CN105120151B - A kind of method and device focused on automatically - Google Patents

Abstract

The present invention provides an automatic focusing method and device, the method comprising: setting a variable num, and setting the initial value of the variable num to the first characteristic value; detecting in real time whether at least one of the focal length and the position of the camera changes; If so, increase the current value of the variable num by a predetermined value; judge in real time whether the current value of the variable num is the first characteristic value; if not, form a focus signal, and subtract the current value of the num The predetermined value; controlling the camera to focus according to the focus signal. The device includes: a first setting unit, a detection unit, a calculation unit, a first judgment unit, a signal generator and a controller. This solution can realize the automatic focus of the camera.

Description

A method and device for auto-focusing

technical field

The invention relates to the field of video monitoring, in particular to an automatic focusing method and device.

Background technique

For safety precautions or to record related processes, surveillance cameras are used more and more widely. For example, shopping malls, traffic intersections, and factories are all equipped with surveillance cameras to record corresponding illegal or criminal acts and provide evidence for public security organs to handle cases. In order to obtain a larger monitoring range and clearer images, laser night vision devices are generally used for monitoring at present. Laser night vision devices include infrared laser illuminator, zoom lens, infrared camera and pan/tilt. After the pan/tilt of the camera is rotated or the camera lens is zoomed in, the object captured by the camera changes, and the laser night vision device needs to be refocused to obtain the clearest video image.

At present, laser night vision devices generally include an auto-focus module. When the pan/tilt of the laser night vision device rotates, or the camera lens zooms in, the corresponding button is manually operated to focus the laser night vision device to obtain better Good video image quality.

In view of the current focusing method of the laser night vision device, after each turning the angle of the laser night vision device or adjusting the shooting distance of the laser night vision device, it is necessary to manually perform tedious focusing work.

Contents of the invention

The invention provides an automatic focusing method and device, which can realize automatic focusing of a video camera.

The embodiment of the present invention provides an automatic focusing method, setting the variable num, and setting the initial value of the variable num to the first eigenvalue, further comprising:

Detecting in real time whether at least one of the focal length and the position of the camera changes;

If so, increasing the current value of the variable num by a predetermined value;

judging in real time whether the current value of the variable num is the first characteristic value;

If not, forming a focus signal and subtracting said predetermined value from said current value of num;

According to the focus signal, the camera is controlled to focus.

Preferably, the forming the focus signal includes: preset a low level time and a high level time, when it is judged that the current value of the variable num is not the first characteristic value, start counting to form a low level time Flat pulse, when the timing duration is equal to the low level time, the pulse is converted from low level to high level, forming a rising edge, when the timing duration is equal to the low level time and the high level When the sum of the level times, the pulse is converted from a high level to a low level to form a falling edge, so as to obtain a focusing signal composed of the rising edge and the falling edge.

Preferably, the controlling the camera to focus according to the focusing signal includes:

The rising edge and the falling edge are received, and according to the rising edge and the falling edge, an auto-focus lens on the camera is triggered to focus the camera.

Preferably, the method further includes: setting the maximum value of the variable num;

After detecting that at least one of the focal length and position of the camera changes, and before increasing the current value of the variable num by a predetermined value, further comprising: judging whether the current value of the variable num reaches the maximum value , if yes, ignore the change, and continue to execute the real-time detection of whether at least one of the focal length and position of the camera has changed, and if not, continue to execute the step of increasing the current value of the variable num by a predetermined value.

Preferably, after detecting that at least one of the focal length and position has changed, and before increasing the current value of the variable num by a predetermined value, the method further includes:

Determine whether the camera is in a focused state when at least one of the focal length and position of the camera changes, and if so, ignore this change, and continue to perform the real-time detection of whether at least one of the focal length and position of the camera changes , if not, continue to execute the step of increasing the current value of the variable num by a predetermined value.

