Security, surveillance camera: How to choose?

Why I need a Pinhole Camera?

Pinhole camera may come with audio or without audio and can be used for a wide variety of purpose in office or at home, for security, surveillance or fun. Pinhole camera is an ideal discreet surveillance camera for the office or home security system, and a must tool for the novice or professional detective. Use it as a nanny camera when you are away from home to make sure that your children or elderly family members are properly taken care of. Installed in the office or the store room, the pinhole camera can monitor whether anyone enters your office or store in your absence. Some surgeons may use the wireless camera with their headlight systems to record their surgery operations on video tapes for teaching or recording purposes.

What is a Pinhole Camera?

A pinhole camera is a video camera with micro lens (pinhole, 1~2 mm viewing diameter). The camera can be as small as 18mm x 18mm x 18mm. Due to the small viewing diameter, pinhole camera can film through very small holes and light-weaved clothing. A pinhole camera will give a real time video image similar to that produced by a camcorder. A pinhole camera may come with audio or without audio capability. You need to connect this camera to the video-in/audio-in connectors of a viewing or recording device such as TV, monitor, VCR, camcorder, computer etc. Pinhole camera is used when a standard security camera is not appropriate for the environment or you wish to hide the camera. You may hide the whole camera inside any object except the pinhole lens opening, which needs to be exposed to the scene where you want to take the video. Basically, the camera can be hidden inside any objects such as clocks, radios, tissue boxes or other household, office items or body worn. This keeps the camera covert for surveillance purpose. There are basically two types of connection between the pinhole camera to the display or recording device: wired and wireless.

How to install Wired Camera

For a wired system, you need to connect the camera to your display/recording device (TV, VCR etc.) by means of a RCA cable (or a coax cable). Depending on the model you order, there are 3 cables with RCA connectors coming from the camera: the DC power wire, and the other two for video and audio respectively. Plug the video and the audio connectors to the RCA video-in and audio-in jacks at the back of your TV or VCR. Then connect the power wire to the included power supply, which then be connected to the AC power source. If AC power is not available at the location where you want to install the camera, you may use the included battery box or connector to connect the camera to a 9V battery. For longer battery life, you may connect the camera to a high capacity Sealed Lead Acid rechargeable battery

How Wireless Camera Works

For a wireless system, connection between the camera and the display device is done by a transmitter and a receiver. The wireless system consists of a camera, a transmitter and a receiver. Though our pinhole camera is so small, we build in the video/audio transmitter inside some of our models of pinhole camera! The transmitter sends the video & audio signals about 300 feet~5 miles away (depending on which camera model) to a small receiver. The receiver can be easily connected to a TV, monitor, camcorder or standard VCR. Your may view the video live or record it on a regular VHS cassette tape up to a duration of 8 hours.  The camera can be hidden inside an object like a clock radio, air filter or CD player etc. Most wireless systems in the market do not include audio capability. There are many models of our wireless camera providing both video and audio transmission. Please make sure you choose the right product.

In all the standard TV, VCR or monitor, you'll find an RCA video-input along with an audio-input usually located at the rear of the unit.

What is Camera Resolution meant?

Resolution is a measurement unit of the camera's clarity. A cameras resolution is determined by the number of horizontal video lines (320~600 lines) that the camera needs in order to reproduce the desired image. The higher the resolution number, the sharper the image will be.

LUX--How it affects picture quality

The illumination factor LUX (1/10 of a foot candle) is a standardized unit to measure a camera's sensitivity to light. The lower the number, the less light it will need to reproduce a clear image. A camera with a LUX of 1 means it can see an image during early evening hours or just before dusk. A camera with 0.5 LUX has the ability to see an image in a dimly lit corridor. A 40W fluorescent lamp will provide sufficient indoor light for a camera with 2 LUX. With the help of infrared light, camera can work with 0 LUX, i.e., under total darkness, even better than the human eyes! 

