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Expo FaceDetector

一个使用 Google Mobile Vision 来检测图片上的人脸的库。

已弃用：从 SDK 51 起，该库将不再可用。如果你需要此功能，我们推荐 react-native-vision-camera。

expo-face-detector 可让你利用谷歌的机器学习套件框架的强大功能来检测图片上的人脸。

¥expo-face-detector lets you use the power of the Google's ML Kit framework to detect faces on images.

已知的问题

¥Known issues

Android

面部检测器无法识别未与界面对齐的面部（界面顶部与头顶匹配）。

¥Face detector does not recognize faces that aren't aligned with the interface (top of the interface matches top of the head).

安装

¥Installation

该模块在 Expo Go 应用中不可用，因为它具有破坏 iOS 模拟器构建的依赖。

¥This module is not available in the Expo Go app because it has dependencies that break builds for iOS Simulators.

你可以创建开发构建来使用此包。

¥You can create a development build to work with this package.

Terminal

- npx expo install expo-face-detector

If you are installing this in an existing React Native app (bare workflow), start by installing expo in your project. Then, follow the additional instructions as mentioned by library's README under "Installation in bare React Native projects" section.

用法

¥Usage

设置

¥Settings

为了配置检测器的行为，模块传递一个 DetectionOptions 对象，然后由该模块解释该对象。

¥To configure detector's behavior modules pass a DetectionOptions object which is then interpreted by this module.

示例

¥Example

你可以使用以下代码片段以快速模式检测人脸，而无需检测地标或人脸是否在微笑。

¥You can use the following snippet to detect faces in a fast mode without detecting landmarks or whether a face is smiling.

Quick face detection

import * as React from 'react';
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;

API

import * as FaceDetector from 'expo-face-detector';

Methods

Deprecated If you require this functionality, we recommend using react-native-vision-camera

`FaceDetector.detectFacesAsync(uri, options)`

Name	Type	Description
uri	`string`	`file://` URI to the image.
options (optional)	`DetectionOptions`	A map of detection options. Default: `{}`

Detect faces on a picture.

Returns:

Promise<DetectionResult>

Returns a Promise which fulfils with DetectionResult object.

Types

`DetectionOptions`

In 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 `FaceDetector.FaceDetectorLandmarks.{all, none}`.
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 `FaceDetector.FaceDetectorMode.{fast, accurate}`.
runClassifications (optional)	`FaceDetectorClassifications`	Whether to run additional classifications on detected faces (smiling probability, open eye probabilities). Use `FaceDetector.FaceDetectorClassifications.{all, none}`.
tracking (optional)	`boolean`	Flag to enable tracking of faces between frames. If true, each face will be returned with `faceID` attribute which should be consistent across frames. Default: `false`

`DetectionResult`

Name	Type	Description
faces	`FaceFeature[]`	Array of faces objects.
image	`Image`	-

`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 `FaceDetectorLandmarks.all`.
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 `faceID`).
leftCheekPosition (optional)	`Point`	Position of the left cheek in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
leftEarPosition (optional)	`Point`	Position of the left ear in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
leftEyeOpenProbability (optional)	`number`	Probability that the left eye is open. Returned only if detection classifications property is set to `FaceDetectorClassifications.all`.
leftEyePosition (optional)	`Point`	Position of the left eye in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
leftMouthPosition (optional)	`Point`	Position of the left edge of the mouth in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
mouthPosition (optional)	`Point`	Position of the center of the mouth in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
noseBasePosition (optional)	`Point`	Position of the nose base in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
rightCheekPosition (optional)	`Point`	Position of the right cheek in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
rightEarPosition (optional)	`Point`	Position of the right ear in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
rightEyeOpenProbability (optional)	`number`	Probability that the right eye is open. Returned only if detection classifications property is set to `FaceDetectorClassifications.all`.
rightEyePosition (optional)	`Point`	Position of the right eye in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
rightMouthPosition (optional)	`Point`	Position of the right edge of the mouth in image coordinates. Returned only if detection classifications property is set to `FaceDetectorLandmarks.all`.
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 `FaceDetectorClassifications.all`.
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.

`Point`

Name	Type	Description
x	`number`	-
y	`number`	-

Expo FaceDetector

已知的问题

安装

用法

设置

示例

API

Methods

`FaceDetector.detectFacesAsync(uri, options)`

Types

`DetectionOptions`

`DetectionResult`

`FaceFeature`

`FaceFeatureBounds`

`Image`

`Point`

Enums

`FaceDetectorClassifications`

`none`

`all`

`FaceDetectorLandmarks`

`none`

`all`

`FaceDetectorMode`

`fast`

`accurate`