NIH Image: An Introduction and System Requirements

Features

NIH Image conforms well to the Macintosh user interface standard, and is visually and graphically oriented, making it easy to use with little experience. For example, NIH Image has a palette of tools for drawing, measuring and examining images which are fully described in the "Tools" section of the NIH Image manual. A variety of measurements can be made on user-specif ied regions of interest and results exported to a spread sheet or plotting package. The LUT (color look up table) and Map windows allow control of the video lookup table, providing flexible contrast enhancement and false color. The Info window displays cursor position, pixel values, selection size, line length, etc. Images, look-up tables, macros and convolution kernels can be opened by dragging them to the NIH Image icon.

System requirements

NIH Image requires a Mac II or later with 8 MB or more of RAM. (Running NIH Image on a 4 MB Mac is a struggle.) System 7 or later is also required for versions 1.56 and later (because of the plug-ins and 24-bit to 8-bit color conversion), and for many of these examples. A Power PC native version is available as well as a non-FPU version for Macs without a floating-point co-processor.

NIH Image Users

There is an active electronic mailing list on the Internet with over 1000 subscribers and a dozen messages or so a day covering topics such as a) news of the latest versions of NIH Image b) special purpose macros c) image processing tips using NIH Image d) hardware - frame grabbers e) bugs, wish list items. Subscribe to the list by sending the one line message "subscribe nih-image <first name> <last name>" to listproc@soils.umn.edu.

Starting up and configuring

Select the Monitors control panel in the Control Panels folder (from the Apple - Control Panels menu) and set the display to 256 colors. (Versions of NIH Image 1.55 and later will work with other monitor settings, but the appearance of the images may differ from those described here, and the performance of NIH Image may be degraded.

In the Finder, click once on the NIH Image icon and use the File - Get Info command to set the preferred size to 4000K. Leave NIH Image in a folder that also contains the macros folder and plug-ins folder. Make an alias of NIH Image and move it to either the Apple Menu items folder (in the System folder) or the desktop. To start up, do one of the following actions to either the NIH Image icon or its alias: double click it, select it in the Apple Menu, drag and drop one or more selected images onto it, or double click on an image that is an NIH Image document. Which application (such as NIH Image) 'owns' the file can be displayed by going to the finder, selecting the file by clicking on it, and using the File - Get Info command or pressing the command-I keys.

In the event of the error message that there was not enough room for various buffers, use the Options - Preferences command in NIH Image to set the Undo and Clipboard buffers to 300K. (The Clipboard and Undo buffers don't need to be larger than the largest example image. You may have obtained a preferences file along with NIH Image, which might have preferences different from those recommended for these examples. ) Also make sure that the Invert Pixel Values box is checked so that black = 0 and white = 255. Save the preferences using File - Record Preferences , Quit and restart NIH Image.