saas_miniprogram/pages3/imgCompare/index.vue

<template>
	<view>
		<nav-bar title="身份证"></nav-bar>
		<div class="camera-wrap">
			<camera ref="camera" resolution="high" class="camera" frame-size="small"  device-position="back" flash="off"  @error="error"></camera>
			<image class="avatar" :src="face ? '../static/avatar.png' : '../static/back.png' "></image>
		</div>
		<canvas class="canvas"  canvas-id="canvas1"></canvas>
		<canvas class="canvas"  canvas-id="canvas"></canvas>
		<view>精度{{point}}</view>
		<view>人脸面符合次数{{frontIsCard}}</view>
		<view>国徽面合次数{{backIsCard}}</view>
		<!-- <image class="img" :src="src" mode="widthFix"></image> -->
		<button @click="takePhoto(true)">人脸面</button>
		<button @click="takePhoto(false)">国徽面</button>
	</view>
</template>

<script>
import { mapGetters } from 'vuex';
import { templateFront, templateBack } from '../../common/isCardTemplate.js'
export default {
	data() {
		return {
			face:true,
			point:0,
			context:null,
			src:"",
			isCompare:false,
			frontIsCard:0,
			backIsCard:0,
			frontData:templateFront, //身份证人脸面模板特征值
			backData:templateBack  //身份证国徽面模板特征值
		};
	},
	computed: { ...mapGetters(['userInfo','goodsAuditionConfigIdList','playSectionId']) },
	onLoad(option) {
		
	},
	onUnload(option) {
		
	},
	mounted() {
		
		this.context = uni.createCanvasContext('canvas')
		const ctx = uni.createCameraContext();
		const listener = ctx.onCameraFrame(frame => {
			if(!this.isCompare) {
				this.isCompare = true;
				
				uni.getSystemInfo({
				　　success: (res) => { // res - 各种参数
				
				　　    let info = uni.createSelectorQuery().select(".canvas");
				　　　  　info.boundingClientRect((data1) => { //data - 各种参数
							var buffer = new Uint8ClampedArray(frame.data);
							//获取是实时拍照原图
							uni.canvasPutImageData({
								  canvasId: 'canvas',
								  x: 0,
								  y: 0,
								  width: frame.width,
								  height: frame.height,
								  data: buffer,
								  success:(res) => {
									  //生成图片
									  uni.canvasToTempFilePath({
									    quality:1,
									    x: 0,
									    y: 0,
									    width: frame.width,
									    height: frame.height,
										destWidth:data1.width,
										destHeight:data1.height,
									    canvasId: 'canvas',
									    success: (res) => {
											// 在H5平台下，tempFilePath 为 base64
											
											//绘制原图到canvas上
											
											this.context.drawImage(res.tempFilePath,0,0,data1.width,data1.height)
											this.context.draw();
										  
											let avatarInfo = uni.createSelectorQuery().select(".avatar");
											
											//获取原图扫描框大小
											avatarInfo.boundingClientRect((data) => {  
												// //data - 各种参数
												let left = data.left;
												let top = data.top;
												let width = data.width;
												let height = data.height;
												
												//获取原图扫描框内容
												uni.canvasGetImageData({
												  canvasId: 'canvas',
												  x: left,
												  y: top,
												  width: width,
												  height: height,
												  success:(res) => {
													// this.isCompare = false;
													  
													  
														//绘制扫描图片
													    uni.canvasPutImageData({
															canvasId: 'canvas',
															x: 0,
															y: 0,
															width: width,
															height: height,
															data: res.data,
															success:(res) => {
													  		  //生成图片
													  		    uni.canvasToTempFilePath({
																  quality:1,
													  		      x: 0,
													  		      y: 0,
																  destWidth:width,
																  destHeight:height,
													  		      width: width,
													  		      height: height,
													  		      canvasId: 'canvas',
													  		      success:async  (res1) => {
													  		  		//绘制并压缩
																	
													  		  		this.context.drawImage(res1.tempFilePath,0,0,width,height,0,0,200,200)
													  		  		this.context.draw();
																	
																		let res = await this.canvasGetImageData('canvas');
																		let newData = Array(res.data.length)
																		newData.fill(0)  
																		res.data.forEach((_data, index) => {  
																		  if ((index + 1) % 4 === 0) {  
																			const R = res.data[index - 3]  
																			const G = res.data[index - 2]  
																			const B = res.data[index - 1] 
																			const gray = ~~((R + G + B) / 3)  
																			
																			res.data[index - 3] = gray  
																			res.data[index - 2] = gray  
																			res.data[index - 1] = gray 
																			res.data[index] = 255 // Alpha 值固定为255  
																		  }  
																		})
																		uni.canvasPutImageData({
																			canvasId: 'canvas1',
																			x: 0,
																			y: 0,
																			width: res.width,
																			height: res.height,
																			data: res.data,
																			success:(res) => {
																				// this.isCompare = false;
																				uni.canvasToTempFilePath({
																					destWidth:res.width,
																					destHeight:res.height,
																					quality:1,
																				  x: 0,
																				  y: 0,
																				  width: width,
																				  height: height,
																				  canvasId: 'canvas1',
																				  success: (res2) => {
																					  this.src = res2.tempFilePath
																				  },
																				})
																			},
																			fail:err => {
																				console.log(err,'err')
																			}
																		})
																		
