OCR PDF

PDFを検索およびコピー可能にします。

仕組み:

  • テキスト抽出: Tesseract OCRを使用してスキャンした画像やPDFからテキストを認識します。
  • 検索可能な出力: 見えないテキストレイヤーを含む新しいPDFを作成し、元の外観を保ちながら文書を完全に検索可能にします。
  • 文字フィルタリング: ホワイトリストを使用して不要な文字を除外し、特定の文書タイプ (請求書、フォームなど) の精度を向上させます。
  • 多言語サポート: 複数言語が混在する文書のために複数の言語を選択します。

クリックしてファイルを選択します またはドラッグ&ドロップ

ファイルがデバイスの外に出ることはありません。

仕組み

1

Upload File

ファイルをクリックまたはドラッグ&ドロップして始めます

2

Process

プロセスボタンをクリックしてスタートします

3

Download

処理したファイルをすぐに保存します

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よくある質問

How do I know if my PDF needs OCR?

Open the file in any viewer and try to select a line of text. If nothing highlights or search finds no matches, the pages are just images (a scan or a photo) and OCR is what adds the missing text. A PDF that already has selectable text doesn't need this tool.

Which languages can it recognize?

Over 100 Tesseract language packs are listed, from English and Spanish to Arabic, Hindi, Japanese, and Chinese. Tick every language that appears in the document; the packs are loaded together so mixed-language pages are recognized in one pass. Some self-hosted deployments bundle a shorter list and say so above the language picker.

Does OCR change how my document looks?

No. The original pages are copied unchanged and an invisible text layer is drawn on top, positioned word by word to match the scan. You see the same image as before, but you can now search, select, and copy the text.

Which resolution setting should I use?

High (288 DPI) is the default and handles typical office documents. Drop to Standard (192 DPI) when speed matters or the file is long, and use Ultra (384 DPI) for small print, footnotes, or poor scans. Higher settings take noticeably longer since every page is rendered at that size before recognition.

What does the character whitelist do?

It restricts the output to a fixed set of characters, which cuts down on errors like a lowercase l being read as a 1. The Invoice preset allows only digits and the symbols $ . , / - # :, Numbers Only suits serial numbers or meter readings, and Custom lets you type your own set.

Can it read handwriting?

Not reliably. Tesseract is trained on printed text, so neat block capitals sometimes work but cursive mostly produces noise. Results are best on clean, well-lit printed pages; the Binarize option helps with faded or low-contrast scans, and Deskew PDF straightens tilted ones first.

Can I get just the recognized text instead of a PDF?

Yes. When OCR finishes, the extracted text appears in a box where you can review it, copy it to the clipboard, or download it as ocr-text.txt. The searchable PDF download is separate, so you can take either or both.

Does OCR upload my scans to a server?

No. Tesseract runs as WebAssembly inside your browser; the only downloads are the OCR engine and the language packs you selected, fetched the first time they're needed. The scanned pages and the recognized text stay on your device.