GB1376941A - Means for producing three-dimensional forms from a photographic image - Google Patents

Abstract

1376941 Three-dimensional photographic reproduction K G O DIXON 11 Aug 1972 [14 May 1971] 14948/71 Heading G2X In reproducing a three-dimensional shape, such as a human head 10, from a photograph of that shape, a series of uniformly spaced parallel lines is projected on to the head from a projector 11 and photographed by a camera 12, the photograph then being projected on to a screen, and each contour line formed by one of the original parallel lines traced out by a stylus linked to a cutting tool which cuts out a corresponding contour on a block of material. The angle between the camera and projector axes should be 90 degrees but since the resolution between the lines would not be satisfactory in this case, an angle of about 36 degrees is used, and compensation made at a later stage. The photographic image (14) Fig. 2 (not shown), is projected on to a translucent screen 16. A slide 18 is mounted for accurately controlled movement in a frame 19. The lower end of slide 18 carries a fixed frame 28 having a transverse slide 29, to which is attached a plate 30 of mouldable material such as clay. A cutting tool 32 is carried by a pantographic mechanism (34), 35, 36 which also carries a stylus 38. As the stylus traces a contour line on the photographic image (14), the tool 32 cuts a corresponding line in block 31. The slide 18 is then advanced, and since this is at an angle # to the horizontal, the block 31 is advanced both horizontally and vertically. The next contour line is now traced, and so on. The compensation referred to above is made by a subsidiary pantograph mechanism which moves the block 31 in the same direction as the X component of the tool 32 by a distance of d sin α where d is the distance between the contour lines and α is the angle between the camera and projector axes. The ratio between the dimensions of the contour line traced by the stylus and that cut by the tool 32 can be varied by changing the ratio of the pantograph arms or by adjusting the size of the image by varying the distance between projector and screen.