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FPV Camera for Quadcopters and Drones

rjrobotics007rjrobotics007 wrote 06/11/2020 at 12:50 • 10 min read • Like

FPV cameras are small, light, and reasonably priced. The FPV camera is mounted onto a drone to send real-time video down to the ground using a video transmitter. The FPV camera allows you to see where the drone is flying and what it is seeing as if it had its own eyes. Depending on the drone, the FPV transmitter will send the live video signal to your Remote Control screen, monitor, smartphone device, tablet.

FPV cameras allow you to fly higher and further with some of the latest drones being able to fly up to 5 miles away using FPV technology. Military drones or large high-end drones can fly thousands of miles using FPV technology. The size and shape of FPV cameras determine how easily the camera can be mounted in a given multirotor frame. Runcam is probably one of the earliest companies who specialized in FPV cameras. They used to make surveillance cameras, but more and more people started using CCTV cameras for FPV so Runcam slowly turned to FPV.

To simplify the buying process, below listed are some of the factors to consider which helps a person to evaluate a FPV camera and pick up the right one.

1. CCD and CMOS — The Types of Imaging Sensor

CCD and CMOS are two main types of image sensors in FPV cameras, each with unique characteristics and advantages.

CCD is an older technology and used to be the go-to image sensor for FPV cameras as it performed better than CMOS at the time.

But CMOS technology has been improving really quickly and it’s now just as good as CCD if not better. Nowadays nearly all new FPV cameras use CMOS sensors and they are constantly getting better and cheaper.

CCD

2. Less jello effect in footage due to global shutter

3. The image is more “raw” and appears to be less processed. Resolution and image detail are normally lower than the best of CMOS cameras

4. Good performance at most lighting conditions, less digital noise in low light

5. Not the best but acceptable dynamic range performance and light/dark transition

6. The image usually has better contrast than CMOS

7. Cameras with CCD sensors across the board perform similarly. Unlike CMOS cameras, performance varies a lot

CMOS

1. The performance and price of CMOS cameras differ vastly — the most expensive cameras are usually CMOS, and ironically the cheapest cameras are also CMOS, while CCD is usually in the mid-price range

2. Generally, lower in latency (with one or two exceptions)

3. Higher resolution and sharper image, the trade-off is heavier digital noise and artifacts

4. Low light / Night FPV cameras tend to use large CMOS sensors

5. More susceptible to jello due to rolling shutter

6. Usually more flexible/dynamic with camera settings

2. Aspect Ratio

There are 2 aspect ratio to choose from in FPV cameras, 4:3 and 16:9. Aspect ratio has nothing to do with resolution, it’s just the different screen shape.


4:3 is more square and has the shape of an old CRT TV while 16:9 is longer like a modern computer monitor.

One isn’t always better than the other, it all comes down to which ratio your FPV goggles or display supports. If you have a 4:3 camera, but your goggles is 16:9, the image will appear stretched. If you have a 16:9 camera but a 4:3 display, the image will appear squashed.

Aspect ratio isn’t directly related to the peripheral view, e.g. 16:9 camera doesn’t necessarily give you a wider field of view. It actually depends on the lens and image sensor of your camera, which we will talk about later.

But it’s worth knowing that CMOS sensors have a native aspect ratio of 16:9, while that of the CCD is 4:3. Some CMOS cameras allow you to choose between 16:9 and 4:3 in the setting, but the 4:3 is achieved by chopping off the sides from a 16:9 image, and therefore you will get a smaller field of view in 4:3.

3. Field of View (FOV)

The field of view (FOV) of an FPV camera is determined by three things, the focal length of the lens, and the sensor size.

Shorter focal length => wider FOV

Larger sensor size => wider FOV

To give you some idea, here is a rough estimation for a camera with 1/3″ sensor size in 4:3 aspect ratio:

Lens Focal Length

Approx. FOV

1.8mm

160° – 170°

2.1mm

150° – 160°

2.3mm

140° – 150°

2.5mm

130° – 140°

2.8mm

120° – 130°

3.0mm

110° – 120°

With smaller FOV, the image is more zoomed in and you can see things more clearly. Wider FOV allows you to see more of the environment which might be preferred for proximity flying and racing.

