In this project you'll learn about how digital image files are encoded, and how digital images can be compressed so that the files take up less storage space and can be transmitted more quickly. You will also measure the quality of compressed and uncompressed images, which will give you important insights into the tradeoffs between file size and image quality.
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Short (2-5 days)
Good computer skills; Project costs lower
depending on printing method and number of images printed.
Your digital photo comprises a certain number of dots in the x and y directions. What happens to the print image quality as you "stretch" those dots out to larger and larger pictures? (Note: This experiment studies the dots per inch in the image itself, not the number of dots per inch that is output by your printer.)
Students who are mathematically inclined can use the student version of a program like MatLab or Mathematica to convert a digital image into numbers, then perform operations such as sharpening or special effects. This is a great way to learn about image processing algorithms.
A video camera records 30 "frames" or distinct images per second. (That's for an NTSC camera in the U.S. PAL cameras in other areas of the world take 25 frames per second.) You can use this fact to time events and measure velocity. One student has used a video camera to measure the velocity of an arrow shot from a bow.
Make a pinhole projector (see ). Use the pinhole to project an image of the Sun onto a wall or a piece of paper. Do you notice any dark spots on the projected image? Trace the projected image and count the dark spots. Use your pinhole projector to make images of the Sun at the same time of day for several consecutive days. How does the pattern of spots change? Can you use your data to figure out how fast the Sun rotates? Sunspot activity rises and falls with an 11-year cycle. At this…
You can measure the diameter of the Sun (and Moon) with a pinhole and a ruler! All you need to know is some simple geometry and the average distance between the Earth and Sun (or Moon). An easy way to make a pinhole is to cut a square hole (2–3 cm across) in the center of a piece of cardboard. Carefully tape a piece of aluminum foil flat over the hole. Use a sharp pin or needle to poke a tiny hole in the center of the foil. Use the pinhole to project an image of the Sun onto a wall or piece…
The concept of beauty changes over time and often differs among societal groups. How strongly do societal conceptions of beauty shape an individual's self-image? There are many fascinating questions you could choose to explore with surveys on this subject. For example, how well do girls' ideas of what is attractive in boys agree with boys' expectations about what girls find attractive (or vice versa)? Try your survey with different generations to see how conceptions change over time. If you…
The author of this project hypothesized that movies often disappoint readers because book-based movies tend to "dumb down" the works on which they are based (Fuhrman, 2002). Naturally, selective compression is necessary when telling a story as a movie, or no one would sit through it. (Hey, maybe there's an idea for a different experiment!) Selective compression is not necessarily the same, however, as simplification. There are ways to objectively measure the complexity of written language…
Minerals are sometimes precious, like diamonds. But most minerals are very common, like sodium, which is found in salt. How are minerals found and identified? How are our mineral resources distributed? Visit the USGS Mineral Resource Program to find mineral resources in your state. How are satellite images used to identify potential mineral sources? You can also find out how minerals are identified using spectroscopy. How are potentially harmful minerals, like mercury, dealt with? Visit the…
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