Vuforia Query Web API

The Vuforia Web Query API enables you to match a submitted image against your Cloud databases. It receives a single image, via HTTP, and returns a list of any matching results.

The Query Web API performs a Cloud Recognition search within the Cloud database associated to the Client Access Keys provided in the Authorization header.

Authentication

All requests to the Web Query API need to be authenticated. The authentication scheme is described in the Vuforia Web API Authentication. Follow the steps described in this article for Making API Calls while replacing the Server Access Keys server_access_key and server_secret_key with your Client Access Keys client_server_key and client_secret_key.

Submitting a Query 

Perform an image recognition query by including the required requests listed below. Include in the request header both Authorization, date, and declaration of the content type. The request body can consist of three fields to submit your image recognition specifications on a query.

Request Method: POST
Request URL: cloudreco.vuforia.com/v1/query
Request Headers:

  • Authorization (required by authentication protocol, see Authentication).
  • Content-Type (multipart/form-data).
  • Optional: Accept (application/json).
  • Date (required by authentication protocol).

Request Body: The Request body is formatted as multipart/form-data. The expected fields are listed in Table 2: Query Request Body.
Notes:

  • Recommended image settings (best recognition performance and latency): JPEG, 640 pixels on the longer image side, compression quality 50-75.
  • Maximum image size: 2.1 MPixel. 512 KB for JPEG, 2MB for PNG.
  • The text fields shall be UTF-8 encoded.
  • The API accepts requests with unknown data fields, and ignore the unknown fields.
  • The API rejects requests with missing, malformed, out-of-range or incomplete data fields.

Query Request Body 

Field

Content-Type

Type

Mandatory

Description

image

image/jpeg or image/png

Binary image file in jpg or png format

Yes

Query Image. See above notes for recommendations and maximum size.

max_num_results

text/plain

Int [1..10]

No

Indicates the maximum number of matching targets to be returned. Default value is 1 (return the best match, if any targets match at all)

include_target_data

text/plain

String

No

Indicates if target_data records shall be returned for the matched targets. Accepted values are top (default value, only return target_data for top ranked match), none (return no target_data), all (for all matched targets)

Response message

The returned response will contain query ID, list of matching targets, and whether the query was successful,

Response Headers:

  • Content-type (application/json or other for some failure cases with unspecified body).

Response Status Code:

Response Body:

  • Success case: JSON object with fields shown in Table 3: Query Response Body.
  • Failure cases: Depending on the type of failure there will be either a JSON body according to Table 3: Query Response Body (without results field), or there will be an arbitrary body (or even no body at all). For details, see the List of failure cases and returned values.

Query Response Body 

Field

Type

Mandatory

Description

query_id

32-character String (UUID)

yes

A unique transaction id for this query.

results

List of Query Result Entry

Mandatory for successful queries, missing for failed queries.

A list of target matches, sorted by the internal recognition confidence.

result_code

String

yes

Result code indicating success ( Success ) or a specific type of failure of the request. See possible values for error cases below.

Query Result Entry 

Field

Type

Mandatory

Description

target_id

32-character String (UUID)

yes

UUID of the target

target_data

Target Data record

No (see description)

Target Data record describing the matched target. Whether or not this field is returned depends on the include_target_data parameter in the request.

Target Data 

Field

Type

Mandatory

Description

name

String

yes

The name of the target

application_metadata

String

yes

The application metadata associated to the target (user-provided). Encoded in base64.

target_timestamp

Int

yes

Timestamp when target was created/updated in seconds since Jan 1, 1970 GMT (Unix time). Note that this is an unsigned 32-bit integer.