you can mix them quite flexibly. I would recommend you to inspect source code of Keras model zoo for clever solutions and patterns that allows you to build complex models using clean API of Keras.
You can insert TensorFlow code directly into your Keras model or training pipeline! Since mid-2017, Keras has fully adopted and integrated into TensorFlow. This article goes into more detail.
This means that your TensorFlow model is already a Keras model and vice versa. You can develop in Keras and switch to TensorFlow whenever you need to. TensorFlow code will work with Keras APIs, including Keras APIs for training, inference and saving your model.
I am using keras to build a multi-output classification model. My dataset is such as
[x1,x2,x3,x4,y1,y2,y3]
x1,x2,x3 are the features, and y1,y2,y3 are the labels, the y1,y2,y3 are multi-classes.
And I already built a model (I ingore some hidden layers):
def baseline_model(input_dim=23,output_dim=3):
model_in = Input(shape=(input_dim,))
model = Dense(input_dim*5,kernel_initializer='uniform',input_dim=input_dim)(model_in)
model = Activation(activation='relu')(model)
model = Dropout(0.5)(model)
...................
model = Dense(output_dim,kernel_initializer='uniform')(model)
model = Activation(activation='sigmoid')(model)
model = Model(model_in,model)
model.compile(optimizer='adam',loss='binary_crossentropy', metrics=['accuracy'])
return model
And then I try to use the method of keras to make it support classification:
estimator = KerasClassifier(build_fn=baseline_model)
estimator.fit()
estimator.predict(df[0:10])
But I found that the result is not multi-output, only one dimension is output.
[0,0,0,0,0,0,0,0,0,0]
So for the multi-output classification problem, we can not use KerasClassifier function to learn it?
You do not need to wrap the model in KerasClassifier. That wrapper is so that you can use the Keras model with Scikit-Learn. The type of model (classifier, regression, multiclass classifier, etc) is ultimately determined by the shape and activation of the final layer of your model.
You can simply use model.fit() function that is part of Keras. Make sure that you pass the data into the function. You can see more info on the fit function here: https://keras.io/models/model/#fit
Also your loss is setup as binary_crossentropy. For a multi-class problem you will want to use categorical_crossentropy.
model.compile(optimizer='adam',loss='categorical_crossentropy', metrics=['accuracy'])
This model isn't really what Keras refers to as multi-output as far as I can tell. With multi-output you are trying to get the output from several different layers and possibly apply different loss functions to them.
Base on the setup in your question you would be able to use the Keras Sequential model instead of the Functional model if you wanted. Keras recommends using the Sequential model if you can because its simpler. https://keras.io/getting-started/sequential-model-guide/
I have successfully gone through the official tutorial, which explains how to retrain inception-v3 model and later successfully retrained the same model o train the model for specific purposes.
The model, however, is complex and slow compared to other, simpler models, such as inception-v1 which accuracy is good enough for some tasks. Specifically, I would like to retrain the model to use it on Android and ideally the performance in terms of speed should be comparable to original TensorFlow Android demo. Anyway, I tried to retrain the inception-v1 model from this link with following modifications in retrain.py:
BOTTLENECK_TENSOR_NAME = 'avgpool0/reshape:0'
BOTTLENECK_TENSOR_SIZE = 2048
MODEL_INPUT_WIDTH = 224
MODEL_INPUT_HEIGHT = 224
MODEL_INPUT_DEPTH = 3
JPEG_DATA_TENSOR_NAME = 'input'
RESIZED_INPUT_TENSOR_NAME = 'input'
As opposed to inception v3, inception v1 does not have any decodeJpeg or resize nodes:
inception v3 nodes:
DecodeJpeg/contents
DecodeJpeg
Cast
ExpandDims/dim
ExpandDims
ResizeBilinear/size
ResizeBilinear
...
pool_3
pool_3/_reshape/shape
pool_3/_reshape
softmax/weights
softmax/biases
softmax/logits/MatMul
softmax/logits
softmax
inception v1 nodes:
input
conv2d0_w
conv2d0_b
conv2d1_w
conv2d1_b
conv2d2_w
conv2d2_b
...
softmax1_pre_activation
softmax1
avgpool0/reshape/shape
avgpool0/reshape
softmax2_pre_activation/matmul
softmax2_pre_activation
softmax2
output
output1
output2
so I guess the images have to be reshaped before being fed into the graph.
Right now the error occurs when hitting the following function:
def run_bottleneck_on_image(sess, image_data, image_data_tensor,
bottleneck_tensor):
"""Runs inference on an image to extract the 'bottleneck' summary layer.
Args:
sess: Current active TensorFlow Session.
image_data: Numpy array of image data.
image_data_tensor: Input data layer in the graph.
bottleneck_tensor: Layer before the final softmax.
Returns:
Numpy array of bottleneck values.
"""
bottleneck_values = sess.run(
bottleneck_tensor,
{image_data_tensor: image_data})
bottleneck_values = np.squeeze(bottleneck_values)
return bottleneck_values
Error:
TypeError: Cannot interpret feed_dict key as Tensor: Can not convert a
Operation into a Tensor.
I guess the data on input node of inception v1 graph has to be reshaped to match the data after passing the following nodes in inception v3:
DecodeJpeg/contents
DecodeJpeg
Cast
ExpandDims/dim
ExpandDims
ResizeBilinear/size
ResizeBilinear
If anyone has already managed to retrain the inception v1 model or has an idea how to reshape the data in inception v1 case to match inception v3, I would be very thankful for any tips or suggestions.
Not sure if you have solved this or not but I am working on a similar problem.
I am trying to use a different model (not Inception-v1 or Inception-v3) with the Inception-v3 transfer learning tutorial. This post seems to be on the right track of remapping the input of the new model (in your case inception-v1) to play nice with the jpeg encoding used in the rest of the tutorial:
feeding image data in tensorflow for transfer learning
The only problem I am having is a error in my input saying "Cannot convert a tensor of type uint8 to an input type of float32" but this may at least put you on the right track.
Good Luck!
(For the ones who are still interested)
Bottleneck tensor size should be 1024 for inception-v1. For me, the following setup works with mentioned inception-v1 for this retrain script. No need for jpeg data tensor or else.
bottleneck_tensor_name = 'avgpool0/reshape:0'
bottleneck_tensor_size = 1024
input_width = 224
input_height = 224
input_depth = 3
resized_input_tensor_name = 'input:0'