Options for the cloud document text recognizer.
API key to use for Cloud Vision API. If not set, the default API key from
firebase.app() will be used.
apiKeyOverride: undefined | string;
Only allow registered application instances with matching certificate fingerprint to use Cloud Vision API.
enforceCertFingerprintMatch: undefined | false | true;
Sets language hints. In most cases, not setting this yields the best results since it enables automatic language detection. For languages based on the Latin alphabet, setting language hints is not needed. In rare cases, when the language of the text in the image is known, setting a hint will help get better results (although it will be a significant hindrance if the hint is wrong).