AVI GRAPH DIGITIZE by Kairos Physiomechanics Srl back to home page
AVI Graph Digitize is the first product on the market designed to numerically extract, from AVI movie file, the data displaied in graphs. It is an extension of programs digitizing single points in a graph, but with a continuously changing window.
The classical example is the signal available from an ultrasonography device. Ultrasound machines, most of which with a clinical target, are capable to freeze the image and provide just the last instantaneous measure of, say, arterial blood flow.
In a more physiological environment, researchers are very interested in time courses of that and other correlated variables (as the vase diameter) rather than a frozen photography (very often transferred to a printer) and a single flow value.
On the other hand, ultrasound device manufacturers only rarely include the time course of the measured variables in the provided output. We offer a viable solution to this limitation.
By using the video output from the ultrasound device (most of them have a plug for that), it is possible to capture the experimental session with the help of an external computer with video acquisition capability or a media station.
The result is an AVI movie file that can be opened and processed by a program we developed by using LabView and its VIsion package. To be able to digitize a series of incoming graph, rountines have been designed that transform the data displaied as grey colors in the graph into numbers corresponding to blood flow.
To do that, OCR (Optical Character Recognition) techiques are used on the ordinate axis labels to set the calibration framework where the curve points will be digitized. On both axes calibration ticks are identified, so that flow and time values could accurately reflect the real signal.
In addition, our software allow to overimpose to the live view on the top of the window a line along which the vase ‘diameter’ will be continuously measured. The final output from a single AVI movie is made of two text files, compatible with Microsoft Excel, containing the time course of blood flow (mean, min and max values) and vase ‘diameter’.
Originally desgned for SIEMENS ACUSON P50, AVI Graph Digitize can be adapted to any other AVI files containing graphs to be digitized.
Further information can be obtained by contacting alberto.minetti@unimi.it
