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RGB cameras: Definition, components, and integration

Step into a world of vivid detail and color, where every shade and hue is captured precisely. This is the domain of embedded vision and RGB cameras, a vital tool in the digital era that transforms the world’s vibrant canvas into a digital marvel. By harnessing the potential of the RGB (Red, Green, Blue) color model, these cameras are not merely tools but gateways to a visually immersive universe. They are indispensable across various domains, from artistic photography to scientific exploration and industrial inspection, providing a glimpse into the authentic colors of our surroundings. This article delves into the components, functionality, and integration of RGB cameras.

RGB camera – definition

RGB cameras are designed specifically to capture visible light. These cameras use a Color Array Filter (CFA) with the standard Bayer BGGR pattern, which is sensitive to the primary colors of visible light: red, green, and blue. The Bayer filter array is arranged in a mosaic over the camera sensor’s pixels, with each pixel dedicated to capturing a specific color.

Green pixels are more prevalent due to the human eye’s sensitivity to green light, producing more ‘visible’ images. The main purpose of an RGB camera is to capture images that closely resemble the human visual experience by mimicking how our eyes perceive color. During image processing, the camera’s software algorithm combines data from individual red, green, and blue pixels through demosaicing to produce full-color images that are detailed and accurate in color representation.

The Bayer Pattern

Components of an RGB camera system

Here, let us look at the different components of an RGB camera.

  • Color sensor: The color sensor is the core component of an RGB camera, typically a Charge-Coupled Device (CCD) or a Complementary Metal-Oxide-Semiconductor (CMOS). It plays a crucial role in capturing and transforming light into an electronic signal. It is sensitive to the visible spectrum (400-700nm), enabling image capture in natural and visible light conditions.
  • Lens: The lens is crucial in directing light onto the sensor. Its quality significantly affects the sharpness and clarity of the captured image by accurately guiding light to the sensor, thus preserving the image’s integrity.

Also read: How to Choose Camera Lens for Embedded Vision Applications

  • Image Signal Processor (ISP): The ISP plays a critical role in handling the colors recorded by the sensor. It transforms the unprocessed sensor data into a format that can be viewed while adjusting to factors such as white balance, hue, saturation, and brightness to create a vibrant and precise image.
  • Interface and connectors: These elements connect the camera with the processor. The bandwidth of the interface determines the amount of image data that can be transmitted in a given time. For example, the FPD-Link III interface offers a bandwidth of about 4 Gbps.
  • Processor: The processor, typically a component within an embedded system or computing device, is tasked with managing the data captured by the camera. Its role involves processing images for various uses, from basic display purposes to detailed image analysis.
  • Adaptor board: An adaptor board is essential when using multiple cameras or specific processors to ensure compatibility between the camera and the processing unit.
  • The heat sink (Optional): Some cameras might need a heat sink, particularly those that generate significant heat. This element is necessary for dispersing heat, guaranteeing that the camera functions within safe temperature thresholds, and upholding its performance in the long run. This also ensures that the camera has a longer life.
  • Enclosure (Optional): Cameras used in rugged conditions require an enclosure to shield their internal parts from dust, moisture, and physical damage. This safeguard is a must for maintaining the camera’s durability in tough environments. For instance, TechNexion’s embedded vision cameras come with an IP68 enclosure, making them suitable for industrial or outdoor use.

Monochrome cameras vs. RGB cameras

Monochrome cameras

  • mage quality: Cameras without a color filter array, known as monochrome cameras, can capture increased light and typically boast a higher quality when compared to their RGB counterparts. This feature makes them well-suited for tasks where precision is prioritized over color, such as barcode reading.
  • Sensitivity and performance in low light: These cameras excel in low-light conditions due to their higher sensitivity, allowing them to capture more details. This makes them the superior choice for dimly lit environments.
  • Cost and complexity: Typically, monochrome cameras have a more straightforward design and may come at a lower cost than RGB cameras. This is because they do not require intricate color processing hardware and software.
  • Spectral sensitivity: Due to their lack of color filters, they have an expanded spectral sensitivity, enabling them to detect a broader range of wavelengths. This quality makes them well-suited for specific uses such as night vision, where capturing the complete light spectrum is essential.

