<title>Evaluation and optimization of contrast enhancement methods for medical images</title>

Abstract

We have developed and are applying two methods of image quality assessment with the aim of optimizing contrast enhancement parameter settings and evaluating competing methods. Our first approach uses observer studies employing psychophysical methods and a realistic clinical task; the second incorporates a model of human vision in a computer simulation of the performance of an observer.

Comparison of Navigation Techniques for Large Digital Images

“…This is less efficient than having both the zoom and the panning operations accomplished from the pointing device. 33 An easy way to do this is to zoom via the scrollwheel now commonly found on mouse devices, and this has been adopted by recent applications (for instance GoogleMaps 42 now supports this). This technique is strongly dependent on a fast interaction.…”

“…These images were chosen because they are of a similar size to the largest digital medical images; they were representative of the general visual task as well as the medical imaging specific task, and they allowed the use of student observers. In a prior work of Puff et al, 42 it was established that the student’s performance on such basic visual detection tasks served as a cost-effective surrogate for radiologist’s performance.…”

“…Prominent paradigms for zooming in and out of images and some example applications that use them include: the use of onscreen buttons–toolbars, 35 – 39 clicking within an image to magnify a small portion of that image (FFView available at http://www.feedface.com/projects/ffview.html , accessed September 2005), or clicking within the image to magnify the entire image with the clicked point at the center (ArcView GIS 40 ). Prominent image-panning paradigms and example applications include the use of scroll bars (Mapquest available at http://www.mapquest.com , accessed September 2005; Microsoft Office Picture Manager and MicroSoft Office Paint available at http://microsoft.com , accessed September 2005; Adobe PhotoShop available at http://adobe.com/ , 2005), 40 moving a “magnification area” over the image in the manner of a magnifying glass (FFView available at http://www.feedface.com/projects/ffview.html , accessed September 2005), clicking on arrows or using the keyboard arrows to move over an image (Mapquest available at http://www.mapquest.com , accessed September 2005), panning vertically only via the mouse scroll wheel (Adobe PhotoShop available at http://adobe.com/ , 2005), 42 and dragging the image via a pointer device movement (Google Maps available at http://maps.google.com/ , accessed September 2005; Microsoft Office Picture Manager and MicroSoft Office Paint available at http://microsoft.com , accessed September 2005).…”

Image Processing and Computer Aided Diagnosis in Digital Mammography: A Radiologist's Perspective

“…This might involve the use of phantom images or com puter generated test images with an array of unknown hidden test objects. Both types of screening tasks are currently being developed and tested at the University of North CarolinaChapel Hill [71]. Ideally, since the visual system is the same across all normal observers, the initial selection of potentially useful algorithms and parameters might be performed by non-radiologists.…”