Schäfter+Kirchhoff SK2048USD User manual

Kieler Str. 212, 22525 Hamburg, Germany • Tel: [phone] • Fax: [phone] • [email protected] • www.SuKHamburg.de
SK2048USD
Line Scan Camera SK2048USD Manual (v. 7.2012)
Monochrome Line Scan Camera
SK2048USD
2048 pixels, 14 µm x 14 µm, 15 MHz pixel frequency
1) Longer exposure times are possible in trigger mode "exposure active".
Contents
Line scan cameras from Schäfter+Kirchhoff are supplied factory-preset for the particular application. If you are not familiar with line scan
cameras, or their operation using the supplied software, then consult the glossary in Section 7. Line Scan Camera Fundamentals, p 10.
Section Page Section Page
Camera SK2048USD
Sensor Single Line Sensor
Type IL-P3-B
Pixel number 2048
Pixel size 14 µm x 14 µm
Pixel spacing 14 µm
Sensor width 14 µm
Active length 28.7 mm
Anti-Blooming yes
Integration Control yes
Shading Correction no
Window Function (ROI) yes
Pixel frequency 15 MHz
Line frequency max 14.1 kHz
Line frequency min 0.03 kHz
Integration time max 35 ms 1)
Integration time min 2 µs
Dynamic range 1:2500 (rms)
Spectral range 400 – 900 nm
Video signal monochrome 8/12-bit digital
Interface
Voltage +5 V (300 mA)
Power consumption 1.6 W
Casing (W x H x D) AU2 (65 x 65 x 73 mm)
Objective mount M40 x 0.75
Weight 0.2 kg
Working temperature +5°C to +45°C
Interface: USB 2.0
Monochrome line scan camera
SK2048USD
with
Clamp set SK5102
Mounting bracket SK5105
Photo lens Nikon AF 1:1.4/f'=50 mm,
M40x0.75 thread, with locking bridge
for fixing focus and aperture
1
2
3
4
2
3
4
1
Interface: USB 2.0
• Robust input and
output connections
• Hot-pluggable
• Ultimate in mobility
Interface: USB 2.0
1. Introducing the SK2048USD Camera 2
2. Connections 2
3. Hardware and Software Installation 3
4. Camera Control and Measurements 4
4.1 Camera Control and Synchronization 4
4.2 Gain / Offset Adjustments 4
4.3 Generating a 2D Image – Scanning a Surface 4
4.4 Anti-blooming Adjustment 5
5. Sensor Performance Specifications 6
6. Dimensions 9
7. Line Scan Camera Fundamentals 10
8. Warranty 12
9. Accessories 12

Page 2
Line Scan Camera SK2048USD Manual (v. 7.2012)
1. Introducing the SK2048USD Line Scan Camera
2. Connections
The line scan camera SK2048USD is designed for ultimate
portability. The robustly attached dedicated connections
enable external synchronization of the camera and the output
of data to the USB 2.0 port of the computer, which also
supplies power to the camera.
The USB 2.0 connection means that the camera is hot-
pluggable and, with the highly robust connection, provides the
greatest degree of flexibility and mobility. The computer does
not require a grabber board, allowing a laptop to be used
when space or weight restrictions are also at a premium.
The line scan camera SK2048USD has two robustly attached
dedicated connections: BNC coaxial for external
synchronization signals and USB 2.0 for supplying power, to
program the camera parameters and for data collection.
The camera requires a USB 2.0 connection or better and is not
backwards compatible with USB 1.1. The USB power supply
should provide +5 V with a minimum current of 500 mA.
Once the camera driver and the SkLineScan® program have
been loaded from the SK91USB-WIN CD then the camera
can be parameterized. The integration time and thresholding
parameters are stored permanently in the camera even after a
power down or disconnection from the PC.
The oscilloscope display in the SkLineScan® program can be
used to adjust the focus and aperture settings, for evaluating
field flattening of the lens and for orientation of the illumination
and the sensor (for further information, see Section 7. Line
Scan Camera Fundamentals, p 10).
Connections
BNC: input control using external synchronization signals
USB-A : connection with computer – supplying power (+5 V
DC, >500 mA) and for data collection
Cable lengths: 1.7 m
BNC
BNC
USB
USB

