DOT Web Face Auto Capture
v3.4.2
Introduction
Web DOT Face Auto Capture is a web component using video stream from available phone or web camera to automatically capture an image of a user’s face with the required quality. The component renders the video stream and overlays it with a placeholder and instructions to guide the user to position their face correctly.
Supported Browsers
Web DOT Face Auto Capture was tested with:
Chrome on desktop (Windows, Mac and Linux) and mobile (Android, iPhone)
Firefox on desktop (Windows, Mac and Linux) and mobile (Android)
Edge on Windows
Safari on Mac and iPhone
WebView on Android
Known issues:
Components don’t work with WKWebView on iPhone
Privacy and security
This component can only be used in secure contexts due to MediaDevices
API used for handling camera access. A secure context is, in short, a page loaded using HTTPS or the file:///
URL scheme, or a page loaded from localhost
. Before accessing any camera, the component must always get the user’s permission. Browsers may offer a once-per-domain permission feature, but they must ask at least the first time, and the user has to specifically grant ongoing permission if they choose to do so. Browsers are required to display an indicator that shows that a camera or microphone is in use. More details can be found on MDN docs.
Basic Setup
Initialization
Web DOT Face Auto Capture can be installed via NPM
npm install @innovatrics/dot-face-auto-capture
or yarn
yarn add @innovatrics/dot-face-auto-capture
To manually integrate the Web DOT Face Auto Capture, download latest version from the Github repository. Then add following line to dependencies in your package.json:
"dependencies": {
"@innovatrics/dot-face-auto-capture": "file:dot-face-auto-capture-[VERSION].tgz"
},
where [VERSION]
is the Web DOT Face Auto Capture version integrated. This installs dot-face-auto-capture
as an external module that can then be used (just like any other module in the code). For example, one could do import '@innovatrics/dot-face-auto-capture';
in the app.
Usage
Face auto capture component is an web component which uses custom HTML <x-dot-face-auto-capture/>
tag.
Properties cameraOptions
needs to be passed into component after <x-dot-face-auto-capture/>
tag was rendered.
import "@innovatrics/dot-face-auto-capture";
const FaceCamera = (props) => {
useEffect(() => {
const faceAutoCaptureHTMLElement = document.getElementById('x-dot-face-auto-capture');
faceAutoCaptureHTMLElement.cameraOptions = props;
});
return <x-dot-face-auto-capture id="x-dot-face-auto-capture" />;
};
const Page = () => {
const handleFacePhotoTaken = (image, resolution) => {
// ...
};
// Save function reference to prevent unnecessary reload of component
const handleError = useCallback(
(error: Error) => {
alert(error)
},
[],
);
return (
<FaceCamera
imageType="png"
cameraFacing="user"
photoTakenCb={handleFacePhotoTaken}
onError={handleError}
/>
);
};
See also DOT Web Samples showing the usage of DOT Web Auto Capture components in different front-end technologies like React, Angular…
TypeScript
Declaration file is bundled inside package. To use with TypeScript, import types from @innovatrics/dot-face-auto-capture
.
import type { FaceCallback, FaceCameraProps } from "@innovatrics/dot-face-auto-capture";
Hosting of SAM wasm
The component needs to have access to the WebAssembly wasm binary file. It’s distributed in the package, and needs to be hosted by the website provider.
By default, component try to fetch wasm file from <PROJECT_ORIGIN>/sam.wasm
. This can be changed using the samWasmUrl
property.
If using Create React App
, copy the`sam.wasm` file to public
folder. In our example the final path is public/sam.wasm
.
