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2016-02-23 03:55:33 -0600 | asked a question | Rotation angle of a given affine transformation matrix I'm developing an image stitching algorithm and I'm using affine transformations. One part of the algorithm is to detect whether an affine transform is garbage. To do this, I want to calculate the rotation angle that each affine transform will produce, to discard it if it's too high. So, how can I determine the rotation angle of a given affine transformation matrix? |
2016-02-23 03:13:23 -0600 | asked a question | Correct the image's borders illumination I'm developing an algorithm to stich images of vines. These images were taken at night with artificial illumination, because of this, the image's center is very well illuminated but their borders are almost black. To correct this I have tried the following: 1 - Convert the image to LAB. 2 - Get the channel L. 3 - Increase that channel's pixel values, following this rule: The incrementation value is the highest in the border's pixels, and it decreases as it reaches the image's center. For example, for an image's line: I think this method is not very good because it's "creating" information. How can I do this in a better way? |
2015-03-04 05:19:02 -0600 | asked a question | Android: Draw contours arround points detected by MSER I'm trying to draw countours to indicate the points detected by MSER in a bitmap. I can detect the points with Now I want to dray the contour of these points using I have tried to convert MatOfKeyPoint to In this case, there is no exceptions, but I have tested this too: In this case there is an exception:
I have read the documentation of OpenCV for java here: But the example is only with I have read that MatOfPoint is only a way used by OpenCV to avoid to copy points between native part and java part, (See: http://www.answers.opencv.org/questio...) so that, I assume that the How can I convert the |
2015-03-03 16:21:43 -0600 | answered a question | Problem adding function to OpenCV4Android: UnsatisfiedLinkError I have solved the problem. As I thought, the problem was that, despite I compiled well the modified OpenCV4Android library, I was loading the library dinamically, these changes were not applied, then I was using the library that comes with OpenCV manager (for android). The solution is make the load to be static, this is, copy Then make the library loading statically. Here an example: NOTE: This solutions is only valid for proyects that not use JNI, otherwise you must follow this tutorial: http://docs.opencv.org/trunk/doc/tuto... |
2015-02-27 06:22:40 -0600 | asked a question | Problem adding function to OpenCV4Android: UnsatisfiedLinkError I have to add a function to OpenCV4Android library (it will be a copy of an existing function, but modifed). For now, I'm trying to add a very simple function for testing, its only objective is to return an integer value. I have compiled the library with no errors, but when I try to call this function from java, I have an error: UnsatisfiedLinkError. I don't know what I'm doing wrong. I'm working on windows. What I have tested: In file ${opencv_folder}\modules\java\generator\src\cpp\utils.cpp Add at the end of file the following: In file ${opencv_folder}\modules\java\generator\src\java\android+Utils.java add at the end of file the following: Finally, in my java project: I have no errors in eclipse, it detects the function in the module. What I do to compile: What's my error? EDIT: I have tested anotherthing, generate jni signatura via javah command, this is what I've test: Open command line in
Then executing the following command:
But I have this error:
I think it's because android.content.Context is an android library that is not in the OpenCV4Android library. How can I say to javah that have to look for that class in other folder? EDIT2: I have used ndk's objdump to see the real name of the function in the .so file. This is what I've found: It's the expected name. The command that I have exectued: First I have gone to
There, I have exectued
And then open "pr.txt" and search for Java_org_opencv_android_test. EDIT 3: I think the problem may be that the .so file I think this may be due to you have to download OpenCV manager in android to execute any application that uses OpenCV, an this manager has its own .so files. Then, how can I replace |
2015-02-27 03:24:49 -0600 | commented question | Modify OpenCV4Android source code There is a function in mser module that returns values that I no need, I need to add a copy of this function without returning this not necessary information. I have to do it because if this function returns me, for example, (3, 5, 7), then I don't know which numbers are that I need, and which not. And yes, of course I only need to add some function that will be a modified copy of another, there is no problem with that. |
2015-02-27 03:12:14 -0600 | commented question | Modify OpenCV4Android source code Ok, it means that I will have to wait for fewminutes in each compilation. When I start to modify the real function I have to modify, how can I make test with rapid compilations? Should I extract a little part of opencv to modify and test, and the re-add to library? |
2015-02-27 03:03:46 -0600 | received badge | ● Editor (source) |
2015-02-27 03:03:42 -0600 | asked a question | Modify OpenCV4Android source code I have to modify a functiont of OpenCVAandroid and re-build it, but for now, I want to add a new function that does something, for example return some value or print "hello world". This is only for testing. I'm working on windows. I have try to compile a single OpenCV module (core). What I have done is to go to core folder location and run "cmake .", but I have an error: Here my questions: 1 - Is there any way to compile only a part (module) of OpenCV instead of to built all library in each compilation? 2 - If the above is "yes", what are the steps I have to follow? 3 - Finally, the code I have to modify will be used from java. It means that, apart of modify c++ pure code, I have to modify the "jni part", and modify the proper .java file, is correct? |