Image processing and enhancement provided by commercial dental software programs

To identify and analyse methods/algorithms for image processing provided by various commercial software programs used in direct digital dental imaging and to map them onto a standardized nomenclature.

Twelve programs presented at the 28th International Dental-Show, March, 2001, Cologne, Germany and the Emago advanced software were included in this study. An artificial test image, comprised of gray scale ramps, step wedges, fields with Gaussian-distributed noise, and salt and pepper noise, was synthesized and imported to all programs to classify algorithms for display; linear, non-linear and histogram-based point processing; pseudo-coloration; linear and non-linear spatial filtering; frequency domain filtering; measurements; image analysis; and annotations.

The 13 programs were found to possess a great variety of image processing and enhancement facilities. All programs offer gray-scale image display with interactive brightness and contrast adjustment and gray-scale inversion as well as calibration and length measurements. While Emago enables arbitrary spatial filtering with user-defined masks up to 7x7 pixels in size, most programs sparsely include filters and tools for image analysis and comparison. Moreover, the naming and implementation of provided functions differ. Some functions inappropriately use standardized image processing terms to describe their operations.

Image processing and enhancement functions are rarely incorporated in commercial software for direct digital imaging in dental radiology. Until now, comparison of software was limited by the arbitrary naming used in each system. Standardized terminology and increased functionality of image processing should be offered to the dental profession.