ACR-NEMA Acquire is a plug-in module for PhotoShop and other programs that allow the use of PhotoShop acquisition modules. (The PhotoShop acquisition module interface has become a defacto standard for acquiring images from such devices as scanners, and for converting images from foreign file types, and is supported by many Macintosh graphics software programs.) The ACR-NEMA plug-in allows you to import ACR-NEMA image files into any such PhotoShop Plug-in compatible program.
How to use it:
Most programs that accept PhotoShop plug-ins require you to place a copy of the plug-in in a specific folder that is searched by the program when launched. For NIH Image (version 1.52 now supports PhotoShop plug-ins) the folder is called “Plug-ins”, and is located in the same folder as the NIH Image application. For Color It!™ 2.3, the folder is called “Scanners & Plug-ins” (or just “Plug-Ins” in Color It! 3.0) and is contained in the “Color It!™ Stuff” folder that resides in the same folder as the application. Other programs will require you to put the plug-in in other similarly named places.
Once a copy of the acquisition module is installed in the correct place, you must start up the program you wish to import ACR-NEMA images into. A menu item labeled “ACR-NEMA” will appear along with other acquisition modules. Each program will put these items in different menus. For NIH Image, you will find it under the File menu, in the “Acquire” hierarchical menu item.
For Color-It, you will find it under “Scan/Import” in the File menu:
Once the ACR-NEMA menu item is selected, you will be presented with a standard file open dialog box. Only files of type ‘ANMM’ and ‘ANVM’ will be presented in the dialog. If you have files that you suspect to be in ACR-NEMA format, but don’t have either of these filetypes, you may by-pass the filtering of only these types by holding the option key down before selecting the ACR-NEMA menu item. This will allow you to attempt to open any file as if it were in ACR-NEMA format. Be careful with this, as recovery from attempts to open non-ACR-NEMA files has not been thoroughly tested.
The acquisition module has been tested with 8 and 12 bit gray-scale images in big-endian (Motorola) and little-endian (Intel) byte order. (There is no need to convert to one or the other, as both byte orders are handled automatically.) Color images are NOT supported. If the bit-depth is greater than 8, the raw pixel values must be scaled down to 8 bits, since PhotoShop (or the Mac in general) does not support gray scale depth greater than 8-bits. In this case, you will be prompted with the following dialog:
The “Top” value is the value that will be represented as white, the “Bottom” value will be represented as black, with all values between these spread evenly across the gray spectrum. (Values above the top or below the bottom will be pegged to white, or black, respectively.) The initial values presented are derived from information provided in the header of the ACR-NEMA image file. The “Largest Value” indicates the range of raw pixel values supplied in the file.
In the above example, the image was a 12-bit image, so the range is 0-4095. Pixel values between 974 and 1074 will be mapped to the entire gray spectrum, values ≤ 974 will be mapped to black, and values ≥ 1074 will be mapped to white.
Other notes:
I have only tested this module with NIH Image 1.52, and Color-It versions 2.3 and 3.0, as these are the only PhotoShop Plug-In compliant programs I own. (No, I haven’t actually tested this Photoshop plug-in with Photoshop! If anyone tries this with Photoshop, I’d appreciate hearing about it!)
Group 6000 or other “overlays” are not supported.
Revision history:
1.2.1
Changed contact information. New email address, and US Mail address. Made some minor updates to ReadMe file. No functional (i.e. code) changes.
1.2
Allow window top and bottom settings to be set outside of the range of valid pixel values. For example, “Bottom” values less than zero are now considered valid. The range of output values is still spread evenly across the range between “Top” and “Bottom”. The fact that some values between the top and bottom are unattainable due to the constraints of the number representation of the pixels values will simply result in the omission of the corresponding values from the output domain. For example, if you specify a "bottom" of -100 and a "top" of +100, and the range of valid pixel values is 0-4096 (typical for 12-bit medical images), input values between -100 and +100 will be mapped to output values from 0 to 255, however, since the lower half of the top/bottom range (-100 through -1) are missing from the input domain of 0-4096, there will be NO pixels in the output domain with values between 0 and 127.
Also, allow window level setting for 8-bit images. (used to assume Bottom=0, Top = 255)
Also, it was pointed out to me that "ACR-NEMA" is a hyphenated acronym, and so all references to it in the documentation and in the menus of the module have been changed to this hyphenated all-caps form.
1.1
Added support for some 12-bit packed formats. Packing must be four 12-bit pixels for every three 16-bit words, and only images whose width is a multiple of 4 pixels are supported. Any non-supported format results in dropping into a dialog that lets you enter the number of rows, columns and pixel data offset. 16-bit pixel data is presumed in this case.
1.0
Original release.
Legal Section:
The ACR-NEMA acquisition module is freeware. The author retains the copyright, including the right to alter or sell the program. You may use and copy ACR-NEMA acquisition module freely only on a non-commercial basis. You may not alter or sell this program without the author's permission.
If you wish to post this to a bulletin board or other publicly accessible archive, you must contact the author for permission.
Author Contact Info:
Feel free to send comments, suggestions, or problem reports. If you find the plug-in useful, please send a postcard of your home town, or at least an e-mail, so I know who’s using this thing.
The author may be reached via e-mail at fowen@spss.com. You can also use regular US mail:
