Laser-computer graphics system for generating portrait and 3-D sculpture reproductions inside optically transparent material

A method for producing an image inside an object which is viewable therethrough comprising the steps of:

• obtaining a basic image comprising at least two of gray shades;
• generating a number of sub-images corresponding to the number of gray shades comprising the basic image;
• determining a number of auxiliary images from the sub-images, each auxiliary image comprising one or more points spaced apart by greater than a first minimum distance for which failure of the object may occur in a first direction and a second minimum distance for which failure may occur in a second direction;
• and
• generating said auxiliary images in said object, each auxiliary image comprising one or more etch points positioned in a plane in said object and formed in said object by laser radiation, said points positioned in said plane spaced apart by a distance no less than said first minimum distance and said auxiliary images lying in parallel planes spaced apart by no less than a said second minimum distance, said auxiliary images, when viewed in a direction generally perpendicular thereto forming a reproduction of said basic image.