Find pattern in image - Teh Forum

<body> <div id="header"> <span class="left"> <span class="back"><a href="lthread_list.php?webtag=DEFAULT"><span class="image mobile_back" title="Back"></span></a></span> <span class="image mobile_logo" title="Beehive Forum Logo"></span> </span> <ul> <li> <a class="reply_all" href="lpost.php?webtag=DEFAULT&reply_to=42326.0&return_msg=42326.9"> <span class="image mobile_reply_all"></span><span class="text">Reply to All</span> </a> </li> <li> <a class="navigation" href="#"> <span class="image mobile_navigation"></span><span class="text">Show messages</span> </a> </li> <li> <a class="main" href="#"><span class="image mobile_menu" title="Menu"></span> </a> </li> </ul> </div> <div class="menu main"> <ul> <li><a href="lthread_list.php?webtag=DEFAULT">Messages</a></li> <li><a href="lpm.php?webtag=DEFAULT">Inbox</a></li> <li><a href="lsearch.php?webtag=DEFAULT">Search</a></li> <li><a href="llogon.php?webtag=DEFAULT">Login</a></li> </ul> </div> <div class="menu navigation"><a href="lmessages.php?webtag=DEFAULT&msg=42326.1">1–10</a><a href="lmessages.php?webtag=DEFAULT&msg=42326.11">11–20</a><a href="lmessages.php?webtag=DEFAULT&msg=42326.21">21–22</a></div> <div id="page_content"> <h3 class="thread_title"><a href="index.php?webtag=DEFAULT&amp;msg=42326.9">Find pattern in image</a> </h3> <div id="messages" data-navigation="42326_9_22_10"> <a name="a42326_9"></a><div class="message" id="message_42326_9"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">17 Mar 2019 01:14</span> <div class="clearer"></div> </div><div class="message_to">To: Chris (CHRISSS) <span><span class="image post_read" title="Read: 17 Mar 2019 01:14"></span></span> <span class="message_count">9 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.9">42326.9</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42326.8">42326.8</a></div> <div class="message_body"> Or possibly Fourier transform.<br /><br /><img alt="" src="https://www.tehforum.co.uk/forum/get_attachment.php?webtag=DEFAULT&hash=ce9c7902365ebb8ef622fa7b982a4ebd&filename=fourier.png" style="width:400px;height:418px;" /></div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.9&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.9"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_10"></a><div class="message" id="message_42326_10"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">17 Mar 2019 01:20</span> <div class="clearer"></div> </div><div class="message_to">To: Chris (CHRISSS) <span><span class="image post_read" title="Read: 17 Mar 2019 01:20"></span></span> <span class="message_count">10 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.10">42326.10</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42326.9#a42326_9" target="_self">42326.9</a></div> <div class="message_body"> Or maybe not. I thought that found the center but doesn't look like it.<br /><br /><img alt="" src="https://www.tehforum.co.uk/forum/get_attachment.php?webtag=DEFAULT&hash=a7e671cc466e6a610546d91a1fa775e2&filename=fourier2.png" style="width:400px;height:398px;" /></div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.10&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.10"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_11"></a><div class="message" id="message_42326_11"> <div class="message_header"> <div class="message_from"> From: Peter (BOUGHTONP)<span class="message_time">17 Mar 2019 20:11</span> <div class="clearer"></div> </div><div class="message_to">To: Chris (CHRISSS) <span><span class="image post_read" title="Read: 17 Mar 2019 20:13"></span></span> <span class="message_count">11 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.11">42326.11</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42326.8">42326.8</a></div> <div class="message_body"> Yeah, a thousand cubed is a billion, must have misread that, and I guess if you're cloning arrays in nested loops you could create enough variables to use that much memory. <p>Of course, any time you find yourself nesting loops in any scenario you should take a step back and check what you're doing, <em>especially</em> if it's more than two levels and using the same data - there'll almost certainly be a different approach worth considering. Pretty sure detecting corner/outermost points doesn't require any nesting.</p></div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.11&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.11"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_12"></a><div class="message" id="message_42326_12"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">18 Mar 2019 22:08</span> <div class="clearer"></div> </div><div class="message_to">To: Peter (BOUGHTONP) <span><span class="image post_read" title="Read: 19 Mar 2019 22:50"></span></span> <span class="message_count">12 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.12">42326.12</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42326.9#a42326_11" target="_self">42326.11</a></div> <div class="message_body"> Oh I know, three nested loops is not a good idea with that many elements. I have no idea what I am doing though <span class="emoticon e_eek" title="8-O"><span class="e__">8-O</span></span> </div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.12&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.12"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_13"></a><div class="message" id="message_42326_13"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">19 Mar 2019 20:40</span> <div class="clearer"></div> </div><div class="message_to">To: ALL<span class="message_count">13 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.13">42326.13</a></div> <div class="message_body"> I thought of one possible way around it. Just get them to upload an image of the chart without all the extra crap around it. I can easily (I think) find 4 points to match up the image then.