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Object Storage Service:Vehicle detection

Last Updated:Jun 28, 2025

You can use the vehicle detection feature to detect vehicle information and license plate information in an image. This topic describes the parameters you can specify when using the vehicle detection feature and provides an example of how to detect vehicle and license plate information in an image.

Scenarios

  • Traffic management: Vehicle detection can be used in traffic monitoring and management systems, such as identifying images captured for traffic violations to help process these violations.

  • Identification of abnormal vehicles: Vehicle detection can detect images uploaded to Object Storage Service (OSS) buckets to help identify vehicle information and license plate information.

    Note

    Vehicle information includes vehicle locations, colors, and types. License plate information includes license plate locations and texts.

  • Traffic analysis: Vehicle detection can help you analyze traffic information such as road usage and traffic distribution.

How to use

Prerequisites

Vehicle detection

The following sample code provides examples of how to specify parameters to detect vehicle information and license plate information in an image using OSS SDKs for common programming languages. If you want to specify parameters to detect vehicle information and license plate information in an image using other programming languages, modify the parameters based on the following sample code.

Java

OSS SDK for Java 3.17.4 or later is required.

import com.aliyun.oss.ClientBuilderConfiguration;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.OSSObject;
import com.aliyun.oss.model.GetObjectRequest;
import com.aliyuncs.exceptions.ClientException;

import java.io.ByteArrayOutputStream;
import java.io.IOException;

public class Demo1 {
    public static void main(String[] args) throws ClientException, ClientException {
        // Specify the endpoint of the region in which the bucket is located.
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Specify the ID of the Alibaba Cloud region in which the bucket is located. Example: cn-hangzhou.
        String region = "cn-hangzhou";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket.
        String bucketName = "examplebucket";
        // If the image is stored in the root directory of the bucket, enter the image name. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg.
        String key = "example.jpg";

        // Create an OSSClient instance.
        // Call the shutdown method to release resources when the OSSClient is no longer in use.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Create a processing instruction to detect vehicle information and license plate information in the image.
            GetObjectRequest getObjectRequest = new GetObjectRequest(bucketName, key);
            getObjectRequest.setProcess("image/cars");

            // Use the process parameter of the getObject method to pass the processing instruction.
            OSSObject ossObject = ossClient.getObject(getObjectRequest);

            // Read and display the query results.
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = ossObject.getObjectContent().read(buffer)) != -1) {
                baos.write(buffer, 0, bytesRead);
            }
            String imageCars = baos.toString("UTF-8");
            System.out.println("Image Cars:");
            System.out.println(imageCars);
        } catch (IOException e) {
            System.out.println("Error: " + e.getMessage());
        } finally {
            // Shut down the OSSClient instance.
            ossClient.shutdown();
        }
    }
}

Python

OSS SDK for Python 2.18.4 or later is required.

# -*- coding: utf-8 -*-
import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider

# Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
auth = oss2.ProviderAuthV4(EnvironmentVariableCredentialsProvider())

# Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
endpoint = 'https://oss-cn-hangzhou.aliyuncs.com'
# Specify the ID of the Alibaba Cloud region in which the bucket is located.
region = 'cn-hangzhou'
bucket = oss2.Bucket(auth, endpoint, 'examplebucket', region=region)

# If the image is stored in the root directory of the bucket, enter the image name. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg.
key = 'example.jpg'

# Create a processing instruction to detect vehicle information and license plate information in the image.
process = 'image/cars'

try:
    # Use the get_object method and pass the processing instruction by using the process parameter.
    result = bucket.get_object(key, process=process)

    # Read and display the query results.
    image_cars = result.read().decode('utf-8')
    print("Image Cars:")
    print(image_cars)
except oss2.exceptions.OssError as e:
    print("Error:", e)

Go

OSS SDK for Go 3.0.2 or later is required.

package main

import (
	"fmt"
	"io"
	"os"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func main() {
	// Obtain the temporary access credentials from the environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Create an OSSClient instance.
	// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint.
	// Specify the ID of the Alibaba Cloud region in which the bucket is located. Example: cn-hangzhou.
	client, err := oss.New("https://oss-cn-hangzhou.aliyuncs.com", "", "", oss.SetCredentialsProvider(&provider), oss.AuthVersion(oss.AuthV4), oss.Region("cn-hangzhou"))
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Specify the name of the bucket. Example: examplebucket.
	bucketName := "examplebucket"

	bucket, err := client.Bucket(bucketName)
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// If the image is stored in the root directory of the bucket, enter the image name. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg.
	// Use the oss.Process method to create a processing instruction to detect vehicle information and license plate information in the image.
	body, err := bucket.GetObject("example.jpg", oss.Process("image/cars"))
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}

	defer body.Close()

	data, err := io.ReadAll(body)
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	fmt.Println("data:", string(data))
}

PHP

OSS SDK for PHP 2.7.0 or later is required.

