High-speed cameras and the related vision accessories (LED illuminators, dedicated lenses, triggering and synchronization systems) are fundamental components of industrial machine vision systems, particularly for quality control on fast lines, analysis of rapid motion, inspection of products in movement and R&D on dynamic processes. Acquisition rates can exceed tens of thousands of frames per second (fps) in specialist versions for scientific applications, while typical industrial cameras operate in the 30-2000 fps range with resolutions from VGA up to several megapixels.
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Sensors and architectures
The sensors used are predominantly global shutter CMOS (for simultaneous acquisition of all pixels, essential on moving parts) with interline or stacked BSI architectures to improve sensitivity and speed. Data transmission interfaces range from GigE Vision (1, 5, 10 Gbps) to USB3 Vision, CoaXPress (up to 12.5 Gbps per channel) and CameraLink. Synchronization between camera, illuminator and process is achieved through hardware triggers with high timing precision (μs).
Lighting
Lighting is a critical component in high-speed systems: short exposure times (tens of μs) require high light intensity. LED illuminators are the most widespread, thanks to their energy efficiency, long life and the ability to operate in pulsed mode synchronized with acquisition (strobe). The most widely used configurations are ring, dome, backlight, collimated beam for silhouettes, structured light for 3D and coaxial light for reflective surfaces. The choice of color (red, blue, IR, white) optimizes the contrast of the defect against the material.
Applications
High-speed cameras are used in the inspection of fast printing and packaging lines, in the control of SMD electronic components, in the inspection of caps and capsules, in the dimensional measurement of moving parts (extrusion, drawing), in the analysis of rapid motion (airbag testing, crash tests, ballistics, fluid dynamics), in the study of mechanical vibration and rotating motion, and in scientific and medical research. Typical industrial applications reach product speeds of several m/s with detectable defect sizes in the order of tenths of a millimeter.
Accessories and lenses
Lenses are sized to the sensor and the application: telecentric lenses for high-precision dimensional measurements (no perspective distortion), macro lenses for fine detail, standard fixed-focus lenses and motorized zooms. Accessories include optical filters (band-pass, polarizers), precision mechanical mounts, shielded industrial cables and dedicated frame grabbers. For harsh environments, housings with IP65/IP67 protection ratings and tempered glass windows are available.
Selection criteria
Selecting a high-speed camera requires an analysis of the speed of the process (to define the minimum fps), the size of the defect to be detected (to define the minimum sensor resolution), the available lighting (sensitivity), the working distance (lens focal length), the acquisition interface and the availability of image processing software. Camera, lens and lighting should be sized together, in order to guarantee the performance actually obtained.
For motion analysis applications, high-speed cameras are often paired with motion analysis software and automatic marker tracking, enabling quantitative measurements of the speed, acceleration and trajectory of mechanical components under dynamic operation — indispensable in the research and development phase of new products.
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