The effect of image variations on fractal dimension calculations

Using fractal dimension to evaluate alveolar bone defects treated with various bone substitute materials

“…Shrout et al [1] state that results of a fractal analysis of alveolar bone may be affected by ROI size and shape, but in our study all ROI were standardized and had sizes of 64x 64 pixels, and were only limited by the neighborhood of a tooth, implants and sinus. Moreover, in present research, all digital radiographs were standardized and projection of images did not influence the FD.…”

“…Augmentation of bone defects by insertion of graft materials is an excellent method to construct a suitable bony bed for implant placement [1,2]. Based on origin, bone replacement materials (BRM) are classified as allogenic, heterologous and alloplastic ones [3].…”

“…In dentistry, fractal dimension on periapical radiographs has been used as a simple descriptor of the complex architecture of the cancellous bone surrounding the dentition [35,38]. The technique appears to be relatively insensitive to variations in film exposure or alignment [1,37,39,40] and is relatively independent of technical settings of periapical radiographs [41] but is affected by the size and shape of the regions of interest [1]. Fractal dimension has been shown to distinguish patients with gingivitis and periodontitis [42] and those with and without osteoporosis [25] and has been used for assessment of dental implant sites [43].…”

Fractal Analysis of Periapical Bone from Lossy Compressed Radiographs: A Comparison of Two Lossy Compression Methods

“…This result confirms the robustness of fractal analysis, as previously reported to be insensible to variations in film exposure, image geometry, and size and position of ROI. [1,20] Certainly, there is a limit in the acceptable amount of information loss, as found to be the CL 30 and CL 50 for JPEG and JPEG2000, respectively. With the use of lossy compression, high-frequency image content is lost first and as the compression level decreases, lower frequencies in image content are progressively reduced.…”

“…Fractal analysis, in comparison to DSR, was reported to be a more robust computer-aided image analysis method, insensible to variations in film exposure, limited image geometry variations and sizes and positions of region of interest (ROI). [1,20] However, the effect of lossy image compression on FD calculation has not been evaluated yet.…”