The application of optical technology permits an accurate measurement of the dimensions of the wood particles, without ruining the sample in any way, with elevated repeatability and rapid response times. The analyzing software, in conjunction with the numerous images taken, calculates the actual width of the particles. The result of each test is stored in the local database and may be consulted over the company network. In addition, the test results may be printed with the figures and the graph showing the granulometry distribution. The impartial verification of test repeatability and/or comparison with previous tests, is made by placing one graph over the other by means of a simple set of menu choices.