What are the factors that affect the clarity of the monitor image?

In the security system, the current image generation mainly comes from CCD camera.

CCD of infrared dual CCD camera is the abbreviation of Charge Coupled Device, which can convert light into charge, store and transfer the charge, and also take out the stored charge to change the voltage, so it is an ideal camera element. The CCD camera composed of it is widely used because of its small size, light weight, unaffected by magnetic field and anti-vibration and impact characteristics.

Working mode of CCD camera

The image of the object is focused on the CCD chip through the lens, and the CCD accumulates corresponding charges according to the intensity of light. Under the control of video sequence, the accumulated charge of each pixel is moved out point by point, and after filtering and amplification, a video signal is output. When a video signal is connected to the video input of a monitor or TV, you can see the same video image as the original image.

CCD cameras can be roughly divided into the following categories:

Divided by imaging color

(1) color camera: It is suitable for distinguishing the details of a scene, such as clothes or the color of the scene. Because of the color, the amount of information increases, which is generally considered to be 10 times that of black and white cameras.

(2) Black-and-white camera: suitable for areas with insufficient light and areas where lighting equipment cannot be installed at night. When only the position or motion of the scene is monitored, a black-and-white camera with a resolution usually higher than that of a color camera can be selected.

At present, Sharp and Sony chipsets are mainly used in China. Chip types are:

icx 226 AK cxa 1267 br 9020 f-W2 aa 87222 AP njm 2267m

icx 227 AK cxa 13 10AQ br 9080 f-W2 aa 88347 AP njm 2267v

icx 228 AK cxd 2463 r br 9080 af-W2 njm 2274 r

icx 229 AK cxd 3 142 r br 9020 Fv-W2 ba 7664

icx 254 AK cxa 2096 br 9040 f-W2 mm 15 10

icx 255 AK cxa 2006 q mm 167 1

ICX259AK CXD2 163BR 24C02

ICX259AL CXD2480R 24C 16

ICX258AK CXD24 18R

icx 258 al 520 cxd 3 172 ar+2006

ICX404AK 408 CXD4 103R+2096

ICX405AK RJ24 1 1 sharp scheme

ICX404AL RJ242 1

ICX405AK LR38603

ICX408AK LR3Y48A

ICX408AL LR3Y48B

ICX409AK RJ232 1

ICX409AL RJ23 1 1

ICX642

Icx643 3142+2096+405a-404 Sony solution

ICX638 3 142+2096+227A-226

ICX639

Scheme: 38603+3Y48+ Sharp

Scheme: 3 142+2096+405 Sony.

AL stands for black and white.

Use AK to represent color.

Divided by camera resolution

(1) The image pixel is about 250,000 pixels, the color resolution is about 330 lines, and the black-and-white resolution is about 420 lines.

(2) The number of image pixels is between 250,000 and 380,000, the color resolution is 420 lines, and the black and white resolution is below 500 lines.

(3) The image is more than 380,000 points, the color resolution is more than or equal to 480 lines, the black-and-white resolution is more than 570 lines.

Divided by camera sensitivity

(1) Normal type: the illumination required for normal operation is 1~3Lux.

(2) Moonlight type: the illumination required for normal operation is about 0. 1 lux.

(3) Starlight type: the illumination required for normal operation is below 0.0 1 lux.

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

According to the size of the CCD target surface of the imaging element

The target size of (1)l inch is 12.7mmX 9.6mm high and 16mm diagonal.

(2) The size of the 2/3 inch target surface is 8.8mmX wide, 6.6mm high and the diagonal is11mm..

(3) The size of1/2 inch target surface is 6.4 mm wide, 4.8 mm high and 8 mm diagonal.

(4) The dimensions of1/3 inch target surface are: 4.8mmX in width, 3.6mm in height and 6mm in diagonal.

(5) The size of1/4 inch target surface is 3.2 mm wide, 2.4 mm high and 4 mm diagonal.

(6) 1/5 inch is under development, and the official product has not yet been launched.

In addition, CCD cameras can be divided into PAL system and NTSC system, and can also be divided according to the image signal processing mode or camera structure.

Introduction of monitoring camera parameters

The monitoring camera is used to shoot the monitoring area and convert it into an electrical signal. According to the specifications, it can be divided into 1/3 ",1/2" and 2/3 ",and the installation methods are fixed and desktop with cloud.

Description of basic camera settings:

(1) AGC ON/OFF (automatic gain control): There is a video amplifier in the camera, which amplifies the signal from CCD to a usable level, and its amplification factor is Gain, which is equivalent to high sensitivity. However, in bright lighting environment, the amplifier will be overloaded, which will distort the video signal. When the switch is turned on, the lens aperture is completely opened in the case of low brightness, which automatically increases the gain and obtains a clear image. When the switch is closed, natural and low-noise images can be obtained at low brightness.

(2) ATW ON/OFF: When the switch is turned on, the characteristic/color temperature of the light source is detected through the lens, thereby automatically and continuously setting the white level, and even if the characteristic/color temperature changes, the gain of the red and blue signals can be controlled.

