{"id":367,"date":"2014-01-09T07:42:53","date_gmt":"2014-01-09T07:42:53","guid":{"rendered":"http:\/\/ahay.org\/blog\/?p=367"},"modified":"2015-08-30T14:17:17","modified_gmt":"2015-08-30T14:17:17","slug":"program-of-the-month-sfinttest1","status":"publish","type":"post","link":"https:\/\/ahay.org\/blog\/2014\/01\/09\/program-of-the-month-sfinttest1\/","title":{"rendered":"Program of the month: sfinttest1"},"content":{"rendered":"<p><a href=\"\/RSF\/sfinttest1.html\">sfinttest1<\/a> performs forward interpolation from a regular grid to irregular locations (in 1-D). <\/p>\n<p>The following example from <a href=\"\/RSF\/book\/sep\/forwd\/chirp.html\">sep\/forwd\/chirp<\/a> shows regularly sampled values of a variable-frequency signal and the error of its interpolation using linear and cubic-convolution interpolators. <\/p>\n<p><img decoding=\"async\" src=\"\/RSF\/book\/sep\/forwd\/chirp\/Fig\/chirp.png\" alt=\"\" title=\"\" \/> <\/p>\n<p><img decoding=\"async\" src=\"\/RSF\/book\/sep\/forwd\/chirp\/Fig\/lincub.png\" alt=\"\" title=\"\" \/> <\/p>\n<p>The irregular coordinates for interpolation are supplied in a file specified by <strong>coord=<\/strong>. The type of the interpolator is specified by <strong>interp=<\/strong>. The currently implemented types are Lagrange (including linear and nearest-neighbor interpolation), cubic convolution, weighted sinc interpolation (with Kaiser, Lanczos, cosine, and Welsh windows), B-spline, and MOM (slightly improved B-spline). The size of the interpolation filter is given by <strong>nw=<\/strong>. The Kaiser-window interpolator requires an additional parameter, which is specified by <strong>kai=<\/strong>. <\/p>\n<p>An alternative (using invertible cubic spline interpolation) is <a href=\"\/blog\/2012\/09\/03\/program-of-the-month-sfiwarp\/\">sfiwarp<\/a>. <\/p>\n<p>A 2-D version is <a href=\"\/RSF\/sfinttest2.html\">sfinttest2<\/a>. The following example from <a href=\"\/RSF\/book\/sep\/forwd\/chirp2.html\">sep\/forwd\/chirp2<\/a> compares the error of Kaiser-windowed 8-point sinc interpolation and 8-point B-spline interpolator applied to interpolating a 2-D signal. <\/p>\n<p><img decoding=\"async\" src=\"\/RSF\/book\/sep\/forwd\/chirp2\/Fig\/plckaispl.png\" alt=\"\" title=\"\" \/><\/p>\n<h3 id=\"10previousprogramsofthemonth\">10 previous programs of the month<\/h3>\n<ul>\n<li><a href=\"\/blog\/2013\/12\/01\/program-of-the-month-sfcausint\/\">sfcausint<\/a><\/li>\n<li><a href=\"\/blog\/2013\/11\/03\/program-of-the-month-sfremap1\/\">sfremap1<\/a><\/li>\n<li><a href=\"\/blog\/2013\/10\/03\/program-of-the-month-sfunif2\/\">sfunif2<\/a><\/li>\n<li><a href=\"\/blog\/2013\/09\/14\/program-of-the-month-sfpatch\/\">sfpatch<\/a><\/li>\n<li><a href=\"\/blog\/2013\/08\/02\/program-of-the-month-sfai2refl\/\">sfai2refl<\/a><\/li>\n<li><a href=\"\/blog\/2013\/07\/01\/program-of-the-month-sftime2depth\/\">sftime2depth<\/a><\/li>\n<li><a href=\"\/blog\/2013\/06\/12\/program-of-the-month-sfwiggle\/\">sfwiggle<\/a><\/li>\n<li><a href=\"\/blog\/2013\/05\/04\/program-of-the-month-sfvscan\/\">sfvscan<\/a><\/li>\n<li><a href=\"\/blog\/2013\/04\/08\/program-of-the-month-sfnmo\/\">sfnmo<\/a><\/li>\n<li><a href=\"\/blog\/2013\/03\/10\/program-of-the-month-sfpow\/\">sfpow<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>sfinttest1 performs forward interpolation from a regular grid to irregular locations (in 1-D). The following example from sep\/forwd\/chirp shows regularly sampled values of a variable-frequency signal and the error of its interpolation using linear and cubic-convolution interpolators. The irregular coordinates for interpolation are supplied in a file specified by coord=. The type of the interpolator [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":4,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":""},"categories":[3],"tags":[],"class_list":["post-367","post","type-post","status-publish","format-standard","hentry","category-programs"],"_links":{"self":[{"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/posts\/367","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/comments?post=367"}],"version-history":[{"count":4,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/posts\/367\/revisions"}],"predecessor-version":[{"id":15073,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/posts\/367\/revisions\/15073"}],"wp:attachment":[{"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/media?parent=367"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/categories?post=367"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ahay.org\/blog\/wp-json\/wp\/v2\/tags?post=367"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}