vds IRC-320GE Series User manual

IRC-320GE IRC-320GE
LWIR Camera (320 x 240 Pixels)
with Integrated Image Processing
and Gigabit Ethernet Output
LWIR Camera (320 x 240 Pixels)
with Integrated Image Processing
and Gigabit Ethernet Output
irc-320ge_manual_v3_00_en.docge_manual_v3_00_en.doc
ManualManual
Version 3.0Version 3.0
Art.-No.: 3143000Art.-No.: 3143000
This document may not in whole or in part be copied, photocopied or otherwise
reproduced without prior permission of the publisher.
This document may not in whole or in part be copied, photocopied or otherwise
reproduced without prior permission of the publisher.
Date: March 2010 Date: March 2010
Technical details are subject to change without notice.Technical details are subject to change without notice.
Weiße Breite 7 ·D-49084 Osnabrück
Phone +49 (0) 541 / 80084-0 ·Telefax +49 (0) 541 / 80084-10
http://www.vdsvossk.de ·email: [email protected]

C O N T E N T S
1INTRODUCTION.........................................................................................................................................4
1.1 COMMON FEATURES ....................................................................................................................................4
1.2 STANDARD MODEL VARIANTS......................................................................................................................4
2TECHNICAL DATA ....................................................................................................................................5
2.1 SPECTRAL RESPONSE ...................................................................................................................................5
2.2 PROTECTION AGAINST ELECTROSTATIC DISCHARGE ...................................................................................6
2.3 ENVIRONMENTAL CONDITIONS....................................................................................................................6
2.4 WARM UP PERIOD........................................................................................................................................6
3MECHANICAL DIMENSIONS..................................................................................................................7
3.1 SIDE VIEW OF THE IRC-320 WITH 18MM F/1.0 LENS ...................................................................................7
3.2 BACK VIEW OF THE CAMERA .......................................................................................................................7
4START UP .....................................................................................................................................................8
4.1 DIRECT CAMERA CONTROL SIGNALS...........................................................................................................8
4.2 CAMERA CONTROL COMMANDS ..................................................................................................................8
4.3 ADJUST THE IMAGE PROCESSING .................................................................................................................9
5CONTROL CONNECTOR (15 PIN SUB-D JACK) ...............................................................................11
5.1 PIN ASSIGNMENT OF THE CONTROL CONNECTOR ......................................................................................11
5.2 POWER SUPPLY (PIN 1-4) .........................................................................................................................11
5.3 SERIAL INTERFACE (PIN 7, 8).....................................................................................................................11
5.4 TRIGGER (RESET)INPUT (PIN 10, 11) ........................................................................................................11
5.5 SENSOR TEMPERATURE TOO LOW (PIN 12, 13) ..........................................................................................12
5.6 SENSOR TEMPERATURE TOO HIGH (PIN 14) ...............................................................................................12
5.7 FRAME-SYNC OUTPUT (PIN 15) .................................................................................................................12
6DATA INTERFACE...................................................................................................................................13
6.1 CAMERA LINK ...........................................................................................................................................13
6.1.1 Trigger (Reset) Input (CC1)......................................................................................................................14
6.1.2 Timing (FVAL, LVAL, DVAL, PCLK).......................................................................................................14
6.1.3 Output Data Specification ........................................................................................................................15
6.2 CONVERSION OF IMAGE DATA TO TEMPERATURE DATA .............................................................................15
6.3 CONSIDERATION OF THE EMISSION RATIO ..................................................................................................16
6.4 GIGABIT ETHERNET ...................................................................................................................................16
7PARAMETERS OF IMAGE PROCESSING ..........................................................................................18
7.1 IMAGE PROCESSING CHAIN........................................................................................................................18
7.2 FILE SYSTEM .............................................................................................................................................19
8INTRODUCTION TO THE TWO POINT CORRECTION (A, B, E, J, K, N) ......................................20
9BASIC PARAMETERS AND COMMANDS...........................................................................................21
9.1 SELECT A CORRECTION DATA SET (S).......................................................................................................21
9.2 AUTOMATIC CALIBRATION (K)...................................................................................................................21
9.3 ELECTROMECHANICAL SHUTTER (I) ..........................................................................................................22
9.4 TEMPERATURE WARNING (T) ....................................................................................................................22
9.5 SOFTWARE VERSION AND CORRECTION DATA INFORMATION (V) .............................................................22
9.6 CURRENT PARAMETER SETTINGS (Y).........................................................................................................22
9.7 SHOW HELP TEXT (?).................................................................................................................................22
10 ADVANCED PARAMETERS AND COMMANDS............................................................................23
10.1 TWO POINT CORRECTION (A,B,E,J,K,N)................................................................................................23
10.2 BACKGROUND CORRECTION (U,M)............................................................................................................25
10.3 BAD PIXEL CORRECTION (C,F) .................................................................................................................26
10.4 TEMPERATURE DRIFT COMPENSATION (M,N,O,P)......................................................................................27
10.5 LOOK UP TABLE „LUT“ (D,G) ..................................................................................................................27
10.6 INTEGRATOR AND IMAGE STORE (H)..........................................................................................................28
10.7 BAUD RATE (S) ..........................................................................................................................................29
10.8 SAVE PARAMETERS IN FLASH (X) ..............................................................................................................30
10.9 RESET PARAMETERS TO STANDARD VALUES (Z).......................................................................................30
10.10 UPLOAD A FILE TO FLASH (Q) ...............................................................................................................30

