17-02-2010, 11:13 PM
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17-02-2010, 11:13 PM
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18-02-2010, 04:51 PM
High-definition television ( HDTV) refers to video having resolution much higher than traditional television systems. today HDTV is digitally broadcast using video compression.HDTV is a revolutionary technology in the television industry that produces pictures far sharper and clearer than the television most of us use today. High-definition televisions are available in four different display technologies - Projection, Directview Cathode Ray Tube (CRT), Liquid Crystal Display (LCD) and Plasma.With HDTV, you could also play movies in their original widescreen format without the letterbox "black bars".
Notation: -Frame size in pixels is defined as number of horizontal pixels × number of vertical pixels, -Scanning system is identified with the letter P for progressive scanning or I for interlaced scanning. -Frame rate is identified as number of video frames per second. The color is an aspect of the HDTV that hasn't received a naming standard. Together , the 24 total bits defining color yields under 17 million possible pixel colors. Equipment and Signal: An antenna: Depending on your location relative to the stations you want to watch, a set of rabbit ears might do, but you might need a rooftop or attic antenna. Cable: a set-top cable box or a CableCARD„¢ to allow your television to receive and decode the cable HDTV signal. Satellite service: You may need a different satellite dish and tuner to receive HDTV signals via satellite. Types of media: Standard 35 mm photographic film used for cinema projection has higher resolution than HDTV systems, and is exposed and projected at a rate of 24fps.Non-cinematic HDTV video recordings intended for broadcast are typically recorded either in 720p or 1080i format as determined by the broadcaster. Recording and compression: HDTV can be recorded to D-VHS to an HDTV-capable digital video recorder. Some cable boxes are capable of receiving or recording two or more broadcasts at a time in HDTV format, and HDTV programming. The data involved are massive. A Hauppauge 1212 Personal Video Recorder is used for this purpose. This device accepts HD content through component video inputs and stores the content in an uncompressed MPEG transport stream (.ts) file or Blu-ray format .m2ts file on the hard drive. digital HDTV signal conversion to MPEG-2 compressed signal in real time is prohibitively expensive. For further details, visit these links: http://en.wikipediawiki/High-definition_television http://electronics.howstuffworkshdtv.htm http://mansci.journal.informscgi/content...39/11/1319
27-07-2011, 02:13 PM
HDTV.ppt (Size: 3.13 MB / Downloads: 106) DEFINITION: HDTV is generally recognized as a digital video broadcast with a minimum resolution of 1280 pixels wide and 720 pixels high, a rate of 30 or more frames/second and usually an aspect ratio of 16:9. A standard definition analog television uses a cathode ray tube with an electron gun to guide the path of an electron beam to “paint” 480 vertical lines across the face of the screen. Each time the beam strikes a dot of phosphor, light is produced. For a color television set, each spot consists of a group of three phosphor elements; one for each primary color. Analog To Digital Conversion Signals in the real world are analog: light, sound, you name it. So, real-world signals must be converted into digital, using a circuit called ADC (Analog-to-Digital Converter), before they can be manipulated by digital equipment
03-09-2012, 03:08 PM
HDTV hdtv.pptx (Size: 1.14 MB / Downloads: 58) INTRODUCTION HD IS DESCRIBED FROM THE LATE 1930s. HIGH DEFINITION TELEVISION . DIGITAL TV BROAD CASTING FORMAT. PROVIDES MUCH BETTER RESOLUTION THAN CURRENT TV. HD TV HAS 1 OR 2 MILLION PIXELS . HD HAS SUPERIOR RESOLUTION AND DIGITAL SURROUND SOUND. HISTORY OF HDTV In the US, the national television system committee(for which the NTSC standard is named) standardized on 525 lines at 30fps 1940, with regular broadcasts starting on July 1,1941. NTSC standard was update to introduce first a non-compatible 441 line color standard in 1950 which was replaced by a compatible 525 lines, 29.97fps color standard approved in 1953 and used to this day. Current high definition video standards were developed during the course of the advanced television process invented by the federal communications in 1987, at the request of American broad-casters. FCC process, led by the advanced television system communication(ATSC) adopted a range of standards form a interlaced 1080 line video with a particular frame rate of 30fps, and 720 line video, progressively scanned, with a maximum frame rate of 60fps. The FCC officially adopted the ATSC transmission standard( which include both HD and SD video standards) in 1996, with a first broadcast on October 28,1998. 720p VS 1080i : 720p signal is made up of 720 horizontal lines. Each frame is displayed in its entirety on-screen for 1/30th of a second. This is know as progressive scan (hence the 'p'). The quality is like watching 30 photographic images in second on TV. .A 1080i signal comprises 1080 horizontal lines but all the lines are not displayed on-screen simultaneously. Instead, they are interlaced (hence the 'i'), i.e. every other lines is displayed for 1/60th of a second and then the alternate lines are displayed for 1/60th of a second. So the frame rate is still 30 frames per second, but each frame is split into two fields, which your brain then puts together subconsciously. CONCLUSION: The image quality improvements brought by high-definition TV has been well received and generates great demand in the consumer market. Consequently, a similar trend can already be seen in the traditional video surveillance market. HDTV-compliant network cameras deliver a resolution, color representation, 16:9 aspect ratio and frame rate that are in accordance with international standards, making them an appealing solution in surveillance situations that require high quality images. |
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