Adaptive tracking system and tracking method for water surface target
An adaptive tracking system and tracking method for a water surface target are provided. The tracking system includes an information acquisition module, a mode selection module for controlling a tracker to enter a tracking mode or a prediction waiting mode, a tracking module for controlling the tracker to track the water surface target, a prediction module for generating a predicted position of the water surface target, and a wake-up module for waking up the tracking module when the water surface target appears at the predicted position. The mode selection unit is introduced, which controls the tracker to enter the prediction waiting mode when the water surface target is occluded or greatly affected by an adverse environmental factor. The design avoids the tracker moving away from the water surface target in a wrong direction, thereby avoiding adverse effects on subsequent tracking of the water surface target.
1. An adaptive tracking system for a water surface target, comprising:
an information acquisition module comprising at least one sensor, configured to acquire, in real time, a visible area m t of the water surface target, a wind scale FL t , a wave scale BL t , a distance between a tracker and the water surface target, and a velocity magnitude and direction of the water surface target, wherein t denotes a serial number of different acquisition times, and t=1, 2, 3, . . . , n;
a mode selection module comprising at least one processor, configured to send, based on the visible area m t of the water surface target, the wind scale FL t , and the wave scale BL t , a first signal to control the tracker to enter a tracking mode or a second signal to control the tracker to enter a prediction waiting mode;
a tracking module comprising at least one processor, configured to receive data on the distance between the tracker and the water surface target as well as the velocity magnitude and direction of the water surface target, and control, upon a reception of the first signal, the tracker to track the water surface target based on the distance between the tracker and the water surface target as well as the velocity magnitude and direction of the water surface target;
a prediction module comprising at least one processor, configured to receive the data on the distance between the tracker and the water surface target as well as the velocity magnitude and direction of the water surface target, and generate, upon a reception of the second signal, at least one predicted position of the water surface target based on the distance between the tracker and the water surface target as well as the velocity magnitude and direction of the water surface target; and
a wake-up module comprising at least one processor, configured to acquire the predicted position, control the information acquisition module to monitor the predicted position, and send, when the water surface target is detected at the predicted position, a wake-up signal to the tracking module, allowing the tracking module to control the tracker to track the water surface target;
wherein the mode selection module comprises a data receiving unit, a data processing unit, and a threshold comparison unit, wherein
the data receiving unit is electrically connected to the information acquisition module, and is configured to receive the visible area m t of the water surface target, the wind scale FL t , and the wave scale BL t transmitted by the information acquisition module;
the data processing unit is electrically connected to the data receiving unit, and is configured to generate a prediction waiting coefficient YD t based on the visible area m t of the water surface target, the wind scale FL t , and the wave scale BL t ; wherein
values are assigned to the wind scale FL t and the wave scale BL t respectively by a 1-9 scale method to generate a wind influence value f(FL t ) and a wave influence value f(BL t );
the prediction waiting coefficient YD t is calculated according to the following equations:
{
YD
1
t
=
α1
⋆
m
0
-
m
t
m
0
+
α2
⋆
e
m
t
-
m
t
-
1
m
0
YD
2
t
=
β1
⋆
f
(
F
L
t
)
+
β2
⋆
f
(
BL
t
)
YD
t
=
w
1
⋆
YD
1
t
+
w
2
⋆
ln
(
1
+
YD
2
t
)
wherein in the equations, t≥2; and m 0 denotes a total area of the water surface target;
YD1 t denotes a first prediction waiting coefficient; α1, α2 denote first preset proportional coefficients; YD2 t denotes a second prediction waiting coefficient; β1, β2 denote second preset proportional coefficients; w1 denotes a weight influence coefficient of the first prediction waiting coefficient YD1 t ; and w2 denotes a weight influence coefficient of the second prediction waiting coefficient YD2 t ;
the threshold comparison unit is configured to receive the prediction waiting coefficient YD t , compare the prediction waiting coefficient YD t with a preset threshold TTH, send the first signal to control the tracker to enter the tracking mode when YD t <TTH, and send the second signal to control the tracker to enter the prediction waiting mode when YD t ≥TTH; and
the visible area m t of the water surface target is acquired by: photographing the water surface target through an optical camera and an infrared camera, and processing an optical image and an infrared image of the water surface target to acquire the visible area m t of the water surface target.
2. The adaptive tracking system for the water surface target according to claim 1 , wherein the at least one sensor of the information acquisition module comprises the optical camera, the infrared camera, a pulse Doppler radar, a wind sensor, and a buoy sensor.
3. The adaptive tracking system for the water surface target according to claim 1 , wherein an assigning criterion for the wind influence value f(FL t ) is as follows:
when the wind scale FL t is 0-6, the wind influence value f(FL t ) is assigned a value of 1;
when the wind scale FL t is 7-10, the wind influence value f(FL t ) is assigned a value of 3;
when the wind scale FL t is 11-16, the wind influence value f(FL t ) is assigned a value of 5;
when the wind scale FL t is 17-21, the wind influence value f(FL t ) is assigned a value of 7; and
when the wind scale FL t is 22 or above, the wind influence value f(FL t ) is assigned a value of 9.