(3) ALC/ELC (Automatic Brightness Control/Electronic Brightness Control): When ELC is selected, the electronic shutter continuously and automatically changes the exposure time of the CCD image sensor according to the brightness of the incident light (generally, it is continuously adjusted from 1/50 to1/000 seconds). When this method is selected, ALC automatic aperture lens can be replaced by fixed or manual aperture lens.

It should be noted that in outdoor or bright environment, ALC lens should be selected because of the limited control range of ELC; Under some unique lighting conditions, the following situations may occur:

(1) There is a strong tailing or blurring phenomenon on high-brightness objects such as spotlights or windows.

(2) The image is obviously flickering, and the color reproducibility is unstable.

(3) The white balance changes periodically. If these phenomena occur, ALC lens should be used.

When using the ELC method with a fixed aperture lens, the depth of field of the image may be smaller than that obtained by using the ALC lens. Therefore, when the camera fully opens the fixed aperture lens and adopts ELC mode. The depth of field will be smaller than when using ALC lens, and distant objects in the image may not be in focus.

When the lens is an automatic aperture lens, you need to turn the switch to ALC mode.

(4)BLC ON/OFF (backlight compensation switch): When strong and useless background light affects the clarity of important objects in the central area, the switch should be turned to the ON position. Note: ① When it is used in cONjunction with the pan/tilt or the light changes rapidly, it is recommended to turn the switch to the OFF position, because when it is in the on position, the aperture speed of the lens will slow down; ② If the desired object is not in the middle of the image, the backlight compensation may not fully play its role.

(5)LL/INT (synchronization selection switch): This switch is used to select the camera synchronization mode, and INT is internal synchronization; LL is power synchronization. Some cameras also have an LL phase power synchronous phase controller. When the camera is used in the power synchronization state, the device can adjust the phase of the video output signal by about one frame. (Adjustment requires professionals)

(6) Video /DC (lens control signal selector switch): ALC automatic aperture lens has two kinds of control signals. When it is necessary to install an automatic aperture lens with DC control signal on the camera, the DC position should be selected, and when it is necessary to install an automatic aperture lens with video control signal, the video position should be selected.

When ALC auto-stop video drive lens is selected, it may be necessary to adjust the video level L/H. The controller adjusts the control level output to the automatic aperture lens to control the opening and closing of the lens aperture (concave light).

In the camera accessories, there is a small black plug with four pins connected to the black socket on the camera. If you are using an automatic aperture lens driven by DC, the plug is already on the lens. Just plug it in the socket and turn the selector switch to DC. If you use a video-driven automatic aperture lens, you need to weld it with a soldering iron according to the instructions. Due to the different definitions of manufacturers, the welding methods are also different, so please pay attention when installing.

(7) Soft/Sharp (Level of Detail Selection Switch): This switch is used to adjust whether the output image is sharp or soft, and is usually set at the sharp position when leaving the factory.

(8) No flicker: In the area where the power frequency is 50Hz, the CCD accumulation time is 1/50s. If the NISC camera is used, its vertical synchronization frequency is 60Hz, which will cause the visual image on the monitor to be unsynchronized and flicker. On the contrary, PAL cameras will also have this image when the power supply is 60Hz. In order to overcome this phenomenon, a flicker-free mode file is set in the electronic shutter, which provides1100 seconds for the NISC camera and1120 seconds for the PAL camera, which can prevent the flicker of the image on the display. Manual electronic shutter: Some users use CCD to shoot fast moving objects. If they shoot at the speed of 1/50 seconds, they will produce a trailing image, which will seriously affect the image quality. Some cameras provide manual electronic shutter to fix the charge coupling speed of CCD at a certain value, such as 1/500,11000, 1/2000 seconds, etc. At this time, the charge coupling speed of CCD is accelerated, which will relatively reduce the trailing image of the collected image, and is also very useful for observing high-speed movement or electric spark. Therefore, some special cameras provide manual electronic shutters for users with special purposes.

Control and flow of monitoring camera in digital film shooting

With the increasing popularity of surveillance systems in commercial and civil fields, surveillance cameras (surveillance cameras) are widely used in various fields to protect social security. Video surveillance cameras are widely used in residential buildings, real estate villas, shopping malls and shops, financial offices and so on. Every different application field needs different types of surveillance cameras, and the camera gun is one of them. According to different applications, the following mainly explains the control and process of monitoring camera in digital film shooting:

1. Use the monitor to control the exposure.

First, adjust the monitor to a relatively standard state, and adjust this state at any time during shooting. The high-definition monitor has a waveform diagram, which is of great practical significance for controlling exposure and distinguishing the details of light and dark parts.

2. Automatic aperture control exposure

At this time, the automatic aperture is used as an exposure meter, and the photographer should have a clear understanding of the dynamic range curve of the monitoring camera.

3. zebra crossing control exposure

A zebra crossing is usually designated with an amplitude of 90%-95% of the signal level. At present, there are two levels of zebra crossing designed for high-definition surveillance cameras. The first stage is set to 70%, that is, the amplitude of 700 mV video signal is 60%-65%, which is basically the level value of video signal corresponding to 23% wampee reflectivity. The other is 100% zebra crossing, 70.

