Focusing photographing method, focusing photographing system, and multi-wavelength imaging device

Abstract

The present application relates to the field of optical imaging technology, and discloses a focusing shooting method, a focusing shooting system and a multi-wavelength imaging device, which comprises the following steps: obtaining a sharpness drop threshold of an image under a focusing illumination light source, and determining an optimal focusing position difference value based on the sharpness drop threshold; configuring a focal length one of the focusing illumination light source and a focal length two of a shooting illumination light source, so that the actual focusing imaging position difference value of the wavelengths of the focusing illumination light source and the shooting illumination light source on the optical axis is equal to the optimal focusing position difference value; starting the focusing illumination light source, adjusting the one-way movement of a transmission assembly at a certain step, and finding a focusing position one and a focusing position two of the focusing illumination light source according to a climbing algorithm; when the focusing position of the focusing illumination light source reaches the focusing position two, the optimal focusing shooting position under the shooting illumination light source is reached, the focusing light source is switched to the shooting illumination light source, and image shooting is performed, thereby solving the problem that the existing focusing method cannot quickly and accurately find the optimal focus point.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, specifically to a focusing imaging method, a focusing imaging system, and a multi-wavelength imaging device. Background Technology

[0002] Conventional focusing techniques typically rely on acquiring a series of images from different positions before and after the optimal focus point. Image analysis algorithms are then used to evaluate the sharpness of these images to determine the location of the optimal focus point. This process usually includes the following steps: First, the system adjusts the lens position in steps, acquiring image sequences from different positions. Next, specific sharpness evaluation algorithms (such as contrast, edge strength, or frequency domain characteristics) are used to calculate the sharpness value of each image. The calculated series of sharpness values ​​presents a single-peak curve, with the peak value corresponding to the optimal focus point location. Once the optimal location is found, the system returns to that location for final imaging and capturing.

[0003] Since the focus curve is usually single-peaked, it is often combined with the "climbing algorithm" in practical applications to achieve fast focusing. The specific implementation of the climbing algorithm is as follows: the system starts from an initial position far away from the optimal focus point and judges the focus state based on the image sharpness evaluation value (such as contrast, edge sharpness, etc.). If the sharpness value is on an upward trend, the system continues to move the lens in that direction. When the sharpness value decreases or stops increasing, it indicates that the optimal focus point position may have been reached or exceeded. The system will then stop moving and return to the optimal position to complete the shooting.

[0004] The advantage of the hill-climbing algorithm is that it is simple to implement and has low computational cost, making it suitable for real-time autofocus. However, the algorithm requires that the system completely traverse the "hilltop" position to determine the best focus point. The system needs to control the focusing component to return to the best position before taking a picture. This introduces gap errors in the transmission components, reduces the accuracy of the return position, and increases the focusing time, thereby reducing the positional accuracy of the found best focus point, which is not conducive to capturing dynamic scenes. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a focusing imaging method, a focusing imaging system, and a multi-wavelength imaging device, thus solving the problem that existing focusing methods cannot quickly and accurately find the optimal focusing point.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A focusing shooting method includes the following steps:

[0008] Obtain the image sharpness reduction threshold under focused illumination source, and determine the optimal focus position difference based on the sharpness reduction threshold;

[0009] Configure the focal length of the focusing illumination source one and the focal length of the shooting illumination source two so that the difference between the actual focusing imaging positions of the wavelengths of the focusing illumination source and the shooting illumination source on the optical axis is equal to the difference between the optimal focusing positions.

[0010] Start the focused illumination source, adjust the transmission component to move unidirectionally in a certain step size, and find the focused position one and focused position two of the focused illumination source according to the climbing algorithm. The distance difference between the focused position two and the focused position one is the optimal focused position difference, and the image sharpness reduction value at the focused position two exceeds the sharpness reduction threshold.

[0011] When the focusing position of the focusing illumination source reaches the second focusing position, the optimal focusing and shooting position under the shooting illumination source is reached, and the focusing light source is switched to the shooting illumination source to perform image shooting.

