There are many types of image processing software, some for general use and others for specific purposes. The best image processing software will be easy to use, intuitive in the design of the interface, and powerful enough to perform the tasks that are requires of it. For general processing of photographs and images, there are a dozens of high-quality programs available both commercially and free as open source products. For more specific uses such as astronomy, digital forensics or optical sorting, the options are more limited and might be restricted to very expensive industrial image processing software. Whatever the application, there are some image processing software packages that allow customizations so nearly any algorithm can be applied to the pixels of a digital image.
One of the first considerations about choosing the best image processing software should be the versatility of the program. This should include features such as being able to load multiple file formats and the ability to convert and write into many of those formats. Another feature to be aware of is the amount of built-in filters that the program is capable of executing. Certain filters — such as Gaussian blurs, edge detection and color reduction — can all be very important in image processing.
A type of functionality that is important when choosing image processing software is the ability to separate, create and delete individual channels of an image. A channel is a single layer of an image and can contain only a single color, such as red or green, or can be a custom channel that holds information about a specific area of the image. There are even alpha channels that hold transparency data for the image. The ability to manipulate an image on only a single channel can make some operations much easier.
If the ultimate goal of using the processing software is to manipulate an image, then a valuable tool is spline pathing. This describes the ability of a program to allow the user to draw a series of irregular, curved or straight lines to define an area of the image. This area can then be edited independently of the rest of the image. Creating and using paths can make complex image editing operations very easy.
Extensibility also is something to look for in the best image processing software. A program that has a predefined framework for extending the abilities of the software can change and be usable as technology and algorithms are developed. A static program that can only be updated by recompiling or rereleasing the core executable files might fall behind current technologies.
It also is important to make sure the image processing software is capable of performing the task needed. Some very general photo editing software can easily perform the tasks needed for clarifying and coloring astronomical images, for example, but that same software might have trouble creating visualizations for chemical formulas or medical data. Understanding the limitations of the software can help to avoid costly mistakes or time wasted trying to make the program perform a function it simply can't perform.