University of Pitesti
Dolnośląska Wyższa Szkoła Przedsiębiorczości i Techniki
w Polkowicach
Television
Simedre Mirel-Adrian
Dr inż. ZDZISŁAW PÓLKOWSKI
Polkowice, 2015
What isTelevision?
• Television is a way of sending and receiving moving images and
sounds over wires or through the air by electrical impulses. The big
breakthrough in technology was the ability to send sound and
pictures over the air. The word television comes from the Greek
prefix tele and the Latin word vision or “seeing from a distance.” The
TV camera converts images into electrical impulses, which are sent
along cables, or by radio waves, or satellite to a television receiver
where they are changed back into a picture.
• As with most inventions, television’s development depended upon
previous inventions, and more than one individual contributed to the
development of television, as we know it today.
http://www.knowitall.org/kidswork/etv/history/television_inv/
The Birth of Television
• Electronic television was first successfully demonstrated in San Francisco
on Sept. 7, 1927. The system was designed by Philo Taylor Farnsworth, a
21-year-old inventor who had lived in a house without electricity until he
was 14. While still in high school, Farnsworth had begun to conceive of a
system that could capture moving images in a form that could be coded
onto radio waves and then transformed back into a picture on a screen.
Boris Rosing in Russia had conducted some crude experiments in
transmitting images 16 years before Farnsworth's first success. Also, a
mechanical television system, which scanned images using a rotating disk
with holes arranged in a spiral pattern, had been demonstrated by John
Logie Baird in England and Charles Francis Jenkins in the United States
earlier in the 1920s. However, Farnsworth's invention, which scanned
images with a beam of electrons, is the direct ancestor of modern
television. The first image he transmitted on it was a simple line. Soon he
aimed his primitive camera at a dollar sign because an investor had
asked, "When are we going to see some dollars in this thing, Farnsworth?"
https://www.nyu.edu/classes/stephens/History%20of%20Television%20page.htm
How Television Works?
• The first principle is this: If you divide a still image into a
collection of small colored dots, your brain will reassemble the
dots into a meaningful image. This is no small feat, as any
researcher who has tried to program a computer to understand
images will tell you. The only way we can see that this is actually
happening is to blow the dots up so big that our brains can no longer
assemble them.
• The human brain's second amazing feature relating to television is
this: If you divide a moving scene into a sequence of still
pictures and show the still images in rapid succession, the brain
will reassemble the still images into asingle, moving scene.
http://electronics.howstuffworks.com/tv2.htm
Additive Color: the RGB Color System
• If we are working on a TV, the colors we see on the screen are
created with light using the additive color method. Additive color
mixing begins with black and ends with white, meaning that as more
color is added, the result is lighter and tends to white.
The RGB color system is an example the light primaries and creates
color with light. Percentages of red, green, & blue light are used to
generate color on a computer screen. The basic colors of light are
red, green and blue.
http://facweb.cs.depaul.edu/sgrais/colorlarge.htm
Subtractive Color: Red Green Blue
• Subtractive color is created when light is reflected off a surface.
Pigment colors are created through such reflected light. As with the
actual red apple, a painted red apple appears when the red
wavelengths of light are reflected while the other colors are
absorbed.
• When we mix colors using paint, or through the printing process, we
are using the subtractive color method. Subtractive color mixing
means that one begins with white and ends with black; as one adds
color, the result gets darker and tends to black.
• In subtractive color, red, yellow and blue are the 3 basic primary
colors. These primaries are the pure colors which can not be
created by mixing any other colors. Secondary hues are the result of
mixing any of the two primaries. Tertiary colors result from mixing
the secondary hues.
http://facweb.cs.depaul.edu/sgrais/colorlarge.htm
Color Television History
• The Development of Color Television
A German patent in 1904 contained the earliest recorded proposal
for a color television system. In 1925, Zworykin filed a patent
disclosure for an all-electronic colour television system. Both of
these systems were not successful, however, they were the first for
color television. A successful color television system began
commercial broadcasting, first authorized by the FCC on December
17, 1953 based on a system designed by RCA.
• "Between 1946 and 1950 the research staff of RCA Laboratories
invented the world's first electronic, monochrome compatible, color
television system." - From IEEE Milestone Plaque.
• quite true to life, the first program was a success.
http://inventors.about.com/library/inventors/blcolortelevision.htm
Inventors and Their Contributions
• Charles Francis Jenkins - In May of 1920,
Jenkins introduced prismatic rings that would
replace the shutter on a film projector (Early
Television Museum).
• Allen B. DuMont - In the 1920’s, DuMont
developed a cheaper version of the cathode
ray tube (CRT), which would last for thousands
of hours - much longer than the German
version of the CRT, which would only last for
25 to 30 hours (Early Television Museum).
http://www.physlink.com/Education/AskExperts/ae408.cfm
• Vladimir Zworykin - In December of 1923, Zworykin
applied for a patent for the iconoscope, which would
scan pictures to produce images. He later developed
a new tube called the kinescope, which is the basis of
modern day televisions. The first entirely electronic
television system was formed using these two
inventions (Early Television Museum).
• John Logie Baird - In 1924, Baird was able to transmit
simple face shapes using a mechanical television
(Early Television Museum).
• Dr. E.W. Alexanderson - On June 5, 1924,
Alexanderson was able to transmit a facsimile
message across the Atlantic Ocean for the first time.
In 1927, Alexanderson used high frequency neon
lamps and a perforated scanning disk to demonstrate
the first home reception of the.
http://www.physlink.com/Education/AskExperts/ae408.cfm