Choosing the Right Shutter Machine Vision System for Your Application

Selecting the right shutter machine vision system depends on several important factors. Users often consider motion speed, image quality, cost, and the specific application. Many industries prefer global shutter solutions for their ability to capture undistorted images, especially when inspecting fast-moving objects. Rolling shutters, on the other hand, work well in static scenes but may cause distortions with rapid motion.

Key selection factors include:

• The speed of the object or process
• Required image quality for analysis or inspection
• Budget constraints and environmental conditions
  Understanding the difference between rolling and global shutter technology helps ensure the chosen machine vision system and camera meet the application’s needs.

Key Takeaways

• Global shutter cameras capture all pixels at once, preventing motion distortion and making them ideal for fast-moving or dynamic scenes.
• Rolling shutter cameras expose pixels row by row, which can cause image distortion with fast motion but offer higher resolution and lower cost for static or slow-moving scenes.
• Choose a global shutter system for high-speed industrial inspection, robotics, and applications needing precise, distortion-free images.
• Rolling shutter cameras work well for stationary imaging, surveillance with little motion, and budget-sensitive projects due to their cost-effectiveness and better low-light performance.
• Use a clear decision checklist considering motion speed, image quality, lighting, and budget to select the best shutter system for your specific application.

Shutter Machine Vision System Types

Rolling Shutter

A rolling shutter camera uses a sensor that exposes each row of pixels one after another, not all at once. This method is common in many CMOS cameras. The sensor starts at the top row and moves down, capturing the image in a wave-like motion. Each row begins and ends exposure at slightly different times. This process can lead to image distortion, especially when objects move quickly or the camera vibrates.

The rolling shutter effect often appears as the "jello effect" or skewed lines in photos and videos. Fast-moving objects, like spinning fan blades or passing cars, may look bent or warped. This happens because the sensor records different parts of the scene at different moments.

Rolling shutter systems work well for static or slow-moving scenes. They offer lower cost and higher resolution compared to some other machine vision systems. However, in high-speed applications, rolling shutter distortion can make it hard to capture accurate images. Increasing the frame rate or shutter speed can help reduce these artifacts, but cannot fully eliminate them.

Global Shutter

A global shutter camera uses a sensor that exposes all pixels at the same time. This method is known as a true global shutter. The sensor captures the entire frame in a single instant, then reads out the data. This approach prevents the timing differences that cause distortion in rolling shutter systems.

A global shutter camera eliminates motion artifacts, making it ideal for capturing fast-moving objects or scenes with sudden changes in light. This type of sensor is often used in industrial inspection, robotics, and other demanding machine vision systems. While global shutter cameras may cost more and sometimes offer lower resolution than rolling shutter models, they provide unmatched image integrity in dynamic environments.

Note: Many modern CMOS sensors now support true global shutter technology, combining the benefits of high speed and low distortion.

Rolling vs. Global Shutter

Image Quality

Image quality stands as a key factor when selecting a shutter machine vision system. A global shutter camera exposes all pixels at the same time, which prevents distortion and ensures accurate capture of fast-moving objects. This feature makes global shutter cameras ideal for applications that demand high-precision imaging, such as industrial inspection and robotics. These cameras eliminate the "jello effect" and other motion artifacts, delivering consistent and reliable results.

Rolling shutter cameras, in contrast, expose the sensor row by row. This sequential exposure can introduce artifacts like skewed lines or wobbly images when capturing rapid motion. However, rolling shutter cameras often provide higher resolution and better dynamic range, especially in low-light conditions. They also tend to produce less noise due to their simpler cmos sensor design. For scenes with minimal movement, rolling shutter cameras deliver excellent image quality and frame-to-frame consistency.

Note: While global shutter cameras offer distortion-free imaging, some models may show higher noise levels and lower dynamic range compared to rolling shutter cameras.

Speed

Speed plays a crucial role in machine vision applications. Rolling shutter sensors read out image data sequentially, row by row. This process creates a time gap between the exposure of the first and last rows. For example, a 1920×1080 rolling shutter sensor at 30 frames per second has a row readout time of about 30.86 microseconds. The entire frame is scanned from top to bottom, which can cause distortion if the scene changes quickly.

