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train.py
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train.py
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from absl import app, flags, logging
from absl.flags import FLAGS
import os
import shutil
import tensorflow as tf
from core.yolov4 import YOLO, decode, compute_loss, decode_train
from core.dataset import Dataset
from core.config import cfg
import numpy as np
from core import utils
from core.utils import freeze_all, unfreeze_all
flags.DEFINE_string('model', 'yolov4', 'yolov4, yolov3')
flags.DEFINE_string('weights', './scripts/yolov4.weights', 'pretrained weights')
flags.DEFINE_boolean('tiny', False, 'yolo or yolo-tiny')
def main(_argv):
physical_devices = tf.config.experimental.list_physical_devices('GPU')
if len(physical_devices) > 0:
tf.config.experimental.set_memory_growth(physical_devices[0], True)
trainset = Dataset(FLAGS, is_training=True)
testset = Dataset(FLAGS, is_training=False)
logdir = "./data/log"
isfreeze = False
steps_per_epoch = len(trainset)
first_stage_epochs = cfg.TRAIN.FISRT_STAGE_EPOCHS
second_stage_epochs = cfg.TRAIN.SECOND_STAGE_EPOCHS
global_steps = tf.Variable(1, trainable=False, dtype=tf.int64)
warmup_steps = cfg.TRAIN.WARMUP_EPOCHS * steps_per_epoch
total_steps = (first_stage_epochs + second_stage_epochs) * steps_per_epoch
# train_steps = (first_stage_epochs + second_stage_epochs) * steps_per_period
input_layer = tf.keras.layers.Input([cfg.TRAIN.INPUT_SIZE, cfg.TRAIN.INPUT_SIZE, 3])
STRIDES, ANCHORS, NUM_CLASS, XYSCALE = utils.load_config(FLAGS)
IOU_LOSS_THRESH = cfg.YOLO.IOU_LOSS_THRESH
freeze_layers = utils.load_freeze_layer(FLAGS.model, FLAGS.tiny)
feature_maps = YOLO(input_layer, NUM_CLASS, FLAGS.model, FLAGS.tiny)
if FLAGS.tiny:
bbox_tensors = []
for i, fm in enumerate(feature_maps):
if i == 0:
bbox_tensor = decode_train(fm, cfg.TRAIN.INPUT_SIZE // 16, NUM_CLASS, STRIDES, ANCHORS, i, XYSCALE)
else:
bbox_tensor = decode_train(fm, cfg.TRAIN.INPUT_SIZE // 32, NUM_CLASS, STRIDES, ANCHORS, i, XYSCALE)
bbox_tensors.append(fm)
bbox_tensors.append(bbox_tensor)
else:
bbox_tensors = []
for i, fm in enumerate(feature_maps):
if i == 0:
bbox_tensor = decode_train(fm, cfg.TRAIN.INPUT_SIZE // 8, NUM_CLASS, STRIDES, ANCHORS, i, XYSCALE)
elif i == 1:
bbox_tensor = decode_train(fm, cfg.TRAIN.INPUT_SIZE // 16, NUM_CLASS, STRIDES, ANCHORS, i, XYSCALE)
else:
bbox_tensor = decode_train(fm, cfg.TRAIN.INPUT_SIZE // 32, NUM_CLASS, STRIDES, ANCHORS, i, XYSCALE)
bbox_tensors.append(fm)
bbox_tensors.append(bbox_tensor)
model = tf.keras.Model(input_layer, bbox_tensors)
model.summary()
if FLAGS.weights == None:
print("Training from scratch")
else:
if FLAGS.weights.split(".")[len(FLAGS.weights.split(".")) - 1] == "weights":
utils.load_weights(model, FLAGS.weights, FLAGS.model, FLAGS.tiny)
else:
model.load_weights(FLAGS.weights)
print('Restoring weights from: %s ... ' % FLAGS.weights)
optimizer = tf.keras.optimizers.Adam()
if os.path.exists(logdir): shutil.rmtree(logdir)
writer = tf.summary.create_file_writer(logdir)
# define training step function
# @tf.function
def train_step(image_data, target):
with tf.GradientTape() as tape:
pred_result = model(image_data, training=True)
giou_loss = conf_loss = prob_loss = 0
# optimizing process
for i in range(len(freeze_layers)):
conv, pred = pred_result[i * 2], pred_result[i * 2 + 1]
loss_items = compute_loss(pred, conv, target[i][0], target[i][1], STRIDES=STRIDES, NUM_CLASS=NUM_CLASS, IOU_LOSS_THRESH=IOU_LOSS_THRESH, i=i)
giou_loss += loss_items[0]
conf_loss += loss_items[1]
prob_loss += loss_items[2]
total_loss = giou_loss + conf_loss + prob_loss
gradients = tape.gradient(total_loss, model.trainable_variables)
optimizer.apply_gradients(zip(gradients, model.trainable_variables))
tf.print("=> STEP %4d/%4d lr: %.6f giou_loss: %4.2f conf_loss: %4.2f "
"prob_loss: %4.2f total_loss: %4.2f" % (global_steps, total_steps, optimizer.lr.numpy(),
giou_loss, conf_loss,
prob_loss, total_loss))
# update learning rate
global_steps.assign_add(1)
if global_steps < warmup_steps:
lr = global_steps / warmup_steps * cfg.TRAIN.LR_INIT
else:
lr = cfg.TRAIN.LR_END + 0.5 * (cfg.TRAIN.LR_INIT - cfg.TRAIN.LR_END) * (
(1 + tf.cos((global_steps - warmup_steps) / (total_steps - warmup_steps) * np.pi))
)
optimizer.lr.assign(lr.numpy())
# writing summary data
with writer.as_default():
tf.summary.scalar("lr", optimizer.lr, step=global_steps)
tf.summary.scalar("loss/total_loss", total_loss, step=global_steps)
tf.summary.scalar("loss/giou_loss", giou_loss, step=global_steps)
tf.summary.scalar("loss/conf_loss", conf_loss, step=global_steps)
tf.summary.scalar("loss/prob_loss", prob_loss, step=global_steps)
writer.flush()
def test_step(image_data, target):
with tf.GradientTape() as tape:
pred_result = model(image_data, training=True)
giou_loss = conf_loss = prob_loss = 0
# optimizing process
for i in range(len(freeze_layers)):
conv, pred = pred_result[i * 2], pred_result[i * 2 + 1]
loss_items = compute_loss(pred, conv, target[i][0], target[i][1], STRIDES=STRIDES, NUM_CLASS=NUM_CLASS, IOU_LOSS_THRESH=IOU_LOSS_THRESH, i=i)
giou_loss += loss_items[0]
conf_loss += loss_items[1]
prob_loss += loss_items[2]
total_loss = giou_loss + conf_loss + prob_loss
tf.print("=> TEST STEP %4d giou_loss: %4.2f conf_loss: %4.2f "
"prob_loss: %4.2f total_loss: %4.2f" % (global_steps, giou_loss, conf_loss,
prob_loss, total_loss))
for epoch in range(first_stage_epochs + second_stage_epochs):
if epoch < first_stage_epochs:
if not isfreeze:
isfreeze = True
for name in freeze_layers:
freeze = model.get_layer(name)
freeze_all(freeze)
elif epoch >= first_stage_epochs:
if isfreeze:
isfreeze = False
for name in freeze_layers:
freeze = model.get_layer(name)
unfreeze_all(freeze)
for image_data, target in trainset:
train_step(image_data, target)
for image_data, target in testset:
test_step(image_data, target)
model.save_weights("./checkpoints/yolov4")
if __name__ == '__main__':
try:
app.run(main)
except SystemExit:
pass