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# PyTorch implementation of Darknet
# This is a custom, hard-coded version of darknet with
# YOLOv3 implementation for openimages database. This
# was written to test viability of implementing YOLO
# for face detection followed by emotion / sentiment
# analysis.
#
# Configuration, weights and data are hardcoded.
# Additional options include, ability to create
# subset of data with faces exracted for labelling.
#
# Author : Saikiran Tharimena
# Co-Authors: Kjetil Marinius Sjulsen, Juan Carlos Calvet Lopez
# Project : Emotion / Sentiment Detection from news images
# Date : 12 September 2022
# Version : v0.1
#
# (C) Schibsted ASA
# Libraries
import torch
import torch.nn as nn
import torch.nn.functional as F
from torch.autograd import Variable
import numpy as np
from utils import *
def parse_cfg(cfgfile):
"""
Takes a configuration file
Returns a list of blocks. Each blocks describes a block in the neural
network to be built. Block is represented as a dictionary in the list
"""
file = open(cfgfile, 'r')
lines = file.read().split('\n') # store the lines in a list
lines = [x for x in lines if len(x) > 0] # get read of the empty lines
lines = [x for x in lines if x[0] != '#'] # get rid of comments
lines = [x.rstrip().lstrip() for x in lines] # get rid of fringe whitespaces
block = {}
blocks = []
for line in lines:
if line[0] == "[": # This marks the start of a new block
if len(block) != 0: # If block is not empty, implies it is storing values of previous block.
blocks.append(block) # add it the blocks list
block = {} # re-init the block
block["type"] = line[1:-1].rstrip()
else:
key,value = line.split("=")
block[key.rstrip()] = value.lstrip()
blocks.append(block)
return blocks
class EmptyLayer(nn.Module):
def __init__(self):
super(EmptyLayer, self).__init__()
class DetectionLayer(nn.Module):
def __init__(self, anchors):
super(DetectionLayer, self).__init__()
self.anchors = anchors
def create_modules(blocks):
net_info = blocks[0] #Captures the information about the input and pre-processing
module_list = nn.ModuleList()
prev_filters = 3
output_filters = []
for index, x in enumerate(blocks[1:]):
module = nn.Sequential()
#check the type of block
#create a new module for the block
#append to module_list
#If it's a convolutional layer
if (x["type"] == "convolutional"):
#Get the info about the layer
activation = x["activation"]
try:
batch_normalize = int(x["batch_normalize"])
bias = False
except:
batch_normalize = 0
bias = True
filters= int(x["filters"])
padding = int(x["pad"])
kernel_size = int(x["size"])
stride = int(x["stride"])
if padding:
pad = (kernel_size - 1) // 2
else:
pad = 0
#Add the convolutional layer
conv = nn.Conv2d(prev_filters, filters, kernel_size, stride, pad, bias = bias)
module.add_module("conv_{0}".format(index), conv)
#Add the Batch Norm Layer
if batch_normalize:
bn = nn.BatchNorm2d(filters)
module.add_module("batch_norm_{0}".format(index), bn)
#Check the activation.
#It is either Linear or a Leaky ReLU for YOLO
if activation == "leaky":
activn = nn.LeakyReLU(0.1, inplace = True)
module.add_module("leaky_{0}".format(index), activn)
#If it's an upsampling layer
#We use Bilinear2dUpsampling
elif (x["type"] == "upsample"):
stride = int(x["stride"])
upsample = nn.Upsample(scale_factor = 2, mode = "nearest")
module.add_module("upsample_{}".format(index), upsample)
#If it is a route layer
elif (x["type"] == "route"):
x["layers"] = x["layers"].split(',')
#Start of a route
start = int(x["layers"][0])
#end, if there exists one.