According to statistics, in 2006, the number of films shot by digital equipment reached 1 10, accounting for 1/3 of the national total output. The technical difference between digital film and film film in actual shooting is mainly the control of color tone and exposure, and the shooting process is also different.

The exposure of digital movies. Lens-spectroscope -CCD-A/D analog-to-digital conversion-black spot correction-gain adjustment-white balance-stray light correction-detail adjustment-color giant array-inflection point adjustment-GMA adjustment-black cutting. Film movies are controlled by exposure meters. Some photographers also use digital exposure instruments. Generally speaking, the sensitivity of digital cameras is equivalent. For SONYF3200K, the exposure of digital movies is controlled by. Shutter 1/48 seconds, 24P mode, equivalent to 320 degrees. Exposure meters are rarely used in digital movies because they are set according to the photographic characteristics of film emulsion. Film is sensitive to blue light and ultraviolet light, while digital is relatively sensitive to red light.

Video surveillance camera. This product has the characteristics of clear image, bright color, high number of lines and low illumination. With the continuous investment in technology research and development, the surveillance camera will promote the market innovation process with the growth of its CCD technology and image sensor solution lineup.

Factors affecting the service life of infrared lamp of surveillance camera

It is inevitable that part of the electric energy consumed by the infrared tube of the camera is converted into effective light energy and part into heat energy. The problem is to reasonably control and treat the generated heat energy. When too much heat energy is generated or proper cooling measures are not taken, the temperature rise in the machine is too high, which leads to the rapid aging of lamps and the rapid decline of irradiation distance. Some producers, in particular, do not have a healthy business philosophy, unilaterally pursue the performance at delivery, ignore the service life of products, and desperately pursue brightness and distance without solving the problems of fever and excessive temperature rise, which makes their service life decline rapidly.

Test Steps and Usage of Monitoring Camera

Testing the monitoring camera mainly tests the clarity and color reproduction, illumination and backlight compensation, followed by measuring the distortion, power consumption and minimum working voltage of the monitoring camera. Firstly, the measurement steps of clarity and color reproduction, illumination and backlight compensation are introduced.

1. Measurement of definition: When testing multiple surveillance cameras, the same lens should be used (fixed focus and two variable lenses are recommended), and the given calibration lines *** 10 vertical lines and 10 horizontal lines should appear on the left and right sides of the surveillance screen according to the central circle of the test card, so as to count clearly and accurately. Represents vertical definition and horizontal definition respectively, and the corresponding groups have given the number of lines. Such as vertical 350 lines and horizontal 800 lines, it is best to use black and white display at this time. When testing, you can focus on the distant scene, or you can focus while measuring. It's better to use both, and you can see the difference (convergence) of this camera.

2. Monitoring camera color reproduction test: A color monitor should be selected to test this parameter. First, observe people and clothes from a distance to see if there is any color distortion, compare brightly colored objects, and see the response sensitivity of the monitoring camera. Put the color picture album in front of the surveillance camera to see if the outline of the picture is clear, too light or too thick. Shoot the moving color object again to see if there is any color difference tailing, delay and blur. The test conditions are as follows: When the first generation illumination of the camera is 50V, it should be measured at the illumination of 50+ 10V, that is, 10V is added to the first generation illumination of the surveillance camera, and the aperture should be kept in the closest state.

3. Illuminance: put the surveillance camera in a dark room, with active 220V self-lighting lights in front and behind the dark room, and set up a voltage regulator. By adjusting the voltage, the brightness of the lights in the dark room can be adjusted, and the voltage can be adjusted from 0V to 250V V, and the indoor illumination can also be adjusted from the darkest to the brightest. During the test, record a minimum illuminance value when the aperture of the camera is opened to the maximum (dim the movable light with the voltage regulator until the built-in picture in the darkroom can't be seen clearly), then record the next minimum illuminance value when the aperture is adjusted to the minimum, or adjust and turn off the front and rear lights respectively.

4. Backlight compensation of the monitoring camera: There are two ways to test this parameter: one is to turn on the voltage-regulating lamp in front of the camera in the darkroom and turn it to the brightest, then put a picture or text under the lamp to shoot the monitoring camera to see if the picture and text can be seen clearly and the picture is not dazzling, and adjust the AL and AX shift switches to see if there is any change, which is the best. The other is to shoot the camera out of the window in sunny conditions to see if you can see the images and words clearly at this time.

5. Monitor the distortion of the camera: put the test card in front of the camera to make the whole sphere appear on the screen, see if there is an ellipse in the circular sphere, move the camera forward to see if the center of the circle is enlarged, and then test the corners and borders for arc distortion at a distance.

6. Monitor the power consumption of the camera: the lowest working voltage, measure the current with a multimeter, and adjust the voltage with a small voltage regulator.

In the security system, the image mainly comes from CCD camera, which is called Charge Coupled Device for short. It can convert light into charge, store and transfer the charge, and also take out the stored charge to change the voltage, so it is an ideal camera element. The CCD camera composed of it is widely used because of its small size, light weight, influence by magnetic field, impact resistance and impact resistance.