VCI-AR0522-SL – AR0522 monochrome camera from TechNexion

  • Dynamic range: Monochrome cameras generally offer a greater dynamic range due to the lack of a color filter, enabling each sensor pixel to capture a broader spectrum of light intensities.
  • Frame rate: Frequently, they achieve higher frame rates because they require less complex processing.
  • Application-specific requirements: They are the top choice for tasks that demand high sensitivity with less emphasis on color accuracy. This includes uses such as astronomical imaging, medical imaging (such as retina scanners), and certain types of industrial inspection.

VCI-AR0821-CB – AR0821 RGB camera from TechNexion

RGB cameras

  • Color information: RGB cameras can effectively capture color using a CFA like the Bayer filter. This feature is essential for tasks that rely on accurate color representation, such as food inspection, object recognition, and robotics.
  • Image processing and application: Reconstructing the color image from the Bayer pattern with RGB cameras may create noise or artifacts in low light conditions. RGB cameras are more appropriate for applications like object identification, where color could serve as a key differentiator.
  • Versatility and use in varied environments: RGB cameras offer greater flexibility thanks to their capacity to deliver color data, making them a popular choice across various environments, including industrial and agricultural applications.
  • Spectral sensitivity: RGB cameras have their spectral sensitivity restricted to some level by the color filters in the CFA. However, modern-day RGB sensors come with superior sensitivity and are suitable for use in low-light conditions.
  • Dynamic range: RGB cameras may have a restricted dynamic range because of the filtering process, as each color channel captures only a segment of the light spectrum. This limitation can result in a narrower overall dynamic range than monochrome cameras. At the same time, sensor technology is very advanced today, and RGB sensors can offer a dynamic range in excess of 130 dB.
  • Frame rate: RGB cameras may experience reduced frame rates when handling color data, particularly with high-resolution images. Modifying factors like the processing platform, interface, and exposure time can help achieve the required frame rate.
  • Application-specific requirements: Perfect for situations where accurate color representation is crucial, such as medical and life science equipment, harvesting robots, and autonomous checkout systems.

How to integrate RGB cameras into embedded vision systems

In this section, let us look at the factors you need to consider when selecting an RGB camera for your embedded vision system.

  • Resolution: Opt for a resolution that suits your needs. Higher resolutions offer more detailed images but require increased processing power and bandwidth.
  • Frame rate: Choose a frame rate that matches the speed of the events you want to capture. Higher frame rates are essential for fast-moving objects but demand more processing power.
  • Bandwidth: Ensure the camera’s data output aligns with your system’s processing and storage capabilities. Higher resolutions and frame rates will require high-end processors like NVIDIA Jetson or TI Jacinto TDA4VM.
  • Shutter type: Decide between a global shutter (captures the entire image at once, suitable for fast-moving objects) and a rolling shutter (captures the image line by line, suitable for static or slow-moving objects).

Next, let us look at some key steps involved in integrating RGB cameras into your device and taking it to the market.

Evaluating the camera with the embedded vision device:

When it comes to evaluating a camera, the following are a few things you need to keep in mind:

  • Examine the camera and the integrated vision device to confirm compatibility.
  • Look for any hardware or software limitations that could impact their performance.
  • Assess the image quality in various scenarios to guarantee it aligns with the application’s requirements.

Making necessary customizations:

  • Fine-tune parameters such as exposure, gain, and white balance to enhance image quality.
  • Tailor the software or firmware as necessary to improve compatibility and performance.
  • Evaluate the requirement for supplementary elements like lenses or lighting.
  • Make necessary customizations to other hardware elements like the interface, ISP, adaptor board, etc.

Testing with the prototype:

  • Integrate the camera into a prototype of the embedded vision system and conduct thorough testing to pinpoint and address any issues that may arise in real-life situations.
  • Verify that the system fulfills all operational criteria and is dependable and consistent.

Going for mass production

After confirming the successful testing of the prototype and meeting all specifications, move forward with mass production while implementing quality control measures to uphold consistency across all units.

Camera selection and integration can be a complex process. And there are many more factors you need to consider depending on the end application. Taking the help of an imaging expert like TechNexion is highly recommended.

 

TechNexion – RGB cameras for every application:

TechNexion provides a selection of RGB cameras designed to meet various needs. They are suitable for various applications, including industrial automation, medical imaging, and agriculture, with options for different resolutions, frame rates, and shutter types. We also have a state-of-the-art manufacturing process with the Package on Package (PoP) Technology. Learn more about our embedded vision solutions here.

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