alexnet: AlexNet model

In stschn/deepANN: Neural Network Toolbox

AlexNet model

Description

AlexNet model

Usage

alexnet(
  include_top = TRUE,
  weights = "imagenet",
  input_tensor = NULL,
  input_shape = NULL,
  classes = 1000,
  classifier_activation = "softmax"
)

Arguments

include_top	Whether to include the fully-connected layer at the top of the network. A model without a top will output activations from the last convolutional or pooling layer directly.
weights	One of NULL (random initialization), 'imagenet' (pre-trained weights), an array, or the path to the weights file to be loaded.
input_tensor	Optional tensor to use as image input for the model.
input_shape	Dimensionality of the input not including the samples axis.
classes	Optional number of classes or labels to classify images into, only to be specified if include_top = TRUE.
classifier_activation	A string or callable for the activation function to use on top layer, only if include_top = TRUE.

Details

The input shape is usually c(height, width, channels) for a 2D image. If no input shape is specified the default shape 227x227x3 is used.
The number of classes can be computed in three steps. First, build a factor of the labels (classes). Second, use as_CNN_image_Y to one-hot encode the outcome created in the first step. Third, use nunits to get the number of classes. The result is equal to nlevels used on the result of the first step.

For a n-ary classification problem with single-label associations, the output is either one-hot encoded with categorical_crossentropy loss function or binary encoded (0,1) with sparse_categorical_crossentropy loss function. In both cases, the output activation function is softmax.
For a n-ary classification problem with multi-label associations, the output is one-hot encoded with sigmoid activation function and binary_crossentropy loss function.

For a task with another top layer block, e.g. a regression problem, use the following code template:

base_model <- alexnet(include_top = FALSE)
base_model$trainable <- FALSE
outputs <- base_model$output %>%
layer_flatten()
layer_dense(units = 1, activation = "linear")
model <- keras_model(inputs = base_model$input, outputs = outputs)

For a task with another input layer, use the following code template:

inputs <- layer_input(shape = c(256, 256, 3))
blocks <- inputs %>%
layer_conv_2d_transpose(filters = 3, kernel_size = c(1, 1)) %>%
layer_max_pooling_2d()
model <- alexnet(input_tensor = blocks)

Value

A CNN model object from typ AlexNet.

References

Krizhevsky, A., Sutskever, I., Hinton, G. E. (2012): ImageNet Classification with Deep Convolutional Neural Networks. In F. C. N. Pereira, C. J. C. Burges, L. Bottou, K. Q. Weinberger (Hrsg.): Advances in Neural Information Processing Systems 25 (NIPS 2012) (Bd. 25, pp. 1097-1105). Curran Associates.
https://papers.nips.cc/paper/2012/file/c399862d3b9d6b76c8436e924a68c45b-Paper.pdf

See Also

Other Convolutional Neural Network (CNN): as_CNN_image_X(), as_CNN_image_Y(), as_CNN_temp_X(), as_CNN_temp_Y(), as_images_array(), as_images_tensor(), images_load(), images_resize(), inception_resnet_v2(), inception_v3(), lenet5(), mobilenet(), mobilenet_v2(), mobilenet_v3(), nasnet(), resnet, unet(), vgg, xception(), zfnet()

stschn/deepANN documentation built on June 25, 2024, 7:27 a.m.