Vgg16 Architecture:
Prerequisites:
ALEXNet : ALEXNet Architecture
* vgg refers to visual geometry group who has developed vgg16 architecture.
* 16 refers to number of layers.
VGG16 or VGGNet is a
convolution neural network and it is a simplified and better version of
Alexnet.
Remembering
Alexnet architecture is very difficult, Later on 2014, vgg16 came as an
architecture and it is very simple to remember.
VGG16 is very
simple where:
· It is built on Convolution
operations with fixed kernel_size=(3x3), padding=’same’, and stride=1
for all Convolution layers.
· And also Maxpooling operation with pool_size=(2x2) and stride=2 for all Maxpool layers.
Let's see the architecture of vgg16
If you observe the figure, As said all
convolution layers have 3x3 kernels and all maxpool layers have size of 2x2.
Note 1: For maxpool layers the padding=‘valid’ which
means there is no padding, so the matrix size will changes.
Note 2: For convolution layers the padding=‘same’ which
means there is padding operation, so the matrix size will remain same.
Now let’s see the architecture in detail
In the above figure, If you observe at convolution operation there is no change in tensor size but at maxpool operation there is a change as said in Note1 and Note2.
There are two variants in this type of CNN, They are
VGG16 and VGG19, Both are different in number of layers, But the accuracy is
almost same.
Advantages:
It gives accuracy better than Alexnet.
Disadvantages:
The VGGNet has more layers than AlexNet so as more parameters to train.
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