In VGG16. the last 4 layers
Convolution using 512 filters+Max pooling
Fully connected with 4096 nodes
Fully connected with 4096 nodes
Output layer with SoftMax activation with 1000 nodes.
Where did the number 4096 come from?
Related
I have two groups of images (concrete cracks and uncracked concrete) so they are binary classification, I am making classification for them by using vgg19.
when I used (1) neuron for the output layer and using softmax I got accuracy 0.5 and fixed during 250 epochs, while when I used 2 neuron with softmax the accuaracy increaced above 0.9.
So, shall I have to use 1 or 2 neurons for the output for VGG19 with binary classification?
Knowing that the total number of layers in EfficientNet-B0 is 237 and in EfficientNet-B7 the total comes out to 813, what is the total number of layers in EfficientNetB2 ?
If you print len(model.layers) on EfficientNetB2 model with keras you will have 342 layers.
import tensorflow as tf
from tensorflow.keras.applications import EfficientNetB2
model = EfficientNetB2(weights='imagenet')
print(len(model.layers))
You can do this with all other versions of EfficientNetBx if you wish.
But as Pradyut said here normally not all layers are taken into account when we count them:
While counting the number of layers in a Neural Network we usually
only count convolutional layers and fully connected layers. Pooling
Layer is taken together with the Convolutional Layer and counted as
one layer and Dropout is a regularization technique so it will also
not be counted as a separate layer.
For reference, the VGG16 mode is defined as a 16 layer model. Those 16
layers are only the Convolutional Layers and Fully Connected Dense
Layers. If you count all the pooling and activation layers it will
change to a 41 layer model, which it is not. Reference: VGG16, VGG16
Paper
So as per your code you have 3 layers (1 Convolutional Layer with 28
Neurons, 1 Fully Connected Layer with 128 Neurons and 1 Fully
Connected Layer with 10 neurons)
As for making it a 10 layer network you can add more convolutional
layers or dense layers before the output layers, but it won't be
necessary for the MNIST dataset.
I hope I answered your question!
Hello every one i'm reading pointnet papper but i cant understand the numbers of network architecture can you explain this to me.
enter image description here
It means 3 fully connected layers, having neurons in each layer as 64, 128 and 1024 respectively. Between each layer, there is batch normalization as well as RELU activation (implemented in the paper).
I am currently trying to understand the following paper: https://arxiv.org/pdf/1703.08581.pdf. I am struggling to understand a part about how a convolution is performed on an input of log mel filterbank features:
We train seq2seq models for both end-to-end speech translation, and a baseline model for speech recognition. We found
that the same architecture, a variation of that from [10], works
well for both tasks. We use 80 channel log mel filterbank features extracted from 25ms windows with a hop size of 10ms,
stacked with delta and delta-delta features. The output softmax
of all models predicts one of 90 symbols, described in detail in
Section 4, that includes English and Spanish lowercase letters.
The encoder is composed of a total of 8 layers. The input
features are organized as a T × 80 × 3 tensor, i.e. raw features,
deltas, and delta-deltas are concatenated along the ’depth’ dimension. This is passed into a stack of two convolutional layers
with ReLU activations, each consisting of 32 kernels with shape
3 × 3 × depth in time × frequency. These are both strided by
2 × 2, downsampling the sequence in time by a total factor of 4,
decreasing the computation performed in the following layers.
Batch normalization [26] is applied after each layer.
As I understand it, the input to the convolutional layer is 3 dimensional (number of 25 ms windows (T) x 80 (features for each window) x 3 (features, delta features and delta-delta features). However, the kernels used on those inputs seem to have 4 dimensions and I do not understand why that is. Wouldn't a 4 dimensional kernel need a 4 dimensional input? In my head, the input has the same dimensions as a rgb picture: width (time) x height (frequency) x color channels (features, delta features and delta-delta features). Therefore I would think of a kernel for a 2D convolution as a filter of size a (filter width) x b (filter height) x 3 (depth of the input). Am I missing something here? What is wrong about my idea or what is done different in this paper?
Thanks in advance for your answer!
I figured it out, turns out it was just a misunderstanding from my side: the authors are using 32 kernels of shape 3x3, which results (after two layers with 2x2 striding) in an output of shape t/4x20x32 where t stands for the time dimension.
In most of the architectures, conv layers are being followed by a pooling layer (max / avg etc.). As those pooling layers are just selecting the output of previous layer (i.e. conv), can we just use convolution with stride 2 and expect the similar accuracy results with reduced process need?
Yes that can be done. Its explained in the paper 'Striving for simplicity: The all convolutional net' https://arxiv.org/pdf/1412.6806.pdf. Quote from the paper:
'We find that max-pooling can simply be replaced by a convolutional
layer with increased stride without loss in accuracy on several image
recognition benchmarks'