From NIH: ImageJ is a free open source application to process images. Automate tasks and create custom tools using macros. Generate macro code using the command recorder and debug it using the macro debugger. Extend ImageJ by developing plugins using ImageJ's built in text editor and Java compiler. Use ImageJ as an image processing toolkit (class library) to develop applets, servlets, or applications. It 8-bit grayscale or indexed color, 16-bit unsigned integer, 32-bit floating-point, and RGB color data types. Open and save all supported data types as TIFF (uncompressed) or as raw data. Open and save GIF, JPEG, BMP, PNG, PGM, FITS, and ASCII. Open TIFFs, GIFs, JPEGs, DICOMs, and raw data using a URL. Tools are provided for zooming (1:32 to 32:1) and scrolling images. All analysis and processing functions work at any magnification factor. Create rectangular, elliptical, or irregular area selections. Supports smoothing, sharpening, edge detection, median filtering, and thresholding on both 8-bit grayscale and RGB color images. Measure the area, mean, standard deviation, min, and max of entire image. Split a 32-bit color image into RGB or HSV components and merge 8-bit components into a color image.
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