Why is USB Cmos Camera Better?

Sep. 09, 2024

What is CMOS sensor size in embedded cameras? How to ...

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Image sensors such as CMOS have seen their use cases grow significantly in size across many industries today. And you can also see major differences among the designs of the image sensors. For instance, these sensors come in varying sizes.

Undoubtedly, the size of the camera sensor is a major parameter that influences key aspects of imaging, including factors such as sensitivity, resolution, dynamic range, and low-light performance. Understanding sensor size and its implications for camera performance is critical in the development and optimization of imaging solutions.

In this blog, you&#;ll gain expert insights by comparing different sensor sizes and knowing their use in embedded vision applications.

But first, let us first try to understand what a CMOS sensor is and how its size is measured.

What is a CMOS sensor?

CMOS (Complementary Metal-Oxide Semiconductor) is a digital device for capturing light and converting it into electrical signals. It has a photodiode and a transistor switch for each pixel. When light strikes the pixel, it creates a voltage proportional to intensity. The voltage is sampled directly at the pixel.

Having an amplifier for each pixel allows the pixel signals to be amplified individually, as shown in the below figure.

Figure 1: CMOS Sensor Architecture

Read: CMOS sensors vs CCD sensors: why CMOS sensors are ruling the world of embedded vision?

Benefits of Using CMOS Sensors

Higher frame rate: CMOS sensors can capture multiple frames per second for real-time imaging and analysis.
High resolution: CMOS sensors ensure high resolution so that applications can deliver exceptional imaging capabilities.
Larger FoV: CMOS sensors provide a larger FoV for wide-angle imaging while equipping applications to capture large objects/scenes.
Cost-effectiveness: CMOS sensors offer reduced costs, especially in comparison to CCD sensors.
Power consumption: CMOS sensors draw less power, which is useful in embedded vision systems that have other power-hungry components.
Current trend: The increasing adoption of CMOS sensors is causing manufacturers to shift focus away from development of other sensors.

Read: CMOS sensors vs CCD sensors: Why CMOS sensors are on top

Read: Five crucial features that highlight the advantage of CMOS cameras

What does camera sensor size mean? How is it measured?

CMOS sensors are generally specified by their physical sizes. The size of the CMOS sensor determines the light-collecting surface area of the sensor. The dimensions of the sensor are defined by the resolution and the pixel size. As you may know, the size of a sensor is often measured in inches. The image sensor format is sometimes referred to as sensor size or optical format.

The value of optical format is the approximate multiplication of the diagonal length of the sensor and 3/2.

Optical format = (3/2) * Diagonal of Sensor

For example, consider the AR-CMOS image sensor from onsemi&#; that has a sensor size of 4.54×3.42 mm and a diagonal of 5.68 mm. Therefore, the optical format is 5.68*3/2 = 8.52 mm, which is expressed as 1/3.2&#;.

Likewise, there are several sensor sizes available in the market as shown in the following figure.

Figure 2: Illustration of Sensor Size Dimensions

CMOS sensor size comparison

The below table shows the comparison of different sensor sizes and the corresponding crop factors:

Type Diagonal (mm) Width (mm) Height (mm) Area (mm²) Crop factor 1/2&#; 8 6.4 4.8 30.7 5.41 1/2.3&#; 7.66 6.17 4.55 28.5 5.64 1/2.5&#; 7.18 5.76 4.29 24.7 6.02 1/3&#; 6 4.8 3.6 17.3 7.21 1/3.2&#; 5.68 4.54 3.42 15.5 7.61 1/4&#; 4.5 3.6 2.7 7.92 10.81 2/3&#; 11 8.8 6.6 58.1 3.93 35mm full-frame 43.1&#;43.3 35.8&#;36 23.9&#;24 856&#;864 1

It is important to note that the crop factor is related to the ratio of the camera sensor&#;s size to a 35 mm film frame.

Crop Factor = Diagonal35mm / Diagonalsensor

How to choose the right CMOS sensor size for an embedded vision application

Each application has different sensor size requirements to produce images. Let us discuss the factors to be considered while choosing a sensor of a particular size.

Resolution
High frame rate and global shutter
Sensitivity
Lens mount selection
Image circle diameter
Low light performance

Resolution

Resolution is the ability of imaging systems to reproduce the exact object detail. Many embedded vision applications like autonomous mobile robots (AMR) and autonomous vehicles demand cameras to achieve precise 3D depth measurement. This would be achieved with the high-resolution feature of that camera. Selecting sensors with large pixel sizes is likely to have higher resolution.

Also, the resolution of the lens must match the pixel size of the sensor to achieve high-quality images. The quite popular camera resolution of x pixels often uses a larger sensor with a size of 1/1.8&#;, and now high-end 4K resolution uses a 1/1.2&#; image sensor format.

High Frame Rate and Global Shutter

Embedded vision applications like automated license plate recognition, gesture recognition, robotic vision, drones, and AMR require high frame rate and global shutter features &#; depending on the nature of the end application. AR from Onsemi is one of the most popular sensors used in such applications.

