Research On Automatic Detection And Recognition Of Morse Signal In Noise Background

In this thesis the Morse telegraph code detection and recognition in noise background is investigated. It is inevitable that the communication system is disturbed by noises, especially in the short wave communication. This is great disadvantage for people who engaged in receiving signals artificially. Realizing short Morse automatic detection and recognition by computer can lighten relevant people's burden and improve their work environment.On the basis of the essential character of Morse signal's periodicity and frequency discontinuity, a method is put forward that Morse signal's spectrogram through STFT(Short Time Fourier Transform ) is considered as a image and researched from the view of two-dimension. With this idea's guidance, digital image processing technology is adapted and various algorithm's advantage and disadvantage and their applicability for Morse signal detection are analyzed.In image enhancement, antiunsharped marking enhancement and contrast enhancement are adopted; In image segmentation, several algorithm, such as, threshold segmentation based on Arithmetic mean of Gray Value, adaptive threshold segmentation based on maximum between-cluster variance and segmentation based on combination of global and local threshold are discussed. At the same time Mathematical Morphology is introduced to deal with noises and feature abstraction algorithm mainly according to object's shape in Morse signal spectrogram is proposed. Finally, statistical pattern recognition and intelligent correction are applied to achieve Morse signal to texts translation.Theory analysis and experimentation for Morse signal with noises shows that the whole algorithm is effective and feasible.