Dahua Technology BF 5421 User manual

Thermal Camera Installation Guide
(BF 5421)
V1.7
Zhejiang Dahua Technology Co., Ltd

Preface
Summary
The temperature of all materials is higher than absolute zero (- 273.15 ℃) and radiates
electromagnetic wave continuously. The thermal imaging camera collects the infrared radiation
energy emitted by the measured objects, and establishes the accurate corresponding relationship
between the target energy and temperature through complex temperature measurement
algorithm and blackbody temperature measurement calibration and other processes, so as to
realize the temperature measurement function of human body. It is characterized by non-contact,
multi-objective, fast, and no risk to the temperature measurer. It can be easily deployed in densely
populated public places, and it can effectively and safely screen the abnormal temperature
preliminarily.
Thermal imaging human body temperature measurement, mainly through the measurement
of human forehead and face temperature (according to the different environment of about 31-
36 ℃), preliminary judgment, found that the suspected abnormal temperature, and then use ear
temperature gun or mercury thermometer to further confirm. As the skin surface of forehead and
face is exposed to the air, the temperature changes due to the influence of air flow and sweat.
Generally, under the indoor ambient temperature of 15 ℃in winter, if the forehead temperature
exceeds 35 ℃, there is a possibility of fever. For other environmental temperature conditions, it is
recommended to measure several samples on site, and increase 1 ℃as the alarm threshold on
the basis of normal forehead temperature.
The human body temperature measurement requires high precision, which requires high
installation mode, environment and debugging. Please read this article carefully.
Combined with the support experience of the thermal imaging R & D technical support
team, this manual describes the installation requirements, common operations and precautions
during the actual use of thermal imaging products, so as to facilitate the quick start and reduce
unnecessary problems. For more detailed instructions, please refer to the product manual and quick
operation manual.
The content described in this article needs to be analyzed in combination with the actual field
equipment, which is not the only way. If you have any questions or good suggestions, please
contact Xu Fangrong (Short NO: 693802), Fang Lu (Short NO: 685718), Li Fuxiang (Short NO:
638137), Fang Shengdong (short: 669126).
⚫This manual is only for internal use of Dahua employees. Please do not directly provide
it to customers or publish it to public platforms such as the Internet.
⚫Reading objects include (but not limited to): Solution Engineer, Pre-sale / in-sale / after-sale
technical support engineer, installation and debugging personnel, product engineer, test
engineer, marketing and sales personnel and other internal personnel of the company

Change Record
Revision date
Version number
Creater
Reviser
2020.01.27
V1.0
房圣东
2020.01.28
V1.1
许芳荣/房圣东
房圣东
2020.01.31
V1.2
房圣东
李静
2020.02.03
V1.3
方璐
房圣东
2020.03.14
V1.7
方璐
房圣东

Content
Preface ...............................................................................................................................................................................I
1Equipment Installation...........................................................................................................................................2
1.1 Installation Preparation .................................................................................................................................................2
1.2 Installation Distance........................................................................................................................................................ 2
1.3 Installation Diagram .......................................................................................................................................................3
1.4 Real Scene Diagram .......................................................................................................................................................3
1.5 Installation Precautions .................................................................................................................................................5
2General Settings.......................................................................................................................................................7
2.1 Equipment Upgrade....................................................................................................................................................... 7
2.2 Debugging Of Human Body Temperature Detection Function ......................................................................8
2.2.1 Selection of human body temperature measurement intelligent scheme...................................... 8
2.2.2 Blackbody Parameter Setting..........................................................................................................................8
2.2.3 Drawing Of Human Body Temperature Detection Area......................................................................10
2.2.4 Alarm Temperature Correction.................................................................................................................13
2.2.5 Binocular target setting and fine adjustment function.........................................................................13
2.2.6 Opening / closing function of visible light face thermometer...........................................................14
3 Announcements ................................................................................................................................................... 15
4 FAQ.............................................................................................................................................................................. 16

1Equipment Installation
1.1 Installation Preparation
⚫Installation Preparation：
◼5 meter long tape for distance measurement on site
◼DC12V adapter, used with camera
◼Some cable lines
⚫Product appearance
BF5421：Blackbody：
Note: the recorded installation guidance video "Dahua indoor human body
temperature measurement product installation video (BF3221)", which adopts
tripod mode, is applicable to portable indoor installation guidance reference,
and other fixed installation needs to be installed in strict accordance with the
specified height, distance and other requirements.
The PPT version of installation guidance video, web operation guidance
and guidance document should be obtained from the regional delivery
supervisor. In the future, it will be synchronized in the group on the mobile app.
1.2 Installation Distance
focal length
Distance between
blackbody and
camera
Distance between
human forehead and
camera
Width at the best
distance of
temperature
measurement
BF5421
（13mm）
3m
3m
(NO Blackbody2m)
1.5m
The distance from the forehead to the camera and the distance from the blackbody to
the camera have the best temperature measurement accuracy. Taking BF542121