																		
																		
																		// for (let i = 0; i < newData.length; i += 4) {  
																		//   let R = newData[i]  
																		//   let G = newData[i + 1]  
																		//   let B = newData[i + 2]  
																		//   let Alpha = newData[i + 3] 
																		// }  
																		let getData = this.getHashFingerprint(res)
																		let similarty = this.cosineSimilarity(this.face ? this.frontData : this.backData,getData)
																		// let distance = this.hammingDistance(this.frontData,result)
																		// let similarty =  (this.frontData.length - distance) / this.frontData.length
																		if(similarty >= 0.8) {
																			this.src = res1.tempFilePath
																			if(this.face) {
																				this.frontIsCard++;
																			} else {
																				this.backIsCard++;
																			}
																			
																		} 
																		
																		this.point = similarty
																		
																		setTimeout(() => {
																			this.isCompare = false;
																		},200)
																		console.log(similarty,'similarty')
																			
													  		  	},
													  		  })
															},
														})
													  
													  
													  
													  
													  
														
													    
													}
												})
											}).exec()
											  
										 }
										 
									  })
								  },
								  fail(err) {
									  console.log(err)
								  }
							})
				　　    }).exec()
					   }
				});
				
				
				
			}
		})
		
		listener.start()
	},
	methods: {
		error(err) {
			console.log(err)
		},
		
		canvasGetImageData(id) {
			return new Promise(resolve => {
				uni.canvasGetImageData({
					canvasId: id,
					x: 0,
					y: 0,
					width: 200,
					height: 200,
					success:(res) => {
						resolve(res)
					},
				})
			})
			
		},
		
		hammingDistance (str1, str2) {  
		  let distance = 0  
		  const str1str1Arr = str1.split('')  
		  const str2str2Arr = str2.split('')  
		  str1str1Arr.forEach((letter, index) => {  
		    if (letter !== str2str2Arr[index]) {  
		      distance++  
		    }  
		  })  
		  return distance  
		} ,
		
		cosineSimilarity (sampleFingerprint, targetFingerprint) {  
		  // cosθ = ∑n, i=1(Ai × Bi) / (√∑n, i=1(Ai)^2) × (√∑n, i=1(Bi)^2) = A · B / |A| × |B|  
		  const length = sampleFingerprint.length  
		  let innerProduct = 0  
		  for (let i = 0; i < length; i++) {  
		    innerProduct += sampleFingerprint[i] * targetFingerprint[i]  
		  }  
		  let vecA = 0  
		  let vecB = 0  
		  for (let i = 0; i < length; i++) {  
		    vecA += sampleFingerprint[i] ** 2  
		    vecB += targetFingerprint[i] ** 2  
		  }  
		  const outerProduct = Math.sqrt(vecA) * Math.sqrt(vecB)  
		  return innerProduct / outerProduct  
		} ,
		
		
		
		getHashFingerprint (imgData) {  
		  const grayList = imgData.data.reduce((pre, cur, index) => {  
		    if ((index + 1) % 4 === 0) {  
		      pre.push(imgData.data[index - 1])  
		    }  
		    return pre  
		  }, [])  
		  const length = grayList.length  
		  const grayAverage = grayList.reduce((pre, next) => (pre + next), 0) / length  
		  return grayList.map(gray => (gray >= grayAverage ? 1 : 0)).join('')  
		} ,
		
		
		takePhoto(bo) {
			this.face = bo
			// const ctx = uni.createCameraContext();
			// ctx.takePhoto({
			// 	quality: 'high',
			// 	success: res => {
			// 		this.src = res.tempImagePath;
			// 	},
			// 	fail: err => {
			// 		console.log(err);
			// 	}
			// });
		}
	}
};
</script>
<style >
	page{
		background-color: #EAEEF1;
	}
</style>
<style scope lang="scss">
	.camera-wrap {
		position: relative;
		
		.camera {
			width: 750rpx;
			height: 916.67rpx;
		}
		
		.avatar {
			opacity: 0.3;
			position:absolute;
			left:50%;
			top:40rpx;
			transform: translateX(-50%);
			width:633rpx;
			height:400rpx;
		}
	}
	
	.canvas {
		position:fixed;
		top:9999999%;
		left:9999999%;  //canvas藏起来
		width: 750rpx;
		height: 916.67rpx;
	}
	
	.img {
		display: block;
		margin:0 auto;
		width:633rpx;
		height:400rpx;
	}
</style>