Camera equipped with non-confocal lens, fast focusing method, and medium

Abstract

The present invention relates to a camera equipped with a non-confocal lens, a fast focusing method, and a medium. The method comprises: collecting and recording a first coordinate offset corresponding to the switching between visible light and infrared light at different magnifications and object distances, and focus coordinates at two different temperatures; performing focus adjustment on the non-confocal lens at the initial moment of installation and recording the current parameters; collecting temperatures at different moments and calculating a second coordinate offset based on the temperature transformation at each moment; when the non-confocal lens is in visible light focus mode, adjusting the focus coordinate at the current moment by the sum of the focus coordinate at the initial moment and the second coordinate offset; and when switching to infrared light focus mode, adjusting the focus coordinate at the current moment by the sum of the focus coordinate at the initial moment, the second coordinate offset, and the first coordinate offset. The present invention can quickly correct focus differences caused by temperature and day / night switching.

Description

Technical Field

[0001] The present invention relates to the field of camera technology, and in particular to a camera equipped with a non-confocal lens, a fast focusing method, and a medium. Background Art

[0002] A non-confocal lens's focal points in visible and infrared light scenarios are not at the same location. In daytime scenarios, the lens's filter removes infrared light, resulting in a single focal point for visible light. However, in nighttime scenarios, the lens does not filter any light to allow the sensor to receive more light. This results in two focal points: one for visible light and one for infrared light. Because the license plate's focal point at night is the infrared focal point, using autofocus technology could cause the visible light focal point to become blurred, potentially causing issues like identifying a license plate under infrared light.

[0003] The confocal lenses currently on the market are basically low-magnification lenses, and there are currently no high-magnification day and night confocal lenses. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a camera equipped with a non-confocal lens, a fast focusing method, and a medium.

[0005] The specific plan is as follows:

[0006] A non-confocal lens fast focusing method comprises the following steps:

[0007] S1: Collect and record the first coordinate offset corresponding to the non-confocal lens at different magnifications and different object distances; the first coordinate offset is the difference between the focal coordinate of the non-confocal lens under visible light and the focal coordinate under infrared light;

[0008] S2: Collect and record the focal coordinates of the non-confocal lens at different magnifications and object distances at two different temperatures;

[0009] S3: At the initial moment when the non-confocal lens is installed, adjusting the focus thereof, and recording the temperature, focus coordinates, magnification, and object distance corresponding to the initial moment; at the initial moment, the non-confocal lens is in a visible light focus mode;

[0010] S4: collecting the temperature at different times, and calculating the second coordinate offset of the focal coordinate required at each time relative to the focal coordinate at the initial time based on the difference between the temperature at each time and the temperature at the initial time, combined with the focal coordinates at two different temperatures corresponding to the magnification and object distance recorded at the initial time;

[0011] S5: When the non-confocal lens is in the visible light focus mode, the focus coordinate at the current moment is adjusted by the sum of the focus coordinate at the initial moment and the second coordinate offset corresponding to the current moment;

[0012] S6: When the non-confocal lens is switched to the infrared focus mode, the focus coordinate at the current moment is adjusted by the sum of the focus coordinate at the initial moment, the second coordinate offset corresponding to the current moment, and the first coordinate offset corresponding to the magnification and object distance recorded at the initial moment.

[0013] Furthermore, the method further includes: enabling the AutoHome function in the gimbal of the camera where the lens is installed, and recording the temperature, focus coordinates, magnification and object distance corresponding to the initial moment through the AutoHome function.

[0014] A camera equipped with a non-confocal lens includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method described above are implemented.

[0015] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method described above in an embodiment of the present invention.

[0016] The present invention adopts the above technical solution and has the following beneficial effects:

[0017] (1) Avoid focusing failure due to different focus points after switching between day and night;

[0018] (2) Based on the measured first coordinate offset of visible light and infrared light, the infrared light focus can be quickly focused, thus shortening the problem of missed detection of targets due to the focusing process;

[0019] (3) Based on the detected temperature deviation, the focus difference caused by temperature can be quickly corrected. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a flow chart of a method according to a first embodiment of the present invention. DETAILED DESCRIPTION

[0021] To further illustrate various embodiments, the present invention provides accompanying drawings. These drawings form part of the present disclosure and are primarily used to illustrate the embodiments and, in conjunction with the relevant description in the specification, to explain the operating principles of the embodiments. By referring to these drawings, those skilled in the art will be able to understand other possible implementations and the advantages of the present invention.

[0022] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0023] Example 1:

[0024] The embodiment of the present invention provides a non-confocal lens fast focusing method, such as Figure 1 As shown, the method includes the following steps:

[0025] S1: Collect and record the first coordinate offset corresponding to the non-confocal lens at different magnifications and different object distances; the first coordinate offset is the difference between the focal coordinate of the non-confocal lens under visible light and the focal coordinate under infrared light.

[0026] Lenses can be divided into confocal and non-confocal lenses. A confocal lens is one in which the focal points are at the same or very close positions in visible and infrared light scenarios. Short-focal-length lenses are generally confocal lenses. Non-confocal lenses are lenses in which the focal points are not at the same position in visible and infrared light scenarios. Long-focal-length lenses are generally non-confocal lenses. To make a long-focal-length lens confocal, special optical processing is required, which increases costs. Experimental verification has shown that there is a fixed difference between the focal coordinates of a non-confocal lens under visible and infrared light, namely the first coordinate offset. Therefore, by simply testing the first coordinate offset of the non-confocal lens at different magnifications, the lens can be quickly and accurately moved to the infrared focus based on the obtained first coordinate offset after switching from visible light to infrared light.

