Gradient based approaches for motion estimation (Optical-Flow) refer to those techniques that estimate the motion of an image sequence based on local changes in the image intensities. In order to best evaluate local changes in the intensities specific filters are applied to the image sequence. These filters are typically composed of a spatio-temporal pre-smoothing filter followed by derivative ...

Among the myriad of techniques used in estimating motion vector fields, perhaps the most popular and accurate methods are the so called gradient-based methods. A critical step in the gradient-based estimation process is the estimation of image gradients using derivative filters. It is well known that the gradientbased estimators contain significant deterministic bias relating the gradient calcu...

Many multi-dimensional signal processing problems require the computation of signal gradients or directional derivatives. Traditional derivative estimates based on adjacent or central differences are often inappropriate for multi-dimensional problems. As replacements for these traditional operators, we design a set of matched pairs of derivative filters and lowpass prefilters. We demonstrate th...

In this paper the application of edge detection techniques to gravity data are described. Edge enhancement in potential-field data helps geologic interpretation. There exist several methods for enhancing edges, such as tilt angle, and the derivative of tilt angle. Most of these methods are high-pass filters based on the horizontal or vertical derivatives of the field. To determine the filters n...

there are several varieties of edge detection method. edge detection and edge enhancement techniques play an essential role in interpreting potential field data. some of common methods are: tilt angle filter (ta), total horizontal derivative of tilt angle filter (thdt), theta filter, tdx filter, hyperbolic tilt angle (hta). these filters maximum values are when facing with the edge of an anomal...

It is well-known that certain non bandlimited signals such as splines can be reconstructed from uniformly spaced samples similar to bandlimited signals. This usually requires noncausal IIR filters. We revisit this result and consider extensions such as derivative sampling theorems and pulse sampling theorems. It turns out that spline-like signals can often be reconstructed from joint sampling o...

The Savitzky–Golay (SG) filters are generally used for smoothing and differentiation in many fields. The properties of the SG smoothing filters have been well studied. However, the properties of the SG differentiation filters or SG digital differentiators (SGDD, for the first order differentiation) are not developed well somehow, although they have been widely used. In the paper, the properties...