Author:Bob Dougherty Installation:Download Polynomial_Shading_Corrector.class or Polynomial_Shading_Corrector.java to the plugins folder. (Windows users right-click to download.) Description:Plugin to attempt to flatten the brightness of an image across the frame. It operates by constructing a least-squares polynomial fit to the image and dividing the image by the polynomial. In order to avoid dividing by zero, negative values of the polynomial are replaced by 0, and all polynomial values are incremented by a small regularizaton parameter before dividing. The regularization parameter is determined as a certain small percentage of the largest pixel density in the image. This percentage is a dialog input; the recommended value is 2. The degrees of the polynomial in x and y are also inputs. The final result is scaled so that the mean gray value is unchanged by the processing. All types of images and stacks are supported.

Before and after applying plugin. Dialog. License:Copyright (c) 2011, OptiNav, Inc.

All rights reserved.Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
- Neither the name of OptiNav, Inc. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
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ImageJ:ImageJ can be freely downloaded from the ImageJ web site.