JPEG2000压缩对头颅侧位数字化X线片标志点识别的影响。
Effect of JPEG2000 compression on landmark identification of lateral cephalometric digital radiographs.
作者信息
Abdelkarim Ahmad, Nummikoski Pirkka, Gakunga Peter, Hatch John P, Dove S Brent
机构信息
Assistant Professor, Department of Care Planning and Restorative Sciences, University of Mississippi College of Dentistry, Schools of Dentistry, University of Mississippi Medical Center, Jackson, Mississippi, and University of Texas Health Science Center at San Antonio, San Antonio, Tex.
Professor, Oral and Maxillofacial Radiology Division, Department of Dental Diagnostic Science, UTHSCSA, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Tex.
出版信息
Am J Orthod Dentofacial Orthop. 2010 Oct;138(4):518-524. doi: 10.1016/j.ajodo.2009.02.029.
INTRODUCTION
As digital imaging improves and digital cephalometric radiography becomes more prevalent, the need for digital storage space and transmission speed will increase. Compression of the image files is 1 method to overcome transmission overload. However, compression could compromise image quality. The purpose of this study was to determine the range of compression ratios, by using the JPEG2000 standard, within which the identification of landmarks on cephalometric radiographs is not compromised.
METHODS
Ten lateral cephalometric digital images were used. Six raters identified 19 landmarks under controlled viewing conditions. The images included the original uncompressed TIFF image and the JPEG2000 format at 3:1, 12:1, 50:1, and 110:1 compression ratios. The images were randomized and displayed with image processing software. The x and y coordinates of each landmark were recorded.
RESULTS
All compression ratios performed equally well compared with the original images with the exception of A-point and nasion at 110:1 and gonion at 3:1 compression ratios. All landmark identifications were precise with the exception of the maxillary incisal apex and edge at the 12:1 and 50:1 compression ratios, respectively.
CONCLUSIONS
JPEG2000 is a reliable file format that can be implemented in orthodontic practice.
引言
随着数字成像技术的提高以及数字头颅侧位X线摄影术的日益普及，对数字存储空间和传输速度的需求将会增加。图像文件压缩是克服传输过载的一种方法。然而，压缩可能会影响图像质量。本研究的目的是确定使用JPEG2000标准时的压缩比范围，在此范围内，头颅侧位X线片上标志点的识别不受影响。
方法
使用了10张头颅侧位数字图像。6名评估者在受控的观察条件下识别19个标志点。这些图像包括原始未压缩的TIFF图像以及压缩比为3:1、12:1、50:1和110:1的JPEG2000格式图像。图像随机排列并通过图像处理软件显示。记录每个标志点的x和y坐标。
结果
与原始图像相比，除了压缩比为110:1时的A点和鼻根点以及压缩比为3:1时的下颌角点外，所有压缩比的表现都同样良好。除了压缩比为12:1和50:1时分别对上颌切牙顶点和边缘的识别外，所有标志点的识别都很精确。
结论
JPEG2000是一种可靠的文件格式，可在正畸实践中应用。
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