11 APPENDIX..............................................................................................................................................32
11.1 COMMAND REFERENCE .............................................................................................................................32
12 DECLARATION OF CE CONFORMITY ..........................................................................................40
13 REVISION HISTORY ...........................................................................................................................41

1 Introduction 4 / 41
1Introduction
With the IRC-320 line VDS Vosskühler offers infrared cameras based on a microbolometer sensor
with 320 x 240 pixels for the LWIR range. As all previous VDS CCD cameras also the IRC-320
provides an excellent image quality. The series IRC-320 is designed as OEM modules with Gigabit
Ethernet output for the long-lasting installation.
According to each application suitable lenses for LWIR with various focal lengths can be offered.
Also different temperature ranges are possible.
1.1 Common Features
•320 (H) x 240 (V) pixels
•Uncooled microbolometer sensor
•8 -14 µm (LWIR) spectral sensitivity
•Measurement temperature range of -20°C up to +80°C (standard version)
•Pixel size: 35 µm x 35 µm
•40 Hz frame rate
•12 bit digital output with Gigabit Ethernet
•Built-in mechanical shutter
•Preprocessor functions included
1.2 Standard model variants
Model VDS Art.-No. Suitable lenses VDS Art.-No.
IRC-320LGE 1043452
12mm, F/0.85
18mm, F/1.0
35mm, F/1.0
9005304
9005306
9005301
VDS Vosskühler GmbH IRC-320

2 Technical Data 5 / 41
2Technical Data
Detector
Detector type Amorphous silicon uncooled microbolometer FPA
Resolution 320(H) x 240(V)
Pixel size 35µm x 35µm
Spectral response 8µm – 14µm (LWIR)
Frame rate 40fps
Sensitive sensor area 11.2mm x 8.4mm
Sensor time constant approx. 7ms
Pixel clock 5.25MHz
Measurement capabilities
Measurement range -20°C … +80°C (standard version)
Sensitivity (NETD) typical 80mK @ 303K @ f/1.0
Environmental characteristics
Operating temperature (Reference to the
internal temperature sensor)
+15°C … +50°C
Optimal working range (Reference to the
internal temperature sensor)
+25°C … +45°C
Storage temperature -30°C … +70°C
Humidity (Operating and storage) 10% to 95% RH, non-condensing
Shock 25G
Vibration 2G
Interface
Power supply 12V (SELV) -0%/+5%, max. 1.5A
Digital interface Gigabit Ethernet (1000Base-T)
Output data 12bit/pixel
Mechanical
Dimension with 18mm F/1.0: 134mm x 90mm x 86mm
Weight with 18mm F/1.0: 600g
Housing material Aluminium alloy (AlMgSi1)
General
CE conform (see page 40, Declaration of
CE Conformity)
EN61000-6-2: 2001; EN61000-6-4: 2001;
EN61000-6-1: 2001; EN61000-6-3: 2001
Made in Germany
Please note:
The correct polarity of the 12 V supply voltage must be assured.
The warranty becomes void in case of unauthorized tampering
or any manipulations not approved by the manufacturer.
2.1 Spectral response
VDS Vosskühler GmbH IRC-320