try:
end = int(x["layers"][1])
except:
end = 0
#Positive anotation
if start > 0:
start = start - index
if end > 0:
end = end - index
route = EmptyLayer()
module.add_module("route_{0}".format(index), route)
if end < 0:
filters = output_filters[index + start] + output_filters[index + end]
else:
filters= output_filters[index + start]
#shortcut corresponds to skip connection
elif x["type"] == "shortcut":
shortcut = EmptyLayer()
module.add_module("shortcut_{}".format(index), shortcut)
#Yolo is the detection layer
elif x["type"] == "yolo":
mask = x["mask"].split(",")
mask = [int(x) for x in mask]
anchors = x["anchors"].split(",")
anchors = [int(a) for a in anchors]
anchors = [(anchors[i], anchors[i+1]) for i in range(0, len(anchors),2)]
anchors = [anchors[i] for i in mask]
detection = DetectionLayer(anchors)
module.add_module("Detection_{}".format(index), detection)
module_list.append(module)
prev_filters = filters
output_filters.append(filters)
return (net_info, module_list)
class Darknet(nn.Module):
def __init__(self, cfgfile):
super(Darknet, self).__init__()
self.blocks = parse_cfg(cfgfile)
self.net_info, self.module_list = create_modules(self.blocks)
def forward(self, x, CUDA):
modules = self.blocks[1:]
outputs = {} #We cache the outputs for the route layer
write = 0
for i, module in enumerate(modules):
module_type = (module["type"])
if module_type == "convolutional" or module_type == "upsample":
x = self.module_list[i](x)
elif module_type == "route":
layers = module["layers"]
layers = [int(a) for a in layers]
if (layers[0]) > 0:
layers[0] = layers[0] - i
if len(layers) == 1:
x = outputs[i + (layers[0])]
else:
if (layers[1]) > 0:
layers[1] = layers[1] - i
map1 = outputs[i + layers[0]]
map2 = outputs[i + layers[1]]
x = torch.cat((map1, map2), 1)
elif module_type == "shortcut":
from_ = int(module["from"])
x = outputs[i-1] + outputs[i+from_]
elif module_type == 'yolo':
anchors = self.module_list[i][0].anchors
#Get the input dimensions
inp_dim = int (self.net_info["height"])
#Get the number of classes
num_classes = int (module["classes"])
#Transform
x = x.data
x = predict_transform(x, inp_dim, anchors, num_classes, CUDA)
if not write: #if no collector has been intialised.
detections = x
write = 1
else:
detections = torch.cat((detections, x), 1)
outputs[i] = x
return detections
def load_weights(self, weightfile):
#Open the weights file
fp = open(weightfile, "rb")
#The first 5 values are header information
# 1. Major version number
# 2. Minor Version Number
# 3. Subversion number
# 4,5. Images seen by the network (during training)
header = np.fromfile(fp, dtype = np.int32, count = 5)
self.header = torch.from_numpy(header)
self.seen = self.header[3]
weights = np.fromfile(fp, dtype = np.float32)
ptr = 0
for i in range(len(self.module_list)):
module_type = self.blocks[i + 1]["type"]
#If module_type is convolutional load weights
#Otherwise ignore.
if module_type == "convolutional":
model = self.module_list[i]
try:
batch_normalize = int(self.blocks[i+1]["batch_normalize"])
except:
batch_normalize = 0
conv = model[0]
if (batch_normalize):
bn = model[1]
#Get the number of weights of Batch Norm Layer
num_bn_biases = bn.bias.numel()
#Load the weights
bn_biases = torch.from_numpy(weights[ptr:ptr + num_bn_biases])
ptr += num_bn_biases
bn_weights = torch.from_numpy(weights[ptr: ptr + num_bn_biases])
ptr += num_bn_biases
bn_running_mean = torch.from_numpy(weights[ptr: ptr + num_bn_biases])
ptr += num_bn_biases
bn_running_var = torch.from_numpy(weights[ptr: ptr + num_bn_biases])
ptr += num_bn_biases
#Cast the loaded weights into dims of model weights.
bn_biases = bn_biases.view_as(bn.bias.data)
bn_weights = bn_weights.view_as(bn.weight.data)
bn_running_mean = bn_running_mean.view_as(bn.running_mean)
bn_running_var = bn_running_var.view_as(bn.running_var)
#Copy the data to model
bn.bias.data.copy_(bn_biases)
bn.weight.data.copy_(bn_weights)
bn.running_mean.copy_(bn_running_mean)
bn.running_var.copy_(bn_running_var)
else:
#Number of biases
num_biases = conv.bias.numel()
#Load the weights
conv_biases = torch.from_numpy(weights[ptr: ptr + num_biases])
ptr = ptr + num_biases
#reshape the loaded weights according to the dims of the model weights
conv_biases = conv_biases.view_as(conv.bias.data)
#Finally copy the data
conv.bias.data.copy_(conv_biases)
#Let us load the weights for the Convolutional layers
num_weights = conv.weight.numel()
#Do the same as above for weights
conv_weights = torch.from_numpy(weights[ptr:ptr+num_weights])
ptr = ptr + num_weights
conv_weights = conv_weights.view_as(conv.weight.data)
conv.weight.data.copy_(conv_weights)