author = "Endrice, Lucas Niquele and Vieira Neto, Hugo",
          affiliation = "Federal University of Technology - Paran{\'a}, Curitiba, Brazil 
                         and Federal University of Technology - Paran{\'a}, Curitiba, 
                title = "Luminance Ratios for Stable SIFT Keypoint Detection in Challenging 
                         Illuminations Scenarios",
            booktitle = "Proceedings...",
                 year = "2020",
               editor = "Musse, Soraia Raupp and Cesar Junior, Roberto Marcondes and 
                         Pelechano, Nuria and Wang, Zhangyang (Atlas)",
         organization = "Conference on Graphics, Patterns and Images, 33. (SIBGRAPI)",
            publisher = "IEEE Computer Society",
              address = "Los Alamitos",
             keywords = "scale space feature detector, SIFT, illumination invariance.",
             abstract = "Invariance to changes in scene illumination is a desirable feature 
                         in computer vision, but its accomplishment is still a challenge 
                         even for modern systems. This paper proposes a novel way to detect 
                         keypoints in scale-space by exploring the concept of luminance 
                         ratio first introduced in Wallach's Lightness Constancy Theory, 
                         instead of using linear difference operators. The hypothesis is 
                         that an operator based on the concept of luminance ratio may 
                         provide more robust results with respect to illumination changes. 
                         In order to test this hypothesis, the SIFT keypoint detector was 
                         adapted to the proposed approach with minimum implementation 
                         effort. Experimental results show that the luminance ratio 
                         approach indeed yields more stable keypoint detection than the 
                         original SIFT based on linear difference operators, specially in 
                         lower illumination conditions. Existing SIFT implementations can 
                         be easily adapted to use the luminance ratio concept for improved 
                         operation in environments with uncontrolled lighting conditions.",
  conference-location = "Virtual",
      conference-year = "Nov. 7-10, 2020",
             language = "en",
           targetfile = "59.pdf",
        urlaccessdate = "2021, Jan. 19"