2 Technical Data 6 / 41
2.2 Protection against Electrostatic Discharge
The camera contains sensible electronic components which can be destroyed by means of electrostatic
discharge. When using the camera one has to take care of a sufficient grounding which is obligatory to
minimize the risk of damage.
2.3 Environmental Conditions
The camera should be operated in dry and dust free environment. The working temperature range
depends on the model version and is for example between 25°C and 45°C (temperature of the camera
housing). Outside this temperature range the image quality can be worse. Also clipping of some
regions or clipping of the whole image is possible outside the working temperature range. Regarding
the signal quality of the IRC-320 it is an advantage to operate the camera under constant ambient air
temperature. This can e.g. be facilitated by assembling the camera on a bigger metal corpus or by an
additional active temperature regulation. The red LED at the backside of the camera (L3) or the value
of the register Tserves for examination. If L3 permanently lights up or rather the lowest bit of Tis set,
the camera housing has a temperature which is outside of the optimum. In this case an additional
heating or cooling has to be provided.
2.4 Warm up Period
Depending on the prevailing environmental conditions, some time might pass after the camera start,
until the image quality reaches its optimum. In case of simple view applications with low demands, the
data are already suitable following an operating period of some minutes. If time stability of the
temperature data is required a longer warm up period of at least 20 minutes is recommended.
VDS Vosskühler GmbH IRC-320

3 Mechanical Dimensions 7 / 41
3Mechanical Dimensions
3.1 Side View of the IRC-320 with 18mm F/1.0 lens
UNC 1/4" UNC 1/4" M4
max. screw depth
4,5mm 4,5mm 3mm
13
31
44
71
GIP-1000Camera
86
Lens 18mm f/1
Ø 1 1/8"
Ø38,1 Ø45,7
62
94
101max.32,7
max.28,9
15,27
3.2 Back View of the camera
Power
L2
L3
L4
L5
Power / Control
connection
Gigabit Ethernet
connection
Ø90
UNC1/4" (2x) and M4
mounting holes are in
the center of main body
LED’s at the Backside of the Housing
L2 Camera is operational
L3 Temperature state (off →temperature is OK)
Power Power state
L4 Trigger (reset) input activity
L5 Frame output
VDS Vosskühler GmbH IRC-320

4 Start up 8 / 41
4Start up
A Gigabit Ethernet port (1000Base-T) on the receiving computer is necessary. First connect the
camera with the appropriate data cable to the computer. Then plug the 15-pin connector of the power
supply to the camera and switch on the power supply.
The camera is controlled over a serial data interface via Gigabit Ethernet.
4.1 Direct Camera Control Signals
A short survey of the CC signals is given below for users who already have some experience in using
Camera Link equipment and who plan to use the IRC-320 with their self-developed software. Some of
the CC signals can also be externally applied to the 15-pin D-SUB control jack, which is compatible to
other VDS cameras.
In case of the Gigabit Ethernet interface option the same camera control signals are used, but they are
controlled by the corresponding outputs of a Programmable Logic Controller accessed over the Pleora
iPORT SDK. Please refer to the Pleora iPORT PT1000-VB User’s Manual and the Pleora iPORT
SDK Documentation for more information.
SIGNAL STATE REMARKS REFERENCE
CC1 0 Trigger (Reset) input (rising edge) 5.4, p. 11
CC2 reserved
CC3 reserved
CC4 reserved
4.2 Camera Control Commands
To configure the internal image processing a serial command interface is provided. By default this
command interface is internally routed to the Gigabit Ethernet port, but the RS232 signals at the 15
pin D-SUB jack may also be used. To access it, a serial terminal program employing the serial port of
the user’s Pleora iPORT software interface or a PC’s RS-232 COM port is required.
For Gigabit Ethernet the Pleora iPORT documentation contains the corresponding information. If the
serial interface is routed over the 15 pin D-SUB jack, then e.g. HyperTerminal, being part of
Microsoft® Windows® deliveries, might be the choice to manually control the camera.
The VDS provided software AcquireControl can operate the camera’s serial port over the Pleora
iPORT Gigabit Ethernet interface or PC standard COM ports. Type <CTRL>+Y to get a camera
control terminal window there.
By default the serial interface uses the following parameters:
•115200 Baud
•8 data bits
•1 stop bit
•No parity
•No handshake
The baud rate is factory-adjusted to 115200 but can also be configured to other values (see chapter
10.7, p. 29).
Each command consists of a command letter, followed by an equality sign and a parameter value in
hexadecimal number representation. The command letter is case sensitive. Hexadecimal values are
always upper case and are 1 to 4 digits long. The command is activated by a carriage return ([CR],
ASCII character number 0x0D. Serial communication operates in echo mode by default. This means
that each character received by the module is echoed back to the sender. In all command examples the
characters send to the camera are represented in Bold Courier Font and the camera’s answer in
Plain Courier Font.
VDS Vosskühler GmbH IRC-320

