A low cost data acquisition system from digital display instruments employing image processing technique

The use of digital instruments in industries and laboratories is rapidly increasing as they are simple to calibrate and have relatively high precision. In this paper, an automatic data acquisition system is proposed using OCR technique from digital multi-meter and other similar digital display devices. The input image is taken from a digital multi-meter having LCD seven segment display using a webcam. The image is then processed to extract numeric digits which are recognized using a feedforward neural network. The recognized values may be then exported to a spreadsheet for graph plotting and further analysis. A distinct advantage of this method is that it can automatically detect decimal point as well as negative sign. This setup can be used in real time systems employing a wide variety of digital display instruments, with high accuracy.