A hydropower station is always characterized by manual work involved in reading the indicators of digital input (DI) board

monitoring images

event lists and alarm apparatus to ensure the validity of the unit

which costs a lot of time and may ignore something by the staff. So the application of image recognition technology is proposed in reading the indicators of DI board. The signal location list is created automatically in image recognition

while the algorithms of image processing

such as template matching

dynamic programming

geometrical positioning and area selection

are integrated into a mobile APP. By taking photographs and recognizing the images

this APP can enable the user to read the indicators of DI board and output the result immediately at any time with an accuracy above 98%. According to the results

the staff can quickly know the validity of signal locations

and then inspect the locations purposefully. It is a great improvement in working efficiency

especially for the initiation of a new hydropower station or the maintenance of a running one. At the same time

the proposed image processing algorithm can be extended to more intelligent recognition applications of indicator lights and instruments in industrial scenes.