A Micro Scale Measurement by Telecentric Digital-Micro-Imaging Module Coupled with Projection Pattern

In general, the applications of telecentric lens can be divided into two major groups, the first one is the telecentric macro lens (TML) commonly used in machine vision inspection and the other one is the telecentric digital-micro-imaging lens (TDMIL), which is a specific magnification of telecentric lens coupled with a pocket digital camera. Due to the limitation of CCD's resolution, the image quality captured by TML cannot meet the biomedical requirement. In order to improve the image quality and the convenience of measurement, the TDMIL can be recommended as a simple instrument to measure the size of an object. However, if the high resolution microscopy image and the minimum total length of TDMIL are required simultaneously, the total magnification of TDMIL system should be less than 5X. This paper presents a micro-scale measurement approach that is performed by the TDMIL coupled with the projection scale pattern, and is easy to get the size of an object.