[0012] Optionally, the formula for calculating the optimal focus position difference is:

[0013] Where u represents the object distance, Indicates wavelength as The focal length of the focused lighting source is one. Indicates wavelength as The focal length of the lighting source for the shooting.

[0014] Optionally, the focus position one and focus position two of the focused illumination source are found according to the climbing algorithm, including the following steps:

[0015] The transmission component acquires an intermediate image every time it moves a step, and calculates the sharpness value of each acquired intermediate image.

[0016] Compare the sharpness values ​​of the intermediate image at the current position with those at the previous position until the sharpness value of the intermediate image at the current position begins to decrease compared to that at the previous position. Record the highest sharpness value that occurs during the comparison process and mark the position corresponding to the highest sharpness value as focus position one.

[0017] The transmission component continues to move unidirectionally in steps and calculates the decrease in sharpness value of the intermediate image at the current position relative to the highest sharpness value.

[0018] When the decrease value reaches the sharpness decrease threshold, the focal point of the focusing illumination source reaches the second focusing position; otherwise, the imaging lens continues to move in fixed step units.

[0019] Optionally, when searching for the focal position one and focal position two of the focused lighting source according to the climbing algorithm, the moving direction of the transmission component remains consistent, including the following steps:

[0020] When the optimal focal point of the shooting illumination source is closer to the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the imaging lens to move from the direction closer to the shooting object to the direction farther away from the shooting object.

[0021] When the optimal focal point of the shooting illumination source is further away from the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the imaging lens to move from a direction away from the shooting object to a direction closer to the shooting object.

[0022] Optionally, when searching for the focal position one and focal position two of the focused lighting source according to the climbing algorithm, the moving direction of the transmission component remains consistent, including the following steps:

[0023] When the optimal focal point of the shooting illumination source is closer to the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the shooting object to move from a direction away from the imaging lens to a direction closer to the imaging lens.

[0024] When the optimal focal point of the shooting illumination source is further away from the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the shooting object to move from the direction close to the imaging lens to the direction far away from the imaging lens.

[0025] Optionally, when searching for the focal position one and focal position two of the focused lighting source according to the climbing algorithm, the moving direction of the transmission component remains consistent, including the following steps:

[0026] When the optimal focal point of the imaging illumination source is closer to the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the imaging sensor to move from a direction away from the imaging lens to a direction closer to the imaging lens.

[0027] When the optimal focal point of the imaging illumination source is further away from the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the imaging sensor to move from the direction close to the imaging lens to the direction far away from the imaging lens.

[0028] Optionally, it also includes: when the focusing position of the focusing light source reaches the second focusing position, verifying the accuracy of the optimal focusing shooting position required to capture the light source.

[0029] Optionally, the accuracy verification includes the following steps:

[0030] Calculate the distance difference between the first focusing position and the second focusing position;

[0031] Acquire the first image sharpness at a focused position one and the second image sharpness at a focused position two under a focused illumination source;

[0032] Calculate the sharpness reduction verification value based on the sharpness of the first image and the sharpness of the second image;

[0033] Determine whether the distance difference is equal to the optimal focus position difference, and whether the sharpness reduction verification value is equal to the sharpness reduction threshold;

[0034] If yes, the verification result is accurate; otherwise, the verification result is inaccurate.

[0035] A multi-wavelength imaging device is used to implement the focusing and imaging method as described in any one of the above, including a focusing illumination source, an imaging illumination source, an imaging object, an imaging lens, a transmission component, and an imaging sensor.

[0036] The focusing illumination source and the shooting illumination source are used to illuminate the object being photographed, and the focusing illumination source and the shooting illumination source have different wavelengths;

[0037] The transmission component is used to drive any one of the imaging lens, imaging sensor or the object being photographed to move unidirectionally by a certain step size.

[0038] The imaging lens is used to focus light from the object being photographed onto the imaging sensor;

[0039] The imaging sensor is used to receive light focused by the imaging lens and convert it into an electrical signal, and generate a digital image based on the electrical signal.

