DOT Android Document library
v3.6.2
Introduction
DOT Android Document provides components for document capture and related functionalities which are easy to integrate into an Android application.
Requirements
DOT Android Document has the following requirements:
Minimum Android API level 21
Minimum Kotlin Gradle plugin version 1.6.0 (if used)
Distribution
Maven Repository
DOT Android Document is distributed as an Android library (.aar
package) stored in the Innovatrics maven repository.
In order to integrate DOT Android Document into your project, the first step is to include the Innovatrics maven repository and Google repository to your top level build.gradle
file.
allprojects {
repositories {
jcenter()
google()
maven {
url 'https://maven.innovatrics.com/releases'
}
}
}
Then, specify the dependency on DOT Android Document library in the module’s build.gradle
file. Dependencies of this library will be downloaded alongside the library.
dependencies {
//…
implementation "com.innovatrics.dot:dot-document:$dotDocumentVersion"
//…
}
Supported Architectures
DOT Android Document provides binaries for these architectures:
armeabi-v7a
arm64-v8a
x86
x86_64
If your target application format is APK and not Android App Bundle, and the APK splits are not specified, the generated APK file will contain binaries for all available architectures. Therefore we recommend to use APK splits. For example, to generate arm64-v8a
APK, add the following section into your module build.gradle
:
splits {
abi {
enable true
reset()
include 'arm64-v8a'
universalApk false
}
}
If you do not specify this section, the resulting application can become too large in size.
Permissions
DOT Android Document declares the following permission in AndroidManifest.xml
:
<uses-permission android:name="android.permission.CAMERA" />
Basic Setup
Logging
Although logging is disabled by default, it can be enabled explicitly by using the following method from the com.innovatrics.dot.core.Logger
class.
Logger.setLoggingEnabled(true);
The appropriate place for this call is within the onCreate()
method of your subclass of android.app.Application
. Each TAG
of a log message starts with the prefix dot-document:
.
This setting enables logging for all DOT Android libraries. |
Keep in mind that logging should be used just for debug purposes as it might produce a lot of log messages. |
Components
Overview
DOT Android Document provides both non-UI and UI components. Non-UI components are aimed to be used by developers who want to build their own UI using the DOT Android Document functionality. UI components are build on top of non-UI components. These are available as abstract fragments and can be extended and then embedded into the application’s existing activity providing more control.
List of Non-UI Components
- DOCUMENT DETECTOR
A component for performing document detection on an image.
- IMAGE PARAMETERS ANALYZER
A component for computing image parameters such as sharpness, brightness or hotspots score.
- IMAGE PERSPECTIVE WARPER
A component for perspective warping an image according detected document card corners.
- DOCUMENT AUTO CAPTURE CONTROLLER
A component for capturing good quality images suitable for optical character recognition.
- MACHINE READABLE ZONE READER
A component for reading Machine Readable Zone (MRZ).
List of UI Components
- DOCUMENT AUTO CAPTURE
A visual component for capturing good quality images suitable for optical character recognition.
Non-UI Components
Document Detector
The DocumentDetector
interface provides a document detection functionality.
Create a DocumentDetector
:
DocumentDetector documentDetector = DocumentDetectorFactory.create();
To perform detection, call the following method on the background thread:
DocumentDetector.Result result = documentDetector.detect(bgraRawImage);
Image Parameters Analyzer
The ImageParametersAnalyzer
interface provides an image parameters analysis functionality.
Create ImageParametersAnalyzer
:
ImageParametersAnalyzer imageParametersAnalyzer = ImageParametersAnalyzerFactory.create();
To perform analysis, call the following method on the background thread:
ImageParameters imageParameters = imageParametersAnalyzer.analyze(bgraRawImage);
Image Perspective Warper
The ImagePerspectiveWarper
interface provides perspective warping functionality.
Create ImagePerspectiveWarper
:
ImagePerspectiveWarper imagePerspectiveWarper = ImagePerspectiveWarperFactory.create();
To perform perspective warping, call the following method on the background thread:
BgraRawImage warpedBgraRawImage = imagePerspectiveWarper.warp(bgraRawImage, corners, targetImageSize);
Document Auto Capture Controller
The DocumentAutoCaptureController
interface provides a stateful document auto capture functionality.
