sampleGrid(image, topLeft, topRight, bottomRight, bottomLeft) {
			let sampler = GridSamplerInstance.getInstance();
			let dimension = this.getDimension();
			let low = dimension / 2 - this.nbCenterLayers;
			let high = dimension / 2 + this.nbCenterLayers;
			return sampler.sampleGrid(image, dimension, dimension, low, low, // topleft
				high, low, // topright
				high, high, // bottomright
				low, high, // bottomleft
				topLeft.getX(), topLeft.getY(), topRight.getX(), topRight.getY(), bottomRight.getX(), bottomRight.getY(), bottomLeft.getX(), bottomLeft.getY());
		}
Creates a BitMatrix by sampling the provided image.
topLeft, topRight, bottomRight, and bottomLeft are the centers of the squares on the
diagonal just outside the bull's eye.