Global shutter cameras expose all pixels simultaneously, capturing the entire frame in one instant. After exposure, the sensor reads out the data, but the exposure itself happens at the same moment for every pixel. This approach eliminates distortion caused by sequential exposure and is essential for high-speed machine vision tasks. Rolling shutter sensors can achieve higher frame rates and lower power consumption, but only global shutter cameras provide true smear-free imaging in dynamic environments.

Cost

Cost differences between rolling shutter and global shutter cameras can be significant. Rolling shutter cameras use a simpler sensor design and often achieve higher pixel density. This makes them more affordable and suitable for budget-sensitive applications. For example, a rolling shutter camera like the Teledyne Dalsa Nano C4900 with an 18MP sensor can cost under $600.

Global shutter cameras require more complex circuitry and often have lower pixel density. The added complexity and larger image format increase both the camera and lens costs. For instance, a global shutter camera module such as the OV9281 for Raspberry Pi may cost around $25.90 for a 1MP sensor, but industrial-grade models are generally much more expensive. The table below summarizes these differences:

Tip: Rolling shutter cameras offer a cost-effective solution for applications where motion distortion is not a concern.

Use Cases

Choosing between rolling and global shutter systems depends on the specific application. Rolling shutter cameras are preferred in scenarios where subjects remain mostly still or move slowly. These cameras work well for:

• Still photography with minimal motion blur
• Scenes with changing light levels
• General photography and consumer devices like smartphones
• Static monitoring, video conferencing, and document scanning
• Applications where slight motion distortion is acceptable or can be corrected by software

Rolling shutter cameras also provide better sensitivity and dynamic range in many cases, making them suitable for low-light environments.

A global shutter camera excels in high-speed and high-precision environments. Common use cases include:

• Quality control inspection on fast-moving assembly lines
• Warehouse autonomous mobile robots (AMRs) for navigation and item recognition
• Parcel sorting on high-speed conveyor belts for barcode and label verification
• Industrial diagnostics in environments with vibration or rapid movement
• Factory automation for product identification, counting, and sorting
• Traffic management, metrology, and robotics inspection requiring distortion-free images

A true global shutter sensor ensures all pixels capture the scene at the same instant, which is critical for applications that cannot tolerate any image distortion.

Global shutter cameras eliminate rolling shutter artifacts, making them the best choice for dynamic scenes and high-speed machine vision tasks.

Application Recommendations

Industrial Inspection

Industrial inspection demands precise and reliable imaging. In a factory setting, products often move quickly along conveyor belts. A global shutter camera captures every pixel at the same instant, preventing motion blur and distortion. This feature proves essential for quality control, where even small defects must be detected. Many high-throughput factory applications rely on global shutter sensors to ensure accurate recognition of product features and barcodes. Recent advancements, such as BSI global shutter sensors, have improved light sensitivity and reduced noise, making these cameras even more effective in challenging lighting conditions. An industrial camera system with a global shutter provides the consistency and speed required for modern inspection lines.

Tip: For high-speed production lines or fast-moving targets, a global shutter camera ensures distortion-free images and reliable defect detection.

Robotics

Robotics applications often involve rapid movement and complex tasks. Robots in warehouses, manufacturing, or autonomous vehicles must process visual information quickly and accurately. The choice between rolling and global shutter cameras depends on the robot’s speed and the need for image integrity. The table below summarizes key performance requirements for robotics:

A global shutter camera offers the best performance for robots that require fast and accurate recognition, such as those used in autonomous navigation or object sorting. For slower-moving robots or those in less dynamic environments, a rolling shutter camera may provide sufficient image quality at a lower cost. Embedded vision system designs benefit from miniaturized global shutter sensors, which fit into compact spaces and deliver high-speed, distortion-free imaging.

Stationary Imaging

Stationary imaging covers applications like document scanning, fixed surveillance, and static monitoring. In these scenarios, the camera and subject remain still. Rolling shutter cameras excel here due to their higher resolution and lower cost. They capture images row by row, but since there is little or no movement, distortion does not occur. Rolling shutter cameras also offer power efficiency, making them popular in consumer and budget-sensitive projects.

