NodeJS 搭建图形识别功能

第一步：创建项目存储路径(C:\node_workspace),创建NodeJs 项目(image_reco) 并初始化

cd C:\node_workspace

mkdir image_reco

cnpm init

第二步：图形识别依赖模块介绍和本地安装

node-images: Node.js 轻量级跨平台图像编解码库
tesseract.js: 纯 JS 的 OCR 库支持 62 种语言。

本地安装:node-images 和 tesseract.js模块

C:\node_workspace\image_reco>npm install tesseract.js
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN [email protected] No description
npm WARN [email protected] No repository field.

+ [email protected]
added 23 packages in 9.246s

C:\node_workspace\image_reco>npm install images

> [email protected] install C:\node_workspace\image_reco\node_modules\images
> node ./scripts/install.js

Downloading binary from https://github.com/zhangyuanwei/node-images/releases/download/v3.0.2/win32-x64-57_binding.node
Download complete..] - :
Binary saved to C:\node_workspace\image_reco\node_modules\images\vendor\win32-x64-57\binding.node
Caching binary to C:\Users\zzg\AppData\Roaming\npm-cache\images\3.0.2\win32-x64-57_binding.node
npm WARN [email protected] No description
npm WARN [email protected] No repository field.

+ [email protected]
added 97 packages in 15.86s

编辑package.json 文件，添加第三方模块

{
  "name": "image_reco",
  "version": "1.0.0",
  "description": "",
  "main": "app.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "images": "^3.0.2",
    "tesseract.js": "^1.0.14"
  }
}

第三步：项目根路径编写app.js 文件，编辑内容如下：

"use strict"
var images = require('images')
var Tesseract = require('tesseract.js');
var request = require('request');
var fs = require('fs');
// 将图片下载到本地
function downloadFile(uri, filename, callback) {
    var stream = fs.createWriteStream(filename);
    request(uri).pipe(stream)
        .on('close', function () {
            callback();
        });
}
// 识别图片
function recognize(filePath, callback) {
    // 图片放大
    images(filePath)
        .size(90)
        .save(filePath);
    // 识别
    Tesseract
        .recognize(filePath, {
            lang: 'eng', // 语言选英文
            tessedit_char_blacklist: 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
                //因为是数字验证码，排除字母
        })
        .then((result) => {
            callback(result.text);
        });
}
function getVcode() {
    var url = 'https://ww1.sinaimg.cn/large/8c9b876fly1fe0bvsibibj201a00p07l.jpg';
    var filename = 'vcode.png';
    // 先下载下来，再识别
    downloadFile(url, filename, function () {
        recognize(filename, function (txt) {
            console.log('识别结果: ' + txt);
        });
    });
}
getVcode();

第四步：安装项目依赖，执行图片识别app.js 代码

C:\node_workspace\image_reco>cnpm install
√ Installed 2 packages
√ Linked 0 latest versions
√ Run 0 scripts
√ All packages installed (used 34ms(network 22ms), speed 0B/s, json 0(0B), tarball 0B)

C:\node_workspace\image_reco>node app.js
pre-main prep time: 37 ms
识别结果: 3128

项目结构：