Plugins for Astronomical Image Processing with ImageJ

Clicking on the links will download these plugins as a zip archive. To install, unzip the archive and place the contents in your ImageJ “plugins” directory.

Download all the plugins on this page in a single zip archive.

SaveAs FITS – Saves an image in FITS format.

Plot FWHM – Fits a Gaussian function to a horizontal and vertical cut that is centred on the brightest point in the image. Returns the FWHM of the function both in numerical and graphical formats. (It may be helpful to crop the image so that it just contains the object to be measured.)

Background Extractor – Extracts the background of a stack of images by normalizing each image in a stack and then combining the stack. Used to produce sky flat images from a sequence of exposures.

Normalize Values – Measures the mean value of all images in a stack and finds the highest mean. Each image is then multiplied by a constant equal to the highest mean/mean of the image. This results in each image of the stack having the same mean value.

Moon Crater Calculator – Calculates the height of a crater wall or lunar mountain using user input from measurements on lunar images.

Image Quality Calculator – Used for assessing the relative quality of a stack of images. The output is a listing of the “quality” factor for each image in the stack. The factor is computed by taking the sum of the differences of adjacent horizontal and vertical pixels. This is done at three different scales (original size, half size, and quarter size). Images that contain a lot of contrast and sharp edges should have a higher quality factor using this method.

Select Frames With Best Edges – Selects the frames with the “best” edges from a stack of images. The edges are computed using the “Find Edges” routine in ImageJ (using a Sobel filter). The mean values of the edge frames are computed and the frames are ordered according to this value. A new stack is created that contains all the frames having a mean value that is at least xx% as high as the highest mean value.

Debayer Image – Creates a colour image from an input Bayer matrix. Allows the option of several different demosaicing algorithms: replication, bilinear interpolation, smooth hue, and adaptive smooth hue. Also has options for filtering the RGB channels with a median and/or gaussian filters and for normalizing the channels before producing the colour image. Returns the grayscale RGB stack and optional merged colour image.

Write LUT from Function – Creates a look-up table from the specified function. Functions include: A*log(Bx), A*sqrt(Bx), A*exp(Bx), A*x^B, and A*sin(Bx), where A and B are user-defined constants.

Remove Hot or Cool Pixels – Replaces all pixels above and/or below a threshold value with either the nearest neighbour median, nearest neighbour mean, or zero.