Document Scanner with tiny OpenCV
example1.mp4
Document Scanner is an Android library (kotlin based) for scanning documents based on CameraX API and a tiny version of OpenCV.
This library was taken and modified from Document-Scanning-Android-SDK. Improved logic of image processing, now the processing time is increased by more than 5 times. Scanning a document under ideal scanning conditions takes approximately 5 seconds.
Features
- tiny version of OpenCV 4.4.0:
- armeabi-v7a: 3.1 MB (original: 10.1 MB)
- arm64-v8a: 5.6 MB (original: 18.8 MB)
- x86: 16.7 MB (original: 38.6 MB)
- x86_64: 25.1 MB (original: 53.7 MB)
- live detection (also detect rectangle with one bent angle)
- auto scan and flash support
- edit detected rectangle
- configure size of results using Compressor
Getting started
Document Scanner is supported on Android devices starting from SDK 21 (Lollipop)
Installation
in root project build.gradle:
allprojects {
repositories {
...
maven { url "https://jitpack.io" }
}
}
in app build.gradle:
android {
...
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
}
dependencies {
...
implementation 'com.github.Krobys:document-scanner-fast:1.0.0'
}
Usage
Initialization
In your Application class:
class MyCustomApplication: Application() {
override fun onCreate() {
...
val configuration = DocumentScanner.Configuration()
configuration.imageQuality = 100
configuration.imageSize = 1000000 // 1 MB
configuration.imageType = Bitmap.CompressFormat.JPEG
DocumentScanner.init(this, configuration) // or simply DocumentScanner.init(this)
}
}
Create an Activity (e.g. AppScanActivity) that extends ScanActivity
In manifest:
">
AppScanActivity:
class AppScanActivity: ScanActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.app_scan_activity_layout)
addFragmentContentLayout()
}
override fun onError(error: DocumentScannerErrorModel) {
}
override fun onSuccess(scannerResults: ScannerResults) {
}
override fun onClose() {
finish()
}
ScannerResults
Document Scanner library will return image files using fun onSuccess(scannerResults: ScannerResults)
. ScannerResults contains 1 file:
- imageFile
Error Handling
All errors are returned to app using fun onError(error: DocumentScannerErrorModel)
data class DocumentScannerErrorModel(
var errorMessage: ErrorMessage? = null,
var throwable: Throwable? = null
)
ErrorMessage
is an enum containing the following error types:
- TAKE_IMAGE_FROM_GALLERY_ERROR
- PHOTO_CAPTURE_FAILED
- CAMERA_USE_CASE_BINDING_FAILED
- DETECT_LARGEST_QUADRILATERAL_FAILED
- INVALID_IMAGE
- CAMERA_PERMISSION_REFUSED_WITHOUT_NEVER_ASK_AGAIN
- CAMERA_PERMISSION_REFUSED_GO_TO_SETTINGS
- STORAGE_PERMISSION_REFUSED_WITHOUT_NEVER_ASK_AGAIN
- STORAGE_PERMISSION_REFUSED_GO_TO_SETTINGS
- CROPPING_FAILED
Throwable
can be null for some error messages like Permissions
Configuration
- imageQuality:
- From 0 to 100
- Default value is 100
- imageSize:
- Image size in bytes
- No default value
- imageType:
- imageType can be Bitmap.CompressFormat.JPEG, Bitmap.CompressFormat.PNG or Bitmap.CompressFormat.WEBP
- Default value is Bitmap.CompressFormat.JPEG
Thanks
- OpenCV
- Compressor
- RxPermissions
- Inspiration from mayuce, adityaarora1 and hannesa2
- Document scanner from zynkware
License
Copyright 2021 Krobys
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.