9. EXTERNAL BLACK BODY
9
External Black Body
In order to measure the temperatures correctly, the camera needs to perform temperature calibra on every few
seconds. To do so, it needs to have a black body of a known temperature (included) in it’s field of view in the
correct distance and have correctly set the BLACK BODY ROI (region of interest).
The distance the blackbody needs to be placed is corresponding to the focused distance of the camera lens -
either 4m from the camera if focused to the 4m mark or 8m from the camera if focused to the 8m mark. The
black body needs to be facing the camera directly and it is suggested to place the black body to a place, where
it won’t be covered by environment or passing people in any me during the measurement. The recommended
posi on of the black body is in the upper le or right corner of the thermal image.
A er you power up the black body, you will see red LED light blinking. This is an indica on that the black body
is hea ng up to the calibrated temperature 40C. Once the calibrated temperature is achieved, the LED turns to
the constant green color. When the black body is cooling down, the LED is blinking blue.
A er the black body is sufficiently heated up and the LED is colored green, you need to set the ROI (region
of interest) of the black body. To set the ROI of the black body, turn on the camera and go to the MENU ->
FUNCTIONS -> SET BLACK BODY ROI. A er you select this op on with ENTER key, the menu will close. You can
then use arrow controls (UP, DOWN, LEFT, RIGHT) or number controls (8, 2, 4, 6) to move the posi on of the
Black Body. The Black Body ROI should be posi oned in the center of the Black Body as seen in the Thermal
view. A er you are done placing the ROI press ENTER key to save the posi on or BACKSPACE key to cancel the
posi on placing.
The camera assumes, that the black body remains on the set posi on, and remembers this posi on a er reboot.
If the posi on of the black body changes, you need to ini alize the black body ROI again. If the measured tem-
perature in the ROI changes quickly by a higher step than ACCEPTANCE SPAN, the camera detects it as passing
object and refuses new value. This is indicated by showing either ”Black body warning” or ”Black body error” in
the INFORMATIONAL PANEL.
9.1 Camera Calibra on
The Workswell MEDICAS is shipped with calibra onal black body. It should always be used only with correctly
calibrated black body. The MEDICAS performs offset calibra on of measured temperatures based on the mea-
sured temperature value of the black body. This calibra on is performed automa cally every 2 seconds. If the
difference between measured and expected temperature of the black body is greater than the set threshold
(ACCEPTION SPAN), the camera asumes that the the view of the black body is blocked and does not calibrate.
When this happens, Black body warning is displayed in INFORMATION PANEL. If the assumed view is not restored
in 5seconds, Black body error is displayed. If the user is sure that the black body works properly and is visible for
the camera and s ll the Black body error is displayed, or if the measurment have obviously some offset, FORCE
CALIBRATION is required. That can be achieved by pressing MENU -> FUNCTIONS -> FORCE CALIBRATION.
In order for calibra on to work properly, it is necessary to set the posi on of Black Body ROI.
Note:
The ACCEPTION SPAN can be set between 1°C and 2.9°C or OFF. Recommended set value is 2°C.
E-mail and Web
[email protected]
www.workswell.eu
Mobile:
+420 725 877 063
ID:
Reg. No.: 29048575
VAT No.: CZ29048575
Headquarters
U Albrechtova vrchu 12
155 00, Prague 13
Czech Republic
Revision 1.2.0 EN, 28
th
May, 2020
All pictures are only for illustra on.
Real values may vary.
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