Create DocumentAutoCaptureController
:
DocumentAutoCaptureControllerConfiguration configuration = new DocumentAutoCaptureControllerConfiguration.Builder(context, validators)
.detectionNormalizedRectangle(detectionNormalizedRectangle)
.imageParametersNormalizedRectangle(imageParametersNormalizedRectangle)
.onDetectionListener(this::handleDetection)
.onCandidateSelectionStartListener(this::handleCandidateSelectionStart)
.onCaptureListener(this::handleCapture)
.build();
DocumentAutoCaptureController documentAutoCaptureController = DocumentAutoCaptureControllerFactory.create(configuration);
DocumentAutoCaptureControllerConfiguration.Builder
arguments
(Required)
[-]
Context context
- Android context.(Required)
[-]
List<DocumentAutoCaptureDetectionValidator> validators
- List of validators. Validations are applied in the same order in which they are stored in the list.(Optional)
[2]
int minValidFramesInRowToStartCandidateSelection
- Minimum number of valid frames in a row to start candidate selection.(Optional)
[1000]
int candidateSelectionDurationMillis
- Duration of candidate selection in milliseconds.(Optional)
[-]
RectangleDouble detectionNormalizedRectangle
- Crop an input image to normalized detection rectangle and use that for document detection.(Optional)
[-]
RectangleDouble imageParametersNormalizedRectangle
- Crop an input image to normalized image parameters rectangle and use that to analyze image parameters.(Optional)
[false]
boolean mrzReadingEnabled
- If Machine Readable Zone reading is enabled.(Optional)
[-]
DocumentAutoCaptureController.OnDetectionListener onDetectionListener
- Listener to be called on each document detection periodically.(Optional)
[-]
DocumentAutoCaptureController.OnCandidateSelectionStartListener onCandidateSelectionStartListener
- Listener to be called when candidate selection is started. This event happens once in a auto capture process.(Optional)
[-]
DocumentAutoCaptureController.OnCaptureListener onCaptureListener
- Listener to be called on auto capture process is done.
In order to get callbacks from the controller, implement these listeners from DocumentAutoCaptureController
interface: OnDetectionListener
, OnCandidateSelectionStartListener
and OnCaptureListener
.
You can use detectionNormalizedRectangle
to specify the region in the input image which will be used for document detection. For example, if you want to ignore top 30% and bottom 30% of the input image, you can do it as follows:
RectangleDouble detectionNormalizedRectangle = RectangleDouble.of(0.0d, 0.3d, 1.0d, 0.7d);
If detectionNormalizedRectangle
is not specified, the source input image is used for document detection.
You can use imageParametersNormalizedRectangle
to specify the region in the input image which will be used to analyze image parameters. For example, if you want to ignore top 35%, left 5%, right 5% and bottom 35% of the input image, you can do it as follows:
RectangleDouble imageParametersNormalizedRectangle = RectangleDouble.of(0.05d, 0.35d, 0.95d, 0.65d);
If imageParametersNormalizedRectangle
is not specified, the source input image is used to analyze image parameters.
To capture a good quality document image, repeatedly call the process()
method using the camera frames:
documentAutoCaptureController.process(bgraRawImage);
The controller evaluates the document image requirements for each frame. Once there are minValidFramesInRowToStartCandidateSelection
valid frames in a row, candidate selection is started with duration of candidateSelectionDurationMillis
milliseconds. After the candidate selection is finished, the best document image candidate is returned by the OnCaptureListener
and the document auto capture process is over.
In case you want to force the capture event, call the requestCapture()
method. After you call the next process()
method, the input image will be returned as a result by the OnCaptureListener
and the document auto capture process will be finished.
documentAutoCaptureController.requestCapture();
In case you want to restart the document auto capture process, call the restart()
method.
documentAutoCaptureController.restart();
Machine Readable Zone Reader
The MrzReader
interface provides a Machine Readable Zone (MRZ) reading functionality.
