tensorflow.js - How to transform a webcam image to grayscale using TensorflowJS?

Question

I am trying to use a model to classify grayscale images.

I used the Webcam class provided in some of the TensorflowJS examples to get an image using the webcam. It worked well, but it returns an RGB image.

What is the best way to transform this image to grayscale? Do I need to compute this getting each element from the tensor and compute a new matrix that represents the grayscale image or is there a more simple or convenient way?

Answer 1

If you need to have it in the form [width, height, 1]:

tf.browser.fromPixels(image)
    .mean(2)
    .toFloat()
    .expandDims(-1)

If you need in the form [1, width, height, 1]:

tf.browser.fromPixels(image)
    .mean(2)
    .toFloat()
    .expandDims(0)
    .expandDims(-1)