The GIF format is useful for encoding and storing digital images of reduced file size, and relies on a lossy storage mechanism that operates by reducing the number of colors utilized to reconstruct the image. Visitors should observe the effects that the various palette selection and dithering algorithms have on the appearance of the specimen image. In a similar manner, the choice of dithering algorithm can be made using the Dithering Method pull-down menu. The Palette Selection Method pull-down menu can be employed to select from among the various color-reduction algorithms that are available in the tutorial. A slider (labeled Number of Colors) is available to vary the maximum number of colors that will be used in the color-reduced image, although the actual number of colors displayed in this image depends upon the techniques used in the color reduction and dithering. The number of distinct colors that appear in the color-reduced image is indicated beneath the Color-Reduced Image window. Appearing adjacent to this window is the Color-Reduced Image window, which displays the image that results from reducing the number of colors in the original specimen image. The number of distinct colors that appear in the unmodified specimen image is indicated beneath the Specimen Image window (this number varies with individual specimens). Visitors will note that specimens captured using the various techniques available in optical microscopy behave differently during image processing in the tutorial. The following nomenclature is used: ( FL), fluorescence ( BF), brightfield ( DF), darkfield ( PC), phase contrast ( DIC), differential interference contrast (Nomarski) ( HMC), Hoffman modulation contrast and ( POL), polarized light. Each specimen name includes, in parentheses, an abbreviation designating the contrast mechanism employed in obtaining the image. The tutorial initializes with a randomly selected specimen image (captured in the microscope) appearing in the left-hand window entitled Specimen Image. This interactive tutorial explores the compression of digital images using GIF algorithms, and how a lossy storage mechanism affects the final appearance of the image when interpolations are made from images having more than 256 colors. The Graphics Interchange Format (GIF), designed for encoding and storing digital images, is currently in worldwide use, being a popular medium for presentation of images by means of Web browser software. Interactive Tutorials Color Reduction and Image Dithering 16 */ 17 package .palette Ģ9 30 import .ImageWriteException ģ1 32 /** 33 * Factory for creating palettes.Molecular Expressions Microscopy Primer: Digital Image Processing - Color Reduction and Image Dithering - Interactive Tutorial 14 * See the License for the specific language governing permissions and 15 * limitations under the License. You may obtain a copy of the License at 8 * 9 * 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License") you may not use this file except in compliance with 7 * the License. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. View Javadoc 1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements.
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