Research And Application On Reading Recognition Of Numeral Instrument And Index-instrument

For now, digital instrument and index-instrument is the most common parameters output device in industrial production and detection, which are used in measure system widely in many industries. Meter automatic recognition technology can monitor variation of parameters continuously,especially in some like Electric power monitoring system.In order to realize the unattended and automatic alarm functions, meter digital and calibration readings recognition technology appears especially important.After the brief introduction of the background and the development of automatic reading recognition in digital instrument and index-instrument,the recognition technology of both kinds of digital instrument and index-instrument have been discussed in this dissertation. According to the application requirements and application characteristics, solutions to instrument display values recognition based on digital image processing technology have been proposed, and around which we done some systematic work.First, in the image preprocessing, using threshold binarization method based on the Bernsen and Otsu algorithms, adopting image denoising method based on both area and focus criterion, using morphological hit or miss transformation to thin images,and etc. At last, a image whose target and background obvious separated is outputted. The experiments have been done using a large number of images under different conditions,and results show that the the methods mentioned above are effectiveSecondly, using GUI achieves the location and segmentation of meter's image. For digital instrument, the thinned singles digits are getted. For index-instrument, after the dial′s image scale area location, using image subtraction method to detect its pointer. Furthermore,we aslo designed a GUI-graphical user interface to complete the above work.Then, based on the analysis of existing recognition research situation on digital characters, a recognition method has been proposed for digital instrument based on structure characteristics and template matching, which can be identify both display forms of the seven segment code LED and LCD. First, digits are classified preliminary using structure characteristics .Because some digits are of similarity in some characteristic, template matching algorithm are used to further distinguish the digits that easy to recognize by mistake in the process of preliminary classification,and which also has narrowed the template matching characters object scope and improved match speed .Achieving the recognition timely requirements.Next, For index-instrument, improved Hough transform algorithm is used to detecte the poiner position and parameters,such as the angle of line,are outputted.Then in accordance with the parameters,angle method is used to judge dial readings. These methods mentioned above are characteristic of simple algorithm and high speed recognition.Several numerical instruments character images are processed in this dissertation and the results show that the algorithm can satisfy our demand well.In the end of this dissertation,concluding the whole work and pointing out the current problems to be resolved.