4 Start up 9 / 41
Recapitulatory the serial commands have the following fixed scheme:
>B=wxyz[CR]
B Command or parameter letter (observe upper and lower case printing!)
= Sign of equality (0x3D)
wxyz 1-4 digits long value in hexadecimal number representation (capital letters)
[CR] Carriage Return (0x0D)
[LF] Line Feed (0x0A)
Example (set Baudrate to 115200 Baud using only RS232 at 15-pin D-SUB jack):
1. The user sends the four characters
s=A[CR]
2. The camera answers with seven characters
s=A[CR][CR][LF]>
3. A terminal program without local echo displays
s=A
>
After successful execution of the command, the command input character ">" is output. If any error
occurred, somewhere previous to the prompt a question mark character "?" is displayed.
To query a parameter value, send the corresponding command letter followed by the equality sign and
a question mark character:
>s=?[CR]
If the intended action does not need any parameter, it is also sufficient in most cases - as a shortcut - to
send the command letter only, directly followed by [CR].
At the beginning of a command sequence it is good practice to check the serial communication by
sending just a [CR] to the camera and verify that the command prompt ">" is returned. There is an
input buffer holding a few characters but no hardware handshake. Thus a sequence of commands
should not be send to the camera without awaiting the intermediate input prompts. Otherwise the
camera’s serial input buffer may overflow.
4.3 Adjust the Image Processing
Subsequently the important commands for quick starting the image correction of the IRC-320 are
mentioned. All further parameters and a description of the correction modules can be found in chapter
7.
The camera is configured ex-factory with parameter settings which ensure a basic image correction. In
the case that the IRC-320 is equipped with multiple correction data sets for different operation
conditions, the image quality can be improved by activating another correction data set if the
conditions of the camera have changed. In addition the IRC-320 models feature an electromechanical
shutter that can further enhance the quality of the corrected image. The selection of a good data set can
be done automatically by use of the serial command k=0. This command also controls the shutter.
Example: Start an automatic calibration process.
>k=0[CR]
S=0A
M=87C8
>
The calibration process needs a few seconds to finish. Please note that during this time no image data
is output. Avoid triggering the camera via CC1 or opto coupler input while the calibration is in
VDS Vosskühler GmbH IRC-320

4 Start up 10 / 41
progress. Depending on the camera model and current jparameter configuration, the actions
accomplished by the kcommand and its output at the serial interface may vary. Refer to the
corresponding command reference in appendix 11.1 for details.
The following table shows an overview of the consumed time by the command “k=0”:
Description Time Max. Time Typical time for a IRC-320
Close shutter (optional) 4 * T 100ms 0ms
Save one image 3 * T 75ms 75ms
Open shutter (optional) 0 * T 0ms 0ms
Choose data set N1 * 2 * T 1600ms 800ms (N1=16)
Close shutter 5 * T 125ms 125ms
Integrate images (N2 + 1) * T 1625ms 1625ms
Open shutter 0 * T 0ms 0ms
Calculate statistics 2 * T 50ms 50ms
At all 3,58s 2,68s
T = Time for one frame-out (IRC-320: 25ms)
N1 = number of data sets (max. 32)
N2 = number of integrated images (max. 64)
VDS Vosskühler GmbH IRC-320