An embodiment of the present invention also provides an automatic focusing device, including:

The first setting unit is used to set the variable num, and set the initial value of the variable num to the first characteristic value;

a detection unit, configured to detect in real time whether at least one of the focal length and the position of the camera changes;

A calculation unit, configured to, according to the detection result of the detection unit, if yes, increase the current value of the variable num set by the first setting unit by a predetermined value;

a first judging unit, configured to judge in real time whether the current value of the variable num is the first characteristic value;

A signal generator, configured to form a focus signal according to the judgment result of the first judgment unit, if not, and subtract the predetermined value from the current value of num;

The controller is configured to control the camera to focus according to the focus signal formed by the signal former.

Preferably, the signal generator is a PWM signal generator;

The PWM signal generator is connected to the first judging unit, and the low level time and the high level time of the PWM signal generator are preset, when the first judging unit judges the current value of the variable num When it is not the first characteristic value, the PWM signal generator starts timing and forms a low-level pulse, and when the timing duration is equal to the low-level time, the pulse is converted from low level to high Level, forming a rising edge, sending the rising edge to the controller, when the timing duration is equal to the sum of the low level time and the high level time, the pulse is converted from high level to low level, forming a falling edge, sending the falling edge to the controller, and forming a focusing signal by the rising edge and the falling edge.

Preferably, the controller is a relay;

The relay is connected to the autofocus lens on the PWM signal generator and the camera respectively, wherein the autofocus lens is connected to the relay through a first trigger wire and a second trigger wire, when the relay receives When the rising edge sent by the PWM signal generator, the relay short-circuits the first trigger wire and the second trigger wire, and when the relay receives the falling edge sent by the PWM signal generator, The relay disconnects the first trigger wire from the second trigger wire, the first trigger wire and the second trigger wire are short-circuited and disconnected again to form a trigger signal, and the autofocus lens After receiving the trigger signal, an automatic focus is performed.

Preferably, the device further includes: a second setting unit and a second judging unit;

The second setting unit is configured to set the maximum value of the variable num;

The second judging unit is configured to judge whether the current value of the variable num reaches the maximum value after the detection unit detects that at least one of the focal length and the position of the camera has changed, and if so, ignore the change, continue to detect whether at least one of the focal length and position of the camera changes in real time by the detection unit, if not, the calculation unit will set the variable num set by the first setting unit to The current value is increased by a predetermined value.

Preferably, the device further includes: a third judging unit;

The third judgment unit is connected to the detection unit and the calculation unit respectively, and when the detection unit detects that at least one of the focal length and position of the camera changes, the third judgment unit judges that the change occurs When the camera is in focus, if so, the detection unit continues to detect whether at least one of the focal length and position of the camera changes in real time, if not, the calculation unit increases the current value of the variable num predetermined value.

The embodiment of the present invention provides a method and device for autofocus. The variable num is set in advance, and its initial value is set as the first characteristic value to detect whether the focal length or position of the camera changes in real time. If there is a change, the first Add a predetermined value to the characteristic value, judge in real time whether the current value of the variable num is equal to the first characteristic value, if not, then form a focus signal, and subtract a predetermined value from the current value of the variable num, and control the camera according to the formed focus signal Carry out a focus, so that each time the lens of the camera zooms or the pan/tilt rotates to change the focal length or position of the camera, the variable num is correspondingly increased by a predetermined value, so that the current value of the variable num is not equal to the first characteristic value , trigger the camera to focus, and subtract a predetermined value from the variable num after the focus signal is sent out, so as to ensure that a focus is triggered every time the focal length or position of the camera changes, without manual operation, so as to realize the automatic focus of the camera.

Description of drawings

FIG. 1 is a flow chart of an automatic focusing method provided by an embodiment of the present invention;

Fig. 2 is a flow chart of an automatic focusing method provided by another embodiment of the present invention;

Fig. 3 is a flow chart of an automatic focusing method provided by another embodiment of the present invention;

Fig. 4 is a schematic diagram of an automatic focusing device provided by an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

As shown in Figure 1, an embodiment of the present invention provides an automatic focusing method, including:

Step 101: Set the variable num, and set the initial value of the variable num to the first eigenvalue;

Step 102: Real-time detection of whether at least one of the focal length and position of the camera has changed, if yes, execute step 103, otherwise continue to execute step 102;

Step 103: increasing the current value of the variable num by a predetermined value;

Step 104: judge in real time whether the current value of the variable num is the first characteristic value, if yes, continue to execute step 104, otherwise execute step 105;

Step 105: forming a focus signal, and subtracting the predetermined value from the current value of num;

Step 106: Control the camera to focus according to the focus signal.

