Measurement of Scars Using Structured-Light 3D Scanning in Forensic Practice

Objective To validate the accuracy and reliability of structured-light three-dimensional （SL-3D） scanning in measuring the length and area of the regular and irregular scars on body surface and discuss its value in forensic practice. Methods The lengths of 30 cases of simulated linear scars and 50 cases of linear scars after injury were measured using soft ruler, vernier caliper + thin line method, and SL-3D scanning. The areas of 35 cases of simulated patchy scars and 15 cases of patchy scars after injury were measured using length × width, film tracing with coordinate paper method, pixel method, and SL-3D scanning, and then statistically analyzed. Results The differences between the length of the simulated linear scars measured by SL-3D scanning and standard length had no statistical significance. When simulated patchy scars and patchy scars after injury were measured with high surface curvature and large irregular areas, the differences between the results of SL-3D scanning measurement and the standard area had no statistical significance. When the length of 50 cases of linear scars after injury were measured using SL-3D scanning, the correlation coefficient between the measurement results of two different investigators was 0.998, and the correlation coefficient between the two measurement results by the same investigator was 1.000. The correlation coefficient between the results of SL-3D scanning and that of vernier caliper + thin line method was 0.996. Conclusion The three-dimensional information of the scars on the body surface can be acquired using SL-3D scanning. The measurement of the length and area of the scars is not influenced by the location of scars, curvature of surface, and human factors. The measurement results are accurate, reliable and has unique advantages.结构光三维扫描技术测量损伤瘢痕的法医学应用.目的 验证结构光三维扫描技术测量体表规则或不规则损伤瘢痕的长度和面积的准确性与可靠性，探讨其法医学应用价值。 方法 采用软尺、游标卡尺+细线法、结构光三维扫描法分别对30例模拟条状瘢痕与50例伤后条状瘢痕的长度进行测量，以长×宽、薄膜描记结合坐标纸法、像素法、结构光三维扫描法分别测量35例模拟片状瘢痕及15例伤后片状瘢痕的面积，并进行统计学分析。 结果 结构光三维扫描法测量的模拟条状瘢痕长度与标准长度差异无统计学意义；对表面曲率较大且大面积不规则模拟片状瘢痕和伤后片状瘢痕进行测量时，结构光三维扫描法测量结果与标准面积差异无统计学意义。使用结构光三维扫描法对50例伤后条状瘢痕长度进行测量时，两名操作人员测量结果的相关系数为0.998，同一操作者两次测量结果的相关系数为1.000，与游标卡尺+细线法测量结果的相关系数为0.996。 结论 采用结构光三维扫描技术测量可获取体表瘢痕的立体信息，对瘢痕长度和面积的测量不受部位、体表曲率及人为因素的影响，测量结果准确可靠，具有独特的优势。.法医学；瘢痕；结构光三维扫描；长度；体表面积.