5 Control Connector (15 pin SUB-D Jack) 11 / 41
5Control Connector (15 pin SUB-D Jack)
5.1 Pin Assignment of the Control Connector
This jack is intended for supplying power as well as for control signals of the camera. Furthermore
some output signals are available, showing the camera state.
Pin Function
1
2 ] + 12 V DC (-0% / +5%), current max. 1.5A
3
4 ] GND
5 Test output (reserved)
6 -
7 RXD (RS232)
8 TXD (RS232)
9 Test input (reserved)
10 -
11 + ]Trigger (Reset) input (opto coupler input)
12 -
13 + ]Sensor temperature too low (opto coupler output)
14 Sensor temperature too high (active low)
15 Frame-Sync output (active low)
5.2 Power Supply (Pin 1 - 4)
The camera requires 12V +5% DC and maximum 1.5A. The voltage should not fall below 12.0V and
should not exceed 12.6V. It is recommended to use respectively both pins (1+2, 3+4) for power
supply.
5.3 Serial Interface (Pin 7, 8)
By use of the serial interface at pin 7 and 8 the camera can be controlled externally via a RS-232 COM
Port. A simple terminal program (e.g. HyperTerminal) is sufficient for manually controlling the
camera. Please note that operating this serial interface and the second available port (via Gigabit
Ethernet interface) concurrently may lead to unexpected results. Both interfaces share the same receive
buffer and thus the characters of simultaneously sent commands may be randomly mixed up. See
chapter 10.7 Baud Rate (s) for more information about serial interface configuration options.
5.4 Trigger (Reset) Input (Pin 10, 11)
Due to a rising edge at the trigger input the image exposure is reset and the camera immediately starts
to output the first line of the new image. In this way a synchronization of several cameras is possible.
Please note that a reset event can render up to two output images invalid. The first image may have
fewer lines because its output was aborted by the reset event. Additionally, the intensity of the second
image may be inaccurate because the microbolometer pixels’ minimal integration time was not
reached. Avoid reset events during integration of correction data or execution of the automatic
calibration function (k).
VDS Vosskühler GmbH IRC-320

5 Control Connector (15 pin SUB-D Jack) 12 / 41
For continuous periodical trigger the pulse must be at least 100µs and the periodic time exact
24.96ms ±10µs.
+
-
1 k opto coupler
pin 11
pin 10
T
he current which flows through the
o
pto coupler should at least amount to
5
mA and should not exceed 20 mA.
(1)
(1)
As a further trigger input line the camera control signal CC1 is available. The two trigger sources are
internally combined with an OR gate.
5.5 Sensor Temperature too Low (Pin 12, 13)
+ 12 V
The current which flows through the opto
coupler should not exceed 20 mA
(at 12 V R ≥600 Ω).
+
-
opto coupler
Pin 13
Pin 12
As long as the sensor operating temperature is too low, the sensor control output at pin 12/13 remains
active (transistor switched on). Following the warm up phase of the camera this output becomes
inactive.
An indication of sensor temperature being too low results in a degradation of image quality and
inexact temperature measurement. In case that this control output will not become inactive after some
minutes of operation the ambient air temperature of the camera might be too low. A heat up of the
camera should resolve this.
5.6 Sensor Temperature too High (Pin 14)
Voltage Logical Level Description
≤0.8 V low Sensor temperature too high
> 4.0 V high Normal operation
An indication of sensor temperature being too high results in a degradation of image quality and
inexact temperature measurement. In case that this control output is permanently active already after
some minutes of operation, the environment temperature of the camera might be too high. A sufficient
cooling of the camera is obligatory, for ideal results the camera temperature should be lower than
45°C.
5.7 Frame-Sync Output (Pin 15)
1 line (80 µs)
5 Vss (no load)
312 lines (24.96 ms)
The frame-sync output (active low) supplies approx. 900 mV at a termination with 75 Ohms.
VDS Vosskühler GmbH IRC-320