[0040] A focusing shooting system, wherein the focusing shooting system performs the focusing shooting method described in any one of the above, includes a parameter acquisition unit, a configuration unit, a focus position finding unit, and a focusing shooting unit;

[0041] The parameter acquisition unit is used to acquire the image sharpness reduction threshold under focused illumination source, and determine the optimal focus position difference based on the sharpness reduction threshold;

[0042] The configuration unit is used to configure the focal length one of the focusing illumination source and the focal length two of the shooting illumination source, so that the difference between the actual focusing imaging positions of the wavelengths of the focusing illumination source and the shooting illumination source on the optical axis is equal to the difference between the optimal focusing positions.

[0043] The focusing position finding unit is used to activate the focusing illumination source, adjust the transmission component to move unidirectionally with a certain step size, and find the focusing position one and focusing position two of the focusing illumination source according to the climbing algorithm. The distance difference between the focusing position two and the focusing position one is the optimal focusing position difference, and the image sharpness reduction value at the focusing position two exceeds the sharpness reduction threshold.

[0044] The focusing and shooting unit is used to reach the optimal focusing and shooting position under the shooting illumination source when the focusing position of the focusing illumination source reaches the second focusing position, and to switch the focusing light source to the shooting illumination source to perform image shooting.

[0045] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0046] By configuring the focal length of the focusing illumination source (focal length 1) and the shooting illumination source (focal length 2), the optimal focusing positions of the focusing illumination source and the shooting illumination source are axially separated on the optical axis, making the focusing process more efficient. Simultaneously, by correlating the sharpness reduction threshold with the difference between the optimal focusing positions, the optimal focusing position under the shooting illumination source can be determined simply by measuring the sharpness reduction of the image acquired under the focusing illumination source. Furthermore, the imaging lens moves unidirectionally during focusing, eliminating the need for reverse adjustment and reducing focusing accuracy issues caused by mechanical structure precision errors, thus improving both focusing efficiency and accuracy. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a flowchart of a focusing and shooting method proposed in Embodiment 1;

[0049] Figure 2 This is a schematic diagram of the movement when the transmission component drives the imaging lens to move unidirectionally in a certain step size, as proposed in Embodiment 1 and Embodiment 2.

[0050] Figure 3 This is a schematic diagram of the movement when the transmission component drives the object being photographed to move unidirectionally in a certain step length, as proposed in Embodiment 1.

[0051] Figure 4 This is a schematic diagram of the movement when the transmission component drives the imaging sensor to move unidirectionally in a certain step size, as proposed in Embodiment 1.

[0052] Figure 5 This is a schematic diagram showing the change curve of image sharpness under the focusing illumination source and the change curve of image sharpness under the shooting illumination source when the imaging lens proposed in this embodiment moves to the right. Detailed Implementation

[0053] The present invention will be further described in detail below with reference to the embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0054] Example 1

[0055] like Figure 1 As shown, a focusing imaging method includes the following steps: obtaining a sharpness reduction threshold of an image under a focused illumination source, and determining an optimal focus position difference based on the sharpness reduction threshold; configuring a focal length one of the focused illumination source and a focal length two of the imaging illumination source, so that the actual imaging focus position difference of the wavelengths of the focused illumination source and the imaging illumination source on the optical axis is equal to the optimal focus position difference.

[0056] Specifically, firstly, the positions of all components within the focusing imaging system are determined when the image captured under the optimal shooting illumination source is obtained. At this position, the shooting illumination source is switched to the focusing illumination source. Then, the image captured when switched to the focusing illumination source is obtained, and the image sharpness is calculated. Next, the image with the highest image sharpness captured under the focusing illumination source is obtained. Then, the sharpness reduction threshold of the image sharpness captured when switched to the focusing illumination source relative to the highest image sharpness is calculated. Finally, the focal point position when switched to the focusing illumination source (i.e., when the image captured under the optimal shooting illumination source) and the focal point position when the image has the highest image sharpness under the focusing illumination source are determined, and the distance between the two focal points is calculated to obtain the optimal focal position difference.

