Hugin Stitcher tab

From Wiki
Revision as of 01:23, 10 February 2009 by Bruno (talk | contribs) (Explain stacking criteria better)
Jump to: navigation, search

The rest of hugin is all about setting up the project and aligning images, the Stitcher tab is where the final output file is created.


Here you can set the output Projection of your project, there are lots to choose from, each with different advantages and disadvantages:

Field of View

This is the horizontal and vertical angle of view of the output image, clicking Calculate Field of View will shrink or enlarge the field of view of the output to fit the arrangement of the input images - The Fit button in the Hugin Preview window does the same thing.

Note that some Projections have a limited field of view, notably:

  • Rectilinear has to be less than 180 degrees both vertically and horizontally.
  • Panoramic (cylindrical) has to be less than 180 degrees vertically.
  • Stereographic has to be less than 360 degrees both vertically and horizontally.
  • Mercator has to be less than 180 degrees vertically.
  • Transverse Mercator has to be less than 180 degrees horizontally.

Panorama Canvas Size

Set the width and height of your output panorama in pixels. Calculate Optimal Size will estimate a size that has about the same resolution as your input images.

Some examples: a three megapixel image has pixel dimensions of 2048 x 1536, an A4 print at 300 pixels per inch will have a pixel size of 3500 x 2480, a full screen spherical Equirectangular Projection image will have pixel dimensions of 6000 x 3000 or greater and a gigapixel image has a pixel size of 32768 x 32768.

Note that the interpolation used by hugin doesn't handle downsampling very well, so output images smaller than about half the size of the Optimal Size will show aliasing artefacts. If you want to create high quality small images, it is better to create an Optimal Size image in hugin and downsize it later in an image editor such as the Gimp.


The crop settings allow just a portion of the panorama to be stitched, there are various reasons to do this:

  • When correcting perspective large areas of the panorama output will be empty anyway.
  • Large 'gigapixel' style panoramas can be stitched in sections then blended later.

The cropped-out areas are shown darkened in the hugin Preview window.


Hugin can output 'normal' stitched images, exposure blended images or high dynamic range (HDR) images. The following options determine which kind of image is created, and allow keeping the intermediate images created during the process.


If Blended panorama is enabled then enblend is used for blending. In the final stitching process nona reprojects and distorts images to fit, enblend takes these images as individual TIFF files and merges them using sophisticated seam positioning and blending. Further enblend settings can be found in the hugin Preferences.

Enable remapped images if you want to keep the intermediate images that enblend uses as input - For example modifying the alpha channel of these images and then blending manually is one technique for including and excluding people or objects that move between shots.

Exposure Blending

If Blended panorama (enfuse) is enabled then hugin will group the input images into exposure stacks by comparing positions, any images with more than 90% overlap are grouped like this. Each of these bracketed exposure stacks will be exposure blended with enfuse and the results stitched together into a panorama with enblend.

Note that for this to work, the scene has to be photographed multiple times using exposure bracketing and the EV exposure values set either manually in the hugin Camera and Lens tab, automatically from EXIF data or by optimising exposure in the hugin Assistant tab or hugin Exposure tab.

Note also that unlike Normal and Merge to HDR options where images are exposure corrected as part of the remapping process, enfuse requires that each exposure layer is supplied uncorrected - Hugin takes care of this automatically and will not apply correction in this case.

Enable Blended exposure layers to additionally stitch each exposure layer into a separate panorama - Useful for manual exposure blending. Note that hugin simply blends any photos with less then 0.2EV exposure difference together into each layer.

Enable Remapped images to keep the intermediate images supplied to enblend.

Merge to HDR

If Blended HDR panorama is enabled then hugin will identify likely bracketed stacks of images, then create remapped, deghosted HDR images which are then blended with enblend.

Note that like the Exposure blending option above, this generally only makes sense if the scene has been photographed multiple times using exposure bracketing, and the EV exposure values optimised in the hugin Exposure tab.

Enable Stacked HDR images to keep copies of the remapped HDR images as supplied to enblend.

Enable Individual non merged images to keep copies of each image remapped in linear colour space before deghosting and merging to HDR.

Click Stitch now! to generate output panoramas immediately. Selecting Save project and send to batch adds the current project to the Hugin Batch Processor stitching queue, note that the queue won't be processed unless this queue manager is running.


nona is the default Remapper (stitching engine) supplied with hugin, normally there is no need to change this or any of the options below.

Set the Interpolator (i) to change the sampling interpolation. You probably won't notice much difference between the various options except that Nearest Neighbour is fast but with very low quality. The default of Poly3 (bicubic) is generally good for most purposes.

Cropped TIFF files are smaller and more efficient because unused parts of the image are not stored in the file. You should always save cropped images unless you need to open them in an image editor without Cropped TIFF support.

enblend is the default Blender for use with hugin, normally there is no need to change this. Additional command-line Options can be set here or in the hugin Preferences for new projects.

enfuse is the default for Image fusion (Exposure Blending), Options are similar to enblend.

File formats

Normal Output can be in one several formats:

  • TIFF, various compression options. 16bit and 8bit depth supported. None compression is supported by most other applications, LZW compression is common in Windows/Mac applications and Deflate compression is more common with Linux tools.
  • JPG, lossy compression suitable for web/email. Quality can vary from 0 (extremely low quality, small file size) and 100 (high quality, large file size). A typical quality setting for web/email would be between 70 and 80
  • PNG, lossless compression. 16bit and 8bit depth supported.
  • EXR, not sure what use this is doing here (TODO).

HDR Output can be either:

  • floating-point TIFF, various compression options.
  • EXR, this is a high dynamic range format which is more compact than a high dynamic range TIFF.