tf.io.decode_image

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Function for decode_bmp, decode_gif, decode_jpeg, and decode_png.

tf.io.decode_image(
    contents, channels=None, dtype=tf.dtypes.uint8, name=None,
    expand_animations=True
)

Detects whether an image is a BMP, GIF, JPEG, or PNG, and performs the appropriate operation to convert the input bytes string into a Tensor of type dtype.

Note: decode_gif returns a 4-D array [num_frames, height, width, 3], as opposed to decode_bmp, decode_jpeg and decode_png, which return 3-D arrays [height, width, num_channels]. Make sure to take this into account when constructing your graph if you are intermixing GIF files with BMP, JPEG, and/or PNG files. Alternately, set the expand_animations argument of this function to False, in which case the op will return 3-dimensional tensors and will truncate animated GIF files to the first frame.

Args:

• contents: 0-D string. The encoded image bytes.
• channels: An optional int. Defaults to 0. Number of color channels for the decoded image.
• dtype: The desired DType of the returned Tensor.
• name: A name for the operation (optional)
• expand_animations: Controls the shape of the returned op's output. If True, the returned op will produce a 3-D tensor for PNG, JPEG, and BMP files; and a 4-D tensor for all GIFs, whether animated or not. If, False, the returned op will produce a 3-D tensor for all file types and will truncate animated GIFs to the first frame.

Returns:

Tensor with type dtype and a 3- or 4-dimensional shape, depending on the file type and the value of the expand_animations parameter.

Raises:

• ValueError: On incorrect number of channels.