The effects of compression on the image quality of digital panoramic radiographs

Abstract

Size reduction through compression is an important issue that needs to be investigated for possible effects on image quality. The aim of the present study was to evaluate the subjective image quality of digital panoramic radiographs which were lossless and lossy compressed for the visualization of various anatomical structures. Fifty-five digital panoramic radiographs in Tagged Image File Format (Tiff) were used in the study. Two types of lossy (Joint Photographic Experts Group (Jpeg)) and one type of lossless (Lempel-Ziv-Welch) compression were applied to the original radiographs. These radiographs were evaluated by two observers separately for the visibility of some anatomical structures with visual grading. Mean quality number for each radiograph was obtained. The differences between the mean quality numbers in each compression and original image mode were evaluated with Friedman test. Pair-wise comparisons revealed that there were statistically significant differences between all groups (p = 0.000) for all comparisons except for Jpeg_1 and Jpeg_2 groups. Kappa statistics was used to evaluate inter- and intra-observer agreements. Intra-observer agreements were ranging from 0.229 to 1.000 and inter-observer agreements were ranging from 0.154 to 1.000. The observers had better inter- and intra-observer agreements in highly compressed Jpeg_1 images. The anatomical structures evaluated in this study had better visibility in Tiff images than Jpeg images except for mandibular canal and mental foramen. While Jpeg compressed images offer high inter- and intra-observer agreements, the visibility of anatomical structures are better in Tiff images except for mandibular canal and mental foramen.

Descriptive study of mandibular canal visibility: morphometric and densitometric analysis for digital panoramic radiographs

“…Various 3-, 4-and 5-point MC visibility rating scales have been proposed by investigators. 7,18,19 Oliveira-Santos et al 12 used two scores for the evaluation of separate MC regions, whereas the overall MC visibility score was the sum of the six evaluated regions. MC depiction in another study was classified into three types for each implant site: visible in the superior and inferior walls; visible in the inferior walls and invisible in the superior walls; or invisible in the superior and inferior walls.…”

Effect of decompression and online transmission on the dimensional changes of .stl files generated by intra-oral scanning

“…This characteristic may be a limitation in its use, since it generates the need for a large amount of free space for storage in computers, servers, and difficulties in the process of online transmission [ 4 ]. To favor this process, data compression can be considered as a strategy to reduce storage space and improve data transfer rates [ 10 , 11 ]. Thus, this study aimed to evaluate the influence of compression and online transmission of images in STL format obtained by intraoral scanners.…”

“…compression can be considered as a strategy to reduce storage space and improve data transfer rates [10,11]. Thus, this study aimed to evaluate the influence of compression and online transmission of images in STL format obtained by intraoral scanners.…”

Comparison of radiograph panoramic quality between conventional and indirect digital methods on mixed teeth period

“…1 Panoramic radiographs are often used to detect eruption patterns, evaluate impact teeth, evaluate trauma, check enlargement of lesions, detect disease and see jaw condition. 2 The result of the image quality of the panoramic radiograph depends on the appropriate method. 3 Panoramic radiography is divided into two methods: conventional panoramic radiography and digital panoramic radiography.…”