The embodiment of the present invention provides a method for automatic focusing. The variable num is set in advance, and its initial value is set as the first characteristic value to detect whether the focal length or position of the camera changes in real time. If there is a change, the first characteristic value Add a predetermined value, judge in real time whether the current value of the variable num is equal to the first characteristic value, if not, then form a focus signal, and subtract a predetermined value from the current value of the variable num, and control the camera once according to the formed focus signal Focusing, in this way, every time the lens of the camera zooms or the pan/tilt rotates to change the focal length or position of the camera, the variable num is correspondingly increased by a predetermined value, so that the current value of the variable num is not equal to the first characteristic value, triggering The camera focuses, and subtracts a predetermined value from the variable num after the focus signal is sent out, so as to ensure that a focus is triggered every time the focal length or position of the camera changes, without manual operation, so as to realize the automatic focus of the camera.

In one embodiment of the present invention, the focus signal is formed by a PWM signal generator, and the low level time and high level time of the PWM signal generator are preset, when the current value of the judgment variable num is not equal to the first characteristic value , the PWM signal generator starts timing and forms a low-level pulse. When the timing duration is equal to the low-level time, the pulse is converted from low level to high level to form a rising edge. When the timing duration is equal to the low-level time When the sum of the flat time and the high level time, the pulse is converted from high level to low level, forming a falling edge, the relay controls the autofocus lens on the camera to automatically focus through the rising edge and falling edge, due to different relays and The corresponding time of the auto-focus lens is also different. By adjusting the high-level time and low-level time, it can adapt to different relays and auto-focus lenses, and realize the auto-focus of various types of cameras.

In one embodiment of the present invention, the automatic focus control of the camera is realized by a relay. When the relay receives the rising edge sent by the PWM signal generator, the two trigger wires of the automatic focus lens are short-circuited, and a high level Time, when the relay receives the falling edge sent by the PWM signal generator, the two trigger wires of the auto-focus lens are disconnected, and the two trigger wires of the auto-focus lens are short-circuited and then disconnected again to form a trigger signal to automatically focus After receiving the trigger signal, the lens performs an automatic focus, so as to realize the conversion between the level signal and the trigger signal.

In one embodiment of the present invention, the maximum value of the variable num can be set. When the focal length or position of the camera is detected to be changed, it is first judged whether the current value of the variable num reaches its maximum value. The current value is increased by a predetermined value. If the maximum value has been reached, the change of the focal length or position will be ignored, so as to avoid continuous multiple changes of the focal length or position, which requires continuous auto-focusing for multiple times, which will affect the shooting effect of the camera. .

In one embodiment of the present invention, after detecting that the focal length or position of the camera has changed, it can be further judged whether the camera is in a focused state when the change occurs. If so, ignore this change and continue to detect the focal length and position of the camera. Whether the position has changed, if not, will add a predetermined value to the current value of the variable num, so that when the camera is in focus, the change of the focal length or position of the camera will be ignored, because after the current focus is completed, the image captured by the camera If it is already in a clear state, repeatedly focusing on the camera in the same state will increase the workload of the auto-focus lens and affect the shooting effect of the camera.

In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 2, an embodiment of the present invention provides an automatic focusing method, including:

Step 201: Set the variable num, and set its initial value to 0.

In one embodiment of the present invention, an integer variable num is defined and its initial value is 0, which is used to record the number of times that the focal length or position of the camera changes.

Step 202: Set the maximum value of the variable num.

In an embodiment of the present invention, the maximum value of the variable num is further set, and when the variable num reaches the maximum value, it is not allowed to continue to increase. For example, set the maximum value of the variable num to 20.

