The ADCP (Acoustic Doppler Current Profiler) technique is the current hot topic of measuring the water velocity. Further more, the frequency estimation algorithm is critical for it. A novel frequency estimator-ELMS for a single complex sinusoid in complex white Gauss noise is proposed. The estimator needs less data than conventional FFT (Fast Fourier Transform) algorithm. The results indicate that the robust algorithm can estimate the spectrum value efficiently when the SNR=0DB.
Previous research about automatic vision systems applied to fruit imaging segmentation fails. Watershed transformation is a powerful morphological tool for image segmentation. However, the performance of segmentation methods based on watershed depends largely on gradient of the image. It's not perfect to segment object with single-scale gradient. In this paper we present a multi-scale algorithm for computing morphological gradient images, after this transformation, there exists a strict causality between gradient watershed under different scales of geodesic reconstruction. The results demonstrate the superior performance of the watershed segmentation over the conventional techniques.