Create MrzReader
:
MrzReaderConfiguration configuration = new MrzReaderConfiguration.Builder(context).build();
MrzReader mrzReader = MrzReaderFactory.create(configuration);
To read a MRZ, call the following method on the background thread:
MrzReader.Result result = mrzReader.read(bgraRawImage, documentDetectorResult);
Or, alternatively if you know the travel document type call this method to order to increase precision of reading:
MrzReader.Result result = mrzReader.read(bgraRawImage, documentDetectorResult, travelDocumentType);
Argument documentDetectorResult
is a product of either Document Detector component, Document Auto Capture Controller component or Document Auto Capture UI component.
The result of successful MRZ reading contains travel document type and machine readable zone. If MRZ reading was not successful, the result will contain an exception and travelDocumentType
and/or machineReadableZone
may be null
.
UI Components
Orientation Change
In order to handle the orientation change in multi-window mode correctly, configure the activity in your AndroidManifest.xml
file as follows:
<activity
android:name=".MyActivity"
android:configChanges="screenSize|smallestScreenSize|screenLayout|orientation" />
Document Auto Capture
The fragment with a document placeholder on the screen. The component is embedded into the application as a fragment from Android Support Library. The fragment is abstract, so it must be subclassed. In order to configure the behavior of DocumentAutoCaptureFragment
, use DocumentAutoCaptureConfiguration
:
DocumentAutoCaptureConfiguration documentAutoCaptureConfiguration = new DocumentAutoCaptureConfiguration.Builder().build();
Bundle arguments = new Bundle();
arguments.putSerializable(DocumentAutoCaptureFragment.CONFIGURATION, documentAutoCaptureConfiguration);
Fragment fragment = new DemoDocumentAutoCaptureFragment();
fragment.setArguments(arguments);
getSupportFragmentManager()
.beginTransaction()
.replace(android.R.id.content, fragment)
.commit();
The following arguments are wrapped in DocumentAutoCaptureConfiguration
:
(Optional)
[CameraFacing.BACK]
CameraFacing cameraFacing
- Camera facing.CameraFacing.FRONT
CameraFacing.BACK
(Optional)
[CameraPreviewScaleType.FIT]
CameraPreviewScaleType cameraPreviewScaleType
- The camera preview scale type.CameraPreviewScaleType.FIT
CameraPreviewScaleType.FILL
(Optional)
[ValidationMode.STANDARD]
ValidationMode validationMode
- Validation mode.ValidationMode.STANDARD
ValidationMode.STRICT
(Optional)
[0.900d]
double confidenceLowThreshold
- Low detection confidence threshold.(Optional)
[0.430d]
double sizeSmallThreshold
- Small size threshold.(Optional)
[0.650d]
double sharpnessLowThreshold
- Low sharpness threshold.(Optional)
[0.250d]
double brightnessLowThreshold
- Low brightness threshold.(Optional)
[0.900d]
double brightnessHighThreshold
- High brightness threshold.(Optional)
[0.008d]
double hotspotsScoreHighThreshold
- High hotspots score threshold.(Optional)
[false]
boolean detectionLayerVisible
- If detection UI layer (tracking rectangle) is visible.(Optional)
[false]
boolean mrzReadingEnabled
- If Machine Readable Zone reading is enabled.
As soon as the fragment is created, the camera preview starts. To start the auto capture process call the start()
method. You can start the process any time.
In case you want to handle detection data, implement onDetected()
callback. This callback is called with each processed camera frame. There is also onCandidateSelectionStarted()
callback, which is called only once for the whole process, when candidate selection is started.
In case you want to force the capture event, call the requestCapture()
method. Document image candidate will be returned via the onCaptured()
callback asynchronously.
In case you want to restart the auto capture process (e.g. you want to capture both sides of the document, one after another), call the restart()
method. The whole process will start from the beginning.
Customization of UI components
Strings
You can override the string resources in your application and provide alternative strings for supported languages using the standard Android localization mechanism.
