修正:夜間に防犯カメラがぼやける
CCTV セキュリティ カメラ システムを所有している人々の主な不満 夜にぼやけたり曇ったりする特定のカメラがあります。
そして、ほとんどの犯罪が夜間に発生していることは事実です。つまり、CCTV カメラがぼやけていたり、霧がかかっていたりすると、セキュリティ カメラ システムを設置する目的全体が無効になります。
ぼやけた、または曇った画像を表示する防犯カメラを使用している場合、問題を解決することは非常に重要です。夜間 (または昼間) に防犯カメラの画像がぼやけたり曇ったりするのには、いくつかの理由があります。
このガイドでは、ぼやけた画像や曇った画像を表示するセキュリティ カメラを修正するいくつかの方法について説明します。セキュリティ カメラ システムからこの問題を取り除くまで、提案を読み、それに従ってください。
修正方法:夜に防犯カメラがぼやける
前述したように、防犯カメラの画像がぼやけたり曇ったりするのには多くの理由があります。IR ライトやガラス、場合によってはソフトウェア関連の物理的な問題である可能性があります (非常にまれですが)。以下に、画像がぼやけたり霧がかかったりする問題を解決するためのヒントをいくつか集めました。
IR 反射の問題 (IR ブリーディング)
現在、ほとんどすべてのセキュリティ カメラ、IP は HD アナログであり、内蔵の IR (赤外線) ライトを使用してエリアを照らし、夜間に画像をキャプチャします。基本的に、IR ライトはセキュリティ カメラが暗闇の中で見えるようにするものです。
ただし、この IR ライトは近くの物体から跳ね返り、戻ってきてカメラのレンズ (目) を「盲目に」することがよくあります。
この光の反射により、画像がぼやけたり曇ったりします。場合によっては、反射が強すぎてカメラが実際に使用できないこともあります。
以下はドーム型防犯カメラの写真です。カメラのレンズの周りにある「ドット」は実際には IR ライトであり、暗くなると自動的にオンになり、監視対象の領域を照らします。
既に述べたように、IR ブロックから放出された光は、外部の固体表面 (壁など) で跳ね返ることがあります。またはドームガラス自体から。その結果、CCTV システムでは画像がぼやけたり曇ったりして表示されます。
一般的に言えば、この IR 反射はドーム型カメラでより一般的ですが、バレット カメラや PTZ カメラでも同じ問題が発生する可能性があります。 There are a few things you can do to fix the IR reflection (or IR bleeding) on a security camera system.
1. Missing rubber ring on the camera
As you probably have noticed, there’s a rubber ring located around the camera’s lens that is pressed firmly against the glass.
This rubber ring is used to avoid IR bleeding which is a technical term for IR lights. Make sure that the rubber ring is there and not damaged.
If the rubber is missing, the IR lights will hit the camera’s lens and make the picture look blurry/foggy. In some cases, rookie CCTV installers remove these rubber rings while pointing the camera and then never put them back.
Inspect the camera, and ensure that the rubber is tightly pressed against the glass (not loose). It has to be so “tight” that the same rubber ring may get a bit deformed when hitting the glass cover (which is a good thing).
2. Dirty dome/glass cover
It may happen that the security camera has collected dust, grease, or even fingerprints on the glass. In this case, the IR lights will bounce back on that dirty surface and hit the camera’s lens creating the blurry/foggy effect.
Inspect the cover glass closely and wipe any dirt or dust located there. Quite often the cameras are installed in dusty environments which means they will get dirty pretty quickly.
Additionally, it’s recommended to clean your cameras once in a while, not wait until you can’t see anything on the footage.
At the same time, check the glass cover for any scratches. If there are scratches, then the IR light may bounce back and blind the lens. If you see scratches, try to smooth them slowly with some paper ground. Or you can replace the glass cover altogether which is the recommended way.
3. Reflection from a solid object close to the camera
If there’s a solid surface close to the camera, the IR lights may hit the object and bounce back to the camera. Technically, that’s how the camera is supposed to detect the light when it’s dark, however, if an object is way too close to the camera, the picture may get affected by the reflection.
