Function crop 

pub fn crop(
    input: &Tensor,
    top: usize,
    left: usize,
    crop_h: usize,
    crop_w: usize,
) -> Result<Tensor, ImgProcError>

Crop a region from an image tensor. Input: [H, W, C] or [H, W]. Crops an HWC tensor to [crop_h, crop_w, C] starting at (top, left).