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.
짧은 답변
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 Pro는 iPhone에서 이걸 해냅니다. 깔끔한 PDF로 스캔하고 기기 안에서 OCR을 돌리며 Face ID로 파일을 잠글 수 있고, 한 번만 결제하면 되는 구독 없는 앱입니다. 최신 기능은 App Store 페이지에서 확인하세요.
선택 전에 확인할 점
- 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
실용적인 선택 절차
- 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.
빠른 비교
| 필요 | 확인할 항목 | 중요한 이유 |
|---|---|---|
| 가격 모델 | 유용한 기능에 구독, 한 번 구매 잠금 해제, 또는 둘 다 필요 없는지 확인하세요. | 처음에 가장 저렴한 앱이 1년 뒤에도 가장 저렴하리라는 보장은 없습니다. |
| 개인정보 보호 방식 | 민감한 콘텐츠라면 기기 내에서 처리되는 방식을 우선하세요. | 개인 문서, 이력서, 학습 데이터, 가족 콘텐츠는 신중하게 다뤄야 합니다. |
| 내보내기 / 종속성 | 파일 형식, 공유, 백업, 삭제 제어 기능을 확인하세요. | 좋은 앱은 작업을 가두는 것이 아니라 완료하도록 도와야 합니다. |
ScanTo Pro이 잘 맞는 경우
구독 없이 기기 안에서만 처리하는 비공개 스캔을 원한다면 ScanTo Pro가 잘 맞습니다.
한 번 구매반복 결제 없음기기 내 처리
이 안내서는 앱 개발자가 직접 작성한 구매 가이드입니다. App Store의 기능과 가격은 변경될 수 있으므로 구매 전에 제품 페이지에서 세부 정보를 확인하시기 바랍니다.
자주 묻는 질문
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.