[0057] By using the above method, the optimal focus position is correlated with the sharpness reduction threshold. This allows the optimal focus position under the shooting illumination source to be determined simply by measuring the sharpness reduction value of the image acquired under the focused illumination source.

[0058] Simultaneously, it is also necessary to configure the focal length of the focusing illumination source and the focal length of the shooting illumination source. In this embodiment, the focusing position is P1 and the focusing position is P2 under the focusing illumination source. The position of the imaging lens corresponding to the focusing position P1 is L1 and the position of the imaging lens corresponding to the focusing position P2 is L2. When the focusing point of the focusing illumination source reaches the focusing position, the focusing point of the shooting illumination source reaches the optimal focusing point.

[0059] At this point, the optimal focus position difference is the distance between focus position one P1 and focus position two P2, based on the relationship between object distance u, image distance v, and focal length f: .

[0060] From this, the object distance at the focal position P1 can be obtained. : ;

[0061] Object distance at focus position P2 : ;

[0062] This leads to the optimal focus position difference. : .

[0063] Furthermore, during focused shooting, the object is positioned at a fixed point on the optical axis, and the object distance under the focusing illumination source and the shooting illumination source is the same, that is: = To further represent the object distance between the two objects using the expression u, the simplified formula for calculating the optimal focus position difference is as follows:

[0064] Where u represents the object distance, Indicates wavelength as The focal length of the focused lighting source is one. Indicates wavelength as The focal length of the lighting source for the shooting.

[0065] By calculating and configuring parameters in advance, the difference between the actual focused imaging position produced by the focused illumination source and the shooting illumination source is equal to the difference between the optimal focused positions.

[0066] On the other hand, since the transmission component in this embodiment moves in one direction by a drive component when it moves in a certain step, and the drive component consists of a motor and a threaded rod fixedly connected to the output shaft of the motor (this is the existing structural setting), the transmission component is sleeved on the threaded rod and is used to fix any one of the imaging lens, the object being photographed, or the imaging sensor, and to drive any one of the imaging lens, the object being photographed, or the imaging sensor to move in one direction by a certain step. Therefore, when the transmission component moves, since the threaded rod and the transmission component are connected by a threaded rotation, the external thread of the threaded rod and the internal thread of the transmission component cannot be tightly engaged, and there is a certain gap. As a result, when the transmission component needs to turn back to return to the best shooting position, the accuracy of the return position is reduced due to the gap error.

[0067] For example, when focus position 1 P1 is located to the right of focus position 2 P2, when using the climbing algorithm to find focus position 2, the imaging lens is set to move from left to right. In this case, the process is to first find focus position 1 P1, and then determine that focus position 2 P2 is to the left of focus position 1 based on focus position 1 P1. Then, the movement direction of the transmission component needs to be changed to move from right to left to find focus position 2 P2. However, such a change in movement direction will affect the error of movement displacement due to the existence of gap error, thus affecting the accuracy of the final return position, thereby increasing the focusing time and being detrimental to the capture of dynamic scenes.

[0068] Therefore, it is also necessary to ensure that the direction of movement of the transmission components remains consistent when searching for the focal position one and focal position two of the focused lighting source according to the climbing algorithm. For example, Figure 2 As shown, when the transmission component drives the imaging lens to move unidirectionally in a certain step size, the specific steps to ensure that the movement direction of the transmission component remains consistent are as follows: when the optimal focal point of the shooting illumination source is closer to the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the imaging lens to move from the direction closer to the shooting object to the direction farther away from the shooting object; when the optimal focal point of the shooting illumination source is farther away from the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the imaging lens to move from the direction farther away from the shooting object to the direction closer to the shooting object.