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Line Scan Camera SK2048USD Manual (v. 7.2012)
3. Hardware and Software Installation
1. Connect the power supply.
2. Attach USB connector to a Windows PC (XP SP3 or above).
3. The Hardware Assistant will look for a USB device driver.
4. Place the SK91USB-WIN CD in the computer. The driver
will be installed and the setup for the SkLineScan
program starts automatically.
5. Follow the dialog instructions and finish the installation of
SkLineScan.
6. Once installed, start SkLineScan.
- The About dialog confirms that the "SK2048USD"
camera is ready for use and the oscilloscope display
window of the camera signal will open.
- If the camera is not identified correctly then the driver
installation must be attempted again.
The oscilloscope display facility of the SkLineScan program is
responsive in real-time, and the zoom function can be used to
highlight an area of interest. The oscilloscope display is ideally
suited for parameterizing the camera, for evaluating object
illumination, for focussing the image or for aligning the line
scan camera correctly.

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Line Scan Camera SK2048USD Manual (v. 7.2012)
4.1 Camera Control and Synchronization
The camera SK2048USD has a maximum line frequency of
14.10 kHz and the programmable range for the exposure
period is 0.07 ms up to 35.0 ms.
• Open the 'USB Camera Control' dialog from the
SkLineScan program.
• The adjustment range is defined by the left vertical slider
and any changes are immediately visible in the
oscilloscope signal display.
• The button 'Default' sets the integration time at the
minimum exposure period. The camera now works with
the maximum line frequency. At shorter integration times
than 0.07 ms, the 'Integr.Ctrl Status' automatically
switches to 'Active' (Shutter mode).
Mode 0: Internal synchronization by the camera. Each line is
acquired and the next scan is started automatically on
completion of the previous line scan (free run mode).
Mode 1: External camera synchronization. Each line scan is
started by an external trigger (TTL) which determines the line
frequency. The exposure time is constant and must be
programmed prior to the first line scan. The TTL period must
be longer than the exposure period. The TTL clock does not
affect the integration time.
Mode 3: The camera exposure period is started by a
software operation.
Mode 4: External synchronization is as for mode 1, but the
falling edge of the trigger clock starts a new exposure period
immediately (Restart-Reset-Mode). The minimum integration
time in mode 4 is 0.07 ms. Mode 4 requires the use of the
Integration Control function by the camera, which precludes
the use of the shutter function.
4. Camera Control and Measurements
Customized settings for gain or offset can be programmed
using the SkLineScan software:
1. Offset: After blocking all light reaching the line sensor,
bring the video signal near to 0 using the Offset slider. The line
signal should be just visible above the baseline.
2. Gain: Fully
illuminate the
sensor and
move the
gain slider
to provide
maximum
clipping of the
signal (255 or
higher).
For cameras with two channel sensors, the 'B'-slider is
activated automatically. The intensities of even and odd pixels
are adjusted to provide the smallest deviations in signal.
4.2 Gain / Offset Adjustments
4.3 Generating a 2D Image – Scanning a Surface
A two-dimensional image is generated by moving the object
or the camera. The direction of the translation movement
must be orthogonal to the sensor axis of the CCD line scan
camera.
To obtain a proportional image with the correct aspect ratio, a
line synchronous transport with the laterally correct pixel
assignment is required.
The optimal object scan rate is calculated from:
WP • fL
VO =
ß
where
VO = object scan velocity
WP = pixel width
fL = line frequency
ß = magnification
S = sensor length
FOV = Field Of View
magnification = sensor length / Field Of View.
Pixel 1
CCD Sensor
Object
structure
VO
FOV
v
S
WP
Example: Object scan velocity for a given FOV and line
frequency for the line scan camera SK2048USD
Pixel size = 14 µm
Line frequency = 7 kHz
S = 28.7 mm
FOV = 90 mm
VO = 0.014 mm * 7000 / ( 28.7 / 90) s
= 307.3 mm/s
If the velocity of the object carrier is not adjustable then the
line frequency of the camera must be adjusted to provide an
image with the correct aspect ratio, where:
VO • ß
fL =
WP
v
V
V
V
V
v
v

