Intrinsic layer based automatic specular reflection detection in endoscopic images.

Endoscopic images are used to observe the internal structure of the human body. Specular reflection (SR) images are mostly a consequence of the strong light and bright regions appearing on endoscopic images, which affects the performance of minimally invasive surgery. In this study, we propose a novel method for automatic SR detection based on intrinsic image layer separation (IILS). The proposed method consists of three steps. Initially, it involves the normalization of the image followed by the extraction of high gradient area, and the separation of SR is done on the basis of the color model. The image melding technique is utilized to reconstruct the reflected pixels. The experiments were conducted on 912 endoscopic images from CVC-EndoSceneStill. The results of accuracy, sensitivity, specificity, precision, Jaccard index, Dice coefficient, standard deviation, and pixel count difference show that the detection performance of the proposed method outperforms that of other state-of-the-art methods. The evaluation of the proposed IILS-based SR detection demonstrates that our method obtains better qualitative and quantitative assessments compared with other methods, which can be used as a promising preprocessing step for further analysis of endoscopic images.

A study of panoramic focal trough for the six-year-old child / 대한구강악안면방사선학회지

PURPOSE: To make a focal trough (image layer) for an average maxillary dental arch of 6-year-old korean in panoramic radiography. MATERIALS AND METHODS: Phantom for the maxillary dental arch was designed using intercanine width, intermolar width, tooth size, and interdental spacing to record the data of 6-year-old child. The characteristics of pre-corrected panoramic machine (for adult) was evaluated using the phantom, resolution test pattern for margin of the image layer, and metal ball for the center of the image layer. Panoramic image layer of the child was developed by means of decreasing the speed of film-cassette and positioning the phantom backwards, and then the characteristics of post-corrected panoramic machine (for child) were reevaluated. RESULTS: At post-corrected panoramic image layer, beam projection angles at all interdental areas increased for about 2.6-3.8 degrees, the position of the image layer was shifted toward the rotation center for about 2.5 mm at the deciduous central incisior area. The width of image layer decreased at all areas. CONCLUSION: Increased beam projection angle will reduce the disadvantage of tooth overlap, and the same form between the center of the image layer and dental arch will improve image resolution.