6 Data Interface 13 / 41
6Data Interface
The IRC-320 camera models are based on an internal Camera Link Base interface. In the following
paragraphs first the Camera Link interface is described. To better understand the Gigabit Ethernet
version it is important to note, that this camera internally uses Camera Link compatible signals also.
The adaptation to Gigabit Ethernet is done by a third party Camera Link frame grabber that is inside
the camera. Thus many of the properties mentioned in conjunction to the Camera Link interface are
also valid for the Gigabit Ethernet interface.
6.1 Camera Link
Camera Link is an interface for the transfer of digital video data. The standard defines data transfer on
a physical base and determines connectors, cables and components for transmission and reception.
Three different configurations (base, medium and full) are available, distinguishing between the
numbers of parallel transferred data bits. While the base configuration is able to operate with one
cable, for the medium and the full configuration two cables between camera and grabber are
necessary.
The transmission components apply the so called “Channel Link” technology. 28 parallel data bits
each are serialized in a ratio of 7:1 and transferred in connection with the clock signal via altogether
five differential signal pairs. By using LVDS, net clock rates up to 85 MHz can be achieved and cable
lengths up to 10 m are possible. Moreover four different control signals for camera control (CC1 –
CC4) from the grabber to the camera are available as well as a bi-directional serial communication
channel which is also designed differential. The following drawing illustrates the Camera Link signals
in the basic configuration which is used internal in the IRC-320.
FVAL, LVAL,
DVAL, SP
Port A, B, C
(3 x 8 Bits)
PCLK
CC1
CC2
CC3
CC4
SerTFG
SerTC
DS90CR287
X0
X1
X2
X3
CLKX
CC1
CC2
CC3
CC4
SerTFG
SerTC
FVAL, LVAL,
DVAL, SP
Port A, B, C
(3 x 8 Bits)
PCLK
CC1
CC2
CC3
CC4
SerTFG
SerTC
X0
X1
X2
X3
CLKX
CC1
CC2
CC3
CC4
SerTFG
SerTC
Camera Cable Grabber
VDS Vosskühler GmbH IRC-320

6 Data Interface 14 / 41
6.1.1 Trigger (Reset) Input (CC1)
This signal can be used to sync the acquisition of multiple cameras or to external events. Please see
chapter 5.4 for details.
6.1.2 Timing (FVAL, LVAL, DVAL, PCLK)
The Camera Link specification provides three synchronization signals:
•FVAL (Frame Valid) – HIGH during transmission of valid lines of an image.
•LVAL (Line Valid) – HIGH during transmission of valid pixels of a line.
•DVAL (Data Valid) – HIGH in case that valid pixel data are present.
The gross pixel rate at the microbolometer sensor of the IRC-320 camera series is 5.25 MHz.
However, the maximum available bandwidth of the “Camera Link Base” configuration is not nearly
exploited; on the contrary, the transmission components require a minimum clock frequency for a safe
operation. For this reason the internal clock frequency is artificially increased by factor four before
being output as “Camera Link” clock signal. As a consequence an unnecessary high data rate would
occur at the grabber, why a multiple of the really needed data volume ought to be moved within the
storage of the receiver. Now the DVAL signal offers the opportunity to explicitly mark particular data
words as valid so that only the really needed pixel data is stored in the grabber’s memory.
For this reason attention has to be paid to the fact that when selecting a grabber and developing
software, the grabber does not only evaluate the signals FVAL and LVAL but also supports DVAL.
The following charts try to illustrate these facts:
DVAL
1 pixel (190 ns / 5.25 MHz)
PCLK
1 Camera Link clock (47.6 ns / 21 MHz)
DVAL
LVAL
320 pixels (60.95 µs)
Blanking
100 Pixels
(19.05 µs)
420 pixels (80 µs)
LVAL
FVAL
312 lines (24.96 ms)
s)
Blanking
ines 72 l
(5.76 ms)
240 lines (19.2 m
VDS Vosskühler GmbH IRC-320

6 Data Interface 15 / 41
6.1.3 Output Data Specification
The image data is output as 12 bit values. A bit assignment for 12 bit grey values according to the
Camera Link specification is used.
Camera Link Port (1 x 12 Bit)
A0 D0 (LSB)
A1 D1
A2 D2
A3 D3
A4 D4
A5 D5
A6 D6
A7 D7
B0 D8
B1 D9
B2 D10
B3 D11 (MSB)
B4
B5
B6
B7
C0
C1
C2
C3
C4
C5
C6
C7
6.2 Conversion of image data to temperature data
Due to the internal LUT, the pixel information can be converted to a corresponding temperature value.
For the IRC-320 the following relation can be used:
oDNrT += *
with: : 12-bit Digital value (Pixel data)
DN
T
: Temperature value [°C]
r
: Resolution (for the IRC-320 standard version: 0.03°C)
: offset for DN=0 (for the IRC-320 standard version: -30°C)o
The following diagram shows the result.
VDS Vosskühler GmbH IRC-320

