EU License Plate OCR Ruby

The Ruby OCR SDK supports the License Plate API.

Using the sample below, we are going to illustrate how to extract the data that we want using the OCR SDK.
License Plate sample


require 'mindee'

# Init a new client
mindee_client = 'my-api-key')

# Load a file from disk
input_source = mindee_client.source_from_path('/path/to/the/file.ext')

# Parse the file
result = mindee_client.parse(

# Print a full summary of the parsed data in RST format
puts result.document

# Print the document-level parsed data
# puts result.document.inference.prediction

Output (RST):

:Mindee ID: f0f48232-2c80-4473-9c6f-88a09111b84d
:Filename: default_sample.jpg

:Product: mindee/license_plates v1.0
:Rotation applied: No

:License Plates: BY-323-YB

Page Predictions

Page 0
:License Plates: BY-323-YB

Field Types

Standard Fields

These fields are generic and used in several products.

Basic Field

Each prediction object contains a set of fields that inherit from the generic Field class.
A typical Field object will have the following attributes:

  • value (String, Float, Integer, Boolean): corresponds to the field value. Can be nil if no value was extracted.
  • confidence (Float, nil): the confidence score of the field prediction.
  • bounding_box (Mindee::Geometry::Quadrilateral, nil): contains exactly 4 relative vertices (points) coordinates of a right rectangle containing the field in the document.
  • polygon (Mindee::Geometry::Polygon, nil): contains the relative vertices coordinates (Point) of a polygon containing the field in the image.
  • page_id (Integer, nil): the ID of the page, is nil when at document-level.
  • reconstructed (Boolean): indicates whether an object was reconstructed (not extracted as the API gave it).

Aside from the previous attributes, all basic fields have access to a to_s method that can be used to print their value as a string.

String Field

The text field StringField only has one constraint: it's value is a String (or nil).


The following fields are extracted for License Plate V1:

License Plates

license_plates (Array<StringField>): List of all license plates found in the image.

for license_plates_elem in result.document.inference.prediction.license_plates do
  puts license_plates_elem.value


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