1. An arrangement to locate an object with a predetermined number of marks, comprising a light source to illuminate the object, a sensor to receive an image of the object and to generate image pixel data, the image pixel data comprising image pixel locations and image pixel intensities for each image pixel location, a processor to receive the image pixel data and to store the image pixel data in a memory, the processor being arranged to perform functions comprising comparing said image pixel intensities with a predetermined threshold; determining object position based on said comparing; using a digital match mask that corresponds with said object with said marks; finding a best match between said digital match mask and said object on said object position; and determining mark positions within said object position from said best match.