A NO-REFERENCE IMAGE ENHANCEMENT QUALITY METRIC AND FUSION TECHNIQUE Name: Headlee, Jonathan Michael University of Dayton Advisor: Dr. Eric Balster Image quality has always been an important aspect of the image processing field. Subjective quality is useful since images are a visual medium, but objective quality measures are needed because they are unbiased and can be used as parts of larger processing systems. Many image quality metrics exist that attempt to give an objective score to an image

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... based on its likeness to a reference. These metrics work well if the reference is known and the test image is assumed to be a distorted version of the reference. However, in areas such as image enhancement, the reference image is generally worse than the test image and measuring likeness between the two is not a good indication of visual quality. A no-reference image enhancement quality metric is proposed in this paper that uses three factors to score images: lightness, contrast, and noise. It has been shown in literature that certain ideal ranges for lightness and contrast exist, and image enhancement techniques tend to push an image towards these. The metric gives each pixel in an image a score based on its neighborhood statistics. An image fusion technique is also proposed that fuses multiple enhanced images into one based on the local scores obtained from the no-reference metric. It is shown that this fused image scores higher using the no-reference metric and also has superior visual quality. iii ACKNOWLEDGMENTS I would like to thank everyone who encouraged and helped me during my time at UD as a graduate student, especially the following people: • Dr. Eric Balster: For advising me throughout my time at the University of Dayton and always being there to assist me. • Dr. Frank Scarpino and Dr. Kevin Priddy: For providing me with imagery to study and test with throughout my research. • Kerry Hill, Bill Turri, and the entire UDRI ADDA Lab Team at the Air Force Research Laboratory at Wright-Patterson Air Force Base: For giving me this opportunity to pursue a master's degree and helping me grow as a professional engineer. • Friends and family: For the constant support throughout my education at UD. iv