What does it mean by LOS (line of sight)

LOS refers to the distance between the AV transmitter and the receiver in open space (line of sight). There are a number of factors that may affect the operating range in actual environment. If there are walls, partitions or other obstacles between the transmitter and the receiver, the effective transmission distance will be much much shorter. The effective transmission distance for clear video/audio signals depends on the structure of the walls, partitions or other obstacles between the transmitter and the receiver. For example, a steel-embedded wall will shorten the effective distance more than a wooden wall. Strong radio frequency of similar range in the area will also adversely affect the operating range. In order to improve signal reception, try to place the transmitter with its antenna upright and put it in a higher position than the receiver whenever possible. Changing the transmitter to different locations may also get a better result. Using a high-gain antenna for the transmitter or receiver will definitely improve the signal transmission/reception.

What are CCD and CMOS image sensors? What are the impacts on choosing the camera?

Both CCD (Charge coupled device) or CMOS (Complimentary Metal-Oxide Semiconductor) image sensors are electronic devices that use a variety of technologies to transform an image (light pattern) into an electric image (electronic charge pattern). In the process of reading the value in the image, CCD sensors create high-quality, low-noise images. While CMOS sensors, traditionally, are more susceptible to noise.

In the conversion and reading processes, CCDs consume lots of electric power. CMOSs operate on lower voltage and therefore consume much less power. The difference in consumption is as much as 100 times. Accordingly, CMOSs have much longer battery life than CCDs.

CCD sensors have been in mass production for a long period of time and therefore a more mature product than CMOS sensors. CCD sensors tend to produce higher quality and more pixels. As a result, the images produced by CCD sensors are much better than those from CMOS sensors.

The third major difference between these two sensors is that the manufacturing costs of CMOS is much less expensive than CCD.

Based on these differences, you can see that CCDs tend to be used in cameras that focus on high-quality images. CMOS sensors tend to have lower quality, lower resolution and lower sensitivity.
There is a trade-off between higher image quality but higher power consumption (CCD) compared with lower image quality but longer power consumption (CMOS).

How to choose a camera for security purpose?

There are lots of hidden camera in the market. Which one is suitable for you? These cameras may come with or without audio capability. Make sure you choose the one to suit your needs. Hidden camera basically includes (1) Pinhole Camera. Some are as small as a sugar cube with lens opening of 1 mm. It can be hidden behind any hole larger than 1 mm. (2) Board Camera: A small PC board with built-in mini camera. Suitable for hiding into many objects. (3) Dome Camera: A mini camera is built inside a dome-size plastic obscure protector. Suitable for installation on the ceiling or wall. (4) Standard Surveillance Camera: Visible security camera installed indoor or outdoor to scare away unwanted visitors; (5) Water-resistant Security Camera: Standard surveillance camera with water-resistant protective case. Suitable for outdoor installation. (6) Water-proof Hidden Camera: A small pinhole or mini camera with water-proof case so that it may be put beneath the water, for example, inside a fish tank.

The technology in these models is basically the same for different models, except that the camera may consist of either a CMOS or CCD image sensor, and the product size is also different for different purpose.

Should I buy a color or a B/W camera?

If you use the camera in an environment where the light condition is very low, it is recommended that you should buy a B/W camera. If a color camera is used under low light condition, the video obtained will be close to B/W anyway. Buy a color camera for a better view if the light condition is fair. 

Should I install a Night Vision Projector?

Night Vision Projector is a device sending out invisible infrared light to compensate the light for the camera. Usually, the light requirement for B/W camera is very low. Some light coming from a dim light bulb or a corridor lamp is already sufficient. If you want to take video from a location where the light is very dim or no light at all, then you need to install an Infrared Night Vision Projector, or a camera with built-in infrared lights. If a color camera is used under low light condition (even with infrared night vision device installed), the video obtained will be in black and white only. Please note that our infrared night projector only works with B/W video camera, NTSC or PAL, but not with color video camera. 