<!-- Document Auto Capture -->
<string name="dot_document_auto_capture_instruction_brightness_too_high">Less light needed</string>
<string name="dot_document_auto_capture_instruction_brightness_too_low">More light needed</string>
<string name="dot_document_auto_capture_instruction_candidate_selection">Hold still…</string>
<string name="dot_document_auto_capture_instruction_document_centering">Center document</string>
<string name="dot_document_auto_capture_instruction_document_not_present">Scan document</string>
<string name="dot_document_auto_capture_instruction_document_too_far">Move closer</string>
<string name="dot_document_auto_capture_instruction_hotspots_present">Avoid reflections</string>
<string name="dot_document_auto_capture_instruction_mrz_not_valid">Scan valid machine readable document</string>
<string name="dot_document_auto_capture_instruction_sharpness_too_low">More light needed</string>
Colors
You may customize the colors used by DOT Android Document in your application. To use custom colors, override the specific color.
<color name="dot_detection_layer">#ffffffff</color>
<color name="dot_instruction_background">#fff8fbfb</color>
<color name="dot_instruction_candidate_selection_background">#ff00bfb2</color>
<color name="dot_instruction_text">#ff131313</color>
<color name="dot_placeholder">#ffffffff</color>
<color name="dot_placeholder_candidate_selection">#ff00bfb2</color>
<color name="dot_placeholder_overlay">#80131313</color>
Styles
Text views and buttons can be styled by overriding the parent style in the application.
<style name="TextAppearance.Dot.Medium" parent="TextAppearance.AppCompat.Medium" />
<style name="TextAppearance.Dot.Medium.Instruction" />
Common Classes
ImageSize
DTO which represents a size of an image. To create an instance:
ImageSize imageSize = ImageSize.of(width, height);
BgraRawImage
DTO which represents and an image. To create an instance:
BgraRawImage bgraRawImage = BgraRawImage.of(size, bytes);
To create an instance from Bitmap
:
BgraRawImage bgraRawImage = BgraRawImageFactory.create(bitmap);
Corners
DTO which represents a document card corners. To create an instance:
Corners corners = Corners.of(topLeft, topRight, bottomRight, bottomLeft);
Appendix
_build: render: false ---
Changelog
3.6.2 - 2022-10-18
Changed
Target Android API level to 33.
Fixed
Document detection accuracy.
Compatibility with latest DOT libraries.
3.6.1 - 2022-08-18
Fixed
Stability issue in Document Auto Capture UI component.
3.6.0 - 2022-08-18
Added
Method
MachineReadableZone.getLines()
.
Fixed
Minor UI issues in Document Auto Capture UI component.
3.5.0 - 2022-07-06
Added
Method
DotDocumentLibrary.getVersionName()
.
Changed
Update CameraX to 1.1.0.
Minimum Kotlin Gradle plugin version to 1.6.0.
Fixed
Machine Readable Zone Reader: Parsing long document number and optional data together.
Machine Readable Zone Reader: Parsing element value with more than one filler in the middle.
3.4.1 - 2022-05-31
Fixed
Stability issue in
BgraRawImageFactory
.
3.4.0 - 2022-05-18
Changed
Target Android API level to 32.
Design of Document Auto Capture UI component.
Rename all color resources.
3.3.3 - 2022-03-09
Fixed
Camera preview resolution selection.
3.3.2 - 2022-02-17
Fixed
Bind the camera to the fragment lifecycle instead of the activity in UI components.
3.3.1 - 2022-02-14
Fixed
Preview overlay in the Document Auto Capture UI component.
3.3.0 - 2022-01-11
Added
Method
DocumentAutoCaptureConfiguration.Builder.validationMode()
.Method
DocumentAutoCaptureConfiguration.Builder.sizeSmallThreshold()
.Method
DocumentAutoCaptureConfiguration.Builder.detectionLayerVisible()
.Enum
ValidationMode
.Class
DocumentOutOfBoundsValidator
.Color resource
dot_document_auto_capture_detection_layer
.Color resource
dot_document_auto_capture_instruction_candidate_selection_background
.Color resource
dot_document_auto_capture_instruction_text
.Color resource
dot_document_auto_capture_overlay
.
Changed
Document detection accuracy improved.
Validator threshold
SharpnessLowValidator.DEFAULT_THRESHOLD
to0.65
.Validator threshold
DocumentNotDetectedValidator.DEFAULT_THRESHOLD_CONFIDENCE
to0.9
.Validator threshold
DocumentDoesNotFitPlaceholderValidator.DEFAULT_THRESHOLD_PENALTY
to0.035
.Class
DocumentSmallValidator
toSizeSmallValidator
.Improved UX of instruction changing in Document Auto Capture.
