Extrusion Asia Edition 2-2018

35 Extrusion Asia Edition 2/2018 测量技术 当决定投资于测量仪器时，除了成本之外，一个重要的 考量因素就是：哪种仪器是最佳选择？或多或少，技术 特性被看成是“最佳选择”的因素，并且看起来容易作出 比较。然而，这种简单化的比较将要承担风险。举例来 说，在数字摄影方面，传感器的尺寸以及单个像素的大 小比像素总量更为重要。但通常，像素总量成为了销售 的卖点。 When deciding about investing in a measuring device, one of the main factors – besides the costs – usually is which device is the “best”. Characteristics where “more” or “less” is considered as “better” are seemingly easy to be compared. This simplifica- tion, however, bears risks. In digital photography, for instance, the size of the sensors and, thus, of the individual pixel in general, is more important than the total number of pixels. The pixel count however is commonly the relevant sales argument. 由于这个原因，有必要审视测量仪器的技术特性，以及其定 义和相互作用。关于这些技术特性的进一步信息，即技术特 性在何种条件下有效，例如温度条件、对位置的依赖等通常 是缺失的。测量仪器的技术特性通常包含下列要点： • 测量范围 • 绝对精度（即正确性） • 可重复性（即精确度） • 测量速率 “测量范围”标志着可测量的目标的最小/最大尺寸。有时，用 可视范围替代，偶尔，还允许在总的测量范围内被测量的目 标有所移动。偶然地，关于可测量的最大/最小尺寸信息也缺 失了。 从通俗的意义上讲，“精度”指的是所有测量误差的总和。但是 ，当评价一个测量仪器时，还是要加以区分：“绝对精度”意为 平均测量值与认证标准值相比较的偏差。“可重复性”是定义为 当投资于测量仪器时，“测量速率”， “求平均值”和“精确度”的意义 Measurement Technology: Meaning of “measuring rate”, “averaging” and “accuracy” when investing in a measuring device F or that reason, it makes sense to question the characteristics of a measuring device, as well as their definition and interac- tion. Often further information about the conditions under which these characteristics are valid such as temperature, posi- tion dependency etc. are missing. Specifications usually contain the following characteristics: • “Measuring range” • “Absolute accuracy” (also “correctness”) • “Repeatability” (also “precision”) • “Measuring rate” “Measuring range” indicates minimum/maximum object sizes that are measurable. Sometimes, the visual range is specified instead, meaning: the overall range in which the objects to be measured are allowed to move. Occasionally, information about the minimum and /or maximum measurable size is miss- ing too. 图1： 采用射击靶为例定义绝对精度和可重复性 Picture 1: Absolute accuracy and repeatability based on the example of a shooter