Function histogram 

pub fn histogram<T, const CHANNELS: usize>(
    input: ImageView<'_, T, CHANNELS>,
    channel: usize,
    bins: usize,
    range: (f64, f64),
    mask: Option<ImageView<'_, u8, 1>>,
) -> Result<Vec<u64>, VisionError>
where
    T: PixelComponent,

Computes a configurable one-channel histogram, optionally through a mask.