# Hugin FAQ

## Installation

### How can I compile Hugin.app on my OSX machine?

See Compiling Hugin on OSX

### How do I compile hugin on my linux machine?

For ubuntu/debian users, Rob Park had written a good Compile Hugin on Ubuntu document, but it no longer seems to be available. For Ubuntu users there is a work-in-progress explaining how to compile hugin and libpano13 (comments welcome).

### How do I compile hugin on my Windows machine?

See Compiling Hugin on Windows

### make install fails when executing the update-desktop script

If make install fails with the following error message

    *** calling /usr/bin/update-desktop-database
    *No directories in update-desktop-database search path could be processed and updated.*

rerun the ./configure script with --disable-desktop

### Compilation of PTWXDlg.cpp failes

If you see this or a similar compilation error

     PTWXDlg.cpp: In function 'void registerPTWXDlgFcn()':
     PTWXDlg.cpp:176: error: invalid conversion from 'void (*)(char*,
     char*)' to 'void (*)(char*, ...)'
     PTWXDlg.cpp:176: error: initializing argument 1 of 'void
     PT_setErrorFcn(void (*)(char*, ...))'
     make[3]: *** [PTWXDlg.lo] Error 1

please update to libpano 2.8.4 or later and recompile. Unfortunately the ./configure script of hugin 0.6.1 only checks for libpano 2.8.1.

### hugin crashes during optimisation

If you have installed hugin 0.6 or later using an rpm package, make sure that you have panotools 2.8.3 or later installed. Hugin 0.6 and later will crash if used with an earlier version of panotools.

### Autopano-SIFT can not be used from inside hugin (LINUX)

Under some Linux systems (for example Fedora Core), mono programs (Autopano-SIFT is written in C#) are not directly executable. When trying to automatically create control points hugin cannot start autopanog.exe. Open the Preferences, and use

     mono `which autopanog.exe`

as the autopano-SIFT program.

## Control Point creation

### How do I add control points

The control points editor is quite powerful, but its usage is probably not obvious on the first try. Here are some ways the developers use the Control Point panel:

1. Selecting control points in 100% zoom.

This method needs some scrolling, if big images are used. You might want to try the fit to window zoom setting in that case. Switch to the Control Points tab, and use the following settings:

    Zoom: 100%
    [X] auto fine tune
    [X] auto add
    [X] auto estimate

Click on a prominent feature in the left image. If the image pair already contains control points, hugin will try to select the point in the other image. If its the first point in this pair, click near the same feature on the right image. The second point will be placed and fine tuned automatically. If you are not happy with the placement, both points can be moved by dragging them to a better position. Press the "f" key to fine tune the point in a small area.

2. Selecting control points in fit to window mode.

I uses this mode if I need to set points on big images. Switch to the Control Points tab, and use the following settings:

    Zoom: fit to window
    [X] auto fine tune
    [ ] auto add
    [X] auto estimate

Click on left image. The image will be shown in 100% view. Within the detailed view, click on a prominent feature. If the image pair already contains control points, hugin will try to select the point in the other image. If its the first point in this pair, click near the same feature on the right image. The point will be placed and fine tuned automatically. If you are not happy with the placement, both points can be moved by clicking at the desired position. Move the point close to the desired feature and press the "f" key to fine tune the point. When the points are on the same feature, press the right mouse button, or press the "a" key to add the control point pair. It will then be shown in the list below the image.

### How do I scroll both images at the same time?

Try pressing the shift key while moving the mouse. The control key or the middle mouse button can be used to scroll only the image under the mouse cursor.

### How do I stop Hugin pausing for a moment after every click?

The preview window updates continuously whenever anything changes, so disable the preview auto-update, close it or make it smaller if you don't need it.

Otherwise, picking control points with auto fine tune selected can involve a lot of processing. You can reduce this by selecting File -> Preferences -> Finetune and lowering the values for Patch width, Search area width and Local search area width. This means you can't be so sloppy when clicking to create control points, but the results will be the same.

