Search On Laser Speckle Technique And Digital Image Processing System

Laser is a kind of light source that has a high degree of coherence. When it irradiate the surface of objects which have the nature of diffuse reflection, we can see the speckle phenomenon. Speckle interferometry technique was developed as a new way of measurement in 20th century 70s. Traditional speckle interferometry technique is limited in many ways, so it have been limited in the laboratory.Speckle interferometry technique is developed from traditional speckle interferometry technique by added digital image processing. We build a single-beam optical speckle interferometry in the issue. The laser speckle interferometry technique, in addition to optical path with a simple, less demanding on the specimen surface, the experimental low, less demanding on the experimental conditions, to facilitate the calculation accuracy reliable, sensitive and can choose a certain extent, but also with non-contact, you can remote sensing, intuitive, and so the audience can give advantages. Load on the specimen through the small plane were taken before and after displacement to obtain speckle image. In order to follow-up to the needs of digital image processing, digital camera equipment replace the original film storage speckle images, directly from the digital speckle image. We transmit the speckle images into computer, then deal with their de-noising for less error. For extracting the information contained in the digital speckle images, we have deliberately designed a cross-correlation factor algorithm, the absolute difference algorithm and extreme displacement algorithm, and make sure they are effective. We can obtain information of plane displacement by letting the de-noising digital speckle images go through one kind of the three algorithm. Experiment is proved to be feasible by its good repeatability. The results met the accuracy of pixel-level now. After further improvement of algorithms, such as interpolation algorithm, it can be sub-pixel accuracy.