Four-Wavelength Color Digital Holography

We propose a color digital holography using four recording wavelengths to improve the color reproduction of three-dimensional imaging of objects. In conventional color digital holography, three-wavelength light beams corresponding to red, green, and blue are used for recording holograms. In this paper, a laser-emitting yellow light is added to the conventional color digital holography. Also spectral estimation technique is introduced to the four-wavelength recording technique to improve the color reproduction of color digital holography. The effectiveness of the proposed method was numerically confirmed. Also the proposed technique was experimentally demonstrated using four lasers operated at 473, 532, 561, and 633 nm, respectively. When Macbeth color chart consisting of 24 color patches was used as objects, in comparison to conventional technique, the average color differences between the objects and the reconstructed images by the proposed technique for the 24 colors are decreased from 7.88 to 6.24 in numerical simulation and from 10.02 to 8.63 in experiment, respectively.