Hikvision ds-2cd4025fwd 2 million ultra wide dynamic gun network camera has good image quality, wide dynamic and low illumination effects. It can cope with complex monitoring environment freely. In addition, it also has fog penetration, strong light suppression and other functions, and can be widely used in shopping malls, supermarkets, buildings and other monitoring places.

Sweep away all the dark side

A camera with excellent wide dynamic effect can provide a clear and accurate color restoration picture in both light and dark scenes, even in the face of scenes with too large bright difference between the front and back scenes. During the inspection of ds-2cd4025fwd gun, in order to better verify its wide dynamic effect, we simulated the following tests:

Detection 1 – strong light source illumination: first, place several dolls in the strong light lampshade (illuminance: 20000 Lux), and place an image behind the lamp (illuminance value: 15.01lux), and then point the camera at the strong light lamp. When the wide dynamic effect is not turned on, the dolls in the lampshade can’t see basically, and can only vaguely find something in the lampshade; The same is true for the back images. The brightness of the facial details of the portrait characters is low and can not be well recognized. After the wide dynamic is turned on, the figure in the lampshade finally appears in front of us. The face details and colors of the doll can be seen clearly. The brightness of the face of the characters in the rear image is improved, and the detail performance is better.

Detection 2 – dark box: in the dark box, the portrait is placed in front of a high brightness panel (portrait illumination 2.77lux, highlight panel illumination value 235lux). When the wide dynamic is not turned on, the image of the highlight panel is visible, but the portrait is dim; After opening, the drawing and panel image can be clearly identified.

Detection 3 – real scene: the tester stands with his back to the window, forming an environment with high brightness contrast against backlight (exterior illumination 3600lux, indoor illumination 268lux). When the wide dynamic is not turned on, the character’s face is dark and can not be seen clearly, and the details are seriously lost. After the wide dynamic is turned on, the tester’s face immediately brightens up, the details of facial features are clear and recognizable, and the effect is excellent.

Wide dynamic off

Wide dynamic opening

Still beautiful

Ds-2cd4025fwd continues the consistent gun camera design style of Hikvision. It still adopts the appearance of square box, white painted cast aluminum shell and diamond lines. Even the familiar gun appearance still makes the author never tire of it. In addition, the machine is equipped with a 2 megapixel 1 / 2.8 “progressive scan CMOS sensor (the maximum resolution is 1920) × 1080, with a maximum frame rate of 60fps, and supports corridor mode). The machine has rich interfaces. From the rear panel, you can see that there are one Ethernet interface supporting audio and video transmission, one audio input / output interface, one BNC analog signal output interface for front-end debugging and one alarm input / output interface. At the same time, it is also equipped with micro SD card local memory card slot (the maximum support is 64GB). In terms of power supply, it supports three power supply modes of AC 24V / DC 12V / POE. The interface design is complete and supports ABF automatic focusing function, The neat arrangement also makes the plug-in and installation more convenient.

Accurate color HD restore

Test limits: [email protected] 、4Mbps

Detection 1- sharpness: align the camera with the sharpness test card at the lowest magnification. It is found that the horizontal sharpness reaches 1100tvl, the vertical sharpness reaches 1050tvl, and the edge sharpness is 900tvl. The picture effect is good;

Detection 2 – color restoration and gray scale: then replace the 24 * * color restoration card, and then compare the test card and monitor image. The color restoration of all color blocks is basically accurate, and no color deviation is found; Then replace the 20 level gray scale test card, which can be easily identified to 17 level;

Detection 3 – network control and real scene: aim the camera at the outdoor road with high-speed vehicles (driving speed is 60-80km / h). Carefully observe the imaging effect of the monitor. It can be found that the overall picture is clear and transparent, and the details such as trees, vehicles and buildings are maintained in good condition. However, the vehicles on the horse road drive smoothly, and no adverse signs affecting the monitoring effect such as jamming and shaking are found. Then, open the code stream test software. After 20 minutes of test, the dynamic code rate is stably controlled between 4.3mbps except for the occasional peak;

Detect 4- delay time: finally, point the camera at the electronic stopwatch of the monitor, and measure the delay time of the machine through synchronous screen capture. The average delay time is controlled at about 163ms, and the minimum delay is 108ms. The effect is worthy of praise.

High quality low illumination effect

Place the camera in the dark box and face the doll, illuminance meter and swing parts in the dark box at the same time. With the continuous reduction of illuminance, the picture color remains good before 6lux, without obvious noise and color fading, and the dynamic track of swing parts is clear without dragging, jamming and other phenomena; When it continues to decrease to 4.5lux, there is slight color fading and noise; Finally, it is reduced to about 1.7lux and switched to black-and-white mode. Before switching, the noise is obvious, and the swaying parts appear smear, but it does not affect the daily monitoring. After switching, the noise is swept away, the details of the doll become better, the layers are clear, the dynamic trajectory of the swaying parts is smooth, there is no jamming and no trailing, and the last reduced illumination value is 0.00lux (actually between 0.001-0.009lux). There is more noise, but the outline of the doll is visible. In addition, the minimum illuminance measured in the color mode is 0.01LUX, and the picture color is seriously lost, but the overall picture outline can still be easily recognized.

Before day night conversion

After day and night conversion

Comments: the machine has clear image quality, accurate color, stable code stream, excellent low illumination imaging, and wide dynamic effect; With ABF auto focus function, it is convenient for staff to install and debug.

Responsible editor: GT

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