Should I buy a Wired Camera or a Wireless Camera?

The advantages of wireless camera are that (a) it is convenient to be installed in those locations where wiring is difficult, if not impossible; (b) it can be moved to different locations easily, as often as you like; (c) it can be hidden inside a moving object like inside your cloth, cap, briefcase or carrying bag etc. The disadvantages are: (a) video stream may be disturbed or influenced by other moving objects or other strong radio frequencies. A wired camera is more stable in this respect. (b) video/audio transmission is limited within the prescribed transmission range. These disadvantages will not occur to a wired camera. 

To overcome the disadvantages of wireless camera, you may:
(a) Buy those wireless models with higher frequency transmission band at least 1.2GHz or above; (b) If you need to take video from the wireless camera a long way from the receiver, or there are walls, metallic or steel obstacles between the wireless camera and the receiver, buy a wireless model with higher transmission power, that is, a transmitter with longer transmission distance; (c) Using a high gain antenna for the transmitter or receiver will improve signal transmission/reception.

Overall, the video/audio signals from a wired camera are more stable than a wireless camera. 

What is Video Standard?

Different areas of the world use different video standards. North America uses NTSC, Europe uses PAL and SECAM, South America uses PAL-M, PAL-N, PAL and NTSC. Almost every area of the world has a mixture of video standards. If your TV/VCR/camcorder support multi-systems, you can use either PAL or NTSC camera. With a multi-system video recorder, you expect an PAL tape to be reproduced as a standard PAL signal, and the same machine if fed with a NTSC tape will reproduce it as a standard NTSC signal. A multi-system VCR can also be expected to make a perfectly normal PAL recording of an PAL input signal, and a perfectly normal NTSC recording of a NTSC input signal.

NTSC and PAL standard are not interchangeable. For example, you can't display video input from a PAL camera on a NTSC only TV.

What is PAL, NTSC and SECAM?

NTSC (National Television Standards Committee) is a standard used in North America and Japan. It has the ability to display up to 525 lines of resolution. PAL (Phase Alternating Line), a standard used almost everywhere else in the world, has the ability to display 625 lines of resolution. SECAM (Sequential Color Memory) is used sparingly around the world and can be found in France, parts of Greece, Eastern Europe, Russia, Africa and a few other parts of the world. However, any SECAM country can display PAL tapes in full color, but not all PAL countries can display all SECAM tapes in color. Only if they are true SECAM and not MESECAM can those VCR's display SECAM.

Note: You don't need to worry about the video standard of our camera because we will supply camera system corresponding to the video standard of your country. Unless it is indicated in the product description that the camera is available for certain video format only, we will ship camera according to the common video format currently used in your country. For example, NTSC camera for orders from United States and Canada. For orders from U.K., we will ship PAL standard camera.  

How to choose a suitable lens for the camera?

Lens with fixed focal length
Choosing a suitable lens for your security camera, you need first to determine how far you want to monitor the scene. A 4mm lens will give a 72 degree visual angle of view for a person's face detail in about 30 feet. This will be adequate for most home or small office surveillance system. Based on this calculation, a 8mm lens will give a 40 degree visual angle and zoom in 2 times of the view in the same distance. Accordingly, a 16mm lens will give a 20 degree visual angle and zoom in about 4 times of the view in the same distance.

Varifocal lens
If you need to change the monitoring distance at times, you may choose a varifocal lens instead of lens with fixed focal length. With a few simple adjustments of the lens, you will be able to zoom in and zoom out and focus a clear picture of the scene. There are various focal ranges offered by the varifocal lens, i.e. 3~8mm, 8~15mm etc.

Auto iris lens
An auto iris lens is a lens that automatically adjusts the lens aperture based on the strength of the incoming light source. If the security camera is installed in the office, you probably don't need an auto iris lens because the light source is stable. If the camera is installed outdoor, you may need an auto iris lens because the light source may change through the day

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