Created
October 14, 2021 18:20
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class PositionalEmbedding(layers.Layer): | |
def __init__(self, sequence_length, output_dim, **kwargs): | |
super().__init__(**kwargs) | |
self.position_embeddings = layers.Embedding( | |
input_dim=sequence_length, output_dim=output_dim | |
) | |
self.sequence_length = sequence_length | |
self.output_dim = output_dim | |
def call(self, inputs): | |
# The inputs are of shape: `(batch_size, frames, num_features)` | |
length = tf.shape(inputs)[1] | |
positions = tf.range(start=0, limit=length, delta=1) | |
embedded_positions = self.position_embeddings(positions) | |
return inputs + embedded_positions | |
def compute_mask(self, inputs, mask=None): | |
mask = tf.reduce_any(tf.cast(inputs, "bool"), axis=-1) | |
return mask | |
class TransformerEncoder(layers.Layer): | |
def __init__(self, embed_dim, dense_dim, num_heads, **kwargs): | |
super().__init__(**kwargs) | |
self.embed_dim = embed_dim | |
self.dense_dim = dense_dim | |
self.num_heads = num_heads | |
self.attention = layers.MultiHeadAttention( | |
num_heads=num_heads, key_dim=embed_dim, dropout=0.3 | |
) | |
self.dense_proj = keras.Sequential( | |
[layers.Dense(dense_dim, activation=tf.nn.gelu), layers.Dense(embed_dim),] | |
) | |
self.layernorm_1 = layers.LayerNormalization() | |
self.layernorm_2 = layers.LayerNormalization() | |
def call(self, inputs, mask=None): | |
if mask is not None: | |
mask = mask[:, tf.newaxis, :] | |
attention_output = self.attention(inputs, inputs, attention_mask=mask) | |
proj_input = self.layernorm_1(inputs + attention_output) | |
proj_output = self.dense_proj(proj_input) | |
return self.layernorm_2(proj_input + proj_output) | |
lr_schedule = keras.optimizers.schedules.ExponentialDecay( | |
initial_learning_rate=1e-2, | |
decay_steps=10000, | |
decay_rate=0.001) | |
optimizer = keras.optimizers.SGD(learning_rate=lr_schedule) | |
def get_compiled_model(): | |
sequence_length = 70 | |
embed_dim = 1280 | |
dense_dim = 32 | |
num_heads = 3 | |
classes = len(label_processor) | |
inputs = keras.Input(shape=(None, None)) | |
x = PositionalEmbedding( | |
sequence_length, embed_dim, name="frame_position_embedding" | |
)(inputs) | |
x = TransformerEncoder(embed_dim, dense_dim, num_heads, name="transformer_layer")(x) | |
x = layers.GlobalMaxPooling1D()(x) | |
x = layers.Dropout(0.5)(x) | |
outputs = layers.Dense(classes, activation="softmax")(x) | |
model = keras.Model(inputs, outputs) | |
optimizer = keras.optimizers.SGD(learning_rate=lr_schedule) | |
model.compile( | |
optimizer=optimizer, loss="sparse_categorical_crossentropy", metrics=["accuracy"] | |
) | |
return model | |
seq_model=get_compiled_model() | |
seq_model.load_weights('video_classifierx (1)') | |
seq_model.save('activity_classifier.h5') |
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