Face Auto Capture Component
(Optional)
['png']
string imageType
– Format of the image returned after successful capture'jpeg'
'png'
(Optional)
['user']
string cameraFacing
– Defines which camera to acquire from the browser’s getUserMedia API'user'
– The video source is facing toward the user; this is the selfie or front-facing camera on a smartphone'environment'
– The video source is facing away from the user, thereby viewing their environment; this is the back camera on a smartphone
function photoTakenCb
– Callback on successful image capture(image, data) ⇒ void
- (see Callback parameters)
function onError
– Callback in the case that an error occurred (see Handling errors)(e: Error) ⇒ void
(Optional)
string samWasmUrl
- URL link to the location where the wasm binary file is hosted(Optional)
object thresholds
- Detection configuration(Optional)
[0.12]
number faceConfidence
- Detection confidence threshold(Optional)
[0.35]
number minFaceSizeRatio
- Minimum face size ratio relative to shorter side of the camera resolution(Optional)
[0.44]
number maxFaceSizeRatio
- Maximum face size ratio relative to shorter side of the camera resolution(Optional)
[0.07]
number faceCenteringNarrowSide
- Size of narrow side for center face validator(Optional)
[0.21]
number faceCenteringWideSide
- Size of wide side for center face validator(Optional)
[400]
number sharpnessThreshold
- Low sharpness threshold(Optional)
[400]
number brightnessLowThreshold
- Low brightness threshold(Optional)
[900]
number brightnessHighThreshold
- High brightness threshold(Optional)
[100]
number hotspotsMediumThreshold
- Medium hotspots threshold(Optional)
[800]
number hotspotsHighThreshold
- High hotspots threshold
(Optional)
object uiCustomisation
- UI customization of the component (see UI Customization).
Callback parameters
Blob image
– Returned image on successful captureobject data
object cameraSettings
- MediaTrackSettings object containing used webcam settings. The object in addition contains device name.(Optional) object detection
- Object contains all detection parameters and its values. Present if image was taken using auto capture (not manual capture).object imageResolution
- Width and height of the captured image.
Multi capture
Face auto capture component allows you to capture an unlimited number of faces without the need to reinitialize the webcam and detector.
Component calls photoTakenCb
callback on every captured face photo. When photoTakenCb
is called, detection is paused. Camera stream and face detector stay initialized.
Component is in waiting state. You should implement a custom UI for waiting state (e.g. overlay over our component). We provide a default UI, but is not customizable. To continue detection, dispatch custom event on face object.
face.dispatchEvent(
new CustomEvent('face-auto-capture', {
detail: { instruction: 'continue-detection' },
}),
);
UI Customization
(Optional)
object placeholder
- Placeholder customization(Optional)
enum facePlaceholder
- One of the predefined placeholders in component that can be selected:'circle-solid'
'ellipse-solid'
'man-solid'
'woman-solid'
'square-rounded-dash'
'square-rounded-solid'
'square-dash'
'square-solid'
(Optional)
string customSVG
- Alternatively, in a future release, a string with custom svg will be able to be provided (see UI Customization examples)
(Optional)
object instructions
- Modification of default messages for localization or customization(Optional)
['Stay still…']
string candidate_selection
- Shown when all validations are passed, i.e. the image is suitable for capture(Optional)
['Move back']
string face_too_close
- Shown when the face is too close to the camera(Optional)
['Move closer']
string face_too_far
- Shown when the face is too far from the camera(Optional)
['Center your face']
string face_centering
- Shown when the face is not centered in the placeholder(Optional)
['Center your face']
string face_not_present
- Shown when no face is detected(Optional)
['Turn face against light']
string sharpness_too_low
- Shown when the face in the image is not sharp enough(Optional)
['Turn face against light']
string brightness_too_low
- Shown when the image is too dark(Optional)
['Less light needed']
string brightness_too_high
- Shown when the image is too bright.(Optional)
['Turn face against light']
string hotspots_medium_present
- Shown when the image has reflections(Optional)
['Move away from bright light']
string hotspots_high_present
- Shown when the face is too bright
(Optional)
colors
- Colors in Web DOT Face Auto Capture may be customized in integration(Optional)
['white']
color placeholderColor
- Color of the placeholder lines(Optional)
['#00BFB2']
color placeholderColorSuccess
- Color of the placeholder lines when all validations are passed(Optional)
['white']
color instructionColor
- Instruction background color(Optional)
['#00BFB2']
color instructionColorSuccess
- Instruction background color when all validations are passed(Optional)
['black']
color instructionTextColor
- Instruction text color
(Optional)
appStateInstructions
- Modification of default messages for component state(Optional)
loading
- Component loading state(Optional)
['Loading. Please wait.']
