text stringlengths 0 4.99k |
|---|
validation_data=validation_ds, |
epochs=epochs, |
callbacks=[edit_distance_callback], |
) |
Epoch 1/10 |
1357/1357 [==============================] - 89s 51ms/step - loss: 13.6670 - val_loss: 11.8041 |
Mean edit distance for epoch 1: 20.5117 |
Epoch 2/10 |
1357/1357 [==============================] - 48s 36ms/step - loss: 10.6864 - val_loss: 9.6994 |
Mean edit distance for epoch 2: 20.1167 |
Epoch 3/10 |
1357/1357 [==============================] - 48s 35ms/step - loss: 9.0437 - val_loss: 8.0355 |
Mean edit distance for epoch 3: 19.7270 |
Epoch 4/10 |
1357/1357 [==============================] - 48s 35ms/step - loss: 7.6098 - val_loss: 6.4239 |
Mean edit distance for epoch 4: 19.1106 |
Epoch 5/10 |
1357/1357 [==============================] - 48s 35ms/step - loss: 6.3194 - val_loss: 4.9814 |
Mean edit distance for epoch 5: 18.4894 |
Epoch 6/10 |
1357/1357 [==============================] - 48s 35ms/step - loss: 5.3417 - val_loss: 4.1307 |
Mean edit distance for epoch 6: 18.1909 |
Epoch 7/10 |
1357/1357 [==============================] - 48s 35ms/step - loss: 4.6396 - val_loss: 3.7706 |
Mean edit distance for epoch 7: 18.1224 |
Epoch 8/10 |
1357/1357 [==============================] - 48s 35ms/step - loss: 4.1926 - val_loss: 3.3682 |
Mean edit distance for epoch 8: 17.9387 |
Epoch 9/10 |
1357/1357 [==============================] - 48s 36ms/step - loss: 3.8532 - val_loss: 3.1829 |
Mean edit distance for epoch 9: 17.9074 |
Epoch 10/10 |
1357/1357 [==============================] - 49s 36ms/step - loss: 3.5769 - val_loss: 2.9221 |
Mean edit distance for epoch 10: 17.7960 |
Inference |
# A utility function to decode the output of the network. |
def decode_batch_predictions(pred): |
input_len = np.ones(pred.shape[0]) * pred.shape[1] |
# Use greedy search. For complex tasks, you can use beam search. |
results = keras.backend.ctc_decode(pred, input_length=input_len, greedy=True)[0][0][ |
:, :max_len |
] |
# Iterate over the results and get back the text. |
output_text = [] |
for res in results: |
res = tf.gather(res, tf.where(tf.math.not_equal(res, -1))) |
res = tf.strings.reduce_join(num_to_char(res)).numpy().decode(\"utf-8\") |
output_text.append(res) |
return output_text |
# Let's check results on some test samples. |
for batch in test_ds.take(1): |
batch_images = batch[\"image\"] |
_, ax = plt.subplots(4, 4, figsize=(15, 8)) |
preds = prediction_model.predict(batch_images) |
pred_texts = decode_batch_predictions(preds) |
for i in range(16): |
img = batch_images[i] |
img = tf.image.flip_left_right(img) |
img = tf.transpose(img, perm=[1, 0, 2]) |
img = (img * 255.0).numpy().clip(0, 255).astype(np.uint8) |
img = img[:, :, 0] |
title = f\"Prediction: {pred_texts[i]}\" |
ax[i // 4, i % 4].imshow(img, cmap=\"gray\") |
ax[i // 4, i % 4].set_title(title) |
ax[i // 4, i % 4].axis(\"off\") |
plt.show() |
png |
To get better results the model should be trained for at least 50 epochs. |
Final remarks |
The prediction_model is fully compatible with TensorFlow Lite. If you are interested, you can use it inside a mobile application. You may find this notebook to be useful in this regard. |
Not all the training examples are perfectly aligned as observed in this example. This can hurt model performance for complex sequences. To this end, we can leverage Spatial Transformer Networks (Jaderberg et al.) that can help the model learn affine transformations that maximize its performance. |
Implement an image captioning model using a CNN and a Transformer. |
Setup |
import os |
import re |
import numpy as np |
import matplotlib.pyplot as plt |
import tensorflow as tf |
from tensorflow import keras |
from tensorflow.keras import layers |
from tensorflow.keras.applications import efficientnet |
from tensorflow.keras.layers import TextVectorization |
seed = 111 |
np.random.seed(seed) |
tf.random.set_seed(seed) |
Download the dataset |
We will be using the Flickr8K dataset for this tutorial. This dataset comprises over 8,000 images, that are each paired with five different captions. |
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