(13mm) as an example, the distance between blackbody and camera is 3M, the best
distance for temperature measurement is 3M (the straight-line distance between the
front of forehead and camera), the best test width at 3m is about 1.3m (about one
gate), the forward temperature at 3m will be higher, and the backward temperature
will be lower. The ideal situation is to place footprints at the 3m position to guide the
thermometer to measure temperature one by one at the designated position.
1.3 Installation Diagram
⚫BF5421(13mm) installation diagram
1.4 Real Scene Diagram
⚫BF5421(13mm) as an example
Blackbody
Height 1.8m
Thermal Camera
Height 2m

Sticking foot stickers at the temperature measurement position
⚫Monitoring picture, the following is the effect of one person in front of the 13mm
lens at the 3m position
1.5 Installation Precautions
⚫The thermal imaging camera and blackbody are installed on the same side to
avoid the occlusion between the camera and blackbody ，the blackbody
radiation surface should be facing the camera. If the blackbody is facing the
camera, the four sides of the blackbody shell will not be exposed, as shown in
the following figure:
⚫The moving direction of the flow of people is toward the camera. During the
test, the forehead of the target person is facing the camera. It is better to stay
and face the camera for temperature measurement. Temporary measures can
be adopted on site to plan the walking route of personnel and guide the person
to the camera position; for scenes with large indoor and outdoor temperature

difference, multiple bow type routes can be planned and the area with wind at
the door shall be avoided, and the temperature measurement can be
conducted after the person reaches the indoor forehead temperature to be
stable.
⚫The black body radiation surface (Note: the radiation surface shall not be
touched or dirty) shall be facing the camera irradiation direction, the black body
shall be on the left or right side of the thermal imaging picture, and the tripod
can be protected by temporary fence.
As follows, we divide the picture into 16 equal parts, the best position of the
blackbody: put it on the top left or top right in the middle position of the ‘Cross
type’:
⚫It is required that the visible light channel has enough illumination and avoid the
influence of backlight / reflection / change of strong light / occlusion, etc.
⚫It is forbidden to have high-temperature heat source or sunlight in the thermal
imaging picture, to avoid the interference of heat source such as heater, hot water
point, microwave oven, high-power lamp, radiator, etc., so as to avoid the damage
of detector.
⚫The installation area shall be relatively isolated from the outside environment
without wind and stability, to avoid the outdoor or the scene connected with the
outside, which is not suitable for the environment with air flow or strong
electromagnetic interference or vibration.

Installation scenarios to avoid
Insufficient light.
Backlight / scene open
to the outside
The direction of people moving is not toward
the camera.
2General Settings
2.1 Equipment Upgrade
The new factory version of the program already supports human body temperature
detection and does not need to be upgraded. If there is a new iterative process will be
notified in the delivery group, please pay attention to the group information in time.
Note:
(1) After 20200210, the black regular box of the program is rectangle.
(2) Programs prior to 20200228 need to be upgraded to the latest, first upgrade the main
program, and then upgrade the thermal imaging core program. After the upgrade, restore
the default and clear the browser cache.
(3) When operating "restore factory settings", "program upgrade", "clear configuration",
"power off and restart", "soft restart", power off is prohibited before the completion of
equipment startup. Important signs of the completion of device startup: Ping connected,
web login.

2.2 Debugging Of Human Body Temperature
Detection Function
2.2.1 Selection of human body temperature measurement
intelligent scheme
2.2.2 Blackbody Parameter Setting
➢Blackbody calibration.
Note: the blackbody parameter setting steps are ignored for the scheme without
blackbody.
a) When the blackbody is actually set to 35 ℃, there may be two situations on the
back of the blackbody, one is the digital tube display (left), the other is the LCD
display (right):

