摘要
目的：目前,内镜测量的主要方式是目测或张钳法等方法。由于内镜图像的桶形畸变,现有测量的方法均有较大误差。本研究验证一个自创的＂虚拟内标＂新概念,并建立应用虚拟内标的内镜测量技术。方法：应用电子胃镜对印有标准刻度的格图在不同物距上进行拍摄,截取到包含虚拟内标信息的桶形畸变格图,通过对于格图的数字特征分析,了解各物距平面视野大小、压缩比、有效测量区域等多种有用数据。根据这些数据建立虚拟内标内镜测量方法,并应用这种方法进行体外、体内测量的试验。结果：物距介于10 mm至40mm之间时,物距与视野之间呈现1∶2的倍比关系。压缩比计算结果提示：物距10~15mm时有效范围为10 mm,物距20~30 mm时有效范围为20mm,物距〉35mm时有效范围为30 mm。各平面有效测量区域占据图像总宽度的2/5到3/5。各物距平面中央格的象素值的排列趋于双曲线改变,当物距在35~50mm之间,每厘米象素值之间的差距趋于接近。体内、体外实验进一步验证了虚拟内标内镜测量法的可行性与准确性。结论：应用虚拟内标法进行内镜测量是一个简便、客观、准确、实用的方法。
Objective： Endoscopic measurement mainly depends on visual estimation or open biopsy forceps, which have been proved lacking in accuracy due to the image barrel distortion caused by wideangle lens in endoscope. This study aimed to validate a new concept of ＂virtual internal standard＂ proposed by ourselves and develop a new method for endoscopic measurement based on the concept. Methods： We photographed planar grid graphs printed with standard calibrations with an electronic endoscope at different object distances, obtained the information on the virtual internal standard from each photo at the corresponding object distance, and analyzed the digital characteristics of the barrel distortion photos, including the size of the visual field, the image compression ratio, and the credible area for measurement with the virtual internal standard. Based on the analyses, the method of endoscopic measurement by the virtual internal standard was established and experiments both in vivo and in vitro were conducted. Results ： The ratio of the object distance to the visual field was 1 ： 2 when the former was between 10 mm and 40 mm. Calculation of the compression ratio showed that the credible area of meas-urement in the central area was 10 mm at the object distance of 10 - 15 ram, 20 mm at 20 - 30 mm, and 30 mm at 30 -50 mm. The credible area of measurement on various planes accounted for 2/5 to 3/5 of the total image width. There was a tendency of double-curve change in the arrangement of pixel values of the central grids on different planes. The differences between the pixel values per centimeter became slight at the object distance of 35 -50 mm. Conclusion： Endoscopic measurement by the virtual internal standard is a objective, accurate, simple and practical method.
出处
《医学研究生学报》
CAS
2009年第5期508-514,共7页
Journal of Medical Postgraduates
关键词
内镜
测量
内标
虚拟
桶状畸变
模糊测量
目测
Endoscopy
Measurement
Internal standard
Virtual
Barrel distortion
Fuzzy measurement
Visual measurement
