Detection of central positions of noisy rounded square function using modified Haar wavelet transform and Haar-Gaussian wavelet transform

We propose and demonstrate new wavelet transforms, the modified Haar wavelet transform and Haar-Gaussian wavelet transform, for the detection of central positions of a noisy rounded square function. The advantage is the immunity of the wavelet transform to random noise. The alternative technique based on first- and second-order differentiation cannot be applied when the signal function is corrupted by noise. The proposed technique can be used for lead inspection of surface mount devices in the electronic industry. (C) 2000 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(00)01705-0].