## Common problems when creating a panorama

### How can I reuse a project as a template?

If you copy a .pto project to a different folder and open it with hugin, you will be prompted for the 'missing' images. You should delete any control points from this template project since they won't be relevant to the new photos.

Alternatively you can load your images as normal, then Apply template from the File menu, this will import image settings and parameters from a previous project.

### How do I straighten a curved horizon?

If the panorama looks nice but the horizon is curved, there are two ways to improve the image and straighten the horizon. First, try optimizing the view by selecting "Positions and View" as the optimization mode and run the optimizer afterwards. By clicking "Calculate Field of View" in the "Stitcher" tab and displaying the preview window afterwards you can check if the image has been improved.

If it is still curved, you have to add vertical guide control points in the "Control Points" tab. Usually two vertical control points are enough to straighten the horizon nicely. Often edges of buildings, poles or other man made structures provide good vertical lines. To add a vertical control point, switch to the control point editor and select the same image on both sides. Place a control point on the left image on the upper area of the vertical feature. In the right image, select a control point on the lower area of the features, and press the Add button. Once the new point has been added, its type should automatically switch to "vertical line". You might want to switch off the auto-add and auto-estimate options while doing this to avoid naggy dialogs while adding these guide points.

Two points that are roughly 90 degrees apart provide the best effect.

See also the related perspective correction tutorials: hugin tutorial on perspective correction, Perspective correction, Leveling a Finished Panorama. While these are concerned with correction of the perspective in one image, the same technique can be used for leveling a panorama.

### Half the panorama is black, my pictures fill only the right half of the output

Hugin uses the first photo as the anchor image and puts it in the middle by default. This means that if you shot a sequence from left to right, the images will fill the right hand side of the panorama. There are two ways to fix this:

- Open the preview window and click the center button.
- or select the middle photo, hit anchor this image for position and reset in the images tab, then reoptimise.

### I get visible bands in the sky and other flat areas, what can I do?

Make sure you are using enblend to do the final image assembly, this will blend the overlap as much as is possible - Enable enblend by stitching the images into a high quality TIFF file in the stitcher tab.

If you still have problems, then you probably have to correct vignetting in your images. In the vignetting area of camera and lens tab, select edit parameters.... Then select division, polynomial and estimate polynomial to calculate a vignetting correction curve for your camera combination - This will be applied to every photo in your project when you click OK.

### My photos never quite line up, what can I do?

It is normal to get little stitching parallax errors if the camera moves between photos. The solution is to rotate the camera around the no-parallax point using a panoramic head or philopod.

Otherwise you can sometimes improve things by optimising the d & e parameters separately - When you optimise everything, unselect Inherit in the camera and Lens panel for 'd & e'.

If these parallax errors are still large, you need to decide which parts of the scene that you want to line-up and which parts don't matter. Select control points only on objects that you do want to line-up and which are all about the same distance from the camera.

The remaining broken lines can then be retouched in a photo editor like the gimp. The shear tool is ideal for bending the lines and getting them to line up.

## Postprocessing

### Why is the ICC profile of my input images not preserved?

Since hugin 0.5 and enblend 2.4 ICC profiles in the input files are transfered to the output panorama. Please update to a current version.

### How can I postprocess the image using multiple layers in The Gimp?

Unfortunately, The Gimp can't read PSD formatted files generated by PTStitcher, and the multiple TIFF output it produces is cumbersome to use. There are two possibilities to work around this:

- Use the nona stitcher, to output to a multilayer TIFF format.

This will will produce a multi_layer.tif file, that contains all remapped images, cropped to their bounding box. This will save a lot of space, compared to a "traditional" PTStitcher layered output file, where all layers have the full panorama size.

Unfortunately, The Gimp 1.2 and 1.3 can't load multilayer TIFF files. Please use Gimp 2.0 or later.

- If you need PTStitcher features not supported by nona, you can also use tif2xcf, to combine the multiple TIFF output into a multilayer XCF.

Unfortunately this requires a lot of memory because it stores each remapped image in a layer with the size of the final panorama.

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