Second level storage space optimization for lossless image compression using diffraction grating

In lossless or near-lossless image compression, the compression ratio should not be very high to avoid loss of information (especially applicable for remote sensing and medical images). To avoid loss of information (especially applicable for remote sensing and medical images), the compression ratio should not be very high in lossless or near-lossless image compression processes. Due to this restriction, storage space consumption in lossless image compression techniques is more compared with lossy processes. In this article, we propose a second level of the storage space optimization method that applies equally to all lossless image compression techniques. This process can be implemented as a preprocessing or postprocessing method in addition to the researcher’s method. As a result, storage space optimization is enhanced to a satisfactory level. Here, initially, the compressed image (for postprocessing) or the original image (for preprocessing) is modulated using the diffraction grating (amplitude) in the optical frequency domain. Due to this modulation, the compressed image is converted into three spectra (one central spectrum and two side spectra). We consider one of the side spectra (circular-shaped) for further processing. Inverse Fourier Transform along with a Low Pass Filter is applied to extract the image information. It has been observed that this circular-shaped spectrum consumes relatively less storage space than compared to the compressed image. In the case of multiple images, the chosen spectra are placed properly on a canvas whose size is also less than the series of compressed images. This optical system is applicable is any lossless image compression method. We have proved that this second level of compression applies to all lossless and near-lossless techniques in terms of storage space optimization and maintaining a good quality the output.