{"id":1098,"date":"2014-07-15T14:06:26","date_gmt":"2014-07-15T19:06:26","guid":{"rendered":"https:\/\/blogs.mathworks.com\/steve\/?p=1098"},"modified":"2014-07-15T14:06:26","modified_gmt":"2014-07-15T19:06:26","slug":"starting-a-radon-transform-visualizer","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/steve\/2014\/07\/15\/starting-a-radon-transform-visualizer\/","title":{"rendered":"Starting a Radon transform visualizer"},"content":{"rendered":"\r\n<div class=\"content\"><p>Today I set out to write a post called \"Radon transform - under the hood.\"<\/p><p>Things didn't turn out the way I expected.<\/p><p>When I considered how to write the post I originally intended, I started thinking about how it would be nice to have a good way to visualize (and therefore help understand) the Radon transform itself. So I started working on that instead.<\/p><p>Of course, I didn't have a lot of time today, so I didn't get anywhere near finished with a working app. But I thought I would post anyway!<\/p><p>I'm inviting you, dear reader, to weigh in about what you think would make a good Radon transform visualizer.<\/p><p>To get you started, here's my sketch:<\/p><p><img decoding=\"async\" vspace=\"5\" hspace=\"5\" src=\"https:\/\/blogs.mathworks.com\/images\/steve\/2014\/radon-transform-visualizer-sketch.jpg\" alt=\"\"> <\/p><p>On the left, you can see a simple image (light square on dark background), and you can see the Radon projection along one particular angle (45 degrees).<\/p><p>On the right, you can see the entire Radon transform, displayed as an image. You can also see a vertical dashed line at 45 degrees, which corresponds to the projection angle shown on the left.<\/p><p>I imagine you could interactively drag either the projection axis on the left or the vertical line on the right to change the projection angle and watch the projection change.<\/p><p>So, what do you think? Good idea, bad idea? Any suggestions?<\/p><script language=\"JavaScript\"> <!-- \r\n    function grabCode_4b0917c3116a443f91437e620f34ddb8() {\r\n        \/\/ Remember the title so we can use it in the new page\r\n        title = document.title;\r\n\r\n        \/\/ Break up these strings so that their presence\r\n        \/\/ in the Javascript doesn't mess up the search for\r\n        \/\/ the MATLAB code.\r\n        t1='4b0917c3116a443f91437e620f34ddb8 ' + '##### ' + 'SOURCE BEGIN' + ' #####';\r\n        t2='##### ' + 'SOURCE END' + ' #####' + ' 4b0917c3116a443f91437e620f34ddb8';\r\n    \r\n        b=document.getElementsByTagName('body')[0];\r\n        i1=b.innerHTML.indexOf(t1)+t1.length;\r\n        i2=b.innerHTML.indexOf(t2);\r\n \r\n        code_string = b.innerHTML.substring(i1, i2);\r\n        code_string = code_string.replace(\/REPLACE_WITH_DASH_DASH\/g,'--');\r\n\r\n        \/\/ Use \/x3C\/g instead of the less-than character to avoid errors \r\n        \/\/ in the XML parser.\r\n        \/\/ Use '\\x26#60;' instead of '<' so that the XML parser\r\n        \/\/ doesn't go ahead and substitute the less-than character. \r\n        code_string = code_string.replace(\/\\x3C\/g, '\\x26#60;');\r\n\r\n        copyright = 'Copyright 2014 The MathWorks, Inc.';\r\n\r\n        w = window.open();\r\n        d = w.document;\r\n        d.write('<pre>\\n');\r\n        d.write(code_string);\r\n\r\n        \/\/ Add copyright line at the bottom if specified.\r\n        if (copyright.length > 0) {\r\n            d.writeln('');\r\n            d.writeln('%%');\r\n            if (copyright.length > 0) {\r\n                d.writeln('% _' + copyright + '_');\r\n            }\r\n        }\r\n\r\n        d.write('<\/pre>\\n');\r\n\r\n        d.title = title + ' (MATLAB code)';\r\n        d.close();\r\n    }   \r\n     --> <\/script><p style=\"text-align: right; font-size: xx-small; font-weight:lighter;   font-style: italic; color: gray\"><br><a href=\"javascript:grabCode_4b0917c3116a443f91437e620f34ddb8()\"><span style=\"font-size: x-small;        font-style: italic;\">Get \r\n      the MATLAB code <noscript>(requires JavaScript)<\/noscript><\/span><\/a><br><br>\r\n      Published with MATLAB&reg; R2014a<br><\/p><\/div><!--\r\n4b0917c3116a443f91437e620f34ddb8 ##### SOURCE BEGIN #####\r\n%%\r\n% Today I set out to write a post called \"Radon transform - under the\r\n% hood.\"\r\n%\r\n% Things didn't turn out the way I expected.\r\n%\r\n% When I considered how to write the post I originally intended, I started\r\n% thinking about how it would be nice to have a good way to visualize (and\r\n% therefore help understand) the Radon transform itself. So I started\r\n% working on that instead.\r\n%\r\n% Of course, I didn't have a lot of time today, so I didn't get anywhere\r\n% near finished with a working app. But I thought I would post anyway!\r\n%\r\n% I'm inviting you, dear reader, to weigh in about what you think would\r\n% make a good Radon transform visualizer.\r\n%\r\n% To get you started, here's my sketch:\r\n%\r\n% <<https:\/\/blogs.mathworks.com\/images\/steve\/2014\/radon-transform-visualizer-sketch.jpg>>\r\n%\r\n% On the left, you can see a simple image (light square on dark\r\n% background), and you can see the Radon projection along one particular\r\n% angle (45 degrees). \r\n%\r\n% On the right, you can see the entire Radon transform, displayed as an\r\n% image. You can also see a vertical dashed line at 45 degrees,\r\n% which corresponds to the projection angle shown on the left.\r\n%\r\n% I imagine you could interactively drag either the projection axis on the\r\n% left or the vertical line on the right to change the projection angle and\r\n% watch the projection change.\r\n%\r\n% So, what do you think? Good idea, bad idea? Any suggestions?\r\n\r\n##### SOURCE END ##### 4b0917c3116a443f91437e620f34ddb8\r\n-->","protected":false},"excerpt":{"rendered":"<div class=\"overview-image\"><img decoding=\"async\"  class=\"img-responsive\" src=\"https:\/\/blogs.mathworks.com\/images\/steve\/2014\/radon-transform-visualizer-sketch.jpg\" onError=\"this.style.display ='none';\" \/><\/div><p>\r\nToday I set out to write a post called \"Radon transform - under the hood.\"Things didn't turn out the way I expected.When I considered how to write the post I originally intended, I started thinking... <a class=\"read-more\" href=\"https:\/\/blogs.mathworks.com\/steve\/2014\/07\/15\/starting-a-radon-transform-visualizer\/\">read more >><\/a><\/p>","protected":false},"author":42,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/posts\/1098"}],"collection":[{"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/users\/42"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/comments?post=1098"}],"version-history":[{"count":3,"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/posts\/1098\/revisions"}],"predecessor-version":[{"id":1101,"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/posts\/1098\/revisions\/1101"}],"wp:attachment":[{"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/media?parent=1098"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/categories?post=1098"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.mathworks.com\/steve\/wp-json\/wp\/v2\/tags?post=1098"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}