What Is a Dome Camera?

The dome camera, as its name implies, is a hemisphere, which is named only for its shape. Due to its small size and beautiful appearance, the dome camera is more suitable for office and high-grade decoration. The dome camera is composed of a camera, an automatic iris manual zoom lens, a dome with excellent sealing performance, and a precise camera mounting bracket. The biggest feature is its compact design, beautiful appearance and easy installation. ^[1]

Dome camera

The dome camera, as its name implies, is a hemisphere, which is named only for its shape. Due to its small size and beautiful appearance, the dome camera is more suitable for office and high-grade decoration. The dome camera is composed of a camera, an automatic iris manual zoom lens, a dome with excellent sealing performance, and a precise camera mounting bracket. The biggest feature is its compact design, beautiful appearance and easy installation. ^[1]

lens

Dome cover

base

Camera plate holder (adjust the tilt)

Video interface

Power interface (DC12V)

Case mounting holes

Camera horizontal angle screw (adjust level) ^[2]

CCD hemisphere cameras can be roughly divided into the following categories:

Divided by imaging color

(1) Color camera: It is suitable for identifying the details of scenes, such as the color of clothing or scenes. The amount of information increases due to the color, which is generally considered to be 10 times that of a black and white camera.

(2) Black and white camera: It is used in areas with insufficient light and areas where lighting equipment cannot be installed at night. When only monitoring the position or movement of the scene, a black and white camera with a resolution higher than that of a color camera can be selected.

Divided by dome camera resolution

(1) Low-grade image pixels with about 250,000 pixels (pixels), color resolution of 330 lines, and black and white resolution of about 420 lines.

(2) Mid-range type with image pixels between 250,000 and 380,000, color resolution of 420 lines, and black and white resolution of 500 lines

(3) Images with a resolution of more than 380,000 dots, a color resolution of 480 lines or more, a black and white resolution, and a high resolution of 570 lines or more.

Divided by Hemispherical Camera Sensitivity

(1) Ordinary type: the illumination required for normal work is 1 ~ 3Lux

(2) Moonlight type: the illumination required for normal work is about 0.1 Lux

(3) Starlight type: The illumination required for normal work is below 0.01 Lux

(4) Infrared illumination type: In principle, it can be zero illumination and use infrared light source for imaging.

Divided by the size of the CCD target surface of the camera element of the dome camera

(1) 1 inch target surface size is 12.7mm wide x 9.6mm high, 16mm diagonal

(2) 2 / 3inch target surface size is 8.8mm wide x 6.6mm high, 11mm diagonal

(3) 1 / 2inch target surface size is 6.4mm wide x 4.8mm high, 8mm diagonal

(4) 1 / 3inch target surface size is 4.8mm wide x 3.6mm high, 6mm diagonal

(5) 1 / 4inch target surface size is 3.2mm wide x 2.4mm high, 4mm diagonal

(6) 1 / 5inch is under development and no official product has been launched. In addition, CCD hemisphere cameras are divided into PAL and NTSC systems. They can also be divided according to image signal processing methods or hemispherical camera structures.

IR Dome Camera

Hemispherical camera refers to manual camera with dedicated auto iris

1, color reproduction

Color reproduction refers to the degree of consistency between the color of the color photographic frame and the color of the original scene after the scene is shot. Factors affecting color reproduction include the quality of the photographic lens, the color temperature of the light,

1. Familiar with product performance

After getting the dome camera product, the engineer and user should be familiar with the technical parameters of the product, such as what is the input voltage, how much power is there, and what is there?

Function, etc., try to be aware of.

2. Check

Check and adjust the dome camera before installation to make the camera in normal working condition.

3. Installation method

Before construction, it can be installed by wall or ceiling according to the environment, safety, and aesthetics.

4.Installation angle

The installation angle of the dome camera directly affects the range of the surveillance image, so it needs to be operated more according to the actual needs during installation. If installed in small

When the area entrance is less than 6 meters, the angle of the camera is preferably 30 ° -60 °; if it is installed at the checkout counter, the angle of the camera should be considered within ± 15 ° -20 °

Wait. In short, the camera avoids the occurrence of backlighting as much as possible, so as to meet the customer's requirements as much as possible.

5. Processing of video interface

The video signal output port, power input port, and control signal port of the dome camera are more important. It should be waterproof and oxygen-proof as much as possible during installation.

Processing. In order to avoid the phenomenon of instability, uncontrollability, and even no display in the future.

Dome cameras generally require 24 hours of uninterrupted work. Therefore, maintenance of the dome camera can extend the life of the camera and ensure the stability of the camera's image effects. Pay attention to the following points.

· Pay attention to the stability of the voltage of the dome camera, otherwise it will affect the image effect and even cause the camera to be damaged;

Check the wires frequently for damage and aging to avoid abnormal situations;

· Try to avoid direct sunlight or strong light for a long time to avoid damage to the camera CCD;

· The dome camera needs to be cleaned frequently, such as cleaning the dust on the surface of the camera's case frequently, try not to open the case, if it needs to be opened, cut off the power first; · Establish the dome camera file for easy inspection and detection in the future. ^[3]