Page 5
Line Scan Camera SK2048USD Manual (v. 7.2012)
4.4 Anti-blooming Adjustment
The electronics of the USD camera series already support the
blooming control possibilities of the sensor and are factory
preset at ~90% of the saturation level VSAT to provide the
greatest dynamic range for the camera with the optimum level
of anti-blooming protection.
The saturation load is regulated by the blooming control voltage
VA. Higher values of VA increase the anti-blooming protection
but at the expense of the dynamic range of the camera, as the
apparent saturation level VSAT is increasingly attentuated.
The anti-blooming effect is switched off completely at zero
voltage VA. The maximum output voltage of the sensor reaches
the saturation level VSAT.
The blooming control voltage VA is factory
preset for optimum anti-blooming and should
only be altered in exceptional circumstances
The optimum anti-blooming effect and greatest dynamic range
for the camera are obtained when the output voltage of the
camera is at ~90% of the saturation voltage VSAT.
Line scan signal with centrally enhanced illumination and
sharply rising signal edges. Integration time tA= 0.158 ms.
Over-exposure caused by a long integration time (tA =
0.533 ms). The blooming effect is increased at the sensor
when overadjusting the blooming control voltage (low VA). The
shapes of the signal are distorted.
The blooming control voltage limits the output signal of the
sensor to about 90% of the saturation voltage VSAT. The anti-
blooming technique is active. Even with a longer integration
time (tA = 0.806 ms), the signal edge positions from 1 are
preserved.
Oscilloscope signal display of the CCD line scan signal
obtained from a barcode illuminated with incident light
1
1
2
2
3
3
P3
The trimmer P3 is accessed from the front of the camera after
the lens has been removed and is factory preset at ~90% of
VSAT.
To prevent maladjustment of the line scan camera, the P3
adjustment should be monitored under sufficient illumination
while observing the oscilloscope display of the line scan signal
on the computer screen.
The anti-blooming control voltage VA is
adjusted using the trimmer P3:
< anticlockwise – raises VA for greater
anti-blooming protection but
reduces dynamic range
> clockwise – lowers VA and reduces
anti-blooming protection
>> fully clockwise – anti-blooming is off
Dynamic range

Page 6
Line Scan Camera SK2048USD Manual (v. 7.2012)
5. Sensor Performance Specifications
Manufacturer: Dalsa
Type: IL-P3-B 2048
Data source: Dalsa Linear Sensor Document 03-036-00187-09
Pin-out and Dimensions

Page 7
Line Scan Camera SK2048USD Manual (v. 7.2012)
Block Diagram and Typical Performance Data

Page 8
Line Scan Camera SK2048USD Manual (v. 7.2012)
Performance Specifications

Page 9
Line Scan Camera SK2048USD Manual (v. 7.2012)
6. Dimensions
Line scan cameras with USB interface
50
3.5 16.5 20 6.5
10
10
15
Ø4.3
50.3 41.7
Ø42
66
36
M3 Ø3.3
M4
M3
6
1/4" 20G
70 63 40
CCD line scan camera, digital
Casing group: AU2
Lens thread: M40x0.75
Distance to sensor: 19.5 mm
Input control: BNC
Data/power interface: USB-A
Camera type:
USD series with 512, 1024 or 2048
pixels
CCD line scan camera, digital
Lens thread M40x0.75
mounted on:
Clamp set SK5102
Camera mount SK5105
Lens
Locking bridge (aperture and
focus)
Mounting bracket SK5105
for digital and analog cameras
Order Code: SK5105
Warp resistant construction for
mounting a CCD Line Scan Camera
Clamp set SK5102
(set of 4)
to lock the CCD Line Scan Camera
at an arbitrary rotation
Cylinder screw
DIN 912-M3x12
Clamp set SK 5102
Clamp
2
1
3
5
4
Ø 65
M40x0.75
Pixel No.1
M3 (4x)
Depth 6.5 mm
Ø 42
2.5 6 12.7
61.5
19.5 CCD sensor
 41.7
36
68.5
1 2 3 54
BNC USB