It is a 1/2.6&#; (Diagonal 6.8 mm) optical format CMOS sensor with a 3.0 μm x 3.0 μm pixel size. It is a global shutter sensor that is used for accurate and fast capture of moving scenes at 120 frames per second at full resolution. See3CAM24_CUG from e-con Systems is a color global shutter camera based on the ARO234 sensor.

Explore: e-con Systems&#; See3CAM24_CUG &#; a color global shutter camera based on the ARO234 sensor

Also, some of the other available sensor sizes are 1/2.9&#; (for Omnivision&#;s OV CMOS image sensor with 3.0 μm x 3.0 μm pixel size) and 1/3&#; (Onsemi&#;s AR CMOS digital image sensor with an active pixel array of H x. 960V).

Sensitivity

Large sensors tend to have large pixel sizes, and this indicates higher sensitivity. To achieve high sensitivity and compact design, an industrial camera usually uses a 1/2.8&#; CMOS image sensor.

This enables a high level of image recognition and detection performance for improved safety for smart city, surveillance, and traffic monitoring systems.

Lens Mount Selection

Mount is used for attaching a lens to a camera body. The selection of mount depends on the sensor size. For instance, the C mount, which is the type of lens mount for machine vision cameras, is appropriate for a 1.5&#; sensor. S mount lens, which is commonly used in industrial applications, is appropriate for a sensor size of 1/2&#;, 1/3&#; or smaller.

Image Circle Diameter

Industrial cameras might have issues like lens vignetting/lens shading, which is a gradual reduction of an image&#;s brightness or saturation from the image center to the four corners/ edges. This happens when the image format (or circle) of the lens is too small for the size of the sensor. So, to mitigate this, the image circle diameter must fit or be larger than the sensor size.

Low-light Performance

As discussed before, a large sensor contains larger photosites that are more receptive to light, thereby enhancing the camera&#;s ability to capture low-light images in comparison to a small sensor. Two of the popular sensor sizes targeted for low light performance are 1/1.2&#; ( such as the Sony® IMX485 based 4K-resolution CMOS image sensor) and 35mm full-frame.

As advancements continue in sensor technology, there remains a constant pursuit of enhanced performance from sensors of varying sizes. However, it&#;s undeniable that in many scenarios, larger sensors offer superior performance.

Yet, it&#;s important to acknowledge that with increased size comes higher costs, making larger sensors typically more expensive compared to their smaller counterparts.

e-con Systems &#; A Leader in Providing CMOS Sensor-Based Cameras

e-con Systems, with 20+ years of experience in designing, developing, and manufacturing OEM cameras, has a track record of equipping clients with world-class CMOS camera modules. Some of the use cases we have successfully covered include industrial, retail, agricultural, medical, and more. These modules are seamlessly compatible with several embedded platforms, including NVIDIA Jetson. Our portfolio includes sensors from various manufacturers, covering a broad spectrum of sizes and capabilities. Below is a comprehensive table of the sensor sizes and corresponding sensor names in our portfolio.

Sensor Size

Sensor Names

1/1.2

IMX485

IMX585

1/1.7

1/1.8

IMX568

1/2.3

IMX477

IMX412

1/2.42

ISX031

1/2.5

IMX317

1/2.6

1/2.7

Contact us to discuss your requirements of USB Cmos Camera. Our experienced sales team can help you identify the options that best suit your needs.

1/2.8

IMX662

IMX462

IMX298

IMX415

IMX290

IMX715

IMX327

1/2.9

1/3

MT9V024

1/3.2

1/3.6

1/4

2/3

IMX264

e-con Systems is also deeply committed to offer custom CMOS camera solutions that align with individual client needs. Our seasoned team of experts collaborates closely with clients to develop bespoke camera solutions. Our customization services include custom sensor selection, lens configurations, and integration with hardware and software components.

Visit the Camera Selector page to see our complete camera portfolio.

If you need help integrating CMOs camera modules into your products, please write to us at .

Prabu is the Chief Technology Officer and Head of Camera Products at e-con Systems, and comes with a rich experience of more than 15 years in the embedded vision space. He brings to the table a deep knowledge in USB cameras, embedded vision cameras, vision algorithms and FPGAs. He has built 50+ camera solutions spanning various domains such as medical, industrial, agriculture, retail, biometrics, and more. He also comes with expertise in device driver development and BSP development. Currently, Prabu&#;s focus is to build smart camera solutions that power new age AI based applications.

Five crucial features that highlight the advantage of CMOS ...

A steady increase in performance, functionality, and miniaturization has characterized the evolution of CMOS cameras. The first CMOS cameras were introduced in the early s and were primarily used in low-end consumer electronics such as webcams and security cameras. These early CMOS cameras had limited resolution and image quality compared to CCD cameras, which were the dominant technology at the time.

However, over the past two decades, CMOS cameras have steadily improved performance, largely thanks to advances in CMOS technology and manufacturing processes. Today, CMOS cameras are used in various applications, including high-end professional photography, scientific research, medical imaging, and industrial inspection.