This is a good example of a different FOV (from narrower to wider).


4. Sensor Sizes

Two main sensor sizes: 1/1.8″ and 1/3″ — the former is larger while the latter is smaller.

Sensor size affects low light performance and dynamic range. It’s almost always true that a camera with larger sensor has better low light performance given the same settings. Larger sensor also offers a larger FOV given the same focal length lens.

5.   Lens Sizes

 You can replace the lens on an FPV camera to get a different FOV or image quality. FPV camera lenses are different in two main things: focal length and thread size.

Full size cameras normally have lenses with 12mm diameter threads you can screw into the housing. We call this M12 lenses.

Smaller lenses are also used in some cameras in order to make it smaller and lighter. These lenses normally have 8mm diameter threads – the M8 lenses.

M12 lenses are bigger and heavier. They are normally used in Mini and Standard size cameras. They let more light in, thus the image quality is usually better than M8 lenses. M8 lenses are very compact and mostly used in Micro and Nano cameras.


6. Wide Dynamic Range (WDR)

Wide Dynamic Range (WDR) is a technology that aims to improve image detail under extreme lighting conditions where both bright and dark areas are present in the same frame.

As you can see the image on the left it’s under exposed, you can see the sun and clouds very well, but the tree and bushes are all dark. On the right we have an image that is slightly over exposed, the trees are all visible now but the sky is blown out. The image in the middle represents the best wide dynamic rangeof the three images, you can see the clouds and the trees at the same time.

Once you understand the concept you will begin to appreciate the importance of WDR capability in FPV cameras because it helps you see better when flying. Most FPV cameras have some degree of WDR, but the WDR performance can vary.

7. Low Light Capability

 If you plan to fly indoor, at sunset/dawn, or even at night, then you have to find out about the low light performance of an FPV camera. Some are designed more specifically for low light than others.

Low light capability of an FPV camera is measured in LUX. The lower it goes the better it is for low light. For example, the Runcam Swift 2 has a minimum LUX value of 0.01, while that of the Runcam Eagle 2 is 0.0001, you know the Eagle 2 is going to be better at low light than the Swift 2.

Cameras with bigger imaging sensor also normally perform better in low light as more light enters the sensor.

Most FPV cameras come with day/night mode. It enables to the camera to output either color and black and white images based on user’s selection, or lighting condition. “Night mode” makes use of near-IR light to deliver black and white images, allows you to see better in low light.

8. Video Encoding Format -NTSC and PAL

The main difference between NTSC and PAL is in resolution and frame rate. PAL offers slightly better resolution, while NTSC allows higher frame rate. If you want to have better picture, go with PAL. But if you want more fluid footage, NTSC does a better job.

PAL: 720 x 576 @ 25fps

NTSC: 720 x 480 @ 30fps

Conventionally, NTSC is used in North America, Japan and South Korea while PAL is used in most of Europe, Australia and large parts of Africa and Asia. It might be a good idea to stick with the standard in your country. But it really doesn’t matter nowadays, because both video formats are supported by all FPV equipment.

9. TVL — FPV Camera Resolution

TVL (TV Lines) is what manufacturers use to measure analog FPV camera resolution.

The number is based on how many alternating black and white lines can be displayed in the image horizontally. A 600TVL camera means it can display 300 black lines and 300 white lines alternately in one frame. The more TV lines, the better the definition image you can get out of the camera. Commonly seen FPV cameras TVL are 600, 700, 800, and 1200.

However higher TVL doesn’t always give you a better image due to the limitation of analog 5.8Ghz video transmission, as well as your monitor or FPV goggles. For example, 1200TVL is not going to be twice as sharp comparing to 600TVL in an analog FPV system.

10. Latency

It takes time for the FPV camera to capture and process the image before sending it to the video transmitter. The delay varies from camera to camera depends on its hardware as well as software.

Latency can be a deciding factor if you are into drone racing or high-speed flying. The lower the latency, the more quickly the pilot can react.

See More about FPV Camera

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