OpenNoteScanner: Android scanner with OpenCV source code

OpenNoteScanner is a powerful Android scanner app that uses OpenCV for edge detection and perspective correction to digitize handwritten notes and printed documents. As an open-source project, the source code is freely available under the GPLv3 license, empowering developers to study, modify, and redistribute the code. Built mainly in Kotlin (with some Java), the app captures an image, detects document boundaries, applies a 90° perspective transformation, and outputs high‑contrast PDFs or JPGs seamlessly. Users can leverage the well‑structured repository to integrate scanning features into their own Android apps.

Key Features:

• Automatic edge detection using OpenCV to find document corners accurately.
• Perspective correction transforming any angle into flat, top-down view.
• Support for special QR‑coded templates for instant scanning.
• Fast image capture with auto-launch from other apps.
• Built-in gallery management and export options (PDF or image).
• Optimized contrast and brightness filters to enhance readability.

Developer & Code Guide:

To build from source, clone the repository and run:

git clone https://github.com/allgood/OpenNoteScanner.git
cd OpenNoteScanner
export ANDROID_HOME=~/Android/Sdk
./gradlew assembleRelease

Alternatively, import the project into Android Studio. The Gradle build scripts auto‑integrate OpenCV libraries and iTextPDF for file creation. You can disable or adjust filters in SettingsActivity.kt, and customize edge detection parameters in EdgeDetectionProcessor.kt.

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This description incorporates key developer terms like source code, Android scanner, OpenCV, edge detection, PDF export, and perspective correction, making it ideal for search engines and relevant to Yoast keyword analysis.

Meta Information

• Author: Claudemir Todo Bom (allgood / ctodobom)
• Programming Language: Kotlin (≈83%), Java (≈17%)
• License: GNU GPLv3 – free to use, modify, and redistribute, but any derivative must use GPLv3 as well (copyleft requirement)
• License Limitations: All distributed modifications must remain open-source under GPLv3; includes attribution and share-alike provisions.
• Repository Link: https://github.com/allgood/OpenNoteScanner