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Chapter 8 Recovering Graphic FilesChapter 8 Recovering Graphic Files==================================================================8-1 Recognizing a Graphics FileGraphic filescontaindigital photographs, line art, three dimensional images, text data converted to images, and scanned replicas of printed pictures.Agraphics program creates one of three types of graphic files: bitmap, vector and metafile.Bitmap Images:collections of dots, or pixels in a grid format that form a graphic.Vector Graphics:graphics based on mathematical instructions to form lines, curves, text and other geometric shapes.Metafile Graphics:graphic files that are combinations of bitmap and vector images.You can use2 types of programs to work with graphic files: graphic editors and image viewers.You usegraphic editors to create, modify, and save bitmap,vector and metafile graphics.Useimage viewers to open and view graphic files but contents can't be changed.When using agraphics editor or an image viewer, you can open a file inone of many graphics file formats such as BMP, GIF and JPEG.Eachformat has different qualities including the amount of color and compression used.If you open agraphic file in a graphic editor that supports multiple file formats, you can save the file in another file format.However,converting graphic filesthis way can change image quality.====================================================================================================================================8-1a understanding Bitmap and Raster ImagesBitmap images store graphics info as grids of pixels short for "picture elements". Raster images are also collections of pixels, but they store pixels in rows tomake images easy to print.In most cases,printing an image converts (rasterizes) it to print pixels line by line instead of processing the complete collection ofpixels.Pixels:small dots used to create images; the term comes from picture element.Raster Images:collection of pixels stored in rows rather than a grid, as with bitmap images, to make graphics easier to print; usually created when a vectorgraphic is converted to a bitmap image.Abitmap's image quality on a monitor is governed by resolution, which determine the amount of detail that's displayed. Resolutionisrelated to the densityof pixels onscreenanddepends on a combination of hardware and software.Monitors can display a range of resolutions; higher the resolutions, the sharper the image.Computersalso use avideo card containing a certain amount ofmemory for displaying images. Themore advanced the video card's electronics and the more memory it has, the more detailed instructions it can takeresulting in higher quality images.Example:A monitor and video card on Windows computer might support a 4096 x 2160 resolution which means displaying a 4096 pixels horizontally and2160 pixels vertically. Because a bitmap image is defined by pixel size, high resolution pics use smaller pixels than low resolution pics do. Are collections of dots or pixels in a grid format that form a graphic?Bitmap images are collections of dots, or pixels, in a grid format that form a graphic.
Which images store graphics information as grids of pixels?Bitmap images store graphics information as grids of pixels (short for “ picture elements”). The quality of a bitmap image displayed onscreen is governed by resolution, which determines the amount of detail displayed. Vector graphics, unlike bitmap and raster files, use lines instead of dots.
In which format are most digital photographs stored quizlet?Most digital cameras use the bitmap format to store photos. When you decompress data that uses a lossy compression algorithm, you regain data lost by compression. Each graphics file type has a unique header value. The two major forms of steganography are ____________________ and substitution.
Which of the following techniques has been used to protect copyrighted material by inserting digital watermarks into a file?The practice of adding a watermark -- a trademark or other identifying data hidden in multimedia or other content files -- is one common use of steganography. Watermarking is a technique often used by online publishers to identify the source of media files that have been found being shared without permission.
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Which of the following graphics/file types includes a collection of dots or pixels in a grid format?
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