Step 203: Detect in real time whether the focal length or position of the camera changes, if yes, execute step 204, otherwise continue to execute step 203.

In one embodiment of the present invention, if the lens of the camera zooms or the pan/tilt rotates, the focal length or position of the camera changes accordingly, and it is detected in real time whether the focal length or position of the camera changes, and if the focal length or position changes , the camera needs to be refocused, correspondingly execute step 204 , if the focal length or position does not change, then need to continue monitoring the focal length and position of the camera, correspondingly continue to execute step 203 .

Step 204: Judging whether the current value of the variable num is equal to its maximum value, if yes, go to step 203, otherwise go to step 205.

In one embodiment of the present invention, after detecting that the focal length or position of the camera changes, it is first necessary to judge whether the current value of the variable num is equal to its maximum value, and if so, the variable num is not allowed to increase again, so as to avoid continuously adjusting the focal length of the camera or position, repeat focusing on the camera, ignore this change of focal length or position, continue to step 203, if not, need to focus on this change, and perform step 205 accordingly. For example, if the current value of the variable num is 20, when it is detected that the focal length of the camera has changed, ignore the change of this focus, the variable num is still 20, continue to monitor the focal length and position of the camera, and execute step 203 accordingly, If the current value of the variable num is 10, when the position of the camera is detected to change, since the current value of the variable num does not exceed its maximum value, the change of this position cannot be ignored, and the change needs to be recorded and executed accordingly Step 205.

Step 205: Add 1 to the current value of the variable num.

In one embodiment of the present invention, when it is detected that the focal length or position of the camera changes, and the current value of the variable num is not equal to its maximum value, it is necessary to perform a focusing for this change, and the current value of the variable num is increased by 1, The number of times focusing was required was recorded.

Step 206: judge in real time whether the current value of the variable num is equal to 0, if yes, continue to execute step 206, otherwise execute step 207.

In one embodiment of the present invention, the current value of the variable num is judged in real time to determine whether it is equal to its initial value 0, if yes, it means that the camera does not need to focus and should continue to be in a waiting state, and the response continues to execute step 206, if If no, it means that the focal length or position of the camera has not been focused, and it needs to be focused, and step 207 is executed in response.

Step 207: Form a focus signal, and subtract 1 from the current value of the variable num.

In one embodiment of the present invention, the focus signal is formed by a PWM signal generator. According to different cameras, the low level time LOWTIME and the high level time HIGHTIME of the PWM signal generator are preset. When judging the current value of the variable num When it is not 0, the PWM signal generator starts timing, and at the same time the PWM signal generator forms a low-level pulse. When the timing duration is equal to LOWTIME, the pulse is converted from low level to high level, forming a rising edge, and the rising edge forms Then it is sent to the relay to continue timing. When the timing is equal to the sum of LOWTIME and HIGHTIME, the pulse is converted from high level to low level to form a falling edge. After the falling edge is formed, it is sent to the relay to stop timing and focus on the signal It is composed of a rising edge and a falling edge. When the focus signal is sent, the current value of the variable num is correspondingly subtracted by 1, indicating that a focus has been performed, and the remaining number of times to be focused is correspondingly subtracted by 1. . For example, the low level time LOWTIME of the PWM signal generator is preset to 10 milliseconds, and the high level time HIGHTIME is 20 milliseconds. When the current value of the variable num is 3, the PWM signal generator starts timing and forms a low level at the same time The pulse, when the timing is 10 milliseconds, the pulse is converted from low level to high level, forming a rising edge, the rising edge is sent to the relay, when the timing is equal to 30 milliseconds, the pulse is converted from high level to Low level, forming a falling edge, sending the falling edge to the relay, stopping timing, and subtracting 1 from the current value of the variable num to become 2.

Step 208: Control the auto-focus lens of the camera to focus according to the focus signal.

