The double superficiality of the frontal image of the Turin Shroud

Photographs of the back surface of the Turin Shroud were analysed to verify the existence of a double body image of the Man, as postulated by J. Jackson in 1990. The body image is very faint and the background not uniform, i.e., the signal-to-noise ratio is lower than one. Therefore, image processing, developed ad hoc, was necessary to highlight body features. This was based on convolution with Gaussian filters, summation of images, and filtering in spatial frequency by direct and inverse bidimensional Fourier Transforms. Body features were identified by template matching. The face and probably also the hands are visible on the back of the Turin Shroud, but not features related to the dorsal image.