In this article, you&#;ll be able to get more details on how CMOS cameras work, their use cases, as well as five imaging features that make them one of the most popular solutions in the market.

What are CMOS cameras &#; and how do they work?

A CMOS camera is a digital camera that uses a Complementary Metal-Oxide-Semiconductor (CMOS) image sensor to capture and process images. Unlike traditional CCD (charge-coupled device) sensors, which use a complex manufacturing process to create a single large sensor, CMOS sensors can be manufactured using standard semiconductor manufacturing techniques, resulting in a smaller and less expensive sensor. Also, unlike older CCD cameras, CMOS cameras use less power and have faster readout speeds, making them popular in various applications.

Read: CMOS sensors vs. CCD sensors: why CMOS sensors are ruling the world of embedded vision?

The basic operation of a CMOS camera is as follows: when light enters the camera lens, it is focused onto the CMOS sensor, which converts the light into an electrical charge. Each pixel on the sensor corresponds to a specific point in the image, and the electrical charge at each pixel is read out and converted into a digital signal. The camera&#;s image processor processes this digital signal to create a final image.

Use cases of CMOS cameras

CMOS cameras have many potential business use cases due to their high-quality image capture capabilities, low power consumption, and versatility. Here are a few examples:

Security: CMOS cameras can be used for surveillance and security purposes in businesses, retail stores, and other public places. They can capture high-quality video and images in well-lit and low-light environments, making them useful for monitoring and identifying potential security threats.

Manufacturing: CMOS cameras can be used in manufacturing processes to inspect products for defects, measure dimensions, and monitor production lines. They can capture images at high speeds, making them useful for inspecting fast-moving objects.

Medical: CMOS cameras can be used in medical imaging applications, such as endoscopy and dental imaging. They can capture high-quality images in small spaces and at different angles, making them useful for diagnosing and treating medical conditions.

Agriculture: CMOS cameras can be used in agricultural applications to monitor crop growth, detect pests and diseases, and optimize irrigation. They can capture high-quality images of crops, soil, and plants, making them useful for precision farming.

Read: How are CMOS cameras used in cell imaging and molecular imaging?

Five key features that showcase the advantages of CMOS cameras

CMOS cameras have several imaging features that highlight their advantages over other types of cameras. These features include high resolution, low noise, high dynamic range, fast readout speed, and low power consumption.

High Resolution

CMOS sensors can produce high-resolution images, allowing for more detailed images with greater clarity. As technology has advanced, CMOS sensors have achieved higher resolutions, up to several hundred megapixels in some cases.

High Sensitivity

CMOS sensors can capture images with high sensitivity, which means they can capture images in low-light conditions without sacrificing image quality. First, the individual pixels on a CMOS sensor can be made larger, allowing for more light to be captured. Additionally, the use of backside illumination (BSI) can increase the efficiency of light capture by placing the photodiodes on the backside of the sensor instead of the front.

Low Noise

CMOS sensors have lower noise levels than other types of sensors, such as CCD sensors, due to how they are designed. Each pixel on a CMOS sensor has its own amplifier, which amplifies the signal from the photodiode. This results in a higher signal-to-noise ratio, reducing the amount of noise in the image. Hence, by producing images with less visual distortion and graininess, CMOS cameras can improve the accuracy and reliability of many imaging tasks.

High Dynamic Range

CMOS sensors are capable of achieving high dynamic range by using a technique called &#;multiple exposure&#;. It involves capturing multiple images of the same scene at different exposure levels and combining them to create a single image with a wider dynamic range. High dynamic range in CMOS cameras is particularly important for outdoor applications where there can be a wide range of light intensity within a single scene. By capturing a wider dynamic range, CMOS cameras can produce images with more detail and better color accuracy.

High-Speed Imaging

CMOS sensors are capable of capturing images at very high frame rates, making them ideal for applications where fast-moving objects need to be captured with high temporal resolution. Some CMOS cameras are also capable of high-speed data transfer, allowing for real-time analysis of the images as they are being captured. This feature is particularly useful in scientific and industrial applications, where analyzing the images in real-time may be necessary to monitor and control a process.

Read: What is CMOS sensor size in embedded cameras? How to pick the right sensor size?

e-con Systems&#; cutting-edge CMOS camera modules for a variety of industries

e-con Systems&#; CMOS camera modules are perfectly suited for industrial, retail, agricultural, and medical environments. Our camera modules can be easily integrated with a wide variety of embedded platforms &#; including NVIDIA Jetson. So, they are ideal for imaging applications like autonomous mobile robots, point-of-care diagnostic devices, fundus cameras, autonomous shopping systems, smart traffic devices, auto farming devices, etc.

We also offer a range of customization options for its CMOS cameras. Our experienced team of engineers can work with clients to develop customized camera solutions that meet their specific imaging requirements. This can include custom sensor selection, lens selection, integration with hardware and software, etc.

Our CMOS cameras include:

Of course, if you are looking to integrate CMOS cameras into your embedded vision products, please write to . You can also visit our Camera Selector to get a full view of our camera portfolio.

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