Lossy compression is all about removing information that is not vital to the image or sound. If you have an 8 × 8 array of pixels (i.e., the normal image) it is impossible to easily remove information to compress the image. If an image is transformed into DCT coefficients, the data becomes ordered in the sense that the 64 DCT coefficients are arranged from 1 to 63 with 0 being the D.C. coefficient (the average luminance) and the other coefficients corresponding to horizontal and vertical waves of increasing frequency. The highest numbered coefficients are the highest visual frequencies and these often tend to be low values (if you photograph a sky with little detail, there are no high?frequency visual components). Consequently, you can sometimes reduce these coefficients to zero with
little effect on the image.
What will be an ideal response?
Multimedia applications tend to have relatively small wordlengths; typically, 8?, 12?, or 16?bits. Moreover,
processing often involves identical operations being applied to a block of data. Suppose you have an image with one million pixels and you are enhancing its contrast by taking the actual range of 8?bit pixels, which may range
from intensities of 40 to 200, and scaling them to the full range of 0 to 255. Clearly, you can scale all one million
pixels in parallel. In practice, SIMD operation lets you take, say, eight 8?bit pixels in a register and apply eight
operations on them in parallel.
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In the accompanying image of a Microsoft Word 2016 document, which of the following boxes points to the Undo button??
?
A. ?Box A B. ?Box B C. ?Box C D. ?Box D
You are one of the first to arrive on a scene and you are asked to perform live memory capture on a machine reporting 4GB of RAM. Upon completion, the size of your actual image file is closer to 5GB. What happened? Did you mess up the memory capture?
a. Yes b. No. The way a computer system works is to report only available memory. Memory in use is not reported. c. No. The 4GB reported is RAM. The utility you used to capture system memory also was able to capture some of the device cache memory on the system. d. No. Most Windows machines "reserve" approximately 20% of system memory for its own use.
?______________________________ is also known as very high-speed DSL and very high bit-rate DSL.
Fill in the blank(s) with the appropriate word(s).
In a troubleshooting situation, a modem failed to work when a replacement USB cable was installed. Which of these critical questions would likely lead a troubleshooter to the source of the modem failure?
A. Have you ever had this problem before? B. Has the modem ever worked? C. Is the problem repeatable? D. Have you made any recent changes to your PC?