[0027] S2: Collect and record the focal coordinates of the non-confocal lens at different magnifications and object distances at two different temperatures.

[0028] The lens includes some physical components in the middle, and there are gaps between these physical components. The physical components themselves have the phenomenon of thermal expansion and contraction. Therefore, after the temperature changes, these physical components will affect the light due to the thermal expansion and contraction phenomenon, thereby affecting the focal position. Experimental tests have shown that the effect of temperature on the focal position is relatively fixed, so it is necessary to test the relationship between the focal position and temperature changes under different magnifications. It should be noted that since the focal coordinates collected in step S2 are only related to temperature changes, the environments corresponding to different temperatures must be the same, such as all under visible light. In addition, it is obtained through experiments that the relationship between the change of the focal coordinates with respect to temperature is a linear change. Therefore, it is only necessary to collect the focal coordinates at two different temperatures to realize the calculation of the focal coordinates at other temperatures.

[0029] The temperature can be collected by the temperature sensor built into the camera or by the temperature sensor arranged in the environment, and there is no restriction here.

[0030] S3: At the initial moment when the non-confocal lens is installed, focus adjustment is performed on it, and the temperature, focus coordinates, magnification and object distance corresponding to the initial moment are recorded; at the initial moment, the non-confocal lens is in a visible light focus mode.

[0031] Focus adjustment is to make the image clear through adjustment.

[0032] Furthermore, to prevent misoperation of the lens after installation, which could cause the gimbal to shift or incorrectly adjust the focus, and to achieve unattended operation, this embodiment also enables the AutoHome function in the gimbal of the camera where the lens is installed. This function records the temperature, focus coordinates, magnification, and object distance corresponding to the initial moment. The AutoHome function ensures that the camera remains in the set position and automatically returns to that position after a certain period of time, even after user operation.

[0033] S4: collecting the temperature at different moments, and calculating the second coordinate offset of the focal coordinate required at each moment relative to the focal coordinate at the initial moment based on the difference between the temperature at each moment and the temperature at the initial moment, combined with the focal coordinates at two different temperatures corresponding to the magnification and object distance recorded at the initial moment.

[0034] In the calculation of the second coordinate offset, the following formula is used:

[0035]

[0036] Among them, ΔFS represents the second coordinate offset, Temp now Indicates the current temperature, Temp save represents the temperature at the initial moment, Temp1 and Temp2 represent two different temperatures (such as 70° and -30°) corresponding to the magnification and object distance recorded at the initial moment, respectively, FS1 represents the focal coordinate at temperature Temp1, and FS2 represents the focal coordinate at temperature Temp2.

[0037] S5: When the non-confocal lens is in the visible light focus mode, the focus coordinate at the current moment is adjusted by the sum of the focus coordinate at the initial moment and the second coordinate offset corresponding to the current moment.

[0038] S6: When the non-confocal lens is switched to the infrared focus mode, the focus coordinate at the current moment is adjusted by the sum of the focus coordinate at the initial moment, the second coordinate offset corresponding to the current moment, and the first coordinate offset corresponding to the magnification and object distance recorded at the initial moment.

[0039] The embodiment of the present invention can quickly correct focus differences caused by temperature and day-night switching.

[0040] Example 2:

[0041] The present invention also provides a camera equipped with a non-confocal lens, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method embodiment of the first embodiment of the present invention are implemented.

[0042] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method in the embodiment of the present invention are implemented.

[0043] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A non-confocal lens fast focusing method, characterized in that: The following steps are involved: S1: Collect and record the first coordinate offset corresponding to the non-confocal lens at different magnifications and different object distances; the first coordinate offset is the difference between the focal coordinate of the non-confocal lens under visible light and the focal coordinate under infrared light; S2: Collect and record the focal coordinates of the non-confocal lens at different magnifications and object distances at two different temperatures; S3: At the initial moment when the non-confocal lens is installed, focus adjustment is performed on it, and the temperature, focus coordinates, magnification, and object distance corresponding to the initial moment are recorded; Initially, the non-confocal lens is in visible light focus mode; S4: collecting the temperature at different times, and calculating the second coordinate offset of the focal coordinate required at each time relative to the focal coordinate at the initial time based on the difference between the temperature at each time and the temperature at the initial time, combined with the focal coordinates at two different temperatures corresponding to the magnification and object distance recorded at the initial time; S5: When the non-confocal lens is in the visible light focus mode, the focus coordinate at the current moment is adjusted by the sum of the focus coordinate at the initial moment and the second coordinate offset corresponding to the current moment; S6: When the non-confocal lens is switched to the infrared focus mode, the focus coordinate at the current moment is adjusted by the sum of the focus coordinate at the initial moment, the second coordinate offset corresponding to the current moment, and the first coordinate offset corresponding to the magnification and object distance recorded at the initial moment.

2. The non-confocal lens fast focusing method according to claim 1, wherein: Also includes: Enable the AutoHome function on the gimbal of the camera where the lens is installed, and use the AutoHome function to record the temperature, focus coordinates, magnification, and object distance corresponding to the initial moment.

3. A camera equipped with a non-confocal lens, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 2 when executing the computer program.

4. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 2 are implemented.

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