These reflective objects can be metal surfaces, doors, fences, walls, etc. Inspect the camera’s placement and check if there are such objects close to the camera that may cause the blurry/foggy issue.
Additional recommendations:avoid leaving plants in front of the camera, especially plants with big leaves. Also, don’t place the security camera in tight corners because the walls will be too close and the IR lights will get reflected.
If you tried all these tips and the CCTV image is still blurry or foggy, try to install the camera on a different spot and see if the picture gets better.
The lens is unfocused
If the camera’s image is blurry or foggy during the nighttime and daytime then the problem can be the focus.
Each camera’s lens needs to focus the light on the right spot on the camera’s image sensor. If unfocused, the picture will look blurry or foggy (day and night time).
Security cameras use different types of lenses, some of them are fixed, and some are varifocal. Either way, the principle of how they function is the same:the light comes through the lens and must be collected/directed at the right spot in the camera’s image sensor.
1. Security camera with varifocal lens
A varifocal lens is a customized lens that can be adjusted to various lens sizes. For example, many varifocal cameras are 2.8mm to 12mm which means you can adjust the camera and go from a white angle lens (2.8mm) to a more narrow one (12mm), or somewhere in between.
If your camera is blurry, you need to adjust the varifocal lens by turning the screws left and right until you get a sharp image.
Basically, by adjusting the focus or the zoom you can make the image clear and sharp. The image below shows a typical varifocal lens with its focus and zoom controls.
The recommended way to adjust the camera is to look at the live images and simply turn the controls on the camera left until you’re happy with the distance (zoom) and clarity (focus) of the picture.
2. Security camera with fixed lens
As the name suggests, on this type of security camera the lens is fixed which means you can’t rotate it until you get the right focus.
This type of camera is already adjusted to the right distance and focus once they come out of the factory line. For example, a 3.6 mm fixed lens camera is adjusted to 3.6mm and you’re not “allowed” to adjust anything.
However, even though the camera is supposed to be adjusted the picture may still look out of focus (blurry/foggy). This happens because the camera somehow is not adjusted perfectly in the first place or the image sensor is incorrect.
Obviously, there’s a way to adjust the lens yourself. Open up the camera and using your hands or pliers, rotate the lens clockwise until the image is clear and sharp. Go slowly and carefully, usually, a little bit of turn will focus the camera.
An example of the fixed lens is shown in the picture above. Note the threads, by twisting the lens a little bit you may fix the blurry picture on the screen.
Bad lens
In some cases, the camera’s lens is simply bad. You can try all the tricks in the book and still not fix the blurry/foggy issue. Many low-cost cameras come with cheap lenses that don’t function the way they’re supposed to. We always recommend going for established CCTV manufacturers .
Additionally, many cameras have the so-called IR filet issue. This is a filter that goes between the lens and the image sensor.
When the light passes through the lens, it hits this filer and then hits the image sensor. However, in some cases, the IR filter is damaged or low quality and doesn’t filter the light properly causing the blurry/foggy issue on the image.
If you have stumbled upon a camera with a bad lens, you can either return the product or ask the manufacturer to warranty it. In most cases, you have to return it. It’s very default to fix a damaged lens’ IR filter.
Factory reset the camera
On rare occasions, the issue may be sort of software-related. Maybe a bug in the software or simply the settings on the camera are messed up. If you have tried all the steps, the last tip is to try to factory reset the camera.
If you’re using an HD analog camera, you can factory reset via the camera’s interface. Play with the toggle on the pigtail and find the “Reset” option. Once reset, the camera will blink and come back online after 5-10 seconds.
If you’re using IP cameras, you can factory reset by using the reset button on the camera itself. Usually, it’s located in the camera’s motherboard, find it and keep it pressed for 10-15 seconds while the camera is powered on. Wait and the camera will come back online, check if the image is clear.
結論
In this article, we discussed ways and tricks to fix a security camera that shows a blurry or foggy image. Make sure the camera is focused and zoomed properly, ensure that the rubber ring is located in the camera and there’s no solid surface close to the camera.
Also, always go for CCTV security cameras that have good reviews and feedback from their users.