扫描件增强

清理扫描 PDF 的阴影、黑边和发黄底色，让文字更清晰，背景更干净。核心处理在你的设备上完成，文件不会上传服务器。

Upload a scanned PDFLocal pixel cleanup, Bradley adaptive thresholding, shadow removal and dark-border crop.

Enhancement presets

Crop dark border

Render scale1.8Local window radius22Text sensitivity0.15Shadow removal0.45JPG quality0.9

Auto-downloads when done · all image processing runs in the browser sandbox

Output is an image-based cleaned PDF. Original hidden text layers are not preserved.

100% 浏览器本地处理