Embedded Semi-virtual Keyboard Application System On STM32

Computer field is undergoing a major change, its development is turning from pc area tothe mobile Internet, and the time personal daily used in mobile devices exponentially growsin recent years, which greatly exceeded people’s expectations, however its growth rate isconstantly faster. Today, the development of the mobile sector has become a trend, and moreand more attentions as well as academic research begin to shift in this field. At the same time,information exchange under mobile environment is an indispensable part and showing itsimportance in this field.so looking for a more efficient input mode, is a very valuable andpromising research work.On the other hand, in recent years, technology of computer visionhas got a rapid development, it has small footprint, low cost, wide range of applications, andthe application of based on this technology has covered most areas of people’s lives, whichdevelop a bright future. So in this paper, combining these features, we propose a virtualkeyboard application system implementation suitable for the embedded environment.Vision-based virtual keyboard combines the forefront of computer image processingtechniques,and it determine the state of the keyboard keys by analyzing the position of fingerin images,the key of which lies in its core logic algorithm. Meanwhile, in order to increasethe feel and comfort of the keyboard, this paper uses a soft keyboard as an input terminal, soit is called semi-virtual keyboard.From the vision of the practical application, this paperstrives to build a semi-virtual keyboard with outstanding performance in various aspects，such as keys accuracy, timeliness, immunity, cost control and so on. We mainly center onhardware and software architecture of this system, real-time image acquisition, real-time keyprocessing and critical software logic. And what’s more, as virtual keyboard accuracy andimage processing rate based on computer vision in embedded environment deficiencies, thispaper then proposes a real-time key correction algorithm. Through the keys coordinate offlineanalysis, and taking decomposition process with the Camera distortion, and then determine aneffective solution through the curve line radial distortion to solve the high false positives.Finally, this paper builds the actual hardware system, based on which experimentalanalysis is achieved. At last, experimental results show that: based on the algorithm this paper establishes, the accuracy and timeliness of the virtual keyboard system gets a good guarantee,so this algorithm has some practical value.