Table of Contents

CRS frequently asked questions

The following are common questions and answers when using the cloud image recognition feature.

Q: Does CRS support loading 3D models/virtual content from the cloud?

A: Yes. CRS supports loading 3D models/virtual content in the following ways:

  • meta property: Store AR content in the meta field of the target image, in text file format. 3D models can be encoded as text through Base64, or saved as cloud storage URLs, such as Alibaba Cloud OSS or AWS S3.
  • Loading process: After the client obtains meta data from CRS, it uses a 3D engine, such as Unity or Three.js, to parse and load the model.
  • Reference documentation: See Create recognition target | POST /targets.
Note

For large files (>2MB), use the URL method to avoid an oversized request body caused by Base64 encoding.

Q: Does CRS have a recognition count limit?

A: There is no total recognition count limit, but there are concurrency tiers:

  • Basic mode: Suitable for applications with QPS < 50. There is no hard limit, but the fair use principle must be followed.
  • High concurrency mode: When QPS >= 50, it is recommended to upgrade to dedicated-resource cloud service to ensure recognition stability and low latency.
Important

If your application may face a temporary surge in concurrency during holidays or large events, be sure to contact EasyAR technical support at least 3 business days in advance to apply for a service upgrade.

Q: Why does Web Service API return 404?

A: A 404 error usually means that the requested URL path does not exist or the resource was not found. Common reasons are as follows:

  • Incorrect URL format: An endpoint that does not exist was accessed. For example, directly accessing http://your_crs_uuid.na1.crs.easyar.com:8888 is invalid. Use a complete endpoint such as http://your_crs_uuid.na1.crs.easyar.com:8888/ping.
  • Empty recognition result: When calling the /search interface, if no target is matched, 404 is also returned, with the message body No result: there is no matching.

Troubleshooting steps:

  1. Confirm that the URL is spelled correctly, including UUID and port.
  2. Use the /ping interface to test service availability.
  3. Check whether request parameters are complete, such as image data and API Key.

Solution suggestion: If /search returns 404, it means the current image did not hit any target. You can guide users to adjust the shooting angle or check whether the target has been uploaded to CRS.

Q: What are the common reasons for Web Service API error response codes?

A: In addition to 404, the following error codes are common:

  • 400 invalid appId (appKey)

    • Reason: The requested Key is incorrect, or signature verification failed.
    • Troubleshooting: Confirm whether your Key was copied from the CRS image library; whether the POST request contains a complete signature; and whether request parameters use Content-Type: application/json.

  • 400 invalid date

    • Reason: The request timestamp is invalid or differs too much from the server time, usually within +/-5 minutes.
    • Troubleshooting: Check whether the device time is accurate, especially the time zone settings.

  • 415 unsupported media type

    • Reason: The HTTP Header does not set Content-Type: application/json, or the request body format is incorrect.
    • Troubleshooting: Ensure that the POST request Header contains Content-Type: application/json and that the Body is valid JSON.

General suggestion: All CRS API requests must strictly follow the CRS API documentation.

Note: The FAQ above covers high-frequency issues in CRS usage. If you need to report a new issue, feel free to provide feedback and contact us!