op {
  graph_op_name: "AdjustContrastv2"
  endpoint {
    name: "AdjustContrast"
  }
  in_arg {
    name: "images"
    description: <<END
Images to adjust.  At least 3-D.
END
  }
  in_arg {
    name: "contrast_factor"
    description: <<END
A float multiplier for adjusting contrast.
END
  }
  out_arg {
    name: "output"
    description: <<END
The contrast-adjusted image or images.
END
  }
  summary: "Adjust the contrast of one or more images."
  description: <<END
`images` is a tensor of at least 3 dimensions.  The last 3 dimensions are
interpreted as `[height, width, channels]`.  The other dimensions only
represent a collection of images, such as `[batch, height, width, channels].`

Contrast is adjusted independently for each channel of each image.

For each channel, the Op first computes the mean of the image pixels in the
channel and then adjusts each component of each pixel to
`(x - mean) * contrast_factor + mean`.
END
}