Area Scan or Line Scan for Wide-Field Large Parts?
Wide-field inspection of large workpieces is usually solved by stitching several cameras, which brings system complexity, calibration volume and cost. This case takes a different route. Static parts use an area-scan model at 12 MP, exposing the whole field once; continuously moving or cylindrical parts use a line-scan model at 2000 pixels per line, building a 32 MP image row by row. Both are IP67 rated, a single imaging cycle is about 8 seconds, and figures are subject to site acceptance results.
The bottleneck in wide-field inspection is rarely the sensor
When a part outgrows one camera, the reflex is to add another. Each addition brings a set of intrinsic and extrinsic calibrations, an overlap region and another link in the error chain. Systems grow complicated, and what sinks the project is often not image quality but the maintenance of calibration and consistency.
Multi-camera cost hides in calibration
A multi-camera layout requires calibrating every camera inside and out, plus the geometric relationship between cameras. More cameras mean a longer error chain. A single camera needs one calibration, so error sources collapse into one link and accuracy is easier to hold.
The decision line is motion
For a part that waits still, an area scan produces the whole image in one exposure: expose, extract features, output a verdict. A part moving continuously on a conveyor is a different problem, because it moves during exposure and the image smears. A line scan acquires row by row, and the object's own motion becomes the scan motion, so rows join naturally and no such blur exists.
Why a cylinder looks more even on a line scan
An area camera viewing a large cylindrical part runs into depth-of-field and viewing-angle problems, and the closer to the edge, the worse it looks. A line scan passes row by row at a constant imaging distance, effectively unrolling the cylinder along its generatrix. The perspective distortion of an area view disappears and consistency improves.
What a single camera gives up
In return for a simpler system, the single camera accepts a resolution ceiling. One sensor has to fill the whole wide field, so the physical size represented by one pixel grows. When detail requirements exceed that ceiling, multi-camera stitching returns to the table.
Three questions order the selection
First, motion: static work favours area scan, while continuous movement, large parts or cylindrical surfaces favour line scan. Second, field of view and resolution: fix the largest workpiece, then the required pixel density. Third, environment: on a constrained station with dust, chips or coolant spray, an IP67 housing is a necessity rather than a bonus. When both part families share a line, two stations can be configured under one system at lower management cost than a multi-camera layout.
Lighting follows the imaging method: even area light for area scan, a linear light aligned to the scan line for line scan. The two models share a software framework and communication protocol, so inspection logic and data interfaces stay the same and a retrofit replaces only the imaging front end.
Questions to settle before the site visit
How do I choose between area and line scan?
By motion. A static part that needs one wide-field image goes to area scan; a continuously moving conveyor part or a large cylindrical surface goes to line scan. Mixed families are handled station by station.
How do 2000 pixels per line and 32 MP relate?
2000 pixels per line is the sensor width sampled on each row. As the object moves, rows accumulate and the stitched image can reach 32 MP. One is line width, the other is the assembled image resolution; they are not in conflict.
What does a single camera actually save?
View stitching, overlap calibration and cross-camera consistency checks, with hardware and maintenance cost following. It does not remove the resolution ceiling; beyond that ceiling, multi-camera returns.
When is IP67 mandatory?
When the line carries dust, chips, coolant or cleaning spray. IP67 means dust-tight and protected against short immersion, which suits direct mounting in cramped, dirty stations.