E-Inkペーパー読みやすさ最適化
電子ペーパー（Kindle等）向けにPDFを最適化：大津二値化による背景除去、輪郭強調、文字の太字化処理。
e-Inkコントラスト最適化
電子ペーパー（e-Ink）のコントラストを最適化するために、PDFの電子書籍をここにドラッグ＆ドロップしてください。
スキャンされたPDFのアップロード
このツールについて
e-Ink Reader Optimizer is a must-have tool custom-made for e-Reader enthusiasts using Kindle, Onyx Boox, Kobo, or other e-paper devices.
Many scanned PDF e-books suffer from faint lettering, muddy gray backgrounds, noise, or scan shadows when viewed on e-Ink screens. This tool analyzes gray-value histograms and applies Otsu's Binarization Thresholding to separate text from background, converting gray backdrops to clean white.
Additionally, it integrates morphological dilation to bold and thicken thin, faded characters, providing crisp, high-contrast typography. The inertia-damped contrast slider allows you to fine-tune the paper-like contrast in real-time.
使用方法
Upload Scanned PDF
Upload e-books or scanned documents with faint text or gray backgrounds.
Adjust Contrast Slider
Drag the damped slider to balance background removal and character bolding in real-time.
Optimize and Download
Process the entire PDF to generate a high-contrast, eye-friendly document tailored for e-Ink.
使用例
Ancient Manuscript Restoration
Thicken faded text in scans of historical books or handwritten manuscripts to make them readable.
Exam Sheet Clean-up
Bleach background shadows from photocopied or photographed exams, returning clean black text on white paper.
E-paper Device Tailoring
Convert colored PDFs to optimized grayscale, preventing messy, dithering artifacts on monochrome screens.
よくある質問
How does the "character bolding" work?
In image processing, this is called dilation. It uses a structuring matrix to expand character margins by a pixel, physically thickening faint strokes to make them legible.
Will this process bloat the file size?
Quite the opposite. By binarizing complex color/grayscale images to simple black-and-white layouts, standard compression (like CCITT Group 4) can shrink the PDF file size significantly.
Does this support native text PDFs?
Yes. Native vector PDFs are rasterized at high resolutions in the background, optimized, and compiled back, ensuring unified high-contrast reading.