Assessing image quality
Warning
The Vision OCR features listed below are legacy features discontinued on May 14, 2024.
To evaluate the quality of an image, use Image classification.
To do this, set the type
property to Classification
in the batchAnalyze method and specify the quality model in the configuration.
Examples
Getting started
To use the examples, install cURL
Get your account data for authentication:
-
Get an IAM token for your Yandex account or federated account.
-
Get the ID of the folder for which your account has the
ai.vision.user
role or higher. -
When accessing Vision OCR via the API, provide the received parameters in each request:
-
For the Vision API and Classifier API:
Specify the IAM token in the
Authorization
header as follows:Authorization: Bearer <IAM_token>
Specify the folder ID in the request body in the
folderId
parameter. -
For the OCR API:
- Specify the IAM token in the
Authorization
header. - Specify the folder ID in the
x-folder-id
header.
Authorization: Bearer <IAM_token> x-folder-id <folder_ID>
- Specify the IAM token in the
-
Vision OCR supports two authentication methods based on service accounts:
-
With an IAM token:
-
Get an IAM token.
-
Provide the IAM token in the
Authorization
header in the following format:Authorization: Bearer <IAM_token>
-
-
With API keys.
API keys do not expire. This means that this authentication method is simpler, but less secure. Use it if you can't automatically request an IAM token.
-
Provide the API key in the
Authorization
header in the following format:Authorization: Api-Key <API key>
Do not specify the folder ID in your requests, as the service uses the folder the service account was created in.
Apply the model to assess quality
-
Prepare an image file that meets the requirements:
- The supported file formats are JPEG, PNG, and PDF. Specify the MIME type
of the file in themime_type
property. The default value isimage
. - The maximum file size is 1 MB.
- The image size should not exceed 20 MP (height × width).
Note
Need an image? Download a sample
. - The supported file formats are JPEG, PNG, and PDF. Specify the MIME type
-
Encode the file into Base64:
UNIXWindowsPowerShellPythonNode.jsJavaGobase64 -i input.jpg > output.txt
C:> Base64.exe -e input.jpg > output.txt
[Convert]::ToBase64String([IO.File]::ReadAllBytes("./input.jpg")) > output.txt
# Import a library for encoding files in Base64 import base64 # Create a function that will encode a file and return results. def encode_file(file_path): with open(file_path, "rb") as fid: file_content = fid.read() return base64.b64encode(file_content).decode("utf-8")
// Read the file contents to memory. var fs = require('fs'); var file = fs.readFileSync('/path/to/file'); // Get the file contents in Base64 format. var encoded = Buffer.from(file).toString('base64');
// Import a library for encoding files in Base64. import org.apache.commons.codec.binary.Base64; // Get the file contents in Base64 format. byte[] fileData = Base64.encodeBase64(yourFile.getBytes());
import ( "bufio" "encoding/base64" "io/ioutil" "os" ) // Open the file. f, _ := os.Open("/path/to/file") // Read the file contents. reader := bufio.NewReader(f) content, _ := ioutil.ReadAll(reader) // Get the file contents in Base64 format. base64.StdEncoding.EncodeToString(content)
-
Create a file with the request body, e.g.,
body.json
:body.json:
{ "folderId": "b1gvmob95yys********", "analyze_specs": [{ "content": "iVBORw0KGgo...", "features": [{ "type": "CLASSIFICATION", "classificationConfig": { "model": "quality" } }] }] }
Where:
folderId
: ID of any folder for which your account has theai.vision.user
role or higher.analyze_specs: content
: Base64-encoded image.
-
Send a request using the batchAnalyze method and save the response to a file, e.g.,
output.json
:BashCMDPowerShellexport IAM_TOKEN=<IAM_token> curl \ --request POST \ --header "Content-Type: application/json" \ --header "Authorization: Bearer ${IAM_TOKEN}" \ --data '@body.json' \ https://vision.api.cloud.yandex.net/vision/v1/batchAnalyze > output.json
set IAM_TOKEN=<IAM_token> curl ^ --request POST ^ --header "Content-Type: application/json" ^ --header "Authorization: Bearer %IAM_TOKEN%" ^ --data "@body.json" ^ https://vision.api.cloud.yandex.net/vision/v1/batchAnalyze > output.json
$Env:IAM_TOKEN="<IAM_token>" curl ` --request POST ` --header "Content-Type: application/json" ` --header "Authorization: Bearer $Env:IAM_TOKEN" ` --data '@body.json' ` https://vision.api.cloud.yandex.net/vision/v1/batchAnalyze > output.json
Where
IAM_TOKEN
is the IAM token you got before you started.The response will contain the properties and the probability of matches. You can use these properties to moderate the image:
{ "results": [{ "results": [{ "faceDetection": { "properties": [{ "name": "low", "probability": 0.001466292142868043 }, { "name": "medium", "probability": 0.003421348333358767 }, { "name": "high", "probability": 0.99511235952377319 } ] } }] }] }
Ready-to-use function for sending requests in bash
The example below is intended to be run in MacOS and Linux. To run it in Windows, see how to work with Bash in Microsoft Windows.
-
If you do not have the Yandex Cloud command line interface yet, install and initialize it.
-
Copy the function to the terminal:
vision_quality() { curl --header "Authorization: Bearer `yc iam create-token`" \ "https://vision.api.cloud.yandex.net/vision/v1/batchAnalyze" \ -d @<(cat << EOF { "folderId": "`yc config get folder-id`", "analyze_specs": [{ "content": "`base64 -i $1`", "features": [{ "type": "CLASSIFICATION", "classificationConfig": { "model": "quality" } }] }] } EOF ) }
Explanations:
yc iam create-token
: get an IAM token.-d @<(cat EOF ... EOF)
: create a request body.yc config get folder-id
: get the ID of the default folder selected in the CLI.base64 -i $1
: Base64 encoding of the image passed in the function arguments.
-
Now you can call this function by passing the image path in the arguments:
vision_quality path/to/image.jpg