title: Sketch-based Image Retrieval with OpenCV or LIRe
body: <p>I'm currently reading for BSc Creative Computing with the University of London and I'm in my last year of my studies. The only remaining module I have left in order to complete the degree is the Project.</p>
  
  <p>I'm very interested in the area of content-based image retrieval and my project idea is based on that concept. In a nutshell, my idea is to help novice artists in drawing sketches in perspective with the use of 3D models as references. I intend to achieve this by rendering the side/top/front views of each 3D model in a collection, pre-process these images and index them. While drawing, the user gets a series of models (that have been pre-processed) that best match his/her sketch, which can be used as guidelines to further enhance the sketch. Since this approach relies on 3D models, it is also possible for the user to rotate the sketch in 3D space and continue drawing based on that perspective. Such approach could help comic artists or concept designers in quickly sketching their ideas.</p>
  
  <p>While carrying out my research I came across <strong>LIRe</strong> and I must say I was really impressed. I've downloaded the LIRe demo v0.9 and I played around with the included sample. I've also developed a small application which automatically downloades, indexes and searches for similar images in order to better understand the inner workings of the engine. Both approaches returned very good results even with a limited set of images (~300).</p>
  
  <p>Next experiment was to test the output response when a sketch rather than an actual image is provided as input. As mentioned earlier, the system should be able to provide a set of matching models based on the user's sketch. This can be achieved by matching the sketch with the rendered images (which are of course then linked to the 3D model). I've tried this approach by comparing several sketches to a small set of images and the results were quite good - see <a href="http://claytoncurmi.net/wordpress/?p=17" rel="nofollow">http://claytoncurmi.net/wordpress/?p=17</a>. However when I tried with a different set of images, results weren't as good as the previous scenario. I used the Bag of Visual Words (using SURF) technique provided by LIRe to create and search through the index.</p>
  
  <p>I'm also trying out some sample code that comes with <strong>OpenCV</strong> (I've never used this library and I'm still finding my way).</p>
  
  <p><strong>So, my questions are;</strong></p>
  
  <p>1..Has anyone tried implementing a sketch-based image retrieval system? If so, how did you go about it?</p>
  
  <p>2..Can LIRe/OpenCV be used for sketch-based image retrieval? If so, how this can be done?</p>
  
  <p>PS. I've read several papers about this subject, however I didn't find any documentation about the actual implementation of such system.</p>
  
  <p>Any help and/or feedback is greatly appreciated.</p>
  
  <p>Regards,</p>
  
  <p>Clayton</p>