In one embodiment of the present invention, the auto-focus lens is controlled by a relay to focus. When the relay receives the rising edge sent by the PWM signal generator, the two trigger wires of the auto-focus lens are short-circuited. When the relay receives the PWM signal After the falling edge sent by the generator, the two trigger wires of the auto-focus lens are disconnected, the two trigger wires of the auto-focus lens are short-circuited and then disconnected to form a trigger signal, and the auto-focus lens operates according to the trigger signal. Achieve camera focus. For example, 10 milliseconds when the PWM signal generator forms a low-level pulse is the response time of the relay. When the relay receives the rising edge, short the two trigger wires of the auto-focus lens. After 20 milliseconds, the relay receives the falling edge , Disconnect the two trigger wires of the auto-focus lens. The 20 milliseconds is the response time of the auto-focus lens. The two trigger wires are short-circuited and then disconnected to form a trigger signal, which makes the auto-focus lens start to operate. Finish focusing the camera.

As shown in Figure 3, an embodiment of the present invention provides an automatic focusing method, including:

Step 301: Set the variable num, and set its initial value to 0.

In one embodiment of the present invention, an integer variable num is defined and its initial value is 0, which is used to record the number of times that the focal length or position of the camera changes.

Step 302: Detect in real time whether the focal length or position of the camera changes, if yes, execute step 303, otherwise continue to execute step 302.

In one embodiment of the present invention, if the lens of the camera zooms or the pan/tilt rotates, the focal length or position of the camera changes accordingly, and it is detected in real time whether the focal length or position of the camera changes, and if the focal length or position changes , the camera needs to be refocused, correspondingly execute step 303 , if the focal length or position does not change, it is necessary to continue monitoring the focal length and position of the camera, correspondingly continue to execute step 302 .

Step 303: Determine whether the camera is in focus when the focal length or position is changed this time, if yes, execute step 302, otherwise execute step 304.

In one embodiment of the present invention, since during the process of camera focusing, if the focal length or position of the camera changes, then this focusing will eliminate the influence of this change of focal length or position on the picture taken by the camera, thus judging the change of focal length or position Whether it happened during the focusing process of the camera, if yes, the impact of this change of focal length or position has been eliminated, and there is no need to focus separately, and correspondingly execute step 302, if no, the change of this focal length or position has not been re-executed focus, correspondingly execute step 303 .

Step 304: Add 1 to the current value of the variable num.

In one embodiment of the present invention, when it is detected that the focal length or position of the camera changes, and the focal length or position change does not occur during the focusing process of the camera, a focus needs to be performed for this change, and the current value of the variable num is increased 1. Record the number of times you need to focus.

Step 305: judge in real time whether the current value of the variable num is equal to 0, if yes, continue to execute step 305, otherwise execute step 306.

Step 306: Form a focus signal, and subtract 1 from the current value of the variable num.

Step 307: Control the auto-focus lens of the camera to focus according to the focus signal.

It should be noted that step 305 to step 307 in the embodiment of the present invention are the same as step 206 to step 208 in the embodiment shown in FIG. 2 , and the description will not be repeated here.

As shown in Figure 4, an embodiment of the present invention provides an automatic focusing device, including: a first setting unit 401, a detection unit 402, a calculation unit 403, a first judgment unit 404, a signal generator 405 and a controller 406 ;

The first setting unit 401 is configured to set the variable num, and set the initial value of the variable num to the first characteristic value;

A detection unit 402, configured to detect in real time whether at least one of the focal length and the position of the camera changes;

The calculation unit 403 is configured to, according to the detection result of the detection unit 402, if yes, increase the current value of the variable num set by the first setting unit 401 by a predetermined value;

A first judging unit 404, configured to judge in real time whether the current value of the variable num is the first feature value;

A signal generator 405, configured to, according to the judgment result of the first judgment unit, if not, form a focus signal, and subtract the predetermined value from the current value of num;

The controller 406 is configured to control the camera to focus according to the focus signal formed by the signal former 405 .

