Three-dimensional image contrast using biospeckle

Abstract

The biospeckle laser (BSL) has been applied in many areas of knowledge and a variety of approaches has been presented to address the best results in biological and non-biological samples, in fast or slow activities, or else in defined flow of materials or in random activities. The methodologies accounted in the literature consider the apparatus used in the image assembling and the way the collected data is processed. The image processing steps presents in turn a variety of procedures with first or second order statistics analysis, and as well with different sizes of data collected. One way to access the biospeckle in defined flow, such as in capillary blood flow in alive animals, was the adoption of the image contrast technique which uses only one image from the illuminated sample. That approach presents some problems related to the resolution of the image, which is reduced during the image contrast processing. In order to help the visualization of the low resolution image formed by the contrast technique, this work presents the three-dimensional procedure as a reliable alternative to enhance the final image. The work based on a parallel processing, with the generation of a virtual map of amplitudes, and maintaining the quasi-online characteristic of the contrast technique. Therefore, it was possible to generate in the same display the observed material, the image contrast result and in addiction the three-dimensional image with adjustable options of rotation. The platform also offers to the user the possibility to access the 3D image offline.

Computer aided techniques to support speckle laser experimental setup and online vision

“…In the graphical approaches the construction of maps of activities are based on online and offline techniques [1] , however the online approaches present a great limitation of resolution of the results, since the contrast method commonly adopted, known mainly as Laser Contrast Analysis (LASCA) [2] , use just one image to get the information of the activity, shortening the contribution of the time history. However, LASCA has some undesirable effects such as the loss of resolution and definition in the resulting image that is proportional to the size of mask used in the processing [3] . In addition, the use of LASCA demands a camera with specific technical properties such as the shutter access and control [4] .…”

“…Efforts have been made to overcome the undesirable low definition and resolution of LASCA, such as integration of multiple digital images [5] . There are some alternatives to overcome those limitations of LASCA such as presenting the maps of activity in three-dimensional view [3] , and among others the Motion History Image (MHI) [6] which allows the use of more frames to represent more the time history without any reduction of the resolution of the output images. The MHI is based on the identification of the history of a movement, commonly used in images formed with non-coherent light and by well defined objects.…”