</div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.13&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.13"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_14"></a><div class="message" id="message_42326_14"> <div class="message_header"> <div class="message_from"> From: Peter (BOUGHTONP)<span class="message_time">19 Mar 2019 22:56</span> <div class="clearer"></div> </div><div class="message_to">To: Chris (CHRISSS) <span><span class="image post_read" title="Read: 19 Mar 2019 22:56"></span></span> <span class="message_count">14 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.14">42326.14</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42326.9#a42326_13" target="_self">42326.13</a></div> <div class="message_body"> Is "them" the staff in a single lab/whatever who might actually listen, or does it include various clients who will blatantly ignore your hand-held instructions the moment you turn your back and go raise an issue claiming there's a bug in what you did despite it being a completely unrelated error that wouldn't occur if they did things how they were told? <span class="emoticon e_angry" title=":@"><span class="e__">:@</span></span></div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.14&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.14"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_15"></a><div class="message" id="message_42326_15"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">19 Mar 2019 23:04</span> <div class="clearer"></div> </div><div class="message_to">To: Peter (BOUGHTONP) <span><span class="image post_read" title="Read: 19 Mar 2019 23:11"></span></span> <span class="message_count">15 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.15">42326.15</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42326.9#a42326_14" target="_self">42326.14</a></div> <div class="message_body"> Haha. Internal staff. Who are probably going to ignore my instructions and raise an issue despite not following instructions <span class="emoticon e_grin" title=":D"><span class="e__">:D</span></span><br /> <br /> I do have another plan though. Which I think would work up to a 9° rotation.<br /> <br /> So. Iterate over points, pick 3, starting with two from top left and bottom right. Find the affine transform between those and my set of known points. Check how many points match.<br /> <br /> Repeat, selecting second and third from top left with bottom right. Keep going for a bit then move in from the bottom left one with 1 and 2 from top left...<br /> <br /> A quick check on my sample image and it's only 3000ish combinations. Not sure how fast affine warping is. I think that would pick out 3 easy to find points.</div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.15&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.15"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_16"></a><div class="message" id="message_42326_16"> <div class="message_header"> <div class="message_from"> From: Peter (BOUGHTONP)<span class="message_time">19 Mar 2019 23:15</span> <div class="clearer"></div> </div><div class="message_to">To: Chris (CHRISSS) <span><span class="image post_read" title="Read: 19 Mar 2019 23:15"></span></span> <span class="message_count">16 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.16">42326.16</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42326.9#a42326_15" target="_self">42326.15</a></div> <div class="message_body"> What's special about 9°?</div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.16&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.16"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_17"></a><div class="message" id="message_42326_17"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">19 Mar 2019 23:20</span> <div class="clearer"></div> </div><div class="message_to">To: Peter (BOUGHTONP) <span><span class="image post_read" title="Read: 19 Mar 2019 23:29"></span></span> <span class="message_count">17 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.17">42326.17</a> In reply to <a href="lmessages.php?webtag=DEFAULT&msg=42326.9#a42326_16" target="_self">42326.16</a></div> <div class="message_body"> It's more like 12°. Due to the order it detects the points while contour matching it would pick up the top two first (well last - it seems to work in reverse). Anything higher and the second point in the list would be the wrong point I want to match up to.<br /><br /><img alt="" src="https://www.tehforum.co.uk/forum/get_attachment.php?webtag=DEFAULT&hash=0f9674330daf4ff41ecac17bfcda82f3&filename=rotate.png" style="width:500px;height:409px;" /></div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.17&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.17"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div><a name="a42326_18"></a><div class="message" id="message_42326_18"> <div class="message_header"> <div class="message_from"> From: Chris (CHRISSS)<span class="message_time">21 Mar 2019 14:47</span> <div class="clearer"></div> </div><div class="message_to">To: ALL<span class="message_count">18 of 22</span><div class="clearer"></div> </div> </div> <div class="message_links"> <a href="lmessages.php?webtag=DEFAULT&msg=42326.18">42326.18</a></div> <div class="message_body"> I think I have found a solution that works <span class="emoticon e_partyblower" title=":-O~~~"><span class="e__">:-O~~~</span></span> Assuming that the contour detection manages to pick out the 3 specific points that are needed.<br /><br /> It's a lot more computationally... er, computational. Somewhere between 10-30,000 iterations for the tests I've tried. I could probably optimise it further, some tests it's doing where the points are not far enough apart, or not the 3 points are in a straight line.<br /><br /> I still need to do some more testing, but initial tests are looking good.</div> <div class="message_footer"> <div class="message_footer_links"><a href="lpost.php?webtag=DEFAULT&reply_to=42326.18&return_msg=42326.9" class="reply"><span class="image post"></span>Reply</a></div> <div class="message_vote_form" data-msg="42326.18"> <span class="rating">0/0</span> <span class="image vote vote_down vote_down_off" title="Vote Down"></span> <span class="image vote vote_up vote_up_off" title="Vote Up"></span> </div> </div> </div></div> <div class="message_page_footer"> <ul> <li class="right_col"><form accept-charset="utf-8" method="get" action="lmessages.php" target="_self"><input type="hidden" name="webtag" id="webtag" class="bhinputtext" value="DEFAULT" dir="ltr" /><input type="hidden" name="msg" id="msg" class="bhinputtext" value="42326.19" dir="ltr" /><input type="submit" name="submit" id="keep_reading" value="Keep reading…" class="button" /></form></li> </ul> </div> </div> </body>