A method to improve the visibility of ghost images obtained by thermal light

A method, which is based on the correlation measurement of intensity fluctuations in time-space-average rage domain, is invented to improve the visibility of ghost images obtained by thermal light. We demonstrate that the visibility of ghost images can be significantly enhanced using this method. A corresponding evaluation standard of the visibility of images and effects influencing the visibility of ghost images, such as the weight factor gamma and speckle frame numbers, are also discussed. (C) 2009 Elsevier B.V. All rights reserved.