4. The adaptive tracking system for the water surface target according to claim 1 , wherein an assigning criterion for the wave influence value f(BL t ) is as follows:
when the wave scale BL t is 0, the wave influence value f(BL t ) is assigned a value of 1;
when the wave scale BL t is 1, the wave influence value f(BL t ) is assigned a value of 3;
when the wave scale BL t is 2, the wave influence value f(BL t ) is assigned a value of 5;
when the wave scale BL t is 3, the wave influence value f(BL t ) is assigned a value of 7; and
when the wave scale BL t is 4 or above, the wave influence value f(BL t ) is assigned a value of 9.
5. The adaptive tracking system for the water surface target according to claim 1 , wherein the wake-up module comprises a predicted position monitoring unit, an image extraction unit, and an image comparison unit, wherein
the predicted position monitoring unit is electrically connected to the prediction module and the information acquisition module, and is configured to receive the at least one predicted position of the water surface target generated by the prediction module, and control the information acquisition module to monitor the at least one predicted position of the water surface target predicted by the prediction module;
the image extraction unit is electrically connected to the information acquisition module, and is configured to extract an image acquired by the information acquisition module at the predicted position; and
the image comparison unit is electrically connected to the image extraction unit, and is configured to compare the image extracted by the image extraction unit with an image of the water surface target stored in the image comparison unit to determine whether the water surface target appears at the predicted position, and send, when the water surface target appears at the predicted position, the wake-up signal to the tracking module, allowing the tracking module to control, upon a reception of the wake-up signal, the tracker to track the water surface target based on the distance between the tracker and the water surface target as well as the velocity magnitude and direction of the water surface target.
6. An adaptive tracking method for a water surface target, applied to the adaptive tracking system for the water surface target according to claim 1 , and comprising the following steps:
S1: acquiring, in real time, the visible area m t of the water surface target, the wind scale FL t , the wave scale BL t , the distance between the tracker and the water surface target, and the velocity magnitude and direction of the water surface target, wherein t denotes the serial number of different acquisition times, and t=1, 2, 3, . . . , n;
S2: sending, based on the visible area m t of the water surface target, the wind scale FL t , and the wave scale BL t , the first signal to proceed to step S3 or the second signal to proceed to step S4;
S3: controlling the tracker to track the water surface target based on the distance between the tracker and the water surface target as well as the velocity magnitude and direction of the water surface target;
S4: generating the at least one predicted position of the water surface target based on the distance between the tracker and the water surface target as well as the velocity magnitude and direction of the water surface target; and
S5: monitoring whether the water surface target appears at the predicted position, and proceeding to the step S3 when the water surface target appears at the predicted position.
7. The adaptive tracking method according to claim 6 , wherein in the the adaptive tracking system for the water surface target, the information acquisition module comprises the optical camera, the infrared camera, a pulse Doppler radar, a wind sensor, and a buoy sensor.
8. The adaptive tracking method according to claim 6 , wherein in the the adaptive tracking system for the water surface target, an assigning criterion for the wind influence value f(FL t ) is as follows:
when the wind scale FL t is 0-6, the wind influence value f(FL t ) is assigned a value of 1;
when the wind scale FL t is 7-10, the wind influence value f(FL t ) is assigned a value of 3;
when the wind scale FL t is 11-16, the wind influence value f(FL t ) is assigned a value of 5;
when the wind scale FL t is 17-21, the wind influence value f(FL t ) is assigned a value of 7; and
when the wind scale FL t is 22 or above, the wind influence value f(FL t ) is assigned a value of 9.
9. The adaptive tracking method according to claim 6 , wherein in the the adaptive tracking system for the water surface target, an assigning criterion for the wave influence value f(BL t ) is as follows:
when the wave scale BL t is 0, the wave influence value f(BL t ) is assigned a value of 1;
when the wave scale BL t is 1, the wave influence value f(BL t ) is assigned a value of 3;
when the wave scale BL t is 2, the wave influence value f(BL t ) is assigned a value of 5;
when the wave scale BL t is 3, the wave influence value f(BL t ) is assigned a value of 7; and
when the wave scale BL t is 4 or above, the wave influence value f(BL t ) is assigned a value of 9.
10. The adaptive tracking method according to claim 6 , wherein in the the adaptive tracking system for the water surface target, the wake-up module comprises a predicted position monitoring unit, an image extraction unit, and an image comparison unit, wherein
the predicted position monitoring unit is electrically connected to the prediction module and the information acquisition module, and is configured to receive the at least one predicted position of the water surface target generated by the prediction module, and control the information acquisition module to monitor the at least one predicted position of the water surface target predicted by the prediction module;
the image extraction unit is electrically connected to the information acquisition module, and is configured to extract an image acquired by the information acquisition module at the predicted position; and
the image comparison unit is electrically connected to the image extraction unit, and is configured to compare the image extracted by the image extraction unit with an image of the water surface target stored in the image comparison unit to determine whether the water surface target appears at the predicted position, and send, when the water surface target appears at the predicted position, the wake-up signal to the tracking module, allowing the tracking module to control, upon a reception of the wake-up signal, the tracker to track the water surface target based on the distance between the tracker and the water surface target as well as the velocity magnitude and direction of the water surface target.