In one embodiment of the present invention, the signal generator 405 can be a PWM signal generator, and the PWM signal generator is connected to the first judging unit 404, and the low voltage of the PWM signal generator is set in advance according to the models of the camera and the controller. Level time and high level time, when the first judging unit 404 judges that the current value of the variable num is not the first characteristic value, the PWM signal generator starts timing and forms a low-level pulse. When the low level time is mentioned, the pulse is converted from low level to high level to form a rising edge, and the rising edge is sent to the controller. When the timing is equal to the low level time and the During the sum of the high level time, the pulse is converted from high level to low level to form a falling edge, and the falling edge is sent to the controller, and a pulse is composed of the rising edge and the falling edge Focus on the signal. For example, the first characteristic value is 0, according to the model of the current camera and the model of the controller, the low level time is set to be 10 milliseconds, and the high level time is 20 milliseconds, when the first judging unit 404 judges the current value of the variable num When it is not 0, the PWM signal generator starts timing and forms a low-level pulse. When the timing duration is equal to 10 milliseconds, the pulse is converted from low level to high level to form a rising edge and continues timing. When the duration is equal to 30 milliseconds, the pulse is converted from a high level to a low level, forming a falling edge, stopping timing, and forming a focusing signal composed of a rising edge and a falling edge.

In one embodiment of the present invention, the controller 406 can be a relay, and the relay is connected to the PWM signal generator and the autofocus lens respectively, wherein the autofocus lens is connected to the relay through its two trigger wires, and the PWM signal generator forms a low level During the pulse process, the relay is in the response stage. When the relay receives the rising edge sent by the PWM signal generator, the relay will short-circuit the two trigger wires of the auto-focus lens. During the high-level pulse process of the PWM signal generator, the auto-focus The lens is in the response stage. When the relay receives the falling edge sent by the PWM signal generator, the relay will disconnect the two trigger wires of the auto-focus lens, and the two trigger wires of the auto-focus lens will be shorted and disconnected again to form a trigger Model, the auto-focus lens starts to operate after receiving this signal to realize the auto-focus of the camera. For example, the auto-focus lens is connected to the relay through trigger wire 1 and trigger wire 2, the low level time of the PWM signal generator is 10 milliseconds, the high level time is 20 milliseconds, and the PWM signal generator forms a low level pulse of 10 milliseconds Time is the response time of the relay. When the PWM signal generator converts the low-level pulse into a high-level pulse to form a rising edge, the relay will connect the trigger wire 1 and trigger wire 2 of the autofocus lens after receiving the rising edge. Short-circuit, the 20 millisecond time for the PWM signal generator to form a Karma-level pulse is the corresponding time for the auto-focus lens. When the PWM signal generator converts the high-level pulse into a low-level pulse and forms a falling edge, the relay receives After the falling edge, disconnect trigger wire 1 and trigger wire 2 of the auto-focus lens, short-circuit trigger wire 1 and trigger wire 2 for 20 milliseconds and then disconnect to form a trigger signal. After the auto-focus lens receives the trigger signal , its internal electric components start to run to realize the automatic focus of the camera.

In an embodiment of the present invention, the device may further include a second setting unit and a second judging unit, the second setting unit is used to set the maximum value of the variable num, and the second judging unit is used to detect the After the focal length or position is changed, judge whether the current value of the variable num has reached its maximum value. If it has reached, the change of focal length or position will be ignored, and the focus will not be carried out for this change. If not, then The calculation unit 403 adds a predetermined value to the current value of the variable num, and performs a focusing for this change, so as to avoid continuously changing the focal length or position and make the camera focus continuously for a long time.

In an embodiment of the present invention, the device may further include a third judging unit, which is used to judge whether the camera is in a focused state when the change occurs after the detection unit 402 detects that the focal length or position of the camera changes. , if yes, then the impact of this change in focal length or position will be eliminated after the focus of the camera is completed when this change occurs, and there is no need to focus separately, so this change in focal length or position will be ignored, and the calculation unit 403 does not need to Add a predetermined value to the current value of the variable num, if not, the impact of this change in focal length or position has not been eliminated, and a focus needs to be performed for this change, and the calculation unit 403 increases the current value of the variable num by a predetermined value , to avoid repeated useless focusing of the camera.

