This is documentation for the next SDK version. For up-to-date documentation, see the latest version (SDK 52).
A library that uses Google Mobile Vision to detect faces on images.
Deprecated: This library is not available from SDK 51. We recommendreact-native-vision-cameraif you require this functionality.
expo-face-detector lets you use the power of the Google's ML Kit framework to detect faces on images.
Face detector does not recognize faces that aren't aligned with the interface (top of the interface matches top of the head).
This module is not available in the Expo Go app because it has dependencies that break builds for iOS Simulators.
You can create a development build to work with this package.
- npx expo install expo-face-detectorIf you are installing this in an existing React Native app, start by installing expo in your project. Then, follow the additional instructions as mentioned by the library's README under "Installation in bare React Native projects" section.
To configure detector's behavior modules pass a DetectionOptions object which is then interpreted by this module.
You can use the following snippet to detect faces in a fast mode without detecting landmarks or whether a face is smiling.
import { Camera } from 'expo-camera';
import * as FaceDetector from 'expo-face-detector';
const App = () => (
<Camera
// other props
onFacesDetected={handleFacesDetected}
faceDetectorSettings={{
mode: FaceDetector.FaceDetectorMode.fast,
detectLandmarks: FaceDetector.FaceDetectorLandmarks.none,
runClassifications: FaceDetector.FaceDetectorClassifications.none,
minDetectionInterval: 100,
tracking: true,
}}
/>
);
const handleFacesDetected = ({ faces }) => {
console.log(faces);
};
export default App;
import * as FaceDetector from 'expo-face-detector';
Deprecated If you require this functionality, we recommend using react-native-vision-camera
FaceDetector.detectFacesAsync(uri, options)| Parameter | Type | Description |
|---|---|---|
| uri | string |
|
| options (optional) | DetectionOptions | A map of detection options. Default: {} |
Detect faces on a picture.
Returns a Promise which fulfils with DetectionResult object.
DetectionOptionsIn order to configure detector's behavior modules pass a settings object which is then interpreted by this module.
| Name | Type | Description |
|---|---|---|
| detectLandmarks (optional) | FaceDetectorLandmarks | Whether to detect and return landmarks positions on the face (ears, eyes, mouth, cheeks, nose).
Use |
| minDetectionInterval (optional) | number | Minimal interval in milliseconds between two face detection events being submitted to JS. Use, when you expect lots of faces for long time and are afraid of JS Bridge being overloaded. Default: 0 |
| mode (optional) | FaceDetectorMode | Whether to detect faces in fast or accurate mode. Use |
| runClassifications (optional) | FaceDetectorClassifications | Whether to run additional classifications on detected faces (smiling probability, open eye
probabilities). Use |
| tracking (optional) | boolean | Flag to enable tracking of faces between frames. If true, each face will be returned with
Default: false |
FaceFeature| Name | Type | Description |
|---|---|---|
| bottomMouthPosition (optional) | Point | Position of the bottom edge of the mouth in image coordinates. Returned only if detection
classifications property is set to |
| bounds | FaceFeatureBounds | An object containing face bounds. |
| faceID (optional) | number | A face identifier (used for tracking, if the same face appears on consecutive frames it will
have the same |
| leftCheekPosition (optional) | Point | Position of the left cheek in image coordinates. Returned only if detection classifications
property is set to |
| leftEarPosition (optional) | Point | Position of the left ear in image coordinates. Returned only if detection classifications
property is set to |
| leftEyeOpenProbability (optional) | number | Probability that the left eye is open. Returned only if detection classifications property is
set to |
| leftEyePosition (optional) | Point | Position of the left eye in image coordinates. Returned only if detection classifications
property is set to |
| leftMouthPosition (optional) | Point | Position of the left edge of the mouth in image coordinates. Returned only if detection
classifications property is set to |
| mouthPosition (optional) | Point | Position of the center of the mouth in image coordinates. Returned only if detection
classifications property is set to |
| noseBasePosition (optional) | Point | Position of the nose base in image coordinates. Returned only if detection classifications
property is set to |
| rightCheekPosition (optional) | Point | Position of the right cheek in image coordinates. Returned only if detection classifications
property is set to |
| rightEarPosition (optional) | Point | Position of the right ear in image coordinates. Returned only if detection classifications
property is set to |
| rightEyeOpenProbability (optional) | number | Probability that the right eye is open. Returned only if detection classifications property is
set to |
| rightEyePosition (optional) | Point | Position of the right eye in image coordinates. Returned only if detection classifications
property is set to |
| rightMouthPosition (optional) | Point | Position of the right edge of the mouth in image coordinates. Returned only if detection
classifications property is set to |
| rollAngle (optional) | number | Roll angle of the face (bank). |
| smilingProbability (optional) | number | Probability that the face is smiling. Returned only if detection classifications property is
set to |
| yawAngle (optional) | number | Yaw angle of the face (heading, turning head left or right). |
FaceFeatureBounds| Name | Type | Description |
|---|---|---|
| origin | Point | Position of the top left corner of a square containing the face in image coordinates, |
| size | {
height: number,
width: number
} | Size of the square containing the face in image coordinates, |
Image| Name | Type | Description |
|---|---|---|
| height | number | Height of the image in pixels. |
| orientation | number | Orientation of the image (value conforms to the EXIF orientation tag standard). |
| uri | string | URI of the image. |
| width | number | Width of the image in pixels. |