[0069] like Figure 3 As shown, when the transmission component moves the object being photographed in one direction with a certain step size, the specific steps to ensure that the direction of movement of the transmission component remains consistent are as follows: when the optimal focal point of the illumination source is closer to the imaging lens than the optimal focal point of the focusing illumination source, the transmission component moves the object being photographed from a direction away from the imaging lens to a direction closer to the imaging lens; when the optimal focal point of the illumination source is further away from the imaging lens than the optimal focal point of the focusing illumination source, the transmission component moves the object being photographed from a direction closer to the imaging lens to a direction farther away from the imaging lens.

[0070] like Figure 4 As shown, when the transmission component drives the imaging sensor to move unidirectionally in a certain step size, the specific steps to ensure that the movement direction of the transmission component remains consistent are as follows: when the optimal focal point of the shooting illumination source is closer to the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the imaging sensor to move from the direction away from the imaging lens to the direction closer to the imaging lens; when the optimal focal point of the shooting illumination source is farther away from the imaging lens than the optimal focal point of the focusing illumination source, the transmission component drives the imaging sensor to move from the direction closer to the imaging lens to the direction farther away from the imaging lens.

[0071] The optimal focal point for both the shooting and focusing light sources is determined by the optical parameters of the shooting and focusing light sources, such as wavelength, type of imaging lens, and material. Therefore, it can be determined based on the actual configuration.

[0072] By determining the focal point in advance, the unidirectional movement direction of the transmission component can be determined, thus avoiding the impact of gap errors on the final focusing accuracy and focusing time.

[0073] After the configuration is completed, the focus position search can be performed. This embodiment takes the unidirectional movement of the imaging lens driven by the transmission component as an example to illustrate the focus position search. First, the focusing illumination source is started, and the transmission component is adjusted to drive the imaging lens to move unidirectionally with a certain step size. Then, the focus position one and focus position two of the focusing illumination source are found according to the climbing algorithm. The distance difference between focus position two and focus position one is the optimal focus position difference, and the image sharpness reduction value at focus position two exceeds the sharpness reduction threshold.

[0074] It should be noted that the "certain step size" mentioned in this application refers to the fact that the same displacement can be used in each movement. This same displacement can be set freely, or different displacements can be used each time, as long as unidirectional movement is guaranteed.

[0075] Specifically, finding the focal position one and focal position two of the focused illumination source using the hill-climbing algorithm includes the following steps:

[0076] The imaging lens acquires an intermediate image every time it moves one step, and calculates the sharpness value of each acquired intermediate image.

[0077] Compare the sharpness values ​​of the intermediate image at the current position with those at the previous position until the sharpness value of the intermediate image at the current position begins to decrease compared to that at the previous position. Record the highest sharpness value that occurs during the comparison process and mark the position corresponding to the highest sharpness value as focus position one.

[0078] The imaging lens continues to move unidirectionally in steps and calculates the decrease in sharpness value of the intermediate image at the current position relative to the highest sharpness value.

[0079] When the decrease in sharpness reaches the threshold, the focal point of the focusing illumination source reaches the second focusing position; otherwise, the imaging lens continues to move in fixed step units.

[0080] More specifically, taking a sharpness reduction threshold of 15% of the maximum value as an example, the imaging lens is in the initial position and then moves unidirectionally in steps. Each step captures an intermediate image, and the sharpness value of the intermediate image is calculated. It is then determined whether the sharpness value of the currently captured intermediate image has decreased compared to the sharpness value of the previously captured intermediate image. If it has not decreased, the first focal position has not yet been found. The imaging lens continues to move unidirectionally until the sharpness value of the currently captured intermediate image intersects with the previously calculated sharpness value and decreases. The intermediate image with the highest calculated sharpness value is determined as the sharpest image, and its corresponding focal point is marked as the first focal position (i.e., the optimal focal position for focusing the illumination source).

[0081] Next, the imaging lens continues to move in the same direction. Similarly, for each movement, an intermediate image is acquired, and the sharpness value of the currently acquired intermediate image is calculated. It is then determined whether the calculated sharpness value of the intermediate image reaches the sharpness reduction threshold, that is, whether it reaches 15% of the sharpest value. If it does, it means that the second focus position has been found. Otherwise, the imaging lens continues to move until the second focus position is found.

