Introduction

Keith's Image Stacker is an image processing utility that provides you with many sophisticated image enhancement tools, including:

• Translational and rotational alignment
• Darkframe subtraction and flatfield division
• DeBayering (demosaicing)
• Normalization
• Averaging and/or summing (collectively known as "stacking")
• Unsharp-masking
• Laplacian sharpening (which is also known by the more general term wavelet sharpening, although there are actually many wavelet-based image-sharpening algorithms, of which Laplacian sharpening is only one)
• Level adjustment
• Gaussian blur
• Wavelet shrinkage denoising
• Fourier Transform editing (for removal of cyclic or periodic artifacts such as electrical interference patterns)
• Star deringing and debloating
• Many other operations as well

The primary purpose of this program is to stack images.

This program is mainly oriented toward astrophotographers, who often take numerous shots of an object and then want to stack the shots to get a single final image that is superior to the original shots. In recent years webcams and video cameras have become popular tools for astrophotography, and as such, are capable of capturing hundreds of individual images of an object in a given night. The basic approach to processing this data is to average the set of images on a per-pixel basis. By doing so, the signal-to-noise ratio of the stacked image is greater than each of the individual images by a factor of the square root of the number of images stacked.

This documentation assumes you are an astrophotographer and is written as such. If you are not and you wish to use the program to stack nonastrophotos (or to use the various other tools for image processing), that's fine. Simply follow the documentation along and figure out how to use the program. There are sample images provided in the documentation directory which you can use as a tutorial if you wish. I offer instructions on each of the two common methods of astrophotography, as well as a command reference page. Take your pick:

• Introduction
• Dynamic Range and 32-bit to 8-bit Image Projection -- It is strongly recommended that you read this first
• About RAW Images -- Please read this before asking any questions with the word RAW in them
• Planetary Imaging
• Deep Sky Imaging
• Multithreading Options
• FAQ (Frequently Asked Questions) -- Look here first, look here last, whatever, just look here before complaining about the program
• Command Reference