A system for identifying test tube types and properties in a sample handling machine using visual information automatically obtained by an optical imager and then processed using vision processing methods. The system includes an optical imager positioned to capture images containing one or more test tubes in a rack and a microcontroller programmed to extract predetermined regions of interest and interpret the optical information in the image to decipher the dimension of the test tubes, determine the presence or absence of caps on the test tubes, decode any encoded data, and interpret custom symbologies. The system may then determine the nature of the test tubes or other containers presented before the image and provide that information to the sample handling machine to assist with processing of samples.