效果图：
第一种是使用camerax进行预览，android camerax预览官方文档，主要通过imageAnalysis，抓帧进行图片处理，然后通过android自带的图片人脸识别FaceDetector判断是否有人脸，有人脸保存当前抓拍的照片：
val file = File(filesDir, "head_tmp.png")val create = Observable.create<File> { emitter ->val intArray = IntArray(2)iv_scan.getLocationInWindow(intArray)val createBitmap = Bitmap.createBitmap(bitmap, intArray[0], intArray[1], iv_scan.width, iv_scan.height)//必须是565才能识别val bitmap1: Bitmap = createBitmap.copy(Bitmap.Config.RGB_565, true)val faceDetector = FaceDetector(bitmap1.width, bitmap1.height, 1)val array = arrayOfNulls<FaceDetector.Face>(1)val faces = faceDetector.findFaces(bitmap1, array)if (faces > 0) {Log.e(TAG, "检测到脸")val fos = FileOutputStream(file.path)press(pressFormat.PNG, 100, fos)fos.flush()fos.close()emitter.onNext(file)} else {Log.e(TAG, "未检测到脸")emitter.onError(Throwable("未检测到脸"))}}var disposable: Disposable? = nullval observer = object : Observer<File> {override fun onNext(t: File) {disposable?.dispose()isOne = falsesetResult(Activity.RESULT_OK)finish()}override fun onError(e: Throwable) {isOne = true}override fun onComplete() {}override fun onSubscribe(d: Disposable) {disposable = d}}create.subscribeOn(putation())//指定被观察者线程.observeOn(AndroidSchedulers.mainThread())//指定观察者线程.subscribe(observer)
第二种使用了免费的虹软识别人脸识别，主要判断指定识别框的rect和虹软人脸识别框的rect,比较两个rect，是否在它的范围内，如果在抓拍人脸：
if (drawInfoList.size > 0) {for (i in drawInfoList.indices) {val rect: Rect = drawInfoList[i].rectval rect1 = Rect()iv_scan.getGlobalVisibleRect(rect1)if (rect1.contains(rect)) {//为了美观，扩大rect截取注册图val cropRect: Rect =CommUtils.getBestRect(previewSize!!.width, previewSize!!.height, faceInfoList[i].rect)cropRect.left = cropRect.left and 3.inv()cropRect.top = cropRect.top and 3.inv()cropRect.right = cropRect.right and 3.inv()cropRect.bottom = cropRect.bottom and 3.inv()headBmp = CommUtils.getHeadImage(nv21,previewSize!!.width,previewSize!!.height,faceInfoList[i].orient,cropRect,ArcSoftImageFormat.NV21)headBmp?.apply {cropBitmap(this)}break}}}
demo：/withyi9223/facesb
Android相机预览 指定区域显示预览框 在区域内出现人脸进行人脸识别 并抓拍人脸照片存在本地 CameraX 虹软人脸识别
