{"id":455,"date":"2015-07-10T16:06:15","date_gmt":"2015-07-10T16:06:15","guid":{"rendered":"http:\/\/ahay.org\/blog\/?p=455"},"modified":"2015-11-14T16:17:15","modified_gmt":"2015-11-14T16:17:15","slug":"program-of-the-month-sfmutter","status":"publish","type":"post","link":"https:\/\/ahay.org\/blog\/2015\/07\/10\/program-of-the-month-sfmutter\/","title":{"rendered":"Program of the month: sfmutter"},"content":{"rendered":"

sfmutter<\/a> performs a mute operation, common in prestack seismic data processing.<\/p>\n

The following example from bei\/wvs\/vscan<\/a> shows a seismic CMP gather before and after a mute.<\/p>\n

\"\"<\/p>\n

sfmutter<\/em> multiples the input by a weight, which follows the equation<\/p>\n

$$W(t,x) = \\left\\{\\begin{array}{rl} 0 & \\quad \\mbox{for} \\quad t – t_0 < p_0\\,(x-x_0) \\\\ 1 & \\quad \\mbox{for} \\quad t – t_0 > \\Delta t + p_1\\,(x-x_0) \\end{array}\\right.$$<\/p>\n

The weight is smoothly interpolated in between the two regions. Different parameters appearing in this equation can be specified as inputs for sfmutter<\/strong>: t0=<\/strong> and x0=<\/strong> correspond to $t_0$ and $x_0$; tp=<\/strong> corresponds to $\\Delta t$; slope0=<\/strong> and slopep=<\/strong> correspond to $p_0$ and $p_1$, respectively. The slope can be specified by velocity v0=<\/strong> such that $p_0=1\/v_0$. By default, $p_1=p_0$.<\/p>\n

The parameter half=<\/strong> indicates whether the horizontal axis corresponds to half-offset instead of the full offset (true by default). In case of irregular offsets, they can be provides in a file specified by offset=<\/strong>. The parameter abs=<\/strong> controls whether to use the absolute value of the offset in the calculation of the mute (true by default).<\/p>\n

To make a hyperbolic mute, instead of the default linear mute, use hyper=y<\/strong>. In this case, the equation changes to<\/p>\n

$$W(t,x) = \\left\\{\\begin{array}{rl} 0 & \\quad \\mbox{for} \\quad (t-t_0)^2 < p_0^2\\,(x-x_0)^2 \\\\ 1 & \\quad \\mbox{for} \\quad (t-t_0)^2 > (\\Delta t)^2 + p_1^2\\,(x-x_0)^2 \\end{array}\\right.$$<\/p>\n

The following example from xjtu\/mcaseislet\/sep2<\/a> applies a hyperbolic mute for an SRME prediction of surface-related multiple reflections:<\/p>\n

\"\"<\/p>\n

For inner mute, specified by inner=y<\/strong>, the signs in the equation are reversed. The following example from milano\/taupvel\/cmp<\/a> applies an inner mute to a Radon-transformed CMP gather:<\/p>\n

\"\"<\/p>\n

10 previous programs of the month:<\/h3>\n