Holographic subtraction of images by Fourier plane recording and spatial filtration with a narrow beam

A simple holographic subtraction method is described that gives a good level of image brightness consisting in obtaining double exposure Fourier holograms, recording two separate images with a small shift of the object in the transverse direction between exposures, and illumination of the hologram with a small diameter laser beam with subsequent optical Fourier transformation of the reconstructed field. Image formation is carried out with an insignificant noise background but the frying noise involved in the use of the small diameter beam is high and limits resolution of dimensions of up to approximately 0.05 mm. Image brightness is approximately two orders better than for a comparable method.