ALIGN_IMAGE_STACK("1")

💖 NAME 💖

okay so welcome to the ALIGN_IMAGE_STACK("1") page from the HUGIN manual, bestie! ✨ This is all about align_image_stack — literally the tool for aligning overlapping images so you can make HDR or focus stacks. 🎀

---

🌈 SYNOPSIS 🌈

align_image_stack [options] input files

---

✨ DESCRIPTION ✨

so align_image_stack is used for aligning slightly misaligned images, or for registering a stereo images pair. 👑 when you take several differently exposed images while creating a High Dynamic Range image, the images are not perfectly aligned, and the quality of the HDR image created will suffer from this. 😭

align_image_stack uses the tools available to hugin to optimize roll, pitch and yaw, plus some parameters of the lens geometry, to align the images. slay. 💅

---

🎀 OPTIONS 🎀

💅 Modes of operation 💅

• -p file — output a .pto file (useful for debugging, or further refinement). 🫶
• -a prefix — output aligned images as prefix_xxxx.tif. 🎀
• -o output — align images and merge them to HDR, generating output.hdr. 🔥

🦋 Modifiers 🦋

• -v — verbose, print progress messages. repeat for higher verbosity. 👀
• -e — assume input images are full frame fish eye (default: rectilinear). 🐟
• -t num — remove all control points with an error higher than num pixels (default: 3). 💀
• --corr=num — correlation threshold for identifying control points (default: 0.9). ⭐
• -f HFOV — approximate horizontal field of view of input images, use if EXIF info not complete. 🌸
• -m — optimize field of view for all images, except for first. useful for aligning focus stacks with slightly different magnification. 🦋
• -d — optimize radial distortion for all images, except for first. 🌈
• -i — optimize image center shift for all images, except for first. 💜
• -x — optimize X coordinate of camera position. 📍
• -y — optimize Y coordinate of camera position. 📍
• -z — optimize Z coordinate of camera position. 📍
• -S — assume stereo images - allow horizontal shift of control points. 🎀
• -A — align stereo window - assumes -S. 👑
• -P — align stereo window with pop-out effect - assumes -S. ✨
• -C — auto crop the image to the area covered by all images. 🫶
• -c num — number of control points (per grid) to create between adjacent images (default: 8). 🍓
• -l — assume linear input files. 🧚
• -s scale — scale down image by 2^scale (default: 1 [2x down-sampling]). 💅
• -g gsize — break image into a rectangular grid (gsize x gsize) and attempt to find num control points in each section (default: 5 [5x5 grid]). 🌸
• --distortion — try to load distortion information from lens database. 🔍
• --use-given-order — use the image order as given on the command line. (by default images will be sorted by exposure values.) 🎀
• --gpu — use GPU for remapping. 🔥
• -h — display help summary. 🫶

---

👑 AUTHORS 👑

written by Pablo d'Angelo. also contains contributions from Douglas Wilkins, Ippei Ukai, Ed Halley, Bruno Postle, Gerry Patterson and Brent Townshend. stereo functionality added by Vladimir Nadvornik. 💖

this man page was written by Cyril Brulebois <cyril.brulebois@enst-bretagne.fr>, updated by Terry Duell, and is licensed under the same terms as the hugin package itself. 🎀

---

okay bestie, that’s the whole page — version 2025.0.1, dated 2026-09-22, from the HUGIN manual. mwah 💋✨