<?php
if (is_file(__DIR__ . '/../autoload.php')) {
    require_once __DIR__ . '/../autoload.php';
}
if (is_file(__DIR__ . '/../vendor/autoload.php')) {
    require_once __DIR__ . '/../vendor/autoload.php';
}
use OSS\Credentials\EnvironmentVariableCredentialsProvider;
use OSS\OssClient;

try {
    // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
    $provider = new EnvironmentVariableCredentialsProvider(); 
    // Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
    $endpoint = 'https://oss-cn-hangzhou.aliyuncs.com';
    // Specify the name of the bucket. Example: examplebucket.
    $bucket = 'examplebucket';
    // If the image is stored in the root directory of the bucket, enter the image name. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg.
    $key = 'example.jpg'; 

    $config = array(
        "provider" => $provider,
        "endpoint" => $endpoint,        
        "signatureVersion" => OssClient::OSS_SIGNATURE_VERSION_V4,
        // Specify the ID of the Alibaba Cloud region in which the bucket is located.
        "region" => "cn-hangzhou"
    );
    $ossClient = new OssClient($config);
  // Create a processing instruction to detect vehicle information and license plate information in the image.
  $options[$ossClient::OSS_PROCESS] = "image/cars";
  $result = $ossClient->getObject($bucket,$key,$options);
  var_dump($result);
} catch (OssException $e) {
  printf($e->getMessage() . "\n");
  return;
}

Parameter description

Action: image/cars

Note

For more information about the response parameters, see DetectImageCars.

Related API

Sample request

GET /example.jpg?x-oss-process=image/cars HTTP/1.1
Host: image-demo.oss-cn-hangzhou.aliyuncs.com
Date: Fri, 21 Jul 2023 08:57:28 GMT
Authorization: SignatureValue

Sample success response

HTTP/1.1 200 OK
Server: AliyunOSS
Date: Fri, 21 Jul 2023 08:57:30 GMT
Content-Type: application/json;charset=utf-8
Content-Length: 250
Connection: keep-alive
x-oss-request-id: 64BA487A5423BA333952334F
ETag: "2CE2EA370531B7CC1D23BE6015CF5DA5"
Last-Modified: Mon, 10 Jul 2023 13:07:30 GMT
x-oss-object-type: Normal
x-oss-hash-crc64ecma: 13420962247653419692
x-oss-storage-class: Standard
x-oss-ec: 0048-00000104
Content-Disposition: attachment
x-oss-force-download: true
x-oss-server-time: 552

{
  "RequestId" : "0C299A82-5D32-57DE-B66B-5E2A814C60BA",
  "Cars": [
    {
    "LicensePlates": [
      {
        "Content": "LuA8***8",
        "Boundary": {
          "Width": 200,
          "Height": 300,
          "Left": 10,
          "Top": 30
        },
        "Confidence": 0.789
      }
    ],
    "CarType": "van",
    "CarTypeConfidence": 0.516,
    "CarColor": "white",
    "CarColorConfidence": 0.604,
    "Boundary": {
      "Width": 200,
      "Height": 300,
      "Left": 10,
      "Top": 30
    },
    "Confidence": 0.999
    }
  ]
}

Billing

During vehicle detection, because the IMM service is called, the following billing items are generated on both the OSS and IMM sides:

  • OSS side: For detailed pricing, see OSS Pricing

    API

    Billing item

    Description

    GetObject

    GET requests

    You are charged request fees based on the number of successful requests.

    Outbound traffic over Internet

    If you call the GetObject operation by using a public endpoint, such as oss-cn-hangzhou.aliyuncs.com, or an acceleration endpoint, such as oss-accelerate.aliyuncs.com, you are charged fees for outbound traffic over the Internet based on the data size.

    Retrieval of IA objects

    If IA objects are retrieved, you are charged IA data retrieval fees based on the size of retrieved IA data.

    Transfer acceleration

    If you enable transfer acceleration and use an acceleration endpoint to access your bucket, you are charged transfer acceleration fees based on the data size.

    HeadObject

    GET requests

    You are charged request fees based on the number of successful requests.

  • IMM side: For detailed pricing, see IMM billing items

    Important

    Starting from 11:00 UTC+8 on July 28, 2025, the IMM vehicle detection service will be upgraded from a free model to a paid model. The specific billing item is ImageDetect. For more information, see IMM billing adjustment announcement.

    API

    Billing item

    Description

    DetectImageCars

    ImageDetect

    You are charged request fees based on the number of successful requests.

Notes

  • Vehicle detection supports only synchronous processing (x-oss-process).

  • Anonymous access will be denied.