PHP WeChat development: How to implement speech recognition

With the popularity of mobile Internet, more and more people are using WeChat as a social software, and the WeChat open platform has also brought many opportunities to developers. In recent years, with the development of artificial intelligence technology, speech recognition technology has gradually become one of the popular technologies in mobile terminal development. In WeChat development, how to implement speech recognition has become a concern for many developers. This article will introduce how to use PHP to develop WeChat applications to implement speech recognition functions.

1. Principles of Speech Recognition

Before introducing how to implement speech recognition, let us first understand the basic principles of speech recognition. Speech recognition is to convert human speech signals into text so that computers can understand and process it. The specific implementation method is as follows:

1. Recording: First, you need to use a microphone to collect the voice signal;
2. Frame splitting: Cut the recording data into small pieces of the same length, each small piece Called "frame";
3. Preprocessing: perform speech processing on each frame of data, including filtering, noise reduction, and noise removal of sound signals;
4. Feature extraction: perform preprocessing on After processing the speech sequences, calculate their corresponding feature vectors. A commonly used feature vector is Mel-Frequency Cepstral Coefficients, which characterizes sound by converting the sound signal into a power spectrum uniformly distributed on the Mel frequency.
5. Recognition: Send the feature vector of each frame into the computer model for actual recognition (compare the distance between the feature vector and each speech mode stored in the model, and find the template with the smallest distance, that is, the speech of the frame identification results). After the structure of the entire process is chosen, a set of training data is used to train the computer model so that the computer can recognize a variety of speech sounds.

2. Speech recognition in PHP WeChat development

After understanding the principles of speech recognition, let’s talk about how to implement the speech recognition function in PHP WeChat development. The WeChat public platform provides a speech recognition interface. We only need to write PHP code to enable the WeChat public account to send requests to this interface.

First, you need to turn on the developer mode in the WeChat public platform, fill in the relevant information, and then obtain the access_token. This token is a necessary parameter for calling the WeChat API interface. Its validity period is 7200 seconds. We can use file caching to store it.

The next step is the key part. To implement the speech recognition function, you need to use the CURL and fopen functions in PHP. The specific process is as follows:

1. After receiving a voice message from a WeChat user, first call the WeChat API interface to obtain the media_id of the voice message.

2. Construct a request link and send a request to WeChat API to obtain the voice file.

3. Obtain the voice file link from the response returned by WeChat.

4. Open the voice file link and use the fread function to read the file content.

5. Use CURL to send a POST request, carrying the voice file content, developer ID and access_token.

6. Receive the recognition results returned by the API.

7. Parse the returned result, extract the identified string, convert it into a text message and return it to the user.

The following is a sample code

function voice2text($media_id)
{
    $access_token = get_access_token(); // 获取access_token
    $url = 'https://api.weixin.qq.com/cgi-bin/media/get?access_token='.$access_token.'&media_id='.$media_id;

    // 发送请求获取语音文件
    $response = http_request($url);
    $header = $response['header'];
    $body = $response['body'];

    // 从响应中获取文件链接
    preg_match('/.*?amr/',$header,$match);
    $file_url = $match[0];
    $file_content = fread(fopen($file_url,'r'),filesize($file_url));

    // 通过API实现语音识别
    $url = 'https://api.weixin.qq.com/cgi-bin/media/voice/addvoicetorecofortext?access_token='.$access_token.'&format=amr&voice_id='.$media_id;
    $post_data = '{voice:{"media_id":"'.$media_id.'"}}';

    $response = http_request($url,'POST',$post_data);

    // 解析响应，提取识别结果
    $text_result = json_decode($response, true);
    $content = $text_result['content'];

    return $content;
}

// CURL function
function http_request($url,$method='GET',$data=null)
{
    $curl = curl_init();
    curl_setopt($curl,CURLOPT_RETURNTRANSFER,true);
    curl_setopt($curl,CURLOPT_TIMEOUT,5000);
    curl_setopt($curl,CURLOPT_SSL_VERIFYPEER,false);
    curl_setopt($curl,CURLOPT_SSL_VERIFYHOST,false);

    switch ($method) {
        case 'GET':
            curl_setopt($curl,CURLOPT_URL,$url);
            break;
        case 'POST':
            curl_setopt($curl,CURLOPT_URL,$url);
            curl_setopt($curl,CURLOPT_POST,true);
            if (!empty($data)) {
                curl_setopt($curl,CURLOPT_POSTFIELDS,$data);
            }
            break;
        default:
            break;
    }

    $response['body'] = curl_exec($curl);
    $response['header'] = curl_getinfo($curl);

    curl_close($curl);

    return $response;
}

3. Summary

This article introduces the basic principles of speech recognition and the key steps to implement speech recognition in PHP WeChat development. By understanding speech recognition technology, we can better utilize the development of API interfaces to implement more complex functions and provide WeChat users with a better service experience.

The above is the detailed content of PHP WeChat development: How to implement speech recognition. For more information, please follow other related articles on the PHP Chinese website!