Note：For the blackbody display of the LED, just press the bottom‘︿’‘﹀’to adjust
the value; for the LCD display device, press the bottom‘<’ to select the value to be
adjusted, and then press the bottom‘︿’‘﹀’to adjust the value.
b) After fixing the camera and the blackbody position, make sure that the blackbody
is on the right or left side of the image and is not blocked (the best position of the
blackbody: put it on the top left or the middle position of the ‘Cross type’ on the
top right: as shown below)
c) (In the procedure before 20200210, the rule window should be in the middle of
the black body, the smaller the window is, the higher the measurement accuracy is,
refer to the green window in the upper right corner of the image below) fill in the
black body temperature 35, double-click the image to enlarge to the full screen
when drawing the area (double-click again after drawing to restore the original
picture size), the rule window should be in the middle of the black body radiation
surface, and the rule window should be as small as possible, and click OK to take
effect;

d) (The rule window of the program after 20200210 is rectangle. The drawing
method is as follows: draw the rectangular area along the highlighted edge of the
blackbody) Black regular window drawing is no longer the smaller the better.
You need to draw the rectangular area along the highlighted edge of the
blackbody. The blackbody temperature is 35 (the default), and the rule box is
shown in the green window below. Click OK to take effect. If the blackbody is
facing the camera, the four sides of the blackbody shell will not be exposed, as
shown in the following figure:
e) Confirm that the highest and lowest temperature is within 35 ±0.2 ℃on
average
2.2.3 Drawing Of Human Body Temperature Detection Area
a) BF5421 （13mm）：
i. The subject stands on the edge of the blackbody (3m away from the camera),
faces the camera, and can see the head and shoulder exposed in the picture;
ii. The lower border of the rule is drawn on the shoulder of the tested person, and
the upper border of the rule can be drawn to the upper edge of the image;
refer to the following figure for the detection area
b) BF5421 （7.5mm）：
iii. The tested person is standing on the edge of the blackbody (2 meters away
from the camera), and the setting method refers to the 7mm lens;
The setting in the figure below indicates that an audible and visual alarm will

be generated when the head temperature of the subject exceeds 37.3 ℃
1) Face frame size scaling. It can scale the thermal imaging face identification frame.
2) The lower limit of temperature detection can be set: for example, if it is set to 25 ℃, the
target below 25 ℃will not be detected.
1) Intelligent detection channel: visible light and thermal imaging are optional. In normal
scenes, visible light is used to detect faces by default. If the effect of visible light is not good
(such as backlight, insufficient light, etc.), thermal imaging detection can be used;
2) The capture angle filter value is 1 Detection front (similar to certificate photo), and the
value is 90 detection side. This function is only supported in visible light intelligent
detection.
3) The matting function is closed by default. It can only be opened when it is used with
special platforms such as H8900. Please close other related supporting facilities.

Optional compensation mode: 1) mercury meter compensation (default); 2) forehead
temperature meter compensation
Note: please confirm whether the "adaptive ambient temperature" is consistent with the real
ambient temperature on site. If not, please input the real and accurate ambient temperature
on site (use a thermometer to measure or point to measure the temperature of the tripod
under the blackbody as a reference, as shown in the figure below). Manual setting must be
accurate, otherwise it will lead to inaccurate temperature measurement of human body!

2.2.4 Alarm Temperature Correction
Due to the difference of environment, there may be errors in the temperature of the measured
person. If more than 5 person samples stand at the best temperature measurement distance
and the measured temperature is generally high or low, they can be compensated by
temperature correction. For example, if it is 0.5 ℃lower, fill in 0.5 ℃for temperature
correction, and if it is 0.5 ℃higher, fill in - 0.5 ℃
Note: if there is no blackbody on site, when the temperature is corrected, the "enable"
in the figure below is not checked, otherwise the temperature measurement will be
inaccurate;
If you have blackbody, you need to turn on enable.
2.2.5 Binocular Target Setting And Fine Adjustment Function
1. When selecting the visible light channel for intelligent detection, the visible light face frame
shall prevail, and the thermal imaging face frame shall be adjusted.
2. When selecting the thermal imaging channel for intelligent detection, the visible light face
frame is adjusted according to the thermal imaging face frame.
3. Adjust the up, down, left and right arrows (set step length 5) according to the actual
situation to fine tune the face frame of thermal imaging or thermal imaging, which must be
accurate. As shown in the figure below:

2.2.6 Opening / Closing Function Of Visual Face
Thermometer Frame

Open：Close：
3Announcements
The following is for blackbody：
➢Warning
A warning indicates a condition that may cause harm to the user. To avoid personal
injury or instrument damage, follow these guidelines:
⚫Ensure that the place is free of oil, chemicals, inflammables and explosives!
⚫Use environment is 5 ℃~ 40 ℃, (ideal temperature of temperature
measurement environment is 10 ℃~ 30 ℃). Do not put it into high and low
temperature box without permission to avoid accidents!
⚫Make sure to use grounding socket to prevent accidental electric shock!
⚫Blackbody cannot be used for applications other than temperature test and
calibration!
⚫It is not allowed to change the boldface range without permission, so as to
avoid damaging the boldface or causing safety accidents!
⚫It is not allowed to dismantle or refit blackbody without permission! Tear up or
damage of the tamper proof label, the product is not warranted.
➢Notice
To avoid damaging the instrument or affecting the test accuracy, please follow the
following instructions:
⚫It is not allowed to touch the blackbody radiation surface, and dirt will lead to
the decrease of blackbody accuracy or scrap, so as to avoid the scratch of
blackbody radiation surface and affect the temperature measurement accuracy.
⚫Only for indoor use. The use environment shall be free from obvious air
convection and strong light irradiation, strong electromagnetic interference

and vibration.
⚫Heat dissipation space shall be reserved around the blackbody, and the
distance from the surrounding objects shall not be less than 10cm.
➢Calibration
⚫In order to ensure the accuracy of blackbody temperature measurement, it is
recommended to send blackbody to Dahua Co., Ltd. for paid calibration on a
regular basis. The calibration cycle is usually one year.
➢Daily maintenance
⚫The blackbody shall be managed and maintained by the designated personnel,
and the maintenance and use records shall be made.
⚫In the process of use, it is not allowed to cover any object on the black body,
so as not to affect the heat dissipation and thus the temperature accuracy.
⚫When it is unnecessary to use, dust prevention shall be done well, and the black
body shall be put into the packing box or covered with a clean cloth. Ensure
that the storage environment temperature and humidity are appropriate.
⚫It is recommended to use neutral detergent to clean the blackbody shell and
soft brush to clean the dust on the radiation surface of blackbody.
4F
A
Q
1. What is blackbody? What is the role? Do you need a physical connection to the
camera?
Blackbody can be simply understood as a constant temperature reference source
(constant temperature can be maintained after power on). When testing human body
temperature, blackbody is generally set at 35 ℃, which is used for temperature
correction of thermal imaging acquisition, so as to meet the accuracy requirements of
±0.3 ℃.
Bold doesn't need to be connected to the camera, it's separate. After power on, it can
be placed in the camera screen according to the installation instructions.
2. Power on stabilization time of equipment.

Blackbody: power on and preheat for 20 minutes; thermal imaging equipment: power
on and preheat for 60 minutes, with the best effect.
3. Whether it can be installed in outdoor or semi outdoor environment.
Because the outdoor temperature, wind, humidity and other environmental factors
have a great impact on the temperature measurement of the thermal imaging surface,
it is not recommended to be installed outdoors or in the area directly connected to the
outdoor, but in a closed and relatively stable environment without wind.
4. Why is it recommended to measure the temperature of frontal forehead?
First of all, different people's forehead temperature also has temperature difference. In
the case of mask, the exposed area of forehead is relatively large, which is more
convenient for temperature measurement.
The actual temperature of the front face and the side face of the same person / same
position is different. With masks, the high temperature points are mainly in the
forehead, ears and neck, and the temperature is different among different people.
Therefore, it is required to face the camera and test the frontal temperature uniformly
to reduce the impact of temperature difference between different parts.
5. What is the best temperature range for temperature measurement?
The best temperature range of indoor wind free and stable environment is 10 ℃~
30 ℃
6. The best distance for temperature measurement?
The best temperature measurement distance is the same as the distance between
blackbody and equipment. 3.5mm detection distance is 2m, and the transverse width
of 2m is about 1.5m; 7mm detection distance is 3m, and the transverse width of 3m is
about 1.3m; the temperature measurement value far from the optimal distance will be
reduced, and the temperature measurement value close to the optimal distance will be
increased.
7. How many heads can be tested?
As shown in the figure below, in normal use, there are not many people (width 1.3-
1.5m) at the best distance of temperature measurement. There is no limit to the number
of heads in the detection area, but it is too far or there is overlap, which may result in
missing or inaccurate temperature measurement. It is recommended to test one by one.
8. Why does the image of thermal imaging channel get stuck after a period of time?
Is it normal?
Normal. In order to ensure image uniformity and temperature measurement accuracy,
thermal imaging needs a period of time to set the blank back to zero for correction.
During the process of setting the blank, the image will get stuck once, and the internal
part of the equipment will "click" once, which is a normal situation.
9. Why thermal imaging does not measure temperature after the first
configuration