# Hugin Preferences

From PanoTools.org Wiki

# General

## Resource usage

To speed things up Hugin keeps a copy in memory of as many input photos as possible. With very large projects, this would use all your system memory, so set Image cache memory to a value below your available free RAM. The default of 256MB should be ok for a system with 512MB of RAM, however this is very conservative, for large projects you will want to set this to a high proportion of your available system memory.

The Preview window is multi-threaded so can use more than one CPU/core if required. Set Number of CPUs to how many CPUs you wish to use.

## User interface

Changing the language of the user interface can be useful e.g. if you want to test your new translation.

Usually, Hugin will use the current locale to determine the language of buttons, menus etc... Set the Language if you need to switch languages temporarily or if you are using a platform such as Windows95 that doesn't support localised software. Hugin won't change language immediately, you will need to stop and restart it.

The "language" option in the Hugin Preferences doesn't work for the Mac version. On Mac OS X the system's country settings will be used instead: change the language setting there (i.e. drag the preferred language to the top of the list), and Hugin will reflect that when you restart the program. An alternative but more time consuming way to set another language than the current system language is to quit Hugin, reveal it's icon in the Finder, click on it and open the Information window (Cmd.-I). After deselecting all unwanted language options you can start Hugin in your preferred language.

If the option Copy log messages to clipboard is activated, all log messages (from the control point detector or the assistant) are copied at the end to the clipboard.

The option Show hints about projections activates or deactivates the hints in the fast preview window.

Normally the images in the mask tab and control point tab are rotated according to their orientation in the final panorama. If you disable the option Autorotate images for display the images are display as stored in the files (independent on their orientation in the panorama).

## Raw converter

In this section you can provide the paths to the external raw converters (dcraw, RawTherapee and darktable). For RawTherapee and darktable you should use the command line version (as indicated by -cli extension) and not the GUI executable.

If you leave these fields empty the default names will be used. (The programs should be in the paths specified by the PATH variable.)

Windows: On Windows the paths can be read from registry when the raw converter is installed correctly. (For RawTherapee this works only for version 5.5 or later.)

MacOS: For MacOS the paths "/Applications/RawTherapee.app/Contents/MacOS/rawtherapee-cli" und "/Applications/darktable.app/Contents/MacOS/darktable-cli" to the corresponding app images is taken as default.

# File names

## File options

Some Hugin actions generate large temporary files, change the Temporary dir to specify an alternative location for writing these files. One reason for setting this independently to the operating system default would be to use a RAM disk to speed up stitching.

Note that intermediate stitching files are created in the output folder and not in this Temporary dir.

## Default file names

Here you can construct a default file name for saving the project and for the output prefix. You can always change the proposal when saving. Several place holders can be used to build the file names.

# Assistant

The Assistant tab automates the entire panorama creation process, these settings allow you to customise the assistant.

## Image loading

Select Automatically align images after loading to run the second Align... step immediately after loading the images.

## Optional assistant steps

Detect vertical lines will run linefind to find vertical lines, which can help the assistant to level your panorama.

Select Remove cloud-like control points (Celeste) to run celeste after detecting control points. Celeste will remove Control points set to clouds, this is useful because clouds will move several pixels between shots and are therefore bad scene objects to use for alignment.

Select Remove outlying control points by statistical method to run cpclean, this will try to remove control points with positions that are not credible under pairwise optimisation.

By default the assistant chooses an approbate panorama projection, calculates the field of view of the panorama and canvas size and crops away the black border around the edges. The user-defined output options allows you to configure this step to your needs. With configure a dialog window opens where you can define which steps the assistant should execute. You can define several different settings which are applied depending on several conditions. In each setting all conditions have to be fulfilled in order to apply this setting (the conditions are combined with an AND operator). Each condition consist of a variable (e.g. PanoHFOV, ImageCount), the operator and the value. Example would be `ImageCount>1`, `PanoHFOV>100` or `Lens=~fisheye`. The help text below the control lists all available variables and operators. Then add these panorama output settings which should be applied for your use case. To do so use the context menu and select which one should be added. With the help of the context menu you can also create new or delete existing settings. Several settings are test and applied (if fulfilled) in alphabetical order.

## Auto align

Auto align uses the default control point detector to generate control points between pairs of images, set Number of Ctrl Points per overlap to control the number of control points. Note that although most pictures can be stitched with just three or four control points, automatically generated points tend not to be very evenly distributed, so this number should be set to ten or more.

