An image processing device receives a captured image as input from an image capturing device installed in a conveying mechanism that conveys and tests works. In particular the present invention provides for interchangeable footwear, wherein the appearance of the footwear is readily interchangeable to suit the style of the intended wearer, the interchangeable components being the toe straps and ankle straps that secure the footwear to an individual’s feet. This analysis may be performed using the data analysis tools of a conventional electronic spreadsheet having matrix multiplication and regression capability.