[0082] After finding the second focal position, the position of the imaging lens is obtained as the optimal focusing and shooting position. At the optimal focusing and shooting position, the focusing light source is switched to the shooting illumination light source, and image capture is performed. Since the optimal focusing position of the shooting illumination light source corresponding to the second focal position can be determined based on the configuration of the focusing illumination light source and the shooting illumination light source, it is not necessary to use the climbing algorithm again after switching to the shooting illumination light source when finding the second focal position. This reduces the switching time between the focusing illumination light source and the shooting illumination light source. Furthermore, by associating the difference in the optimal focusing position with the sharpness reduction threshold, this application enables the search for the second focal position based on the mapping relationship between the obtained sharpness reduction threshold and the accurately calculated difference in focusing position after obtaining the first focal position. This avoids the problem of inaccurate optimal focusing points found when the imaging lens needs to return because the optimal focusing point position is exceeded when using the climbing algorithm to find the second focal position of the shooting illumination light source.

[0083] Finally, the accuracy of the position of the imaging lens when the focusing position of the focusing illumination source reaches the second focusing position can be verified as the optimal focusing shooting position. The accuracy verification includes the following steps: calculating the distance difference between the first focusing position and the second focusing position; obtaining the first image sharpness when located at the first focusing position and the second image sharpness when located at the second focusing position under the focusing illumination source; calculating the sharpness reduction verification value based on the first image sharpness and the second image sharpness; determining whether the distance difference is equal to the optimal focusing position difference and whether the sharpness reduction verification value is equal to the sharpness reduction threshold; if so, the verification result is accurate; otherwise, the verification result is inaccurate.

[0084] This verification further confirms that when the focusing illumination source is switched to the shooting illumination source, the image captured under the shooting illumination source is the clearest image, and the second focusing position is the optimal focusing position of the imaging lens under the shooting illumination source.

[0085] Example 2

[0086] A multi-wavelength imaging device is disclosed for implementing the focusing and imaging method described in Embodiment 1. The device includes a focusing illumination source, an imaging illumination source, an object to be imaged, an imaging lens, a transmission assembly, and an imaging sensor. The focusing illumination source and the imaging illumination source illuminate the object. The focusing illumination source and the imaging illumination source have different wavelengths. The transmission assembly drives any one of the imaging lens, the imaging sensor, or the object to move unidirectionally in a certain step size. The imaging lens focuses light from the object onto the imaging sensor. The imaging sensor receives the light focused by the imaging lens and converts it into an electrical signal, generating a digital image based on the electrical signal. In this embodiment, the imaging sensor is a CMOS chip, the wavelength of the focusing illumination source is λ1, and the wavelength of the imaging illumination source is λ2.

[0087] Specifically, such as Figure 2 As shown, taking the transmission component driving the imaging lens to move unidirectionally in a certain step as an example, the optimal focusing position of the wavelength of the focusing illumination source is set to P1 on the optical axis, and the corresponding imaging lens position is L1; the optimal focusing position of the wavelength of the imaging illumination source is set to P3 on the optical axis, and the corresponding imaging lens position is L2. When the imaging lens is at L2, when using the focusing illumination source for shooting, the focusing position of the imaging lens on the optical axis is P2, and P2 (L2) and P1 (L1) do not coincide. The initial position of the imaging lens is L0.

[0088] During the focusing phase, illumination is performed using the focusing wavelength. The imaging lens is gradually moved from the initial position L0, which is far from the optimal focus, to the optimal focus point L1 / P1 (i.e., focus position one) via the transmission component. Then, the imaging lens is moved in small steps. After each movement, the sharpness of the received image is calculated, and it is determined whether the sharpness of the current image is better than that of the previous step.

[0089] like Figure 5 As shown, according to the climbing algorithm, the imaging lens needs to completely pass through the "peak" position (L1 / P1) of the sharpness curve of the focused illumination source and continue to move to the "downhill" position (L2 / P2) so that the L1 / P1 point is accurately determined as the optimal position of the focused illumination source by judging the sharpness difference.