Note: Hugins cpfind does not support this parameters. So in default settings this parameter is ignored.

The size of the output Panorama Image Size is usually set in the Stitcher tab where it is also possible to Calculate Optimal Size based on the sizes of the input images. The Auto align process does something similar, though here you can set a smaller output as a percentage. Generally setting a percentage of 70% leads to no great loss of quality due to the way a camera CCD samples data.

# Control Points Editor

## HDR and 16bit display

Hugin supports both HDR and 16bit imaging. These image formats contain a lot more brightness and colour information than can be displayed on a standard computer monitor, so Hugin only shows a rough representation of these pictures.

16bit data can have linear or corrected gamma. Linear images appear very dark on many monitors, so set the Curve to gamma 2.2.

For HDR data, try setting the Curve to logarithmic.

Changes to the HDR and 16bit display mode require restarting Hugin to take effect.

The size of the magnifier on the control points tab can be configured here. Depending on your preferences select between the different sizes.

## Fine-tune

Hugin helps position control points to within a fraction of a pixel distance automatically:

- When auto fine-tune is selected in the Control Points tab while picking control points.
- When clicking Fine-tune in the Control Points tab
- When picking Fine-tune all Points in the Panorama editor window Edit menu.

- Patch width, the size of the square of pixels taken from the left photo to match with the right photo when picking control points, reduce if this is taking a long time on your system.
- Search area width, the percentage area of the right photo that is searched when picking control points, reduce if this is taking a long time on your system.
- Local search area width, the region of the right photo searched when you click Fine-tune in the Hugin Control Points tab or Fine-tune all Points in the Panorama editor window Edit menu.
- Correlation Threshold. For each Fine-tune, Hugin calculates the quality of the control points match, raise this threshold to reject dubious matches.
- Peak Curvature Threshold, Currently unused.

## Rotation search

Enable this if your photos:

- have a very wide angle Field of View or fisheye Projection.
- are tilted up or down, control points near the zenith or nadir may need to have full 360 degree rotation search

# Control Point Detectors

Hugin uses an internal or external tool for automatically creating control points for a set of images either when

- clicking the 2. Align... button in the Hugin Assistant tab or
- clicking the Create control points button in the Photos tab.

Note: If you have upgraded from an older release of Hugin, you will need to Load Defaults to update these preferences.

In the Control Point Detector Programs list box you can choose between several presets such as:

- Hugin's CPFind - This is the internal general purpose control point generator of hugin.
- Hugin's CPFind + Celeste - This is the same as the CPFind setting but it will also remove points in areas of sky using the celeste[*] tool. See Using Celeste with hugin for more details.
- Cpfind (multirow/stacked) - This is the same as the CPFind setting, except that Align image stack is used to match photos in bracketed stacks.
- autopano-sift-C - a C version of autopano-sift, wwhich needs to be installed separately.
- Panomatic (by Anael Orlinski), which needs to be installed separately.
- autopano-sift-c (multirow/stacked) - This is the same as the autopano-sift-C setting, except that Align image stack is used to match photos in bracketed stacks.
- Align image stack - part of Hugin suite. Note that align_image_stack is not a general purpose control point detector, but it is very effective for aligning images within stacks.
- Align image stack FullFrameFisheye - This the same as the Align image stack setting above except with an additional setting suitable for fisheye images.

Parameters for these tools can be customized in the Hugin Parameters for Control Point Detectors dialog which you can access by clicking one of the buttons Edit... or New....

These parameters are also helpful if you want to use a similar command line tool that isn't already listed. Click the New... button to configure a new preset to use in the Assistant or the Photos tabs.

The Set default button will mark the preset selected in this list box to be used automatically in the Assistant tab when clicking the 2. Align... button.

# Stitching

The Output format defines the default output format for new projects. You can select TIFF, JPEG or PNG and the compression settings depending on the selecting format.

Under blender you can select whether enblend or the internal blender is the default blender for new project. You can change it for existing projects on the stitcher tab[*].

Important note: The settings here are the defaults for new projects, change settings for the current project in the Hugin Stitcher tab.

The complete stitching process (reprojecting image, blend and fuse images...) can be done by PTBacherGUI or hugin_stitch_project. Select here which processor should be used:

- PTBatcherGUI can queue several projects and can also work unattended and shutdown the computer at the end (e.g. running over night)
- hugin_stitch_project can only work on one project. It is not recommended to start several processes simultaneously.