According to the above solution, an automatic focusing method and device provided by the embodiments of the present invention have at least the following beneficial effects:

1. In the embodiment of the present invention, the variable num is preset, and its initial value is set as the first characteristic value, and whether the focal length or the position of the camera is changed in real time is detected, and if a change occurs, a predetermined value is added to the first characteristic value, Determine in real time whether the current value of the variable num is equal to the first characteristic value, if not, then form a focus signal, and subtract a predetermined value from the current value of the variable num, and control the camera to focus once according to the formed focus signal, so that every When the lens of the secondary camera is zoomed or the pan/tilt is rotated to change the focal length or position of the camera, the variable num is correspondingly increased by a predetermined value so that the current value of the variable num is not equal to the first characteristic value, triggering the camera to focus, and After the focus signal is sent out, a predetermined value is subtracted from the variable num to ensure that a focus is triggered every time the focal length or position of the camera changes, without manual operation, so as to realize the automatic focus of the camera.

2. In the embodiment of the present invention, by detecting whether the focal length and position of the camera have changed, and recording the number of changes, an automatic focus is performed for each change, and the corresponding automatic focus is performed immediately after the focal length or position is changed. Manual intervention can adjust the image captured by the camera to a clear state in time, improving the shooting effect of the camera.

3. In the embodiment of the present invention, both the relay and the auto-focus lens are self-contained components on the camera. Only by compiling the relevant software and appropriately modifying the existing hardware, the auto-focus of the camera can be realized, and the cost is relatively low. Low.

4. In the embodiment of the present invention, the maximum value of the variable num can be set. When the current value of the variable num reaches the maximum value, the change of the focal length or position of the camera will be ignored, and the predetermined value will no longer be added to the variable num. In this way, it is possible to avoid Continuously adjusting the focal length or position of the camera keeps the camera in the state of automatic focus for a long time, which affects the shooting effect of the camera.

5. In the embodiment of the present invention, after the focal length or position of the camera is detected to change, it can be further judged whether the camera is in the state of auto-focus when the focal length or position changes, and if so, the impact of this change of focal length or position It will be eliminated during the autofocus process that is carried out at the same time. There is no need to perform autofocus for this change alone, so there is no need to increase the predetermined value of the variable num. If not, the impact of this focal length or position change has not been eliminated. Need Carry out an automatic focus for this change, and thus increase the value of the variable num by a predetermined value. In this way, useless automatic focus of the camera can be avoided, the burden of the automatic focus lens can be reduced, the life of the device can be extended, and the shooting effect of the camera can be improved.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or sequence. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a """""" does not exclude the presence of additional same elements in the process, method, article or apparatus comprising said element.

Those of ordinary skill in the art can understand that all or part of the steps to realize the above method embodiments can be completed by program instructions related hardware, and the aforementioned programs can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

Finally, it should be noted that the above descriptions are only preferred embodiments of the present invention, and are only used to illustrate the technical solution of the present invention, and are not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention.

Claims (8)

1. A kind of 1. method focused on automatically, it is characterised in that variable num is set, and the initial value of the variable num is set for the One characteristic value, in addition to：

   At least one whether changing in the focal length of detection video camera and position in real time；

   If it is, the currency of the variable num is increased into predetermined value；

   Whether variable num currency described in real-time judge is the First Eigenvalue；

   If not, forming focus signal, and the currency of the num is subtracted into the predetermined value；

   According to the focus signal, the video camera is controlled to be focused；

   Forming focus signal includes：A low level time and a high level time are preset, ought when judge the variable num When preceding value is not the First Eigenvalue, start timing, a low level pulse is formed, when timing duration is equal to the low electricity When between usually, the pulse is high level by low transition, forms a rising edge, when the timing duration is equal to described low When level time is with the high level time sum, the pulse is converted to low level by high level, forms a trailing edge, with Obtain the focus signal being made up of the rising edge and the trailing edge.
2. 2. according to the method for claim 1, it is characterised in that it is described according to the focus signal, control the video camera Be focused including：

