RegionOfInterestNode
====================

Overview
--------
Extracts a rectangular region from a grayscale image.

Inputs
------
- Image (GrayScaleImage)
- x (Int)
- y (Int)
- width (Int)
- height (Int)

Parameters
----------
- x: default 0. Left edge of the ROI in pixels
- y: default 0. Top edge of the ROI in pixels
- width: default -1. ROI width; <= 0 uses the remaining image width
- height: default -1. ROI height; <= 0 uses the remaining image height

Outputs
-------
- Result Image (GrayScaleImage)

Example
-------
Set x=100, y=100, width=256, height=256 to crop a 256x256 region.