TensorFlow 2.0 Keras: How to write image summaries for TensorBoard

Question

I\'m trying to setup an image recognition CNN with TensorFlow 2.0. To be able to analyze my image augmentation I\'d like to see the images I feed into the network in tensorb

Answer 1

You could do something like this to add input image to tensorboard

def scale(image, label):
    return tf.cast(image, tf.float32) / 255.0, label


def augment(image, label):
    return image, label  # do nothing atm


file_writer = tf.summary.create_file_writer(logdir + "/images")


def plot_to_image(figure):
    buf = io.BytesIO()
    plt.savefig(buf, format='png')
    plt.close(figure)
    buf.seek(0)
    image = tf.image.decode_png(buf.getvalue(), channels=4)
    image = tf.expand_dims(image, 0)
    return image


def image_grid():
    """Return a 5x5 grid of the MNIST images as a matplotlib figure."""
    # Create a figure to contain the plot.
    figure = plt.figure(figsize=(10, 10))
    for i in range(25):
        # Start next subplot.
        plt.subplot(5, 5, i + 1, title=str(y_train[i]))
        plt.xticks([])
        plt.yticks([])
        plt.grid(False)
        image, _ = scale(x_train[i], y_train[i])
        plt.imshow(x_train[i], cmap=plt.cm.binary)

    return figure


# Prepare the plot
figure = image_grid()
# Convert to image and log
with file_writer.as_default():
    tf.summary.image("Training data", plot_to_image(figure), step=0)

dataset = tf.data.Dataset.from_tensor_slices((x_train, y_train))
dataset = dataset.map(scale).map(augment).batch(32)

model = tf.keras.models.Sequential([
    tf.keras.layers.Flatten(input_shape=(28, 28)),
    tf.keras.layers.Dense(128, activation='relu'),
    tf.keras.layers.Dropout(0.2),
    tf.keras.layers.Dense(10, activation='softmax')
])

model.compile(optimizer='adam', loss='sparse_categorical_crossentropy', metrics=['accuracy'])

model.fit(dataset, epochs=5, callbacks=[tf.keras.callbacks.TensorBoard(log_dir=logdir)])