This tutorial was originally prepared by Richard Cozzens
Panoramic images or photo mosaics from videos are often used in human rights research, and are especially useful for matching up visual features such as landmarks with satellite imagery. For example, Human Rights Watch used a photo mosaics in a January 2014 report on housing demolitions in Syria (see p. 22). A more detailed case study in the use of panoramic images can be found here.
For the following tutorial, I am using a video from Aleppo.
Step 1: Select frames from video
Open the video in the VLC Video Player and play the video. Consider having the video run in slow motion to aid with identifying appropriate frames.
Tip about selecting frames: Look for a segment of the video when the camera sweeps over the area you want covered in a relatively short space of time. An ideal set of images has at least half a frame-width of overlap between each adjacent image. Less than that and the photo stitcher program will have difficulty. More than that doesn’t seem to be necessary.
Step 2: Take snapshots of the video
If you have identified an appropriate segment from which you can pull frames, start taking several snapshots or “screenshots”, which will later be stitched together to create one single image.
Repeat this step until you have enough frames.
Step 3: Put snapshots into one folder
Next, put all the individual snapshots that you have extracted from the video into a separate folder. (Note: On a Mac, the snapshots will be saved in the pictures folder by default).
Step 4: Load images in Hugin and “Align”
Open Hugin, click “Load Images” and select all snapshots you have extracted from the video.
Tip: When the program asks for HFOV, try “35”
After clicking “Align”, wait until the processing is finished and the “Fast Panorama Preview” opens.
Did the images automatically connect well? Skip to Step 6
If the images look disconnected or mis-aligned, continue with the next step.
Step 5: Edit Control Points (if necessary)
Close the “Fast Panorama Preview” window and click on the “Control Points” tab in the main Hugin window .
General advice about Control Points: Control Points are the overlapping points between each pair of overlapping images. Ideal control points are on stationary objects that have a clear corner or line that can be matched between photos. Each overlapping pair should have at least 4 or 5 points between them, spread out if possible.
Make sure that auto-guessed control points are correct between each relevant pair of images. Add control points to overlapping image pairs that do not have enough if necessary. In the “Optimizer” tab, click “optimize now!”
Open the Fast Panorama Preview again and proceed to next step.
Here you have several options to give the final touch to your mosaic:
- Adjust Projection: Experiment with different projections to see which looks best (Cylindrical and Equirectangular have worked well). Optional: adjust vertical and/or horizontal field of view sliders at edges of images
- Move/Drag: Click and drag images to move and/or rotate the panorama
- Crop: Adjust edges of crop to desired size
Step 7: Create panorama
After closing the “Fast Panorama Preview”, you can select the output format (for example .jpg) under the “Stichter” tab.
Click “Stitch” to create your panorama (it will be saved in the same folder that contains the snapshots from the video).