Page 10
Line Scan Camera SK2048USD Manual (v. 7.2012)
A charge-coupled device is a linear array
designed for moving discrete electrical
charges from one element of the array to
the next by successively applying a voltage
to each element in turn. The discrete charge
packets emanating from the end of the
linear array are converted into a voltage and
digitized for further transmission.
A line scan signal is produced by moving
the object to be imaged in a trajectory
perpendicular to the camera sensor.
By synchronizng data acquisition, high
frequencies and resolutions are achieved.
The choice of line scan camera is primarily
determined by the customer application
requirements, which influence sensor length,
pixel number and line scan frequency – see
Imaging Definitions, below.
Our considerable experience in line scan
camera design and software production
allows us to get the best possible imaging
performance within the constraints of the
technology. Potential problems are simply
designed out – or an intrinsic constraint is
tuned away – according to circumstance.
For example, illumination over-exposure of
the sensor causes blooming and signal blur
or loss, from charge leakage across pixels.
Blooming can be either designed out (anti-
blooming) or cut by reducing the integration
time or lens aperture.
Similarly, gain and offset tuning can increase
signal-to-noise ratios, while shading correction
negates any problems of pixel variability, lens
vignetting or inhomogeneous illumination,
whether initially present or not.
Other custom features can be chosen, such
as specialized or filtered illumination, choice
of color or monochrome line sensors as well
as type of interface, with either GigE VisionTM,
Gigabit Ethernet, LVDS, CameraLink® or USB
2.0 interfaces available for data output.
The oscilloscope display facility of the supplied
software is responsive in real-time, and the
zoom function can be used to highlight an
area of interest. The oscilloscope display is
ideally suited for parameterizing the camera,
for evaluating object illumination, for focussing
the image or for aligning the line scan camera
correctly – see Section 7.2 Alignments and
Adjustments.
A line scan camera 2D area scan can easily be
performed by simply specifying the number of
line scans to be integrated.
• Exposure Period and Integration Time
The illumination cycle of a line scan sensor, of
a particular length and number of pixels, for a
set period of time is designated the exposure
period.
Within a single exposure period, the
integration time is the duration designated for
signal accumulation of charges by the sensor.
In continuous mode, the next exposure cycle
is simply begun at the time of read-out of
the previous exposure and, so, the durations
of exposure period and integration time are
identical. Cameras with integration control
are capable of curtailing the integration time
within an exposure period (emulating a shutter
mechanism).
• Pixel and Line Scan Frequencies
The pixel frequency for an individual sensor
is the rate of charge transfer from pixel to pixel
and its ultimate conversion into a signal. The
minimum exposure period of a sensor is the
minimum time required for the read-out of
a whole line scan and is dependent on the
maximum pixel frequency and the number of
pixels (plus a sensor-dependent overhead of
passive pixels).
The line scan frequency is inversely
proportional to exposure period. During the
time the charges from a finished line scan
are read out, the next line scan is being
exposed. Thus, the minimum exposure period
determines the maximum line scan frequency.
• Optical Resolution
The optical resolution of a line scan camera is
determined primarily by the number of pixels in
the linear sensor and secondarily by their size
and spacing, the inter-pixel distance.
Currently available line scan cameras have up
to 12 000 pixels, ranging from 4 to 14 µm in
size and spacing, for sensors up to 56 mm in
length and line scan frequencies up to 83 kHz.
During a scanning run, the effective resolution
perpendicular to the line scan camera is
determined by the velocity of the scan and by
the line scan frequency, i.e. the number of line
scans per second.
Imaging Definitions
7. Line Scan Camera Fundamentals
7.1 Features and Characteristics
Pixel 1
CCD Sensor
Object
structure
GigE SK7500GTO
Line scan cameras from Schäfter+Kirchhoff are supplied factory-preset for the particular application, with optional accessories and appropriate
software – for parameterization of the camera or for optimizing signal acquisition. The advantages and constraints of the technology are described
below and some essential aspects of sensor alignment, lens focussing and signal optimization are presented.
• Region of Interest
A freely programmable window (region of
interest, ROI) can be applied to the line sensor
so that only the pixel information within the ROI
can reach the memory.
By only illuminating these ranges, data volume
and data processing is accelerated for both line
and area scan acquisitions.
Constraint: the ROI memory allocation must be
divisible by 8.
Data Reduction and Acquisition Acceleration
• Thresholding (B/W cameras only)
The thresholding process generates a binary
signal from the gray scale data, with values below
the threshold yielding 0 and those above yielding
1. Only the pixel addresses of the location and
threshold transition (from high→low or low→high)
are transmitted, reducing data throughput.
Thresholding is particularly appropriate for
measuring widths or edge positions, by simply
masking the required pixel addresses.
GigE SK7500GTF-XB

