2014-04-09 00:39:32 -0600 | asked a question | Weird map orientation using sobel gradients I tried to follow this method of drawing orientation map http://answers.opencv.org/question/9493/fingerprint-orientation-map-through-gradient/ And i used a block size of 5x5 on my 480x320 image. The gradients i got was from 0-270 degrees. And there are constant values that keep on repeating like 44.7623 and 224.762. I wonder if my gradients are wrong. After that, i add all the gradients in the 5x5 block and divide them by 25 (averaging) like what the link said. I divided the degrees into 8 sections of 45degree intervals and plotted them out. But it looks nothing like my original image. Can anyone tell me what's wrong? I just want to detect the core(circle-like) feature of the image. My original image is this _________________________________________________ But my orientation map is this: This is what I'm doing What's wrong ? =( I got the gradients from this method : Here's the full code. (more) |
2014-04-08 05:04:31 -0600 | asked a question | What is gradient from Sobel operator mean? I have the gradients from the Sobel operator for each pixel. In my case 320x480. But how can I relate them with the orientation? For an example, I'm planning to draw an orientation map for fingerprints. So, how do I start? Is it by dividing the gradients into blocks (example 16x24) then adding the gradients together and diving it by 384 to get the average gradients? Then from there draw a line from the center of the block using the average gradient? Correct me if i'm wrong. Thank you. |
2014-03-29 09:23:29 -0600 | received badge | ● Editor (source) |
2014-03-29 09:21:50 -0600 | asked a question | Orientation map+ sobel+histogram Hi, I'm trying to get a edge orientation map to detect the "core" feature of a fingerprint. Now I'm stuck in creating the orientation map. I'm using sobel and trying to create a map for it. Can someone enlighten me on what's wrong with this code? It "stopped working". Btw I can detect terminations & bifurcations for fingerprints but I can't match them due to variation in areas n rotation. Any method I can solve this apart from using orientation map to detect the core feature and linking it from there? Thanks |