Problem one: the color distortion and color cast of the infrared dome camera may be improper white balance switch (AWB) setting, or the ambient lighting conditions may change too much. At this time, you should check whether the switch is set to the OFF position and try to improve the ambient lighting. condition.
Problem 2: The night vision infrared hemisphere camera has normal images during the day and whitish at night. This phenomenon is generally caused by reflective objects in the machine's use environment or in a small area. It is caused by infrared light reflection. To resolve this phenomenon, first determine whether the use environment If there are reflectors, try to improve the use environment as much as possible, and then check whether the effective infrared distance of the machine corresponds to the actual use distance; if a long-range infrared machine is used in a small space, the machine's image will become white due to excessive infrared light.
Problem three: The infrared dome camera series machines have poor image illuminance, whitening or bright white aperture at night. It should be said that the phenomenon is caused by improper assembly of the machine. The distance between the photosensitive device (photoresistor) and the infrared dome camera during assembly will cause Incomplete startup of the infrared light causes poor illumination of the machine at night; the phenomenon of white or bright white aperture in the image is mainly caused by the infrared light emitted by the infrared light tube refracted to the lens through the dome cover. To solve this problem, it is necessary to avoid infrared light refracting to the lens surface. Generally, a sponge ring is used to isolate the lens from infrared light. When assembling, the ball cover must be close to the sponge ring.
Question 4: Several black vertical bars or horizontal bars are mixed on the screen. This situation usually means that the ripple of the output voltage of the power supply of the machine is too large. It is necessary to strengthen the filtering and use a high-performance DC stabilized power supply.
Question 5: After a long period of unsatisfactory waterproof and heat dissipation effects, more or less soda will appear in the camera (this phenomenon is mainly concentrated in the northern region). The main reason for this phenomenon is the insufficient sealing effect of the casing and The temperature difference is not taken into account when fashion machines. When the infrared lamp starts to work, a large amount of heat is generated, and at the same time, the heat dissipation effect of the casing is not enough, which will greatly reduce the service life of the camera. To solve this problem, consider making the casing of the infrared dome camera into multiple wire grooves. Conducive to heat dissipation.
Question 6: The color reproduction during the day is not enough. I do nt know if you have noticed that the color of the infrared dome camera will be more or less discolored during the day. The most direct reason is the problem of the camera filter. Generally, the infrared dome camera is transparent. A double-peak filter that passes a certain proportion of infrared light has the advantage of low cost, but because natural light contains more infrared components, it will interfere with color reproduction when it enters the CCD, such as green plants turning gray and so on (have The sunny environment outside the city is particularly noticeable). The use of the IRCUT dual filter effectively solves this problem. The IRCUT dual filter is composed of an infrared cut filter and a full-spectrum optical glass. When the daylight is sufficient, the infrared cut filter works and the CCD is restored. The true color is displayed. When the night light is insufficient, the infrared cut-off filter is automatically removed, and the full-spectrum optical glass starts to work, so that the CCD makes full use of all the light, thereby greatly improving the infrared performance.
Question 7: There is no image in the infrared dome camera. First check whether the polarity of the external power supply is correct and whether the output voltage meets the requirements (power supply error: DC12V ± 10%, AC24V ± 5%), and then check whether the video cable is in good contact; if using a manual aperture The lens needs to check whether the aperture is open, and the automatic aperture lens needs to adjust the LEVEL potentiometer to make the aperture in the appropriate position.
Problem eight: The image quality of the infrared dome camera is not good a. Check whether the lens has fingerprints or is too dirty;
b. Check whether the aperture is adjusted properly;
c. Check the video cable for bad contact;
d. Check if there is any problem with the electronic shutter or white balance setting;
e. Check if the transmission distance is too far;
f. Check whether the voltage is normal;
g. Check whether there are interference sources nearby;
h. Check to ensure insulation with the elevator from interference when installing in the elevator;
i. Check whether the CS interface is connected correctly.
Problem 9: The image of the infrared dome camera is distorted or geometrically distorted. This phenomenon may be a problem with the geometric correction circuit of the infrared dome camera or monitor or a problem with the optical lens. It may also be the characteristic impedance of the video connection cable or device and the infrared hemisphere. The output impedance of the cameras does not match.
When the above phenomenon occurs, please check whether the optical lens used is abnormal and the input impedance switch of the monitor is set at 75, and then check whether the impedance of the video connection cable used is 75.

First of all, from the selection of equipment, engineers and users should try to use mature equipment on the market and elevator-only dome cameras with strong anti-interference ability. At the same time, use the dedicated cable of the elevator when wiring. Be careful not to break the cable. As far as possible, use the monitoring power interface reserved by the elevator in the camera's power consumption to prevent accidental leakage; and in the normal mode, the interference problem cannot be solved, and anti-interference measures can be considered in the transmission line.

Most elevator monitoring systems are built in a wired transmission mode using analog signals. They are connected and displayed on the display platform in the monitoring room. As for the display position, there are no special requirements. According to the user's needs, it is displayed in a prominent and easy-to-view position. can.

Due to the small space of the elevator and crowded personnel, once an accident is difficult to rescue, you should pay attention to strict operating procedures and installation specifications when installing surveillance cameras; do not connect or pull irrelevant cables, and the line interface must meet the specifications. Do not overlap randomly; the quality of the products used should be as reliable as possible (such as cameras, transformers, cables, etc.), and relevant test reports and certificates must be available. In this way, the occurrence of various accidents can be reduced.

In addition, the longer the video line is, the greater the possibility of clutter signals to interfere with the video, and the quality of the video signal transmission will decrease; in some large industrial areas, where centralized monitoring is required, this analog signal transmission System will be ineffective. At this time, engineers and users can use digital signal transmission mode to reduce signal interference and simplify wiring, or use wireless transmission to eliminate the tedious things of construction wiring.