Camera
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The real world is analog. Light and sound come in waves that our senses interpret. Unfortunately it’s difficult to invent a technology that records an analog wave Fortunately, storing a series of numbers is much simpler. You can carve them in stone, write them on paper, or store them on a ! "hen you record, them there’s no loss of data !igiti#ing $ the process of converting something into numbers
Film vs !igital Film and digital cameras record an image by using a lens to focus light onto a focal plane The lens focuses the light through an aperture and a shutter onto a piece of film held on the focal place %n a digital camera, instead of a piece of film, an image sensor sits on the focal plane. An image sensor is a special type of silicon chip with light&sensitive capabilities The most common 'ind of image sensor is called a !, a charge coupled device "hen you ta'e a picture, the image sensor samples the light coming through the lens and converts that light into electrical signals After the image sensor sensor is e(posed, e(posed, these these signals are boosted boosted by an amplifier and and sent to an analog & to digital converter that turns the signals into digits )nce the camera’s on&board computer has calculated the final image, the new image data is stored on a memory card •
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!ay * From +lac' and "hite to olor •
ames ler' -a(well as'ed photographer Thomas utton to ta'e three photographs of the same piece of fabric /e too' three photographs with three different filters0 red, blue and green. Then, o he pro1ected them onto a screen with three different pro1ectors covered in corresponding filters, leading to the first color image 2 in 34567
/ow are colors mi(ed 8ed, green, and blue & the three additive primary colors & can be mi(ed to ma'e other colors. here the colors overlap creates new colors0 cyan, magenta, and yellow. These are the primary colors of in' •
9hotosites, Arrays, %nterpolation and the 9hotoelectric :ffect 9hotographic film is covered with an emulsion of light&sensitive, silver&laden crystals. "hen light hits the film the silver atoms clump together. The more light there is the bigger the clumps The photoelectric effect occurs when some metals release electrons when e(posed to light ;founded by :instein < got him that =oble 9ri#e doh> 9hotosites & the image sensor in your digital camera is a silicon chip that is covered with a grid of small electrodes ;one for each pi(el> +efore you can shoot a picture, your camera charges the surface of the ! with electrons. Than's to the photoelectric effect, when light stri'es a particular photosite, the metal in the site relates some of its electrons •
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+ecause each photosite is bounded by non&conducting metal, the electrons remain trapped. :ach photosite is li'e a little well, strong up more and more electrons as more and more photons hit it After e(posing the ! to light, your camera simply has to measure the voltage at each site to determine how many electrons are there, and, thus, how much light hit that particular site The term ?charge&coupled device@ is derived from the way the camera reads the charges of individual photosites %nterpolation & filling in the missing pi(els ;all digital cameras do it to ma'e color images> :ach photosite on your camera’s image sensor is covered by a filter && red, green, or blue. This combination of filers is called a color filter array A common pattern is the +ayer 9attern Your digital camera will calculate the color of any given pi(el by analysing something They eye is most sensitive to green ;for humans>
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The real world is analog. Light and sound come in waves that our senses interpret. Unfortunately it’s difficult to invent a technology that records an analog wave Fortunately, storing a series of numbers is much simpler. You can carve them in stone, write them on paper, or store them on a ! "hen you record, them there’s no loss of data !igiti#ing $ the process of converting something into numbers
Film vs !igital Film and digital cameras record an image by using a lens to focus light onto a focal plane The lens focuses the light through an aperture and a shutter onto a piece of film held on the focal place %n a digital camera, instead of a piece of film, an image sensor sits on the focal plane. An image sensor is a special type of silicon chip with light&sensitive capabilities The most common 'ind of image sensor is called a !, a charge coupled device "hen you ta'e a picture, the image sensor samples the light coming through the lens and converts that light into electrical signals After the image sensor sensor is e(posed, e(posed, these these signals are boosted boosted by an amplifier and and sent to an analog & to digital converter that turns the signals into digits )nce the camera’s on&board computer has calculated the final image, the new image data is stored on a memory card •
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!ay * From +lac' and "hite to olor •
ames ler' -a(well as'ed photographer Thomas utton to ta'e three photographs of the same piece of fabric /e too' three photographs with three different filters0 red, blue and green. Then, o he pro1ected them onto a screen with three different pro1ectors covered in corresponding filters, leading to the first color image 2 in 34567
/ow are colors mi(ed 8ed, green, and blue & the three additive primary colors & can be mi(ed to ma'e other colors. here the colors overlap creates new colors0 cyan, magenta, and yellow. These are the primary colors of in' •
9hotosites, Arrays, %nterpolation and the 9hotoelectric :ffect 9hotographic film is covered with an emulsion of light&sensitive, silver&laden crystals. "hen light hits the film the silver atoms clump together. The more light there is the bigger the clumps The photoelectric effect occurs when some metals release electrons when e(posed to light ;founded by :instein < got him that =oble 9ri#e doh> 9hotosites & the image sensor in your digital camera is a silicon chip that is covered with a grid of small electrodes ;one for each pi(el> +efore you can shoot a picture, your camera charges the surface of the ! with electrons. Than's to the photoelectric effect, when light stri'es a particular photosite, the metal in the site relates some of its electrons •
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+ecause each photosite is bounded by non&conducting metal, the electrons remain trapped. :ach photosite is li'e a little well, strong up more and more electrons as more and more photons hit it After e(posing the ! to light, your camera simply has to measure the voltage at each site to determine how many electrons are there, and, thus, how much light hit that particular site The term ?charge&coupled device@ is derived from the way the camera reads the charges of individual photosites %nterpolation & filling in the missing pi(els ;all digital cameras do it to ma'e color images> :ach photosite on your camera’s image sensor is covered by a filter && red, green, or blue. This combination of filers is called a color filter array A common pattern is the +ayer 9attern Your digital camera will calculate the color of any given pi(el by analysing something They eye is most sensitive to green ;for humans>
