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Is there a way to display cv::Mat using __android_log_print()

I know you can display a cv::Mat using cout << Mat << endl; But I am examing this on a android phone it can't handle cout; So is there a established way to send it through...

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OpenCV 4.0 Android (NDK) With NEON: Why And Why Not?

I am using the OpenCV for Android NDK, which can be downloaded from [here](https://sourceforge.net/projects/opencvlibrary/files/4.1.0/opencv-4.1.0-android-sdk.zip/download), and I just use the...

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Writing video in .mp4

Hello, I've been able to save videos in ANDROID using OpenCV VideoWriter (MJPEG) in .avi format but now I was interested in saving it directly to MP4 format. I can open .avi videos in my laptop but not...

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White paper on a white background not working

I use below code for detecting a page and show the rectangle on paper and its work perfectly while background is black but if the background is white and paper also white then not able to draw the...

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Steps to build native OpenCV for Android

Hello everyone 😄 ----------------- I want to build openCV for Android on Linux like in [this tutorial](https://amin-ahmadi.com/2019/02/03/how-to-build-opencv-4-x-for-native-android-development/) Here...

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problem while load trained svm android

hello guys, i'm working on regions detection, so i'm using SVM with opencv 3.4 on Android studio, i tried to save the trained model of SVM and loaded after but for some reasons that i don't know the...

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HSV values in openCV

Hi, I've tried to isolate yellow-orange-ish color from an image, using inRange function. I've used an online color picker (https://pinetools.com/image-color-picker) and than tried to isolate by the...

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Cannot find function definations in libopencv_java3.so exported symbols

I want to produce a libopencv_java3.so for android including only the functions I need (opencv_core, opencv_imgproc and opencv_calib3d) based on opencv3.4.3. Because there's no official documentation...

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How to run OpenCV DNN ON GPU ANDROID

Hello everybody, I recently tested my pre trained MobileNet on my android machine by using dnn module in c++. It seems my code is only computing on CPU. I used OPENCV ANDROID v.3.4.6 and I tried to...

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Imported module not shows up on 'Add Module Dependency' dialog

So I'm trying to add OpenCV as a dependency for my Android Studio project. And I've followed this tutorial https://github.com/davidmigloz/go-bees/wiki/Setup-OpenCV-3.1.0-in-Android-Studio-2.2 . So at...

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64 bit library on Android

As of August 1, 2019, in the Play Store, only applications with 64-bit libraries can be published. I have an App with 32 and 64 bit OpenCV libraries. However, in the Play Store, I can't publish it now...

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= 2" Assertion failed">OpenCV on Android: net.forward yields "blobs.size() >= 2" Assertion failed

Following [this tutorial from openCV](https://docs.opencv.org/master/d0/d6c/tutorial_dnn_android.html), and it should be straight forward. However, it crashes with an assertion fail on the...

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Two camera feeds in OpenCV4Android

Seems like a straight forward question, but couldn't find an answer (yet). How can I read 2 camera streams on Android (front and rear) and analyse them individually. I can create 2 listeners and bind...

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Problem about compiled In Opencv 4

Hi guys, I am using Opencv and have a question to ask your opinion. I am using the OpenCV for Android NDK, and I just use the libopencv_java4.so. It seems that it is not compiled with NEON (correct me...

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copyTo don't work

I want to make app which swap faces in picture. The mat of the picture is picMat, and I want to copy a mat of detected face on picmat, but the function copyTo don't work. here is the code: Bitmap...

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findContours() with detailed images

Hi all, I am implementing a custom barcode code reader (to read custom codes that look like a QR-code) with openCV on Android. At some point, I am using findContours() with tree hierarchy. My problem...

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Opencv 4.1.1 and Android Studio

Hello, i tried since three days to create a new project including opencv4.1.1 on Android Studio 3.4.2 I follow a lot of article but nothing append : when my app is starting, the opencv library won't...

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When I build OPENCV 3.4.6 with OPENCL ENABLED NOT WORK WITH abi:ARM64-V8A

Hello, I'm trying to build opencv with opencl for ABI ARM64-V8A but when I launch `ninja.exe install/strip`, i received the follow message. I've tried also the ndk 16b. All works fine if I use...

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How to run OpenCV DNN ON GPU ANDROID

Hello everybody, I recently tested my pre trained MobileNet on my android machine by using dnn module in c++. It seems my code is only computing on CPU. I used OPENCV ANDROID v.3.4.6 and I tried to...

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Why is Utils.bitmapToMat changing Mat type?

I'm working with Android and the OpenCV Android library. I have a Bitmap of config RGB_565 and want to convert it to a 3 channel Mat. In order to do so, I have the following code: Bitmap bmp =...

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