tf.keras.ops.image.rgb_to_grayscale

Convert RGB images to grayscale.

tf.keras.ops.image.rgb_to_grayscale(
    images, data_format=None
)

This function converts RGB images to grayscale images. It supports both 3D and 4D tensors.

images Input image or batch of images. Must be 3D or 4D.
data_format A string specifying the data format of the input tensor. It can be either "channels_last" or "channels_first". "channels_last" corresponds to inputs with shape (batch, height, width, channels), while "channels_first" corresponds to inputs with shape (batch, channels, height, width). If not specified, the value will default to keras.config.image_data_format.

Grayscale image or batch of grayscale images.

Examples:

import numpy as np
from keras import ops
x = np.random.random((2, 4, 4, 3))
y = ops.image.rgb_to_grayscale(x)
y.shape
(2, 4, 4, 1)
 
x = np.random.random((4, 4, 3)) # Single RGB image
y = ops.image.rgb_to_grayscale(x)
y.shape
(4, 4, 1)
 
x = np.random.random((2, 3, 4, 4))
y = ops.image.rgb_to_grayscale(x, data_format="channels_first")
y.shape
(2, 1, 4, 4)