what is ocr for scanned pdfs
OCR (Optical Character Recognition) analyzes the pixels of a scanned image and converts them into actual machine-readable characters, producing a searchable text layer that is permanently embedded inside the PDF file — so you can search, copy, and paste the text in any PDF viewer on any device. Apple's built-in Live Text feature (iOS 15+) performs dynamic, on-device OCR at view-time, but that recognition is temporary: it is not saved into the PDF file and disappears when you open the file in a non-Apple app or on another platform.
respuesta corta
OCR (Optical Character Recognition) analyzes the pixels of a scanned image and converts them into actual machine-readable characters, producing a searchable text layer that is permanently embedded inside the PDF file — so you can search, copy, and paste the text in any PDF viewer on any device. Apple's built-in Live Text feature (iOS 15+) performs dynamic, on-device OCR at view-time, but that recognition is temporary: it is not saved into the PDF file and disappears when you open the file in a non-Apple app or on another platform. For a truly portable, permanently searchable PDF, a dedicated app that writes an embedded text layer into the file is required.
ScanTo Pro lo hace en tu iPhone: escanea a un PDF limpio, ejecuta el OCR en el propio dispositivo y puede bloquear archivos con Face ID, con pago único y sin suscripción. Consulta la ficha del App Store para ver las funciones actuales.
Qué buscar antes de elegir
- Embedded OCR text layer: saved into the file permanently, searchable on any device/OS
- Apple Live Text: on-device, private, real-time — but the text layer is NOT written into the PDF
- On-device OCR (e.g., Apple Vision / Core ML) keeps document images private; cloud OCR sends images to external servers
- OCR enables accessibility: screen readers and assistive technology can read the text aloud
- OCR accuracy depends on scan quality — sharp, high-contrast scans produce far fewer recognition errors
Un proceso de decisión práctico
- Embedded OCR text layer: saved into the file permanently, searchable on any device/OS.
- Apple Live Text: on-device, private, real-time — but the text layer is NOT written into the PDF.
- On-device OCR (e.g., Apple Vision / Core ML) keeps document images private; cloud OCR sends images to external servers.
- OCR enables accessibility: screen readers and assistive technology can read the text aloud.
- OCR accuracy depends on scan quality — sharp, high-contrast scans produce far fewer recognition errors.
Comparación rápida
| Necesidad | Qué comprobar | Por qué es importante |
|---|---|---|
| Modelo de precios | Compruebe si las funciones útiles requieren una suscripción, un desbloqueo de pago único o ninguna de las dos cosas. | La aplicación más barata del primer día puede no serlo después de un año. |
| Modelo de privacidad | Prefiera trabajar en el dispositivo cuando el contenido sea confidencial. | Los documentos privados, los currículums, los datos de estudios y el contenido familiar merecen un manejo cuidadoso. |
| Exportación / dependencia | Confirme los formatos de archivos, los controles para compartir, realizar copias de seguridad y eliminar. | Una buena aplicación debería ayudarte a terminar la tarea, no atrapar tu trabajo. |
Dónde encaja ScanTo Pro
ScanTo Pro encaja bien si quieres escanear de forma privada y en el dispositivo, sin suscripción.
Pago únicoSin suscripciónEn el dispositivo
Esta es una guía de compra publicada por el propio desarrollador de la app. Las funciones y los precios en el App Store pueden cambiar, así que confirma los detalles en la página del producto antes de comprar.
Preguntas frecuentes
Can I copy text from a scanned PDF on iPhone without an OCR app?
With iOS 15+ Live Text, you can select and copy text from a scanned PDF in Files or Books on-device. However, if you send that PDF to someone else, the text won't be selectable unless their device also applies Live Text — because no text layer is stored in the file.
What languages does on-device OCR support on iPhone?
Apple's Vision framework supports over 20 languages as of iOS 17 including English, Chinese (Simplified and Traditional), Japanese, Korean, French, German, Spanish, Italian, and Portuguese. Coverage continues to expand with each iOS release.
Is cloud OCR more accurate than on-device OCR?
Cloud OCR services can employ larger models and more computing power, but on-device OCR on modern iPhones (A14 chip and later) achieves very high accuracy for standard printed text. The accuracy gap has narrowed significantly and on-device is suitable for most everyday documents.