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Looking for a recent guide to build Opencv4Android.

I am developing a mobile application and plans to use native OpenCV library by jni approach. Reference this tutorial as my environment:...

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How to classify image of object on a game board

Imagine I have a squared game board the same as Match-3 game (namely Candy Crush, Puzzle and Dragon, etc), my objective is to detect the orb type on their screen and save the result as an array. I have...

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Opencv4Android build error with arm64-v8a

I succesfully build Opencv 3.4.1 for Android for target **armeabi-v7a**. But when in CMAKE I specify target ANDROID_ABI: **arm64-v8a**, I got this error at the end on build process: [100%] Linking CXX...

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OpenCV4.3.0 build with OpenCL

Hi all , I built OpenCV4.3.0 with OpenCL , NEON and set the TBB, openmp on , I tried the built opencv in two ways . I: I tested it on the real phone which could support LibOpencl.so ,and found that...

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Separating conjoined blobs

I'm developing an android application using OpenCV 4.0.1 to detect platelets. What I've done so far is I've removed the background by applying threshold and detected the platelets using approxpolydp...

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Android canny edge detection opencv error Assertion failed

I would make edge detection of the image in Android with openv. But I got this error : E/cv::error()( 2698): OpenCV Error: Assertion failed (_dx.type() == (((3) & ((1 << 3) - 1)) + (((1)-1)...

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How to find a border between sky/ground on a photo?

Hello, I have the android app that capture a camera view. I want to postprocess an image from camera to modify a sky on image. I need a way to find where the sky is on an image. I need to detect a...

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detecting multi color document with OpenCV4Android

I am new to OpenCv with Android.I am trying to make an application which auto detects documents using OpenCv - 2.4.13 . In my app, there is a functionality of detection documents (like a Scanbot app)...

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OpenCV camera works really strange (Android)

Hello! I tried different OpenCV tutorials for Android and every time native camera is not full screen and I get distorted image& It looks like this: ![image...

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Project QT game has interface errors

Hello friends. I just bought a Samsung S20. Then I downloaded the game Project QT on CHPlay to play. When the installation is complete, everything. In the game, sometimes I see the interface blink on...

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Track point or rect and replace with another mat

I try to make app like ink hunter, make it to detect object but on live camera overlaped image blink cause every time i detect object again n again in every frame.I read lot about track object but not...

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Building Opencv4.3 Android shared libs error

I'm trying to compile Opencv4.3 to crosscompile with Android but if I user "DBUILD_SHARED_LIBS=ON" I got an error when running make command. Command: [ 57%] Built target opencv_xphoto [ 57%] Linking...

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Error to cross compile into arm64-v8a by CV 4.3.0

I use CMake-GUI with Newest NDK 21.2.6472646 on Windows 10. If I remove BUILD_opencv_java, CMake will finish. [ 98%] Built target gen_opencv_java_source [ 98%] Linking CXX shared module...

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Mobile app crashes when detecting facial landmarks

Hi, Recently github enabled opencv's extra classes through Python-for-android (including the face class). It has no trouble detecting the face binding boxes. It loads the LBF model, but then crashes...

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Error with building OpenCV in Android

When I start building app, AS show me an error Also in gradle.properties I wrote something like: **opencvsdk=C:\\Program Files\\Android\\Android Studio\\opencv\\sdk** but it didn't help me. So how to...

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Does OpenCV 4.3 support video capture from android?

I know that versions below 4.1 did not support and always returned an error, but in 4.1.1 support was added. *"VideoCapture C++ interface supports Android Media NDK (21+) video I/O file capture...

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Using opencv to capture feet and look at hex color of feet

Hello All. I was hoping someone here could lead to the right direction of what OpenCV projects to include for an app I'm making in Android Studio. I'm just overwhelmed by the number of applications...

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Detect head using Haar Cascade, wont detect tilted head?

Hi all, I am very new to OpenCV and computer vision. However I have managed to make a simple android app that detects faces/eyes. I have designed a template that draws around the face, eyes, pupils...

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android opencv optical mark recognition

I want to use opencv for OMR sheet or Bubble sheet .I dont have fix number of questions or columns in my omr sheet so i am trying to detetct rows and column (also i need to detect the title of the...

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Android dnn in native C++

Hello, i succesfully linked opencv to my android c++ native app.. now I encountered a problem where i cannot read my models (ex. YOLO) I pasted them here: */storage/emulated/0/DCIM/ * but when running...

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