DocumentAutoCaptureConfiguration.Builder
: MethodconfidenceThreshold()
renamed toconfidenceLowThreshold()
.Redesign of the UI of Document Auto Capture component.
Rename color resource
dot_document_auto_capture_placeholder_capturing
todot_document_auto_capture_placeholder_candidate_selection
.
Removed
Class
DocumentLargeValidator
.String resource
dot_document_auto_capture_instruction_document_too_close
.Dimension resource
dot_document_auto_capture_placeholder_dash_path_effect_interval
.Dimension resource
dot_document_auto_capture_placeholder_stroke_width
.
3.2.0 - 2021-11-29
Changed
Target Android API level to 31.
Improve
DocumentDoesNotFitPlaceholderValidator
.Validator threshold
DocumentDoesNotFitPlaceholderValidator.DEFAULT_THRESHOLD_DETECTED_TO_PLACEHOLDER_CORNERS_DISTANCE
toDocumentDoesNotFitPlaceholderValidator.DEFAULT_THRESHOLD_PENALTY
.
3.1.0 - 2021-11-05
Added
Callback
DocumentAutoCaptureFragment.onDetected()
.Callback
DocumentAutoCaptureFragment.onCandidateSelectionStarted()
.
Changed
Validator threshold
DocumentNotDetectedValidator.DEFAULT_THRESHOLD_CONFIDENCE
to0.6
.
3.0.2 - 2021-10-08
Fixed
Restarting the Document Auto Capture UI component.
3.0.1 - 2021-10-06
Fixed
Image conversion in
BgraRawImageFactory.create(Bitmap)
.
3.0.0 - 2021-09-27
Added
Machine Readable Zone Reader component (
MrzReader
,MrzReaderConfiguration
andMrzReaderFactory
).Image Perspective Warper component (
ImagePerspectiveWarper
andImagePerspectiveWarperFactory
).Class
DocumentDetectorFactory
.Class
ImageParametersAnalyzerFactory
.Class
DocumentAutoCaptureControllerConfiguration
.Class
DocumentAutoCaptureControllerFactory
.Class
DocumentAutoCaptureDetection
.Class
Corners
.Class
BgraRawImageFactory
.Class
BitmapFactory
.
Changed
groupId
com.innovatrics.android
tocom.innovatrics.dot
.Minimum Android API level to 21.
Class
DocumentAutoCaptureArguments
toDocumentAutoCaptureConfiguration
.Method
DocumentAutoCaptureController.detect()
toDocumentAutoCaptureController.process()
.Class
DocumentAutoCaptureController.OnStayStillPhaseEnterListener
toDocumentAutoCaptureController.OnCandidateSelectionStartListener()
.Class
DetectionResult
toDocumentDetector.Result
.Class
Point
toPointDouble
.Method
DocumentAutoCaptureController.onPhotoCaptured()
toDocumentAutoCaptureController.onCaptured()
.Method
DocumentAutoCaptureController.postCaptureRequest()
toDocumentAutoCaptureController.requestCapture()
.Class
DetectedDocument
toDocumentAutoCaptureResult
.Performance of document detection is significantly improved.
Removed
Interface
DocumentAutoCaptureFrameParametersEvaluator
.Class
DefaultDocumentAutoCaptureFrameParametersEvaluator
.Method
DocumentAutoCaptureFragment.onCameraAccessFailed()
.Method
DocumentAutoCaptureFragment.onCameraInitFailed()
.Class
PlaceholderEvaluatorFactory
.Method
DocumentAutoCaptureController.onAutoCaptureReady()
.Enum
DocumentAutoCaptureHint
.
2.3.1 - 2021-06-17
Fixed
Requesting camera permission if it is already denied.
