Tools · Line scan camera
Line scan · moving web

Inspect the full web without gaps

Enter the material width, minimum defect, and line speed to select one camera and check line-rate margin, illumination, optics, and synchronization.

Typical lines
Line
Material width
The full width that must fit within one line
mm
Minimum defect
Pinhole, inclusion, or streak
mm
Line speed
How fast the web moves
Inspection task — pixels per defect
The number of pixels across the smallest feature. The magnified view shows how the pixel grid covers it
System task
Measurement requires an encoder position reference; defect detection can allow known distortion
Camera color
A color camera distinguishes hues; a monochrome camera is generally more sensitive and less expensive
Synchronization
An encoder keeps the image scale stable when the conveyor speed changes
Line encoder
Rated periods per revolution and effective roller diameter
periods/rev mm
Quadrature decoding: with both phases connected, the camera counts four edges per period
Scale-error tolerance along motion
Compared with the encoder setup error, or with speed variation when no encoder is used
%
Working distance
The formula measures it from the lens principal plane to the web
mm
Calculation settings
Line-rate margin
Operating line rate = required line rate × (1 + margin)
%
Line period available for exposure
The camera uses the remaining period for readout; the rated limit of the selected model is also applied
ratio
Adjacent-camera overlap
Alignment allowance for merging fields in a multi-camera layout
%
Inspection geometry
3 px per defect defect ⌀0.3 mm camera line LINE SCAN CAMERA 1000 mm/s web motion width = field of view · 800 mm
Required line width
Line rate
Available exposure time
Counts per line
Calculating…Loading the camera catalog.
Line scan cameras for this task
SelectModelQuoteLine widthMax. line rateMarginInterfaceStatus
Cameras that meet the line rate with the least excess margin come first; a simpler interface breaks ties.
Calculation details

How it is calculated

A line-scan camera captures one line at a time, and the image is assembled from lines as the web or part moves. The tool therefore treats two independent axes: across the motion — how many pixels the line must have; along the motion — how fast lines must be captured. It then checks the exposure, the frequency headroom, whether an encoder is required, and selects catalogue cameras whose line length and maximum line rate satisfy the requirements.

Formulas

Worked examples

Example 1. Line rate. Speed 500 mm/s, resolution 24.48 px/mm: line rate 12 240 Hz. With 20 % headroom the camera must deliver at least 14 700 lines/s.

Example 2. Web inspection. Web 1250 mm, defect 0.5 mm, 5 px per defect: 12 500 px per line — a 16k camera. 60 m/min equals 1000 mm/s; with a square 0.1 mm pixel the line rate is 10 000 Hz and the exposure no longer than 80 µs. Such an exposure needs a high-intensity line light.

Example 3. Width measurement. Web 1250 mm, tolerance ±0.1 mm, 3 px per tolerance: 37 500 px across. If sampling is needed in both directions at 1000 mm/s — 30 000 lines/s, 36 000 with headroom. If only the width is measured, the along-motion step can be 1 mm — 1000 lines/s. Without an encoder this setup is not considered fit for measurement.

Example 4. Several cameras. When the required line length exceeds available cameras, the web is split between several cameras with overlap; the optics of each camera is computed from its own field and working distance.

Common mistakes

Questions and answers

When is a line-scan camera needed instead of an area camera?

When the object is long or continuous (web, belt, sheet, pipe), moves at a known speed and needs high resolution across its width. An area camera either lacks the resolution or requires complex frame stitching.

Is an encoder mandatory?

For measurement — yes, it drives the line rate from actual displacement. For defect detection at stable speed the internal generator is acceptable if the speed deviation stays within 10 %; beyond that the tool requires an encoder.

How is the exposure chosen?

No longer than 0.8 of the line period; the rest is readout. At 10 000 lines/s that is 80 µs. If light is insufficient, use a brighter line light, a larger aperture or a TDI camera.

What is line-rate headroom?

The camera must deliver a line rate 20 % above the calculated one. This covers speed fluctuations and overhead. A camera at the limit gets the “at the limit” status and does not qualify.

What is passed to the configurator?

The selected camera, the number of cameras and the lens focal length rounded to 0.1 mm. Cables, frame grabber and power are checked further in the configurator.

Required line rate

Speed, m/minObject sampling, mmpx/mmLine rate, Hz
100.05203,333
100.1101,667
100.25833
100.52333
300.052010,000
300.1105,000
300.252,500
300.521,000
600.052020,000
600.11010,000
600.255,000
600.522,000
1200.052040,000
1200.11020,000
1200.2510,000
1200.524,000
3000.0520100,000
3000.11050,000
3000.2525,000
3000.5210,000

Required line width

Web width, mmFeature, mmPixels per featureRequired, pxNearest catalog width, px
3000.234,5007,360
3000.257,5008,192
3000.531,8002,048
3000.553,0004,096
300139002,048
300151,5002,048
6000.239,00016,384
6000.2515,00016,384
6000.533,6004,096
6000.556,0007,360
600131,8002,048
600153,0004,096
1,2500.2318,75023,424
1,2500.2531,250
1,2500.537,5008,192
1,2500.5512,50016,384
1,250133,7504,096
1,250156,2507,360
2,0000.2330,000
2,0000.2550,000
2,0000.5312,00016,384
2,0000.5520,00023,424
2,000136,0007,360
2,0001510,00016,384