tf.keras.backend.ctc_decode

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Decodes the output of a softmax.

tf.keras.backend.ctc_decode(
    y_pred, input_length, greedy=True, beam_width=100, top_paths=1
)

Can use either greedy search (also known as best path) or a constrained dictionary search.

Arguments:

• y_pred: tensor (samples, time_steps, num_categories) containing the prediction, or output of the softmax.
• input_length: tensor (samples, ) containing the sequence length for each batch item in y_pred.
• greedy: perform much faster best-path search if true. This does not use a dictionary.
• beam_width: if greedy is false: a beam search decoder will be used with a beam of this width.
• top_paths: if greedy is false, how many of the most probable paths will be returned.

Returns:

• Tuple: List: if greedy is true, returns a list of one element that contains the decoded sequence. If false, returns the top_paths most probable decoded sequences. Important: blank labels are returned as -1. Tensor (top_paths, ) that contains the log probability of each decoded sequence.