• Rolling shutter cameras provide excellent image quality for static scenes.
• They offer cost and power advantages for stationary or low-motion applications.
• Global shutter cameras eliminate motion distortion but usually come with higher cost and lower resolution.

For most stationary imaging needs, a rolling shutter camera delivers adequate performance. However, if the application requires capturing occasional fast-moving objects, a global shutter camera may be considered.

Surveillance

Surveillance systems must adapt to varying lighting conditions and security requirements. The choice of shutter system depends on the environment and the level of motion in the scene. The table below outlines key considerations for surveillance applications:

For outdoor or high-security surveillance, a global shutter camera ensures clear images of moving subjects, even in low light or challenging weather. BSI global shutter sensors further enhance performance by improving low-light sensitivity and reducing noise. In indoor or static monitoring, a rolling shutter camera may suffice, offering cost savings and adequate image quality.

Note: Matching the shutter type to the motion and lighting conditions of the surveillance environment ensures optimal performance and reliability.

Choosing Your Shutter Machine Vision System

Decision Checklist

Selecting the right shutter machine vision system involves several clear steps. A structured approach helps users match their needs to the best camera and sensor technology. Here is a practical checklist:

1. Define the application and vision tasks. Identify the smallest detail the image processing system must resolve.
2. Measure the working distance. This affects focus and the required focal length.
3. Assess the object size to determine the field of view.
4. Specify the required resolution. This impacts both the sensor and pixel size.
5. Identify if the camera or object will move. Note the speed, as this influences the choice between rolling and global shutter.
6. Evaluate lighting conditions. Consider if lighting can be controlled or if the environment changes.
7. Review motion implications. Adjust shutter speed and lens aperture (f-number) as needed.
8. Check camera connectivity and interface options for system compatibility.
9. Set a budget, including the total cost of ownership.
10. Choose a manufacturer with strong support and a wide range of options.

Tip: For high-speed or dynamic scenes, a global shutter camera prevents distortion. For static or slow-moving scenes, a rolling shutter camera offers higher resolution at a lower cost.

Product Factors

Several technical factors influence the final choice of camera and sensor. The table below compares key features:

Recent advancements, such as BSI global shutter sensors, have improved image quality and sensitivity. Integration challenges often include managing lighting, ensuring real-time communication between hardware and software, and maintaining system calibration. Modular design and vendor support help future-proof the machine vision system. Many modern cameras now feature AI and edge computing, which enhance the performance of the image processing system.

Note: Always consider how the camera, sensor, and software will work together for reliable results.

Selecting between rolling and global shutter systems requires careful alignment with application needs and technical requirements. Industry experts recommend these steps:

1. Identify inspection categories and industry-specific needs.
2. Choose devices tailored to the task, including camera and lighting.
3. Test on actual targets and review environmental factors.
4. Fine-tune automation controls and perform on-site validation.

Many users overlook lighting, sensor resolution, and environmental effects, which can reduce accuracy. For further guidance, resources include technical papers, certification programs, and expert consultation services. Using the checklist and seeking expert advice ensures reliable machine vision performance.

FAQ

What is the main difference between rolling and global shutter cameras?

A rolling shutter exposes the sensor row by row. A global shutter exposes all pixels at once. Global shutters prevent motion distortion. Rolling shutters may show artifacts with fast movement.

Can a rolling shutter camera work for moving objects?

Rolling shutter cameras can capture moving objects, but fast motion may cause distortion. For slow or moderate movement, they often perform well. Users should test the camera in real conditions.

Are global shutter cameras always more expensive?

Global shutter cameras usually cost more because of complex sensor design. However, prices have dropped as technology advances. Users should compare features and performance before deciding.

How do lighting conditions affect shutter choice?

Lighting affects image quality for both shutter types. Global shutter sensors may show more noise in low light. Rolling shutters often provide better dynamic range. Proper lighting improves results for any camera.

See Also

Comprehensive Overview of Machine Vision Systems for Semiconductors

How To Properly Position Equipment Within Machine Vision Systems

Understanding The Role Of Cameras In Vision Systems

Comparing Firmware-Based Machine Vision With Conventional Systems

An In-Depth Look At Electronics In Machine Vision Systems