[0090] By configuring the system, the optimal focusing positions of different wavelength illumination sources are separated axially, so that L2 / P2 coincides with the optimal focusing position for the shooting wavelength λ2. Therefore, when the focusing judgment is completed and the system is at the L2 / P2 position, the system can directly switch to the shooting illumination source for shooting without returning or readjusting the position.

[0091] Example 3

[0092] A focusing and shooting system includes a parameter acquisition unit, a configuration unit, a focus position finding unit, and a focusing and shooting unit;

[0093] The system includes a parameter acquisition unit for acquiring the image sharpness reduction threshold under the focused illumination source and determining the optimal focus position difference based on the sharpness reduction threshold; a configuration unit for configuring the focal length one of the focused illumination source and the focal length two of the shooting illumination source, so that the difference between the actual focused imaging positions of the wavelengths of the focused illumination source and the shooting illumination source on the optical axis is equal to the optimal focus position difference; a focus position finding unit for activating the focused illumination source, adjusting the transmission component to move unidirectionally in a certain step size, and finding the focus position one and focus position two of the focused illumination source according to the climbing algorithm, wherein the distance difference between focus position two and focus position one is the optimal focus position difference, and the image sharpness reduction value at focus position two exceeds the sharpness reduction threshold; and a focus shooting unit for reaching the optimal focus shooting position under the shooting illumination source when the focus position of the focused illumination source reaches focus position two, switching the focused illumination source to the shooting illumination source, and performing image shooting.

[0094] Since the focusing imaging system in this embodiment performs the focusing imaging method described in Embodiment 1, it will not be repeated here.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A focusing photographing method characterized by comprising: The method comprises the following steps: obtaining a sharpness drop threshold of an image under a focus illumination light source, and determining an optimal focus position difference value based on the sharpness drop threshold; configuring a focal length one of the focus illumination light source and a focal length two of a shooting illumination light source, so that the actual focus imaging position difference value of the wavelength of the focus illumination light source and the shooting illumination light source on the optical axis is equal to the optimal focus position difference value; starting the focus illumination light source, adjusting the transmission assembly to move in one direction at a certain step, and finding a focus position one and a focus position two of the focus illumination light source according to a climbing algorithm, wherein the distance difference value between the focus position two and the focus position one is the optimal focus position difference value, and the image sharpness drop value at the focus position two exceeds the sharpness drop threshold; when the focus position of the focus illumination light source reaches the focus position two, the optimal focus shooting position under the shooting illumination light source is reached, the focus light source is switched to the shooting illumination light source, and image shooting is performed.

2. The method of claim 1, wherein, The calculation formula of the optimal focus position difference value is: wherein u denotes the object distance, denotes the focal length one of the focused illumination light source with a wavelength of denotes the focal length two of the shot illumination light source with a wavelength of ​​ 3. The method of claim 1, wherein, finding the focus position one and the focus position two of the focus illumination light source according to the climbing algorithm, which comprises the following steps: collecting an intermediate image at each step of the movement of the transmission assembly, and calculating the sharpness value of each collected intermediate image; comparing the sharpness value of the intermediate image at the current position with that of the intermediate image at the previous position until the sharpness value of the intermediate image at the current position starts to drop compared with the sharpness value of the intermediate image at the previous position, recording the highest sharpness value appeared in the comparison process, and marking the position corresponding to the highest sharpness value as the focus position one; continuing to move the transmission assembly in one direction at a certain step, and calculating the drop value of the sharpness value of the intermediate image at the current position relative to the highest sharpness value; when the drop value reaches the sharpness drop threshold, the focus point of the focus illumination light source reaches the focus position two, otherwise the imaging lens is moved in the unit of the fixed step.

