Posts Tagged ‘ CCTV frame rate’



Frame Rate vs Resolution

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Tuesday, September 23rd, 2014

Frame rate or resolution

Today, devices from televisions to mobile phones are being able to project lifelike videos and realistic motion. This is something that has become possible for our everyday videos and movies. When it comes to our security cameras, we may want to record with the same effect as our entertainment but might not have the money or technology. So we have a choice: either lose camera resolution or frame rate. Learning about Frame Rate vs Resolution will help you understand how you can still have the realistic look that we want but fit any budget.

Resolution

When it comes to pictures, the main thing you look for is the resolution of the camera, which is easily defined as the size of the picture. The measurement is in pixels which run horizontal and vertical in a picture. An example would be 1280px horizontal × 720px vertical. The more pixels that you capture in a single picture the more you see. This means when you zoom in on a picture it is possible to see more of the scene. Whether it’s a billboard size picture or capturing the fine detail of a butterfly wing, pixels are what let this happen. Video pixels work the same way as pictures, the only difference is that a video is a collection of pictures clumped together to make a motion picture. The clarity of the video all depends on what resolution it is recorded at. A typical video is recorded at 1080p which in resolution terms is 1920px × 1080px, which is also considered high definition. Most televisions display at 1080p resolution, so anything higher would be overkill. Overall resolution has a great deal to do with the clarity of the picture or video that you are recording or viewing.

Pixels

Frame Rate

Frame Rate

The way a video works is by combining many pictures together, like a flipbook, and playing them out at a certain speed to create a realistic motion. The speed at which the pictures are played back is the frame rate, usually measured in seconds. The human eye can only see 10-12 frames individually but as the frames increase your brain can’t depict them, so it starts to become real-time. The normal frame rate for when things start to look real is around 24-30 FPS (frames per second). Frame rate is most important in cinema movies and video games where every millisecond can make the difference. Displaying anything higher than 120 FPS is just used to show slow motion footage for sports or high speed activity. As the frame rate starts to slow down, the video becomes choppy and you might miss things that happen in between frames. Having a sufficient frame rate is important in some cases but can be tweaked when needed.

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What’s More Important?

Understanding how Resolution and Frame Rate work and the benefits of both can help you choose which one is more important if one were suppressed. The most important out of the two would be resolution when it applies to security cameras. The reason for this is because having a higher resolution will give you a better picture of what you’re capturing.
If needed, you could zoom in on a face or see exactly what was taken. When talking about zoom with a high resolution camera there are two different types. One is an optical zoom, which uses optical lenses to zoom in on an event without distorting the image itself. The other is called a digital zoom, which means that given a high resolution image, you can zoom in on an event and be able to make out what is happening with minimal distortion. Frame rate is important so you can gather more footage in a second. Adjusting the frame rate of a camera down to 8-10 FPS will still allow you to collect a sufficient amount of footage so you won’t miss anything. It does tend to cause the playback to become a little choppy, but in the case of security cameras, it does not need to playback like a cinema movie. If you set your DVR/NVR to use a higher resolution and a lower frame rate, you can attach more cameras to cover more ground and for every camera have the highest resolution recording. That means that for every second of every camera you have, 8-10 pictures to review is more than enough evidence to catch anyone in the act.

Help Your Budget

Bag of Money
Knowing what you want to spend on a camera system will help you make a better decision on what is possible for you project. Retailers might try to deter you from asking questions about frame rate and resolution because their systems record at the lowest resolution possible and 10 FPS. They sell these units at low prices but as the old saying goes, “you get what you pay for,” and that applies to cameras as well. With high quality products it is possible to achieve high resolution video with 30 FPS on all channels but your equipment will not come cheap. In some cases this might be necessary, but in a residence or a small business you can get away with lowering the frame rate. That doesn’t mean you have to resort to a cheap system found at your local name brand store, you just have to do your research and be sure to ask the right questions. Doing so will help you save money not only on your DVR/NVR system, but also on your cameras, cables, switches, and hard drives.

Conclusion

Resolution and Frame Rate are two very important things to look for when buying a camera system and are almost always overlooked by consumers as a bargaining tool. Learning about the two can help you understand why frame rate can be adjusted to achieve a higher resolution and still capture what you need. It also helps complete your project by staying within a budget.

