Simple example of Vector Graphics a line A line can be described mathematically

Simple example of vector graphics a line a line can

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Simple example of Vector Graphics, a line. A line can be described mathematically with equation
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Rasterizing Vector Graphics Raster means convert vector graphics into pixel-based images. Most vector graphics programs let you rasterize vector graphics. Because you are making a resolution independent into resolution dependent, Need to specify a resolution for rasterizing, that is, how coarse or how fine the sampling. 17
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Aliasing The rasterized image will appear sharp. This jagged effect is called aliasing caused by insufficient sampling Original vector graphics Rastered vector graphics without anti-aliasing 18
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Anti-aliasing Techniques To soften the edges, we can color the pixels with intermediary shades in the area where the sharp color changes occur. This technique is called anti-aliasing Original vector graphics Rastered vector graphics without anti-aliasing Rastered vector graphics with anti- aliasing 19
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File Size and File Compression
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File Compression Compression is a method for reducing the size if a file by squeezing the same information into fewer bits In lossless compression algorithm, no information is lost In lossy compression, some information is lost
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Why Compression? higher resolution or higher bit depth larger file size Without compression, image files would take up an unreasonable amount of disk space. Larger files take longer time to transfer over the network. 27
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How many bits? Let’s look at the size of a typical high resolution image file without compression. 28
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Suppose 6-megapixel digital camera may produce digital images of 3000 2000 pixels in 24-bit color depth. Total pixels: 3000 2000 pixels = 6,000,000 pixels File size in bits: 6,000,000 pixels 24 bits/pixel = 144,000,000 bits File size in bytes : [ 1 byte = 2 -10 Megabytes ] 144,000,000 bits / (8 bits/byte) = 18,000,000 bytes 17 MB How many bits? 29
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Strategies To Reduce File Sizes Reducing the pixel dimensions Lowering the bit depth (color depth) Compress the file 30
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Reducing Pixel Dimensions Capture the image at a lower resolution in the first place Resample (resize) the existing image to a lower pixel dimensions Returning to our calculation of the file size of an image of 3000 2000 pixels in 24-bit color depth. Let's calculate the file size of an image of 1500 1000 pixels in 24-bit color depth. 31
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How many bits if half the size in each pixel dimension? Total pixels: 1500 1000 pixels = 1,500,000 pixels File size in bits: 1,500,000 pixels 24 bits/pixel = 36,000,000 bits File size in bytes: 36,000,000 bits / (8 bits/byte) = 4,500,000 bytes 4.3 MB It's 1/4 th of the file size. 32
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Lowering the Bit Depth Bit depth determines the number of distinct colors available in the image Returning to our calculation of the file size of an image of 3000 2000 pixels in 24-bit color depth. Let's calculate the file size of an image if we reduce the bit depth to 8- bit. 33
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How many bits if reduced to 8-bit? Total pixels: 3000 2000 pixels = 6,000,000 pixels File size in bits: 6,000,000 pixels 8 bits/pixel = 48,000,000 bits File size in bytes: 48,000,000 bits / (8 bits/byte) = 6,000,000 bytes 5.7 MB It's 1/3 rd of the file size. 34
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24-bit vs. 8-bit 24-bit: 2 24 (about 16 million) colors 8-bit: 2 8 (about 256) colors 24-bit 8-bit: You lose about 16 million colors!
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  • Summer '18
  • north
  • Pixel, RGB color model, Color space, Portable Network Graphics

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