php实现ocr文字识别

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OCR的百度定义 （Optical Character Recognition，光学字符识别）是指电子设备（例如扫描仪或数码相机）检查纸上打印的字符，通过检测暗、亮的模式确定其形状，然后用字符识别方法将形状翻译成计算机文字的过程；即，针对印刷体字符，采用光学的方式将纸质文档中的文字转换成为黑白点阵的图像文件，并通过识别软件将图像中的文字转换成文本格式，供文字处理软件进一步编辑加工的技术。

作为一个工程师，在实际编程中，可能需要把图片中的文字显示出来，这就需要用到ocr技术。因为php开发，所以优先选择php，找了php的ocr扩展测试了下，结果发现不可用（地址：http://sourceforge.net/projects/phpocr.berlios）？网上也看了很多朋友的demo，基本上原理都是对图片分解成0，1矩阵，然后根据特征，转化成相应的字符串。测试几个都是不可行的。然后看到别人说PHP搞OCR的很少，也不适合，语言效率太低，这种算法需要很高的效率。可以尝试C,MATLAB 等的OCR算法。搞matlab的玩OCR这类偏算法的很多。

无奈才虚学浅，不会C。无意中却发现百度有ocr的api提供：http://apistore.baidu.com/apiworks/servicedetail/146.html。

写了个玩下：

<ol>
<li value="1">
<span></span><span>php</span>
</li>
<li>
<span>header</span><span>(</span><span>"Content-type: text/html; charset=utf-8"</span><span>);</span>
</li>
<li><span> </span></li>
<li>
<span>function</span><span> curl</span><span>(</span><span>$img</span><span>)</span><span></span><span>{</span>
</li>
<li><span> </span></li>
<li>
<span>    $ch  </span><span>=</span><span> curl_init</span><span>();</span>
</li>
<li>
<span>    $url </span><span>=</span><span></span><span>'http://apis.baidu.com/apistore/idlocr/ocr'</span><span>;</span><span></span><span>//百度ocr api</span>
</li>
<li>
<span>    $header </span><span>=</span><span> array</span><span>(</span>
</li>
<li>
<span></span><span>'Content-Type:application/x-www-form-urlencoded'</span><span>,</span>
</li>
<li>
<span></span><span>'apikey:69c2ace1ef297ce88869f0751cb1b618'</span><span>,</span>
</li>
<li>
<span></span><span>);</span>
</li>
<li><span> </span></li>
<li>
<span>    $data_temp </span><span>=</span><span> file_get_contents</span><span>(</span><span>$img</span><span>);</span>
</li>
<li>
<span>    $data_temp </span><span>=</span><span> urlencode</span><span>(</span><span>base64_encode</span><span>(</span><span>$data_temp</span><span>));</span>
</li>
<li>
<span></span><span>//封装必要参数</span>
</li>
<li>
<span>    $data </span><span>=</span><span></span><span>"fromdevice=pc&clientip=127.0.0.1&detecttype=LocateRecognize&languagetype=CHN_ENG&imagetype=1&image="</span><span>.</span><span>$data_temp</span><span>;</span>
</li>
<li><span></span></li>
<li>
<span>    curl_setopt</span><span>(</span><span>$ch</span><span>,</span><span> CURLOPT_HTTPHEADER </span><span>,</span><span> $header</span><span>);</span><span></span><span>// 添加apikey到header</span>
</li>
<li>
<span>    curl_setopt</span><span>(</span><span>$ch</span><span>,</span><span> CURLOPT_POST</span><span>,</span><span></span><span>1</span><span>);</span>
</li>
<li>
<span>    curl_setopt</span><span>(</span><span>$ch</span><span>,</span><span> CURLOPT_POSTFIELDS</span><span>,</span><span> $data</span><span>);</span><span></span><span>// 添加参数</span>
</li>
<li>
<span>    curl_setopt</span><span>(</span><span>$ch</span><span>,</span><span> CURLOPT_RETURNTRANSFER</span><span>,</span><span></span><span>1</span><span>);</span>
</li>
<li>
<span>    curl_setopt</span><span>(</span><span>$ch </span><span>,</span><span> CURLOPT_URL </span><span>,</span><span> $url</span><span>);</span><span></span><span>// 执行HTTP请求</span>
</li>
<li>
<span>    $res </span><span>=</span><span> curl_exec</span><span>(</span><span>$ch</span><span>);</span>
</li>
<li>
<span></span><span>if</span><span></span><span>(</span><span>$res </span><span>===</span><span> FALSE</span><span>)</span><span></span><span>{</span>
</li>
<li>
<span>        echo </span><span>"cURL Error: "</span><span></span><span>.</span><span> curl_error</span><span>(</span><span>$ch</span><span>);</span>
</li>
<li>
<span></span><span>}</span>
</li>
<li>
<span>    curl_close</span><span>(</span><span>$ch</span><span>);</span>
</li>
<li><span></span></li>
<li>
<span>    $temp_var </span><span>=</span><span> json_decode</span><span>(</span><span>$res</span><span>,</span><span>true</span><span>);</span>
</li>
<li>
<span></span><span>return</span><span> $temp_var</span><span>;</span>
</li>
<li><span> </span></li>
<li><span>}</span></li>
<li><span> </span></li>
<li>
<span>$wordArr </span><span>=</span><span> curl</span><span>(</span><span>'4.jpg'</span><span>);</span>
</li>
<li>
<span>if</span><span>(</span><span>$wordArr</span><span>[</span><span>'errNum'</span><span>]</span><span></span><span>==</span><span></span><span>0</span><span>)</span><span></span><span>{</span>
</li>
<li>
<span>    var_dump</span><span>(</span><span>$wordArr</span><span>);</span>
</li>
<li>
<span>}</span><span></span><span>else</span><span></span><span>{</span>
</li>
<li>
<span>    echo </span><span>"识别出错:"</span><span>.</span><span>$wordArr</span><span>[</span><span>"errMsg"</span><span>];</span>
</li>
<li><span>}</span></li>
</ol>

测试了几张图片，准确度还是蛮高的。百分百的话，是不现实的~

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以上就介绍了php实现ocr文字识别，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。