Please click on question to show answer…
Hardware Compression: Both Capturing Video Signal and Compressing Video Signal are done by DSP chipset integrated on DVR Board. It doesn’t need the computer’s CPU to do this work. It’s low cost of CPU and RAM resources. In this system the computer CPU’s task focus on answering network request, streaming the video/audio to network and saving recorded data to local hard disk.
Software Compression: The DVR Board only capture video signal but doesn’t compress it, it is the computer CPU and RAM to do this compression work. It’s high cost of CPU and RAM resources. In this system the computer CPU and RAM are often overloaded. It is easier to crash than hardware compression system.
This in general is a comparatively difficult decision. Many aspects of the installation must be taken into consideration in order to obtain the correct performance that meets your requirements.
A high-resolution camera should be considered where greater detail of scene is required. E.g. Color 460 TVL, Monochrome 570 TVL. Choosing a more sensitive camera will improve reproduction in poorly lit areas. The sensitivity of a camera is indicated by the minimum amount of light in order for the camera to produce a usable picture. e.g. Color 1.0 Lux at F1.2.
A conventional camera produces a pale backdrop when an object is shot against a bright background. BLC (Back Light Compensation) will counter strong light sources retaining picture quality.
Concentrated light sources directed towards the camera (e.g. car head lamps) can be inverted by an optional peak white inverter or an eclipser function. This has the effect of bringing detail to areas and making an object clear, that would otherwise be shadowed.
The picture is mixed. While proponents of CCTV are inclined to describe opposition to the technology as marginal, the reality is much less conclusive. In one survey commissioned by the UK Home Office a large proportion of respondents expressed concern about several key aspects of visual surveillance.
The extent of concern was highlighted by the outcome that more than fifty per cent of people felt neither government nor private security firms should be allowed to make decisions to allow the installation of CCTV in public places. 72% agreed “these cameras could easily be abused and used by the wrong people”. 39% felt that people who are in control of these systems cold not be “completely trusted to use them only for the public good”. 37% felt that “in the future, cameras will be used by the government to control people”. While this response could be interpreted a number of ways, it goes to the heart of the privacy and civil rights dilemma. More than one respondent in ten believed that CCTV cameras should be banned.
Another interesting conclusion of the Home Office survey was that 36 per cent of respondents did not agree with the proposition “the more of these cameras we have, the better”. Contrast this with the view of Leslie Sharp, chief constable for the Scotland’s Strathclyde Police Department. Referring to his forces mania for CCTV he told ABC news’ 20/20 program: “We will gradually drive the criminal further and further away, and eventually I hope to drive them into the sea”.
The most crucial element of the Home Office survey was the conclusion that the public were less inclined to unconditionally support CCTV once issues were raised and discussed within groups.