Select Overwrite existing files if existing file should be overwritten, otherwise you will be asked each time.

PTBatcherGUI has two additional options:

- Start stitching jobs immediately will start the processing directly after adding a project to the queue. Otherwise you can select several project in the queue and start the processing in PTBatcherGUI at any later time.
- Verbose output will activate an additional log window which will print more details about the process.

# Stitching (2)

Exiftool options allows you to customize which metadata are copied to intermediate and final image with exiftool. (Metadata can only be copied to blended and/or fused intermediate images, but not to remapped only images.)

You can specify 2 argfile: The first one is used to copy metadata to all exposure layer or stacks. The second one is used for the final image(s). In the final ExifTool argfile you can also use placeholders to add some information about the panorama into the metadata (e.g. number of images, projections, field of view).

When the option Create Photo Sphere XMP data is checked, the Photo Sphere XMP are automatically added to equirectangular images. These information are used by some viewer to display the panorama in an interactive viewer.

Under Advanced options you can limit the number of threads for the called programs. The number 0 indicates to use maximum number of threads.

# Programs

Here you can define programs for the different stitching steps and set default options for them.

## Nona

Here you can set the Default interpolator used during stitching. Interpolation is a quality setting, but the default of Poly3 (Bicubic) is good for most purposes. You are unlikely to notice any difference between interpolators other than that Nearest neighbor is fast but very low quality.

You can Create cropped images by default, these Cropped TIFF images will speed up stitching, but some image editors do not process the offsets correctly.

Use GPU for remapping will activate experimental nona code to remap images using the shading language of the Graphics Processing Unit in modern video hardware. However some projections and the translation parameters are not yet supported by this experimental code. In this case Nona will automatically switch back to CPU calculation.

## Enblend

The Use alternative Enblend program option allows you to use other tools with a similar interface such as smartblend[*].

Enblend supports a range of Additional arguments which depend on the actual version of enblend you are using. Since also other features and limitations may change depending on version number and building options it is recommended to download and read the version specific manual from Enblend's home page. An easy way to ask your version of Hugin about Enblend's version number is to add -v or --version to the line of arguments in the Stitcher tab, than stitch a simple panorama and have a look at the stitching log.

Note that setting Additional arguments here will only effect new projects, to change enblend and enfuse settings for the current project use the Hugin Stitcher tab.

## Enfuse

If one of Exposure fusion output options is selected in the Stitcher tab then enfuse will be used to merge bracketed exposures during stitching.

# Misc

## Celeste

Often a project has many control points attached to clouds in the sky, this is usually unwanted as clouds move between photos. celeste will attempt to identify 'sky' control points and delete them.

## Photometric optimizer

The photometric optimizer on the Exposure tab samples the here given number of points and tries to determine with which camera response curve, vignetting and exposure compensation the images need to be stitch to get no changes in colour or luminescence. For difficult projects it can be helpful to increase this number.

## Warnings

Here you can activate or deactivate some warning messages or information boxes.

## Edit cp tool

After adding or deleting control points with the cp tool on the fast preview window it is recommended to re-optimize the project. Here you can configure if this optimization should happen automatically or if you want to do it by yourself.

# Troubleshooting

Sometimes when updating a hugin installation new features such as the settings for a new control point editor won't appear where expected. The cause might be a conflict with the preferences file of a previous version of hugin. A good idea before pressing the "Reset do defaults" button might be to back up the old preferences file since it is a plain text file that contains your specific settings in a readable format. Saving this file gives you the chance to recreate these individual settings later on. The name and location of the preferences file is this for the following platforms:

- Linux: ".hugin" can be found in your home directory (FIXME)
- Mac OS X: the file "hugin Preferences" can be found in Macintosh HD/Users/<YourUserAccount>/Library/Preferences/. This folder is usually hidden by the system, so in Finder search the "Go to..." menu for the "go to folder..." command - or just use the keyboard shortcut shift+cmd+G. In the dialog insert ~/Library/Preferences/ and press the "open" button. Make sure Hugin isn't open and then either rename, move or delete this file to make Hugin start with the default preferences for that version.
- Windows: the preferences are stored in the registry : \HKEY_CURRENT_USER\Software\hugin

Quit hugin, rename the preferences file (e.g. add the previous version number) and on the next start of hugin a new preferences file will be generated.

Other fixes for occurring problems can be found in the Hugin FAQ.

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