Posts Tagged ‘ digital video camera monitoring and recording’



LCD Video Camera Monitor

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Wednesday, June 22nd, 2011

Most digital video security systems today are designed for use with an LCD video camera monitor.  There are a few reasons for this, but there are also reasons why it may be difficult to use an LCD monitor.  In the following article will discuss LCD monitors how they differ from CRT (Cathode Ray Tube) monitors and some of the advantages of using them instead of a CRT.

First of all, to understand the difference that exists between the two types of monitors let’s briefly discuss how each one works.  The CRT monitor receives an analog radio frequency signal that contains the information for drawing a picture on the front of the CRT or screen.   The CRT shoots horizontal beams of light back and forth from behind the screen very rapidly.  If your camera is a 500 TVL (TeleVision Line) camera and your CRT monitor screen is made up of 500 horizontal lines or more, then you’ll see every bit of the video image that is sent to the CRT in good detail.

In other words, the analog resolution measurement as it pertains to non-digital hardware is the TVL.  The higher the number the TVL the higher the resolution of the picture display.  A 500 TVL display means there are 500 horizontal lines (created by the ray of beams from the CRT).  This obviously will show less detail than say a 380 TVL of the same image.

Remember too that these lines can vary in size from monitor to monitor.  A 19 inch monitor will have much finer (thinner) lines than a 32 inch monitor.

Also, most analog screens have only two types of possible input/output connectors; a 75 ohm cable connector or an RCA plug.  These are a “standard” for analog video connections and are on the backs of most monitors and televisions.

A digital video security camera system Liquid Crystal Display or LCD video camera monitor differs from the CRT type in many ways.  First an LCD monitor is designed for digital input not analog.  This means there are different standards of measurement for the LCD monitor as compared to the CRT.

Another major difference is in the way the LCD video camera monitor displays its images.  Unlike the CRT whose picture consists of horizontal lines, the LCD monitor displays are in pixels.  Pixels are very small dots usually round or square in shape that make up the image and entire LCD screen viewing area.  Like the CRT’s horizontal lines being an indication of resolution or detail, the LCD’s standard for measurement is the pixel.  Keep in mind that pixels vary in size especially from small monitors to large monitors.

However, because these pixels on the average are much smaller than the TVL the LCD video camera monitor automatically makes for a good competitor to the CRT because of the enhanced capability to display a greater resolution or in other words, higher detail.

So the pixel is really the standard of measurement with an LCD video camera monitor.  This can be confusing as well because both resolution and size on an LCD video camera monitor are based on pixel measurements.  For example your monitor may have a screen that is 800 x 600 pixels.  Let’s re-emphasize that the 800 x 600 is the total amount of pixels available for displaying an image.

The image could be 340 x 280 pixels, so what does that tell us?  Basically it tells us the SIZE of the image–on your monitor or anyone else’s, the image will be 340 x 280 pixels.  (Remember that earlier we said pixel size can change with total screen size.)  The actual resolution or detail hasn’t been stated yet but generally speaking, the greatest resolution that can be obtained on an LCD Video Camera Monitor is 96 dpi or dots per inch.

So 96 dpi is actually the resolution.  Any image viewed on the monitor with a resolution greater than 96 would be wasting information.

To summarize then, a CRT monitor’s resolution is displayed as TVL or horizontal lines; the more the TVL the more detailed the picture.  High definition monitors and TV’s display 1080 TVL.  An LCD video camera monitor’s resolution is usually around 96 dots per inch.  The pixel measurement, such as 800 x 600 tells how big the image is but not what the resolution is.

So when shopping for an LCD video camera monitor be sure to keep these things in mind to make sure you get the type/size you need.

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Spy Camera CCTV

Written By:
Thursday, December 2nd, 2010

Covert digital video camera monitoring and recording is sometimes referred to as spy camera CCTV. Although the term “spy” may conjure up images of secret agents, under cover operatives and the like, a spy camera CCTV system can have very practical applications suited for every day residential and commercial applications.

It is possible to describe process of digital video monitoring and/or recording as either overt or covert. Overt digital video systems operate without an attempt to disguise or hide the equipment in any manner. In fact, many systems are installed in such a way as to be obvious, since there is an added advantage of deterrence of criminal acts associated with video security systems.

However, there are many applications where the process of digital video monitoring and/or recording is required without the subject being aware of the presence of any video security equipment. These are called covert video systems or spy camera CCTV (Closed Circuit Television). Sometimes the interpretation of the words “spy camera” are so loosely interpreted that some use it to mean any type of video security type camera.

The acronym “CCTV” in spy camera CCTV is basically a term that originated to describe or differentiate the system from an “open” broadcast system. When video cameras were first used for security systems, the cameras were analog cameras that were basically miniature versions of the video cameras used in television stations to record live shows and newscasts. Television cameras however, sent their signal to a powerful transmitter and antenna that openly broadcast the video to anyone that could receive it (owned a television).

Video security systems including modern digital video security systems send their video signals via a video transmission cable, usually an RG-59 type coaxial cable. These cables carry the signal from each camera to the video recorder or Digital Video Recorder (DVR) and are not openly broadcast, hence the term “Closed” Circuit Television. Spy camera CCTV is covertly designed video monitoring and recording that is wired in a closed circuit.

With ever increasing technological advances, including wireless digital video cameras and Internet Protocol (IP) ready cameras, it may be necessary to broaden the definition of CCTV a bit. Since these cameras do broadcast a signal using radio waves or utilize the Internet as a networking medium, it is difficult to say they are working in a closed circuit. However, the intent is still the same and that is; the video signal is only intended for a specific receiver or receivers and is not intended for open broadcast to the public.

Spy camera CCTV systems today are exceptionally good and disguising or hiding themselves. That’s because the digital video cameras have been able to take advantage of the tremendous technological innovations in computing and electronic circuitry. Sensors, lenses, and Integrate Circuit (IC) chips can be integrated into unusually small packages making the camera easy to hide or disguise.

For example, Security Camera King offers an ink pen (our product # HC-PEN) or a wrist watch (our product # HC-WATCH) that contain a color spy camera CCTV complete with a color video camera, audio recording, and a Digital Video Recorder or DVR!

Other spy camera CCTV systems may include several hidden or disguised cameras or a combination of covert and overt camera types. Security Camera King offers a huge selection of spy camera designs including cameras disguised as:
• Wall clocks;
• Exit signs;
• Buttons;
• Screw heads;
• Speakers;
• Telephones; and
• Many other objects.

These cameras can be connected to typical digital video monitors and DVRs to create custom designed spy camera CCTVs. Not only have these systems benefited from technology that permits them to be incredibly small, but they have also benefited from technology to improve in function.

For example, there are two different types of electronic sensor chips used in digital video cameras today that transfer the light from images into electrical energy that can be used to create video images. Not only can these sensor chips create video images, but they are inherently able to detect infrared light (light that the human eye cannot see) as well. With the proper filters and lights, these cameras can record video in total darkness conditions.

If you are looking for specific type of spy camera CCTV check out Security Camera King’s wide selection of cameras and equipment. Spy cameras and equipment can be found by clicking on the left hand side of our web pages, “Security Cameras” then “Hidden Security Cameras” or “Hidden Camera Systems.”

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