vgg_network.py

# Copyright (c) 2015-2016 Anish Athalye. Released under GPLv3.
# Most code in this file was borrowed from https://github.com/anishathalye/neural-style/blob/master/vgg.py

import tensorflow as tf
import numpy as np
import scipy.io
import os

# download URL : http://www.vlfeat.org/matconvnet/models/imagenet-vgg-verydeep-19.mat
MODEL_FILE_NAME = 'imagenet-vgg-verydeep-19.mat'

def _conv_layer(input, weights, bias):
    conv = tf.nn.conv2d(input, tf.constant(weights), strides=(1, 1, 1, 1), padding='SAME')
    return tf.nn.bias_add(conv, bias)

def _pool_layer(input):
    return tf.nn.max_pool(input, ksize=(1, 2, 2, 1), strides=(1, 2, 2, 1), padding='SAME')

class VGG(object):
    layers = (
        'conv1_1', 'relu1_1', 'conv1_2', 'relu1_2', 'pool1',
        'conv2_1', 'relu2_1', 'conv2_2', 'relu2_2', 'pool2',
        'conv3_1', 'relu3_1', 'conv3_2', 'relu3_2', 'conv3_3', 'relu3_3', 'conv3_4', 'relu3_4', 'pool3',
        'conv4_1', 'relu4_1', 'conv4_2', 'relu4_2', 'conv4_3', 'relu4_3', 'conv4_4', 'relu4_4', 'pool4',
        'conv5_1', 'relu5_1', 'conv5_2', 'relu5_2', 'conv5_3', 'relu5_3', 'conv5_4', 'relu5_4'
    )

    def __init__(self, data_path):
        self.data = scipy.io.loadmat(os.path.join(data_path, MODEL_FILE_NAME))
        mean = self.data['normalization'][0][0][0]
        self.mean_pixel = np.mean(mean, axis=(0, 1)).astype(np.float32)
        self.weights = self.data['layers'][0]

    def preprocess(self, image):
        return image-self.mean_pixel

    def net(self, input_image, name=None):
        net = {}
        current = input_image
        with tf.variable_scope(name):
            for i, name in enumerate(self.layers):
                if name[:4] == 'conv':
                    kernels, bias = self.weights[i][0][0][0][0]
                    kernels = np.transpose(kernels, (1, 0, 2, 3)).astype(np.float32)
                    bias = bias.reshape(-1).astype(np.float32)
                    current = _conv_layer(current, kernels, bias)
                elif name[:4] == 'relu':
                    current = tf.nn.relu(current)
                elif name[:4] == 'pool':
                    current = _pool_layer(current)
                net[name] = current
        return net