An image projection converter between cubemap/fisheye/equirectangular formats

17, Mar, 2017

Dome Master, Original source of this image is Cube, Original source of this image is Equirectangular, Original source of this image is  


This is a projection converter of serial-numbered/single cubemap, fisheye and camera images/movies to equidistant/equirectangular/perspective/user-defined projection.



  1. Extraxct the downloaded file.
  2. Execute Cube2DM.exe


  1. Remove the extracted files.

Available Conversions


Input file format (png, bmp, jpg, tif, jp2, ppm, mp4, avi, etc.)

Output file format (png, bmp, jpg, tif, jp2, ppm, mp4, avi)

Just press start conversion button after setting start, end number, and output size, then the converted images are saved.

File names

This program tries to find files with the following format.
[left input form]@front[right input form][serial number][.extension]

If you want to convert hippliner_@front_#00000.png to hippliner_@front_#00022.png, set Input Type to AllSkyViewer-type-CubeMap, and input

For converting yokohama@front.jpg, set Input Type to AllSkyViewer-type-CubeMap, and input

For converting Inage_Madoka.jpg, set Input Type to one of fisheye projections, and input

In case input file type is fisheye, the ratio of area where horizontal angle becomes 180 deg. is set as width(%).
For example, when the fisheye image circle is 800 pixel in a 1000 pixel square, set 80 in the width.
When Mask is checked, pixels with view angles over 180 deg is not read.

By pressing Preview Input, input image is displayed.
By pressing Preview Output, output image is displayed.
If the image have serial number, number in current box is used.
By checking sync, preview is synchronized with current number.
Preview image conversion is separately performed from file conversion.

Interpolations are applied only for resizing
from temporary resolution to output resolution.

Input angle determination

For correct conversion, determination of input angle is important. The following is the determination process.

  1. Input the folder name and filename (or drag & drop the image) and choose the input type that correspond to the projection of the lens the image was taken.
  2. Choose the output type to dome master (equidistant projection). Input the output angle to the viewangle of the fisheye image circle (e.g. 214 deg for SP360, 180 deg for Madoka, etc. usually it is written in a spec sheet). Also, check Mask checkbok next to the output angle and push preview outpu button to show the preview.
  3. Adjust the input angle and input offset to become that the size of the image circule and the circular mask is the same size.
  4. The input angle detemination is finished. After above adjustment, input angle and input offset should not be changed.
  5. Choose the output projection type you want. and set the output view angle.
  6. Choose altitude, azimuth and rotation.
  7. Set the output folder filename and size, and by pushing "Start Convert" button, the concersion starts.

Usage of user-defined projection

  1. The relationship between the angle from the lens center and the distance from the center are plotted.
  2. The distance should be normalized to be 1 where the angle is 90 degree as below sample
  3. Fit the graph using fitting functions (such as polynomial or sine) that crosses the origin
  4. Input the obtained parameters to coef_in.txt.
  5. Use Cube2DM for conversion.
Smaples: The parameter file should be named coef_in.txt in the folder of Cube2DM.

Raynox DCR-CF187PRO

(sinusoid version is recomendded for actual usage.)
(The data is based on the star position and analyzed by Hoshikaze-P

Entaniya Fisheye 250 MFT

(Data was obtained from Entaniya.)
(In the sample, parameter for chromatic aberration is also adjusted.)

Adjustment of lateral chromatic aberration (Applying different magnifications for each color channel)

  1. Set the input type to user-defined projection
  2. Set the projection parameters of coef_in.txt to the corresponding lens, and adjust input view angle.
    Examples of coef_in.txt: Equidistant, Equisolid angle, Orthographic, Stereographic
  3. Show the edge image using output preview (set the azimuth to near 90 deg. see below tables)
    Change 15th line of coef_in.txt (R channel) to around 1.001 and show preview.
    Adjust the 15th line value to see the clearest image.
  4. If needed, 17th line parameters can also be changed to obtain the best image.

samples: edge images of fisheye lens, equidistant prjection parameters are used for user-defined

(lens:Fujinon YV2.2×1.4A-SA2)
Just chose equidistant input and
perspective projection output
(azimuth:-62 deg, altitude: 8 deg)

user-defined + color adjustment
to perspective projection
(R: 1.0035, G:1.0, B:0.997 )

user-defined + color adjustment
to perspective projection
(R: 0.985, G:1.0, B:1.0 )(too small)

user-defined + color adjustment
to perspective projection
(R: 1.0035, G:1.0, B:1.0 )

user-defined + color adjustment
to perspective projection
(R: 1.015, G:1.0, B:1.0 )(too large)



Windows 64 bit, with .NET framework


This software is provided to you "AS-IS" and without warranty of any kind.

NOMOTO Tomonori (Mail address is in image file)

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