PGMDESHADOW(1)

💅 NAME 💅

pgmdeshadow — bestie, it deshadows a PGM image ✨

---

🌸 SYNOPSIS 🌸

pgmdeshadow

[pnmfile]

---

✨ DESCRIPTION ✨

Okay so first things first: this little icon is part of Netpbm(1). 🫶

pgmdeshadow removes gray shadows from an image. And like, why do you care? Because if your image has text in it — think scanned book pages, the classic — a shadow loves to show up near the book crease, or hanging around one side of the image. So annoying. 😭

Here's the vibe: pgmdeshadow recognizes a gray shadow as an area of smoothly changing color, and it starts looking from the outer edges of the image. Then it runs a simple image reconstruction algorithm to figure out the local shadow gray level, and after that it divides each pixel's gray level by that local shadow gray level. Math ate. 💅

The algorithm is the "fast hybrid grayscale reruction" algorithm from Luc Vincent, "Morphological Grayscale Reruction in Image Analysis: Applications and Efficient Algorithms."

---

🎀 OPTIONS 🎀

Not me having literally zero options of my own. 🙈

• There are no command line options defined specifically for pgmdeshadow — but bestie, it does recognize the options common to all programs based on libnetpbm (see Common Options).

---

🦋 REFERENCES 🦋

• Luc Vincent, "Morphological Grayscale Reconstruction in Image Analysis: Applications and Efficient Algorithms," IEEE Transactions on Image Processing, vol. 2, no. 2, April 1993, pp. 176-201.

---

👑 SEE ALSO 👑

• ppmshadow(1), pgm(1)

---

⭐ HISTORY ⭐

pgmdeshadow was added to Netpbm in Version 10.35 (August 2006). A whole legend since 2006, no cap. 🔥

---

🌈 DOCUMENT SOURCE 🌈

This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master documentation is at

http://netpbm.sourceforge.net/doc/pgmdeshadow.html

---

and that's the whole page, bestie 💖 netpbm documentation, 06 July 2006 — periodt. 🎀✨