2.3.0 - 2021-05-14
Added
DocumentAutoCaptureArguments.Builder
: MethodconfidenceThreshold()
.DocumentAutoCaptureArguments.Builder
: MethodsharpnessLowThreshold()
.DocumentAutoCaptureArguments.Builder
: MethodbrightnessLowThreshold()
.DocumentAutoCaptureArguments.Builder
: MethodbrightnessHighThreshold()
.DocumentAutoCaptureArguments.Builder
: MethodhotspotsScoreHighThreshold()
.BrightnessHighValidator.Builder
: Methodthreshold()
.BrightnessLowValidator.Builder
: Methodthreshold()
.DocumentDoesNotFitPlaceholderValidator.Builder
: MethoddetectedToPlaceholderCornersDistanceThreshold()
.DocumentLargeValidator.Builder
: MethoddocumentWidthToImageWidthRatioThreshold()
.DocumentNotDetectedValidator.Builder
: MethodconfidenceThreshold()
.DocumentSmallValidator.Builder
: MethoddocumentWidthToImageWidthRatioThreshold()
.HotspotsScoreHighValidator.Builder
: Methodthreshold()
.SharpnessLowValidator.Builder
: Methodthreshold()
.
Changed
All
DocumentAutoCaptureFrameParametersValidator
implementations: Instance creation via aBuilder
.PlaceholderEvaluatorFactory
: Instance creation via aBuilder
.
2.2.1 - 2021-03-29
Added
Support for
x86
andx86_64
architectures.
2.2.0 - 2021-03-17
Changed
Update documentation.
Fixed
Configuration change issue in Document Auto Capture UI component.
2.1.0 - 2021-01-25
Added
Callback
DocumentAutoCaptureFragment.onAutoCaptureReady()
.Method
DocumentAutoCaptureFragment.start()
.
Changed
DocumentAutoCaptureFragment
: Auto Capture process is not started implicitly. Client needs to call methodDocumentAutoCaptureFragment.start()
to start the process.DocumentAutoCaptureFragment
: As soon as the photo is captured all views are reset.
2.0.1 - 2021-01-21
Fixed
Issue in method
DocumentAutoCaptureFragment.restart()
.
2.0.0 - 2021-01-11
Added
Possibility to restart the Document Auto Capture Controller component (method
DocumentAutoCaptureController.restart()
).Possibility to restart the Document Auto Capture UI component (method
DocumentAutoCaptureFragment.restart()
).New non-UI component: Image Parameters Analyzer.
DefaultDocumentAutoCaptureController.Builder
: MethoddetectionFrame()
.DefaultDocumentAutoCaptureController.Builder
: MethodimageParametersFrame()
.HotspotsScoreHighValidator
for validating hotspots presence.
Changed
Update target Android SDK version to 30 (Android 11).
DetectionResult
DTO does not containsharpness
andbrightness
anymore (these are present inImageParameters
DTO).DefaultDocumentAutoCaptureController.Builder
: MethoddetectionResultEvaluator()
renamed todocumentAutoCaptureFrameParametersEvaluator()
.DetectionResultEvaluator
renamed toDocumentAutoCaptureFrameParametersEvaluator
.DefaultDetectionResultEvaluator
renamed toDefaultDocumentAutoCaptureFrameParametersEvaluator
.DetectionAttributeValidator
renamed toDocumentAutoCaptureFrameParametersValidator
.DetectionHint
renamed toDocumentAutoCaptureHint
.Update documentation.
Removed
DocumentDetector
: MethodDetectionResult detectDocument(Nv21Image nv21Image)
.DefaultDocumentAutoCaptureController.Builder
: MethodcroppingFrame()
.
1.1.0 - 2020-11-25
Added
Possibility to force capture in Document Auto Capture Controller component (method
DocumentAutoCaptureController.requestCapture()
).Possibility to force capture in Document Auto Capture UI component (method
DocumentAutoCaptureFragment.postCaptureRequest()
).
Changed
Update documentation.
Fixed
Proguard rules.
1.0.0 - 2020-07-31
Changed
Preview image is cropped before document detection (placeholder area and margin).
Document Auto Capture design.
Update documentation.
Fixed
Fix camera preview freezing.
Placeholder position calculation for
cameraPreviewScaleType
:ScaleType.CENTER_CROP
.
0.3.0 - 2020-07-13
Minor changes.
0.2.0 - 2020-07-11
Changed
Update documentation.
0.1.0 - 2020-07-10
Added
First release.