4. The focusing photographing method according to any one of claims 1-3, characterized in that, When finding the focus position one and the focus position two of the focus illumination light source according to the climbing algorithm, the moving direction of the transmission assembly always remains consistent, which comprises the following steps: when the optimal focus point of the shooting illumination light source is closer to the imaging lens relative to the optimal focus point of the focus illumination light source, the transmission assembly drives the imaging lens to move from the direction away from the shooting object to the direction close to the shooting object; when the optimal focus point of the shooting illumination light source is farther away from the imaging lens relative to the optimal focus point of the focus illumination light source, the transmission assembly drives the imaging lens to move from the direction close to the shooting object to the direction away from the shooting object.

5. The method of any one of claims 1-3, wherein the focusing is performed by a camera. When finding the focus position one and the focus position two of the focus illumination light source according to the climbing algorithm, the moving direction of the transmission assembly always remains consistent, which comprises the following steps: when the optimal focus point of the shooting illumination light source is closer to the imaging lens relative to the optimal focus point of the focus illumination light source, the transmission assembly drives the shooting object to move from the direction away from the imaging lens to the direction close to the imaging lens; when the optimal focus point of the shooting illumination light source is farther away from the imaging lens relative to the optimal focus point of the focus illumination light source, the transmission assembly drives the shooting object to move from the direction close to the imaging lens to the direction away from the imaging lens.

6. The method of focusing according to any one of claims 1 to 3, wherein, When the focusing position of the focusing illumination light source reaches the second focusing position, the accuracy of the best focusing position required for shooting the illumination light source is verified. The verification includes the following steps: calculating the distance difference between the first focusing position and the second focusing position; 7. The method of claim 1, wherein, obtaining the first image clarity when the focusing illumination light source is at the first focusing position and the second image clarity when the focusing illumination light source is at the second focusing position; calculating the clarity drop verification value based on the first image clarity and the second image clarity; 8. The method of claim 7, wherein, determining whether the distance difference is equal to the best focusing position difference and whether the clarity drop verification value is equal to the clarity drop threshold value; if yes, the verification result is accurate; otherwise, the verification result is inaccurate. The multi-wavelength image device is used to implement the focusing shooting method according to any one of claims 1-8, and includes a focusing illumination light source, a shooting illumination light source, a shooting object, an imaging lens, a transmission assembly, and an imaging sensor. The focusing illumination light source and the shooting illumination light source are used to illuminate the shooting object, and the focusing illumination light source and the shooting illumination light source have different wavelengths. The transmission assembly is used to drive any one of the imaging lens, the imaging sensor, or the shooting object to move in one direction at a certain step. The imaging lens is used to focus the light on the shooting object onto the imaging sensor.

9. A multi-wavelength imaging device, characterized in that, The imaging sensor is used to receive the light focused by the imaging lens and convert it into an electrical signal, and generate a digital image based on the electrical signal. The focusing shooting system executes the focusing shooting method according to any one of claims 1-8, and includes a parameter acquisition unit, a configuration unit, a focusing position finding unit, and a focusing shooting unit. The parameter acquisition unit is used to acquire the clarity drop threshold of the image under the focusing illumination light source, and determine the best focusing position difference based on the clarity drop threshold. The configuration unit is used to configure the focal length one of the focusing illumination light source and the focal length two of the shooting illumination light source, so that the actual focusing imaging position difference of the wavelengths of the focusing illumination light source and the shooting illumination light source on the optical axis is equal to the best focusing position difference. The focusing position finding unit is used to start the focusing illumination light source, adjust the one-way movement of the transmission assembly at a certain step, and find the first focusing position and the second focusing position of the focusing illumination light source according to the climbing algorithm, wherein the distance difference between the second focusing position and the first focusing position is the best focusing position difference, and the image clarity drop value at the second focusing position exceeds the clarity drop threshold.

10. A focusing photographing system, characterized by, ​ ​ ​ ​ The focusing shooting unit is used for reaching the best focusing shooting position under the shooting illuminating light source when the focusing position of the focusing illuminating light source reaches the second focusing position, switching the focusing light source to the shooting illuminating light source, and performing image shooting.

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