string text
- Text shown while component is loading(Optional)
[true]
boolean visible
- Show/hide loading instruction while component is loading
(Optional)
waiting
- Component waiting state(Optional)
['Waiting for input']
string text
- Text shown while component is waiting(Optional)
[true]
boolean visible
- Show/hide waiting instruction while component is waiting
UI Customization examples
<FaceCamera
photoTakenCb={handleFacePhotoTaken}
uiCustomisation = {{
placeholder: {
facePlaceholder: 'ellipse-solid',
},
instructions: {
face_too_close: 'Your face is too close',
face_too_far: 'Your face is too far',
},
colors: {
placeholderColor: '#EEEEEE',
instructionTextColor: '#080808',
},
appStateInstructions: {
waiting: {
visible: false
}
},
}}
/>
Custom SVG placeholder images are not yet supported, but will be available in a future release
Handling errors
When an error occurs, we call onError
callback with one parameter of type Error
. We set name
property to AutoCaptureError
, and also message
with more details.
Component renders default UI for error state, but is not customizable, and integrator should implement own error handling.
Component uses the MediaDevices API that provides access to connected media input devices like cameras and microphones.
If the user denies permission to access or the webcam is not present, an error is thrown. We provide original error thrown by browser inside cause
property of the error object.
List of possible errors can be found on MDN docs.
Error example:
{
name: "AutoCaptureError",
message: "The webcam is already in use by another application",
cause: DOMException: Could not start video source // Original error thrown by browser MediaDevices API
}
Appendix
Changelog
3.3.1 - 2022-07-06
Fixed
Zero height of component when error occurs
Add
add
appStateInstructions
property to uiCustomisationadd option to change appState instructions text and visibility
Change
interface for changing
Loading
appState instruction text
3.3.0 - 2022-06-15
Added
Add support for capturing multiple face photos
Add custom event
face-auto-capture
withcontinue-detection
instruction to continue detection
Changed
When
photoTakenCb
is called, component switches into waiting stateRemove needs for using wrapper with defined height and width
3.2.0 - 2022-05-25
Added
Countly analytics tracking
Optional threshold
sharpnessThreshold
with default value400
andTurn face against light
instructionOptional threshold
brightnessLowThreshold
with default value400
andTurn face against light
instructionOptional threshold
brightnessHighThreshold
with default value900
andLess light needed
instructionOptional threshold
hotspotsMediumThreshold
with default value100
andTurn face against light
instructionOptional threshold
hotspotsHighThreshold
with default value800
andMove away from bright light
instructionTypeScript support. Import types from
@innovatrics/auto-capture
Changed
onError
callback returnsAutoCaptureError
onError
callback is requiredShow error screen when error occurs
Fixed
Stuck component when error occurs
3.1.2 - 2022-04-04
Changed
Remove force manual capture on instruction click
3.1.1 - 2022-03-15
Changed
Change
optimalFaceSizeLimit
andoptimalFaceSizeParam
tominFaceSizeRatio
andmaxFaceSizeRatio
Change
faceCenterLimit
tofaceCenteringNarrowSide
andfaceCenteringWideSide
Set
minFaceSizeRatio
default value to0.35
andmaxFaceSizeRatio
to0.44
Set
faceCenteringNarrowSide
default value to0.07
andfaceCenteringWideSide
to0.21
3.1.0 - 2022-02-03
Fixed
Unify loading and instruction design
3.0.2 - 2022-01-28
Added
Add loading screen
Add
loading.text
property inuiCustomisation
for configuring text on loading screen
Changed
Show new instruction only if 600ms elapsed since last instruction change
3.0.1 - 2022-01-25
Added
file
sam.wasm
Fixed
safari version 15 on mac
Changed
Face detection accuracy improved.
Detection engine
Removed
blaze_models
packagemodelUrls
option from cameraOptions
2.3.1 - 2022-01-10
Fixed
Fix bug causing integration error
2.3.0 - 2022-01-05
Added
add
cameraSettings
intophotoTakenCb
callBack functionRedesign of the UI of Face Auto Capture component.
Changed
photoTakenCb
callBack function structure
2.2.2 - 2021-12-17
Incremental version upgrade
2.2.1 - 2021-12-09
Changed
Hide switch camera button if there is only 1 webcam available
2.2.0 - 2021-11-30
Added
thresholds.faceConfidence
- Detection confidence threshold with default value0.12
modelUrls
- Object with path to the models needed for detection
Changed
integrated new neural network for face detection
dynamic import of TensorFlow.js libraries
2.1.0 - 2021-11-18
First released version