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Line Scan Camera SK2048USD Manual (v. 7.2012)
Integration Time and Aperture Optimization
The line scan signal is optimum when the
signal from the brightest region of the object
corresponds to 95% of the maximum gain. Full
use of the digitalization depth (255 at 8-bit, 4096
at 12-bit) provides an optimum signal sensitivity
and avoids over-exposure (and blooming).
The range of intensity distribution of the line scan
signal is affected by the illumination intensity, the
aperture setting and the camera integration time.
Conversely, the aperture setting influences the
depth of field as well as the overall quality of the
image and the perceived illumination intensity.
A A camera signal exhibiting insufficient gain:
the integration time is too short as only
about 50% of the B/W gray scale is used.
B Optimized gain of the camera signal after
increasing the integration time, by a factor
of 4, to 95% of the available scale.
B
A
Gain / Offset and Shading Correction
white balance or flat-field compensation
are all related techniques that automatically
compensate for any variation in pixels,
lens vignetting or inhomogeneity in the
illumination, etc, whether initially present
or not. All lenses show some vignetting as
a function of the field angle (collectively,
the relationship between sensor and focal
lengths and magnification). Hence, even with
homogeneous object illumination, the image
signal intensity decreases with increasing
image height.
A reference signal for shading correction,
for example, is obtained by taking an image
of a diffuse white surface, followed by
algorithmic compensation of each pixel to
provide a maximum overall intensity. Many
alternative solutions are available, such as
using the R, G and B gain sliders directly to
superimpose the individual channels.
Corrected parameter settings can be stored
within the non-volatile memory of the
camera and are retained for subsequent use
even after a complete shutdown.
A
B
C
Cameras are shipped prealigned with gain and
offset factory settings, although they can be
customized using the SkLineScan software.
A Offset. After blocking all light reaching
the line sensor, the video signals are adjusted
to zero using the offset sliders. The line signal
should be just visible at the bottom of the
oscilloscope display.
B Gain. The sensor is fully illuminated and
the gain sliders adjusted to provide a close
to maximum signal intensity (255 for 8-bit or
4095 for 12-bit) and superimposed signals for
each camera or RGB channel.
C Shading Correction. Shading correction,
Lens Focussing
The oscilloscope display can also be used to
focus a line scan camera system by using the
variations in edge steepness at dark/bright
transitions – observed as modulations in the
zoomed line scan signal.
Initial focussing is performed with a fully
opened aperture (smallest depth of field and
largest sensitivity to focus adjustment). The in-
tegration time can also be reduced to provide a
sufficiently sensitive, low amplitude signal.
A
Out of focus: edges are indistinct, signal
peaks blurred with low density modulation
B Optimal focus: dark-bright transitions have
sharp edges, highly modulated signal peaks
with high frequency density variations
B
A
7.2 Alignments and Adjustments
Sensor Alignment
For linear illumination sources, rotating the line
sensor results in asymmetric vignetting. The
camera and illumination optics can be aligned
optimally by monitoring the object illumination
using the oscilloscope display. Sensor and
optics rotated in apposition A and aligned B.
AB

Kieler Str. 212, 22525 Hamburg, Germany • Tel: [phone] • Fax: [phone] • [email protected] • www.SuKHamburg.de
SK2048USD
Line Scan Camera SK2048USD Manual (v. 7.2012)
8. Warranty
EC Declaration of Conformity
This product satisfies the
requirements of the EC
directive
89/336/EEG as
well as
DIN EN 61326.
This manual has been prepared and
reviewed as carefully as possible but
no warranty is given or implied for any
errors of fact or in interpretation that
may arise. If an error is suspected then
the reader is kindly requested to inform
us for appropriate action.
The circuits, descriptions and tables
may be subject to and are not meant
to infringe upon the rights of a third
party and are provided for informational
purposes only.
The technical descriptions are general in
nature and apply only to an assembly
group. A particular feature set, as well as
its suitability for a particular purpose, is
not guaranteed.
The warranty period for the CCD line
scan camera when used for the
purpose for which it was intended is
24 months.
The warranty is immediately void on
inappropriate modification, use or
damage.
9. Accessories
Lenses:
• high resolution enlarging and macro lenses
• high speed photo lenses
• lenses with additional blocking bridge for locking of
focus and aperture setting
Adapter:
Lens adapter AOC-...
• for fitting photo lenses onto the CCD line scan
camera
Focus adapter FA22-...
• for fitting enlarging or macro lenses
Software:
SK91USB-WIN
* Order Code
SK91USB-LX **
SkLineScan operating program with oscilloscope
display and scan function for setting camera
parameters via USB
Operating systems: * Windows XP/2000, ** Linux
Mounting bracket
SK5105 Order Code
Warp-resistant construction for mounting the line
scan camera
Clamp set
SK5102 Order Code
to lock the line scan camera in desired position
(set of 4)
Mounting Console
SK5105-2 Order Code
for indirect mounting of the line scan camera via the
extension tube, suitable for extension tube larger than
50 mm, for example with macro lens.