   The rising edge and the trailing edge are received, according to the rising edge and trailing edge, is triggered automatic on the video camera Amasthenic lens, the video camera is focused.
3. 3. according to the method for claim 1, it is characterised in that further comprise：The maximum of the variable num is set；

   After at least one in detecting the focal length of the video camera and position changes, and by the variable num Currency increase predetermined value before, further comprise：Judge whether the currency of the variable num reaches the maximum, If it is, ignore this change, continue executing with the video camera of detection in real time focal length and position at least one whether send out It is raw to change, if it is not, then continuing executing with the currency by the variable num increases predetermined value.
4. 4. according to any described method in claims 1 to 3, it is characterised in that detect the focal length and position described In it is at least one there occurs change after, and increase taking a step forward for predetermined value in the currency by the variable num Including：

   Judge the video camera focal length and position in it is at least one when changing, whether the video camera in focusing on shape State, if it is, ignore this change, continue executing with the video camera of detection in real time focal length and position in it is at least one whether Change, if not, continuing executing with the currency by the variable num increases predetermined value.
5. A kind of 5. device focused on automatically, it is characterised in that including：

   First setting unit, for setting variable num, and it is the First Eigenvalue to set the initial value of the variable num；

   Detection unit, for detect in real time video camera focal length and position at least one whether change；

   Computing unit, for the testing result according to the detection unit, if it is, the institute that first setting unit is set State variable num currency increase predetermined value；

   First judging unit, whether the currency for variable num described in real-time judge is the First Eigenvalue；

   Shaping unit, for the judged result according to first judging unit, if not, form focus signal, and by institute The currency for stating num subtracts the predetermined value；

   Controller, for the focus signal formed according to the shaping unit, the video camera is controlled to be focused；

   Shaping unit is PWM signal generator；

   The PWM signal generator is connected with first judging unit, presets the low level of the PWM signal generator Time and high level time, when first judging unit judges the currency of the variable num not for the First Eigenvalue When, the PWM signal generator starts timing, and forms a low level pulse, when timing duration is equal to the low level During the time, the pulse is high level by low transition, forms a rising edge, the rising edge is sent into the control Device, when timing duration is equal to the low level time with the high level time sum, the pulse is converted into by high level Low level, a trailing edge is formed, the trailing edge is sent to the controller, by the rising edge and the trailing edge group Into a focus signal.
6. 6. device according to claim 5, it is characterised in that the controller is relay；

   The relay is connected with the automatic amasthenic lens on the PWM signal generator and the video camera respectively, wherein institute State automatic amasthenic lens by the first triggering wire and the second triggering wire with the relay to be connected, when the relay receives To the PWM signal generator send rising edge when, the relay will described first triggering wire with described second trigger Wire short circuit, after the relay receives the trailing edge that the PWM signal generator is sent, the relay is by described the One triggers wire disconnects with the described second triggering wire, after the first triggering wire and the described second triggering wire short circuit again Disconnect, form a trigger signal, after the automatic amasthenic lens receives the trigger signal, carry out once automatic focus on.
7. 7. device according to claim 5, it is characterised in that further comprise：Second setting unit and the second judgement are single Member；

   Second setting unit, for setting the maximum of the variable num；

   Second judging unit, for the detection unit detect the video camera focal length and position in it is at least one After changing, judge whether the currency of the variable num reaches the maximum, if it is, ignore this change, after It is continuous by the detection unit detect in real time video camera focal length and position in it is at least one whether change, if it is not, then The currency of the variable num for setting first setting unit is increased into predetermined value by the computing unit.
8. 8. according to any described device in claim 5 to 7, it is characterised in that further comprise：3rd judging unit；

   3rd judging unit, is connected with the detection unit and the computing unit respectively, when the detection unit detects When at least one into the focal length of the video camera and position changes, the 3rd judging unit judges that when institute occurs for the change State whether video camera is in focus state, if it is, continuing the focal length of detection video camera and position in real time by the detection unit In it is at least one whether change, if not, the currency of the variable num increased by the computing unit predetermined Value.