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Frame Rate vs Resolution in Security DVRs – Which is More Important

Written By:
Wednesday, May 21st, 2014

When configuring a DVR a very common question is what is the difference between frame rate and resolution and which is more important to have at a higher rate? Of course my answer is it depends… Both are very important but, depending on what you want to use the cameras for is which is more important than the other.

Now to begin you really need to understand what frame rate is. We will take a trip back in time to the 1800’s when cameras were first invented. They only took one picture at a time. The mechanism and film were designed that way. It was a physical limitation for decades. It was tedious and horribly long with the extra processing steps. You had to have fairly dangerous chemicals to actually develop the pictures. To take a picture, people had to stand as perfectly still as possible, because the camera’s shutter speed was so slow and the film need exposure times of ten minutes to an hour depending on the film. As film paper became more sensitive to light it reacted faster, so shutter speeds eventually had to be faster. I remember in the 1980’s the hot thing was Kodak High speed film. What set them apart from everybody else for a few years was Kodak figured out a way to get the film paper extremely sensitive. Coupled with cameras that had extremely fast shutter speeds Kodak figured out to how to take out the blur you may get when objects are moving. The pictures coming out of the Olympics that year were amazing there were no blur and the images extremely crisp. The faster shutter speed means a camera can take more pictures per second. Better film allowed for this by being more responsive to less light. A fact that is not well known by people is that the faster the shutter speed the less light comes in the iris which will create dim images.

Resolution is a separate aspect of the image compared to frame rate. CIF is 320 X 240 pixels. 2CIF is 720 X 240 pixels. 2CIF is a wider image than CIF depending on the need is if you would pick the wider shot or standard CIF. VGA is 640 X 480 pixels. D1 is 720 X 480 pixels. As image processing has improved the pixels have increased. With more pixels the colors become more vibrant and the images more clear. To better understand the clarity parts pixels are a very tiny piece of the puzzle known as your picture. The more pixels you can get the smaller the piece gets to represent that part of the picture. The down side is that this increases the need for better hardware to handle the increased load of imaging, which of course drives the price higher. That said the saying, “you get what you pay for”, could not be truer with DVR systems.

Resolution Comparisons

Now that we understand what both frame rate and resolution really are we can determine which is more important per the application. A few months ago I was helping a customer that had a DVR-EL4120ME. This DVR is capable of all the analog resolutions and the D1 at 7 frame rate but CIF at 30 frames per second. . I will say “John” was using this system to monitor a manufacturing process. The issue he was running into was that he was getting blurry images so he called his tech support GURU Daniel (that’s me). He goes on to describe what he is doing and the images he is getting. I logged into his system to see what he described. His process was happening so fast that he was not really getting an image of what he wanted, so I asked what is more important the resolution or frame rate. John said, “Gee I really don’t know. I thought resolution but with the images I’m getting I need help.” I told him no problem I have the knowledge to get it right. Instead of running the DVR at D1 and 7 frames per second, let’s adjust the system to CIF at 30 frames per second. POOF!!! Just like that the conveyor belt that was carrying some electronic device to be soldered could be seen. It was not about seeing exactly what was being soldered but making sure the robotic arm was hitting the part in time as it passed by. In minutes I was able to take John from not being that satisfied of a customer to being ecstatic about his equipment.

An example of the resolution being more important than frame rate is in monitoring your cash register. In many if not all retail environments keeping a close eye on the money is important. Typically people are not moving at warp speed so they do not look like a blur on camera. Giving way to frames per second while boosting resolution. Being able to make out the print on the one hundred, twenty, ten, five, and one dollar bills is important. People make mistakes on both sides of the register. The clerk gave the wrong change, the customer paid with the wrong bill etc. Now all of a sudden being able to make out the print is a big deal, so you know without a doubt who gave what to who.

Cash register

I can tell you having a customer have a meltdown at the main register is really not good so, as a manager you need a way to quickly defuse the situation before it carries over to other customers. Having your DVR configured to the highest resolution lets you see the 10, the 20, the 50, and 100 dollar bills. You can go back to where the DVR is setup, review the footage and know with confidence what happened or who made the mistake. Also, you can show the customer in real time “who” made the mistake.

Now you know the difference between resolution to frame rate and in which applications makes either feature more important. Should you run into a scenario when you are not able to compromise, IP cameras typically are the way to go. They support the mega pixel resolutions which are considerable higher than analog as well as 30 frame rate per second.

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