The Challenge of Capturing Moving Objects

Industrial machine vision systems, utilizing high-precision hardware such as a Basler industrial machine vision camera, inspect products while they move through production lines. They measure dimensions, identify defects, read codes, and verify assembly conditions.

When an object moves during image capture, the camera may record motion distortion.

This problem becomes more significant at high conveyor speeds, during vibration, or when inspecting rotating components.

Global shutter image sensors address this challenge by exposing the image pixels at the same time.

1. Understand Global Shutter and Rolling Shutter

A rolling shutter sensor captures different image rows at different times. During rapid movement, this timing difference can distort the object's shape or position.

A global shutter sensor captures the entire image with synchronized exposure. This helps preserve the geometry of moving objects.

Global shutter technology is useful for applications involving fast conveyors, robotic picking, rotating machinery, and high-speed inspection, standard in high-speed devices like Basler area scan cameras.

2. Select an Appropriate Exposure Time

Exposure time determines how long the sensor collects light for an image.

Shorter exposure times can reduce motion blur. However, they also reduce the amount of light reaching the sensor.

For high-speed inspection, engineers should consider object velocity, camera distance, field of view, lighting intensity, and required measurement resolution.

Strobe lighting can help provide sufficient illumination during short exposure periods.

3. Balance Resolution and Frame Rate

Higher resolution provides more image detail, but it also increases data volume and processing requirements.

Frame rate determines how frequently the camera can capture images. The required frame rate depends on product speed and the spacing between inspection opportunities.

For example, an inspection station operating on a fast conveyor must capture each product before it leaves the camera's field of view.

Camera bandwidth, interface capacity, computer processing, and storage must all support the expected data rate, often backed by reliable infrastructure such as a MOXA industrial Ethernet switch.

4. Consider Dynamic Range and Lighting Conditions

Industrial inspection environments often contain reflective metal surfaces, dark materials, bright illumination, or uneven backgrounds.

Dynamic range affects the camera's ability to capture details across different brightness levels.

High dynamic range imaging can help in challenging scenes, but the camera's exposure strategy and lighting design remain important.

Test the actual product surface under production lighting rather than relying only on laboratory image samples.

5. Evaluate the Complete Camera Interface

Image sensors operate inside a complete camera architecture. The sensor output must connect to image processing hardware and the industrial computer or controller, such as an Allen-Bradley machine vision interface module.

Review interface bandwidth, cable distance, synchronization, trigger support, and software compatibility.

Some sensor devices use interfaces such as sub-LVDS or MIPI internally. The camera manufacturer determines how these signals are exposed to the final system.

Do not assume that an image sensor's internal interface is directly compatible with a standard industrial PC.

6. Test Image Quality Under Real Production Conditions

Before deployment, test the camera with representative products, conveyor speeds, lighting conditions, and environmental vibration.

Check image sharpness, trigger consistency, defect visibility, and processing latency.

Also verify how the inspection system behaves when a trigger is missed or an image cannot be processed in time.