6 Data Interface 16 / 41
y = 0,03x - 30
-30
0
30
60
90
0 1000 2000 3000 4000
12-bit value
temperature [°C]
6.3 Consideration of the emission ratio
Every material has his own emissivity value for IR, so the measured value is not equal to the real
temperature. The best result can be reached with materials that have emissivity ratio near to 1.0
(100%).
The following formula allows correcting the temperature value, when the emissivity ratio is known:
4
444 )1(
][
ε
ε
bm
t
TT
KT
⋅−−
=
with : Corrected value in Kelvin][KTt
m
T: Measured value in Kelvin
b
T: Background temperature in Kelvin
ε
: Emission ratio
Notes:
•Normally the background temperature can be assumed to be equal to the environmental
temperature.
•The emission grades of many different materials can be found on various internet sources.
6.4 Gigabit Ethernet
The IRC-320 cameras are equipped with a 1000Base-T Ethernet interface (RJ-45 connector). The data
connection between camera and PC can be established via a standard CAT5e patch cable. The Gigabit
Ethernet models of this camera internally use Camera Link signals, so many of the facts mentioned in
the chapter 6.1 are also valid for the Gigabit Ethernet interface option. For details one can refer to the
Pleora iPORT PT1000-VB Documentation.
VDS Vosskühler GmbH IRC-320

6 Data Interface 17 / 41
8 ... ... 1
Front view of the
Gigabit Ethernet jack.
Pin Signal
1 D1+
2 D1–
3 D2+
4 D3+
5 D3-
6 D2-
7 D4+
8 D4–
VDS Vosskühler GmbH IRC-320

7 Parameters of Image Processing 18 / 41
7Parameters of Image Processing
This chapter explains the function of the IRC-320 firmware. It is related to the individual modules of
image processing and shows in what way the user can control these modules via the serial Interface.
7.1 Image Processing Chain
Due to the fact that the uncorrected sensor image from the microbolometer sensor is very
inhomogeneous and that each sensor element has its own characteristic curve, an individual
adjustment of each pixel is necessary. The standard firmware of the IRC-320 contains a chain of
correction modules which undertake these tasks in real time.
LUT
Integrator /
Image Store
Two Point
Correction
Bad Pixel
Correction
Drift
Compensation Output
(CL, GigE)
Input
(Camera
Raw Data)
E,J,K,N F m,n,o,pH
Correction Data
Memory Access Module
S
(C)(A,B)(H/U,A,B)(H/U)
Flash Memory
Access Module
A,B,C
Background
Subtraction +
Integrator /
Image Store
M,U
(U/H)(U/H)
D,G
Each module can have various parameters which control the operation mode. In the sketch above and
as well within the text of this manual, these parameters are always marked by “Courier” font in
order to highlight them to be parameters (or commands) adjustable via the serial Interface.
For fast access all available correction data (e.g. reference images for the two point correction and bad
pixel correction control data) are copied from the non-volatile flash memory into a correction data
memory (SDRAM) when starting the camera. From this point the correction data is available for real-
time image correction. The image data from the camera head is shifted through the correction modules
and the corresponding correction data is applied. Some modules may also write new data back to the
correction memory – but currently only to the SDRAM and not to the non-volatile Flash memory.
The main correction modules are in detail:
1. Two Point Correction
2. Background Correction
3. Bad Pixel Correction
4. Drift Compensation
5. Look Up Table (LUT)
With help of the two point correction (likewise “Gain Offset Correction”) the normally distinctive
underground structure of the microbolometer sensor can be equalized. The gain and the offset for each
pixel of the input image can be adapted to the set values on the basis of two reference images so that in
the optimum case no image structure is discernible.
The IRC-320 models feature an electromechanical shutter. In conjunction with the second correction
module in the chain – the background correction – the image quality can additionally be enhanced.
The shutter is closed to acquire a temporary background correction image. This image is subtracted
from the two point corrected image data to reduce the remaining fixed pattern noise.
VDS Vosskühler GmbH IRC-320

