The images were transformed using two standard transforms – (1) wavelet transform (5 level) and (2) Fourier transform – that are often used by the imaging community. For comparison, they were all normalized to contain the same L2-norm energy. All the images used for comparison were in 8-bit grayscale format and with 512 × 512 pixels. ![]() The results are presented below with the hope that researchers looking to switch from Lenna to another test image will at least have some guidelines at hand when submitting their manuscripts. We downloaded some alternative test images (Pirate, Mandril, Fishing Boat, Cameraman and Peppers) from the USC database and performed a comparative analysis between Lenna and these alternatives. So we decided to do something about this. Simply suggesting the use of alternatives without sufficient technical reasoning could be counterproductive for this group. They are going to read prior literature which extensively uses Lenna as a standard, but will be discouraged from using it themselves. While experts should have no problem with this policy, such directives can leave young imaging researchers (who may not even know the origin of Lenna) in a state of confusion. Several journals and scientific societies are therefore discouraging the Lenna image in publications and suggesting the use of alternative test images. Whatever its merits, the Lenna image’s origin is incompatible with our community’s sincere attempts to encourage diversity and respect in Science and Technology ( Citation 3, 4). Arguments of this nature have appeared before in the literature ( Citation 1, 2) and while there are possibly several other alternative test images available in standard repositories, such as the USC Signal and Image Processing Institute database ( ), Lenna is still the most prevalent test image found in imaging literature. The image has probably become popular in the imaging community because it contains several features – such as light and dark illumination regions, sharp edges, flat regions, smoothly varying regions and textured regions intertwined with each other – which make it useful when testing the behaviour of image-processing or reconstruction algorithms. Even the popular JPEG and MPEG image compression standards used Lenna as a test case. ![]() The Lenna (or sometimes ‘Lena’) image has appeared in tens of thousands of publications and conference proceedings on imaging research since its first use in the 1970s.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |