Lens and infrared lamp debugging method and lens installation method

Debugging method of lens and infrared lamp

     What is the method of adjusting the rear intercept of the fixed focus lens? Use the camera's automatic electronic shutter function to adjust the lens aperture to the maximum, the focus ring is adjusted according to the actual distance of the scene, and then adjust the rear intercept until the image is clearest. What is the method of adjusting the intercept?

     1. Turn on the camera's automatic electronic shutter function
     2. Use the controller to adjust the lens aperture to the maximum
     3. Aim the camera at an object 30 meters away and adjust the focus to infinity (most lenses face the lens and rotate the front focus adjustment ring clockwise to the head)
     4. Use the controller to adjust the lens zoom to push the scene to the farthest, and adjust the intercept after the lens to make the scene clearest
     5. Use the controller to adjust the lens zoom to draw the scene to the nearest, and fine-tune the lens focus to make the scene clearest
     6. Repeat 4-5 steps several times until the scene is always clear during zooming of the lens
     Infrared lamps have different powers and two wavelengths of 715 and 830nM. What factors does the choice of wavelength depend on?

     1. If the user does not mind that the infrared light is seen by the naked eye, the 715nM infrared lamp should be the first choice because of its long illumination distance and good effect.
     2. If the red storm problem is taken into consideration, an infrared lamp of 830nM must be used, and a low-illumination camera should be used.
     3. Choose a lens with a relatively large aperture
     4. The divergence angle of the infrared lamp should match the field of view of the lens

     The maximum illumination range depends on the weather conditions, the reflectivity of the object and the surrounding light level.The farthest projection range of the infrared spotlight is as follows:
     500W = 150-200 meters 300W = 80-120 meters
     50W = 15-30 meters 30W = 5-15 meters
How to install the lens

     There are two types of C type and CS type, both of which have a thread of 1 inch and 32 teeth and a diameter of 1 inch. The difference is that the distance of the lens from the CCD target surface is different. The distance of the C type mounting base from the reference surface to the focal point is 17.562 mm The distance from the CCD target to the CCD target surface is one more than the CS type. The distance between the CS type and the focal point is 12.5 mm. Don't underestimate this connection. Without it, the lens and camera cannot focus properly, and the image becomes blurred. So before installing the lens, take a look at whether the camera and the lens are the same interface. If not, you need to increase or decrease the connection ring according to the specific situation. Some cameras do not need a ring, but use a rear image adjustment ring (such as Panasonic products). During adjustment, use a screwdriver to loosen the screw on the adjustment ring and turn the adjustment ring. At this time, the CCD target surface will be backward (front) relative to the mounting base Sports also play a role in catching circles. In addition (such as SONY, JVC) adopts a method similar to the rear image adjustment ring, its fixing screw is generally on the side of the camera. After unscrewing, adjusting one of the gears at the top can also make the image clear without adding or subtracting the ring.

     AGC ON / OFF (automatic gain control): There is a video amplifier in the camera that amplifies the signal from the CCD to a level that can be used. Its amplification is gain, which is equivalent to higher sensitivity, but the amplifier is in a bright light environment. It will overload and distort the video signal. When the switch is ON, the lens aperture is fully opened under low-brightness conditions, and the gain is automatically increased to obtain a clear image. When the switch is OFF, a natural and low-noise image can be obtained at low brightness.

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

     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 continuously adjusted from 1/50 to 1/10000 seconds) . When choosing this method, you can replace the ALC automatic iris lens with a fixed or manual iris lens. ?

     It should be noted that in outdoor or bright environments, due to the limited ELC control range, the ALC lens should be selected; under certain unique lighting conditions, the following situations may occur:

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

     ② The image flashes remarkably and the color reproducibility is unstable.
     ③ The white balance changes periodically. If these phenomena occur, use an ALC lens. When the ELC method is used with a fixed aperture lens, the depth of field of the image may be smaller than that obtained by using an ALC type lens. Therefore, when the camera fully opens the fixed aperture lens and adopts the ELC method. The depth of field will be smaller than when using an ALC lens, and distant objects on the image may not be in focus. When the lens is an auto iris lens, the switch needs to be set to ALC mode.

     BLC ON / OFF (Backlight Compensation Switch): When strong and useless background lighting affects the clarity of important objects in the middle, you should turn the switch to the ON position.

note:

     ① When used with the gimbal or when the lighting changes rapidly, it is recommended to put the switch in the OFF position, because in the ON position, the lens aperture speed becomes slower
     ② If the desired object is not in the middle of the image, the backlight compensation may not be fully effective.

     LL / INT (synchronization selection switch): This switch is used to select the camera synchronization mode, INT is internal synchronization 2, 1 interlaced 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, this device can adjust the phase of the video output signal, the adjustment range is about one frame. (Adjustment requires professionals)

     VIDEO / DC (lens control signal selection switch): There are two kinds of control signals for ALC automatic iris lens. When the automatic iris lens with DC control signal needs to be installed on the camera, the DC position should be selected. When using an iris lens, you should choose the VIDEO position. When selecting the ALC auto iris video drive lens, there will also be a video level control (VIDEO LEVEL L / H) that may need to be adjusted. This controller adjusts the control level output to the auto iris lens to control the opening of the lens iris Large and small (recessed light). Among the accessories of the camera, there is a small black plug with four pins, which is connected to the black socket on the camera. If you use a DC-driven automatic iris lens, the lens has already been plugged. Just plug it into the socket and set the selector switch to DC. If you use a video-driven automatic iris lens, you need to use the user's label according to the instructions. Soldering iron is good. Due to the different manufacturer definitions, the welding method is also different, please pay attention when installing.

     SOFT / SHARP (detail level selection switch): This switch is used to adjust whether the output image is clear (SHARP) or smooth (SOFT), usually set at the SHARP position at the factory.

     FLICKERLESS (flashless mode): In areas where the power frequency is 50 Hz, the CCD accumulation time is 1/50 second. If you use a NISC camera, the vertical synchronization frequency is 60 Hz, which will cause the visual image to be out of sync on the monitor. Flashing occurs; conversely, this phenomenon will also occur with PAL cameras in areas where the power supply is 60 Hz. To overcome this phenomenon, a flicker-free mode is set in the electronic shutter, which provides 1/100 second for the NISC camera and a fixed shutter speed of 1/120 second for the PAL camera, which prevents flickering of the image on the monitor.

     Manual electronic shutter: Some users use the CCD to capture objects with relatively fast movement speed. If you shoot at a speed of 1/50 of a second, tailing will occur, which will seriously affect the image quality. Some cameras provide a manual electronic shutter to fix the charge coupling speed of the CCD at a certain value, such as 1/500, 1/10001/2000 seconds, etc. At this time, the charge coupling speed of the CCD is increased, so the collected images are relatively It will reduce the phenomenon of tailing, and it must be used for observing objects such as high-speed motion or electric sparks. Therefore, some special cameras provide manual electronic shutters for users with special purposes. The adjustment of the manual electronic shutter needs to refer to the random manual, which will not be repeated here.