7 Parameters of Image Processing 19 / 41
The bad pixel correction uses up to six non-false neighbour pixels to determine an interpolated value
from the neighbour pixels that replaces the bad pixel. In this way the image appears without disturbing
“hot” or “cold” pixels.
As the temperature of the camera itself directly influences the output data, for stable measurements it
is necessary to compensate this drift. Therefore the correction module drift compensation can be used.
It directly incorporates an internally measured temperature into a drift correction function.
The temperature characteristic curve of the microbolometer sensor usually is not linear. With help of
the LUT there is the possibility to linearize the data at the end of the processing chain, so that more
precise temperature values are resulting.
Ex factory camera specific correction data for each correction module are determined and stored in the
camera so that an optimum image quality is available at the Gigabit Ethernet interface. A PC with a
Gigabit Ethernet interface can transmit the temperature data directly to the main memory or rather to
the display. To reach more exact temperature measurements only an emission factor correction
depending on the surface and material of the object as well as of the environment temperature within
the object scene is necessary at the receiving end.
In case of high quality requirements with regard to exactness and image quality it is recommended to
determinate ex factory more than one correction data set by means of which some influence caused by
changing operating conditions of the camera are mostly compensated. Several different correction sets
for the two point correction are stored inside the camera. By transmitting commands over the serial
interface the user is able to activate (manually or automatically) the correction set which is most
suitable for the actual environment conditions of the camera.
7.2 File System
The IRC-320 camera models are equipped with a non-volatile data memory (64MByte flash) which
records configuration and correction data. Due to resource reasons the data is managed in a minimalist
file system. Because of this there are some restrictions briefly listed as follows:
•Files are identified via one byte. Regarding to its function this file number is somewhat
comparable to the file name (including extension) from the PC-world. Valid file numbers are
between 1 (0x01) and 254 (0xFE).
•The file type can be defined via a further byte. It is an optional clustering feature for files, but
it has no relevance for the file identification.
•There is no directory structure. All files are on one single hierarchy level within the main
directory. This results in a maximum possible number of 254 simultaneously stored files,
because each file number can only be allocated once.
Ex factory the camera is usually already equipped with several files, containing system and correction
data. The IRC-320 don’t use the whole 64MByte, so that a customer can also use this memory for own
data. Refer to chapter 10.10 “Upload a File to Flash (Q)” for details.
VDS Vosskühler GmbH IRC-320

8 Introduction to the Two Point Correction (A, B, E, J, K, N) 20 / 41
8Introduction to the Two Point Correction (A, B, E, J, K, N)
The two point correction is the most elaborate correction module of the IRC-320 camera models. For
this reason initially a general survey of the two point correction functioning shall be given. This
information in connection with the indications of the following section Basic Parameters and
Commands will probably be sufficient for most users, due to the fact that the determining and
adjustment of nearly all parameters is already executed ex factory and normally, no user intervention
is necessary at all. In case that nevertheless a more extensive understanding of the current parameters
should be required, chapter 10 Advanced Parameters and Commands can help.
By means of the two point correction (also called “Gain Offset Correction”) usually, the distinctive
underground structure of the microbolometer sensor can be equalized. The target is to transmit the
individual characteristic curve of each pixel to a set characteristic curve, being valid for all pixels. In
order to achieve this result, initially the effective characteristic curve of each single pixel is determined
by taking up data samples. A linear characteristic curve is supposed so that two data samples are
sufficient for a definite determination. By means of recording two reference images at the scene
temperatures TAund TB the data samples can be determined for all pixels. Furthermore the digital set
values J and K each belonging to the temperatures TAand TBare determined.
Owing to the four parameters mentioned above, the two point correction is now able to modify the
gain and the offset of each pixel characteristic curve in a way that it is congruent with the set
characteristic curve. Therefore, in an optimum case, an image structure, caused by the sensor, does no
longer occur. The below mentioned sketch tries to exemplary explain the facts on the basis of one
single pixel characteristic curve:
Counts
Set Characteristic
Curve
The reference images are stored in several files within the flash and are directly transferred into the
correction memory following the camera start-up. The parameter Aindicates the file number of the
correction image at low reference temperature TA. The parameter Bserves the same purpose for the
reference image at temperature TB.
For improvement of image quality the camera usually is delivered ex-factory with several sets of
correction data, which are determined for diverse operating conditions. I.e. diverse correction images
(A,B) including the according set values (J, K) may exist for the two point correction, being loaded
during the camera start-up to the correction memory.
T
A
TB
J
K
Effective
Characteristic
Curve
Temperature [°C]
B
A
Cold Reference pixel )Warm Reference pixel )
VDS Vosskühler GmbH IRC-320