CN113031199B

CN113031199B - Image distance adjusting device and image distance adjusting method for optical imaging

Info

Publication number: CN113031199B
Application number: CN201911353301.1A
Authority: CN
Inventors: 张华林
Original assignee: Hangzhou Hikrobot Technology Co Ltd
Current assignee: Hangzhou Hikrobot Co Ltd
Priority date: 2019-12-25
Filing date: 2019-12-25
Publication date: 2022-09-02
Anticipated expiration: 2039-12-25
Also published as: CN113031199A

Abstract

The invention provides an image distance adjusting device and an image distance adjusting method for optical imaging. Based on the above-described embodiment, the photosensitive surface of the imaging element may be arranged outside the straight light path of the optical module, and a reflection light path is formed between the straight light path of the optical module and the photosensitive surface of the imaging element by using the reflection mechanism. The reflection mechanism can be switchably constrained in any one of the at least two calibration poses, and based on the reflection light paths formed by the reflection mechanism in different calibration poses, the path lengths of the variable imaging light paths equivalent to the image distance between the optical module and the imaging surface can be different from each other, but the position deviation of the projection position of the photosensitive surface is within a preset deviation tolerance range, so that the image distance can be adjusted by switching the calibration pose of the reflection mechanism. The switchable position and posture constraint of the reflecting mechanism at different calibration positions and postures can use the variable non-contact constraint force to reduce abrasion, thereby reducing the precision adjustment misalignment and the attenuation speed of the service life.

Description

Image distance adjusting device and image distance adjusting method for optical imaging

Technical Field

The present invention relates to optical imaging technologies, and in particular, to an image distance adjusting apparatus for optical imaging, an optical imaging apparatus, and an image distance adjusting method for optical imaging.

Background

The light transmitted from the optical module (such as a lens) is projected on the photosensitive surface of the imaging element, so that light sensing imaging on the imaging element can be realized.

In order to adapt to the change of the object distance between the shooting target and the optical module, so that the light sensing imaging can obtain a clear image, a motorized zoom lens or an Auto Focus (AF) device can be adopted to adaptively adjust the image distance between the optical module and the light sensing surface of the imaging element.

The electric zoom lens realizes image distance adjustment by driving an optical module including a lens surface to perform linear motion in the optical axis direction, and the AF device realizes image distance adjustment by driving an imaging element to perform linear motion in the optical axis direction.

Therefore, the image distance adjustment cannot be realized under the condition that the imaging element and the optical module are prevented from moving at the same time by the scheme.

Disclosure of Invention

In one embodiment, there is provided an image distance adjusting apparatus for optical imaging, including:

the reflecting mechanism is used for forming a reflecting light path which is continuous with the direct transmission light path between the direct transmission light path of the optical module and the photosensitive surface of the imaging element positioned outside the direct transmission light path;

the control module is used for determining an expected image distance according to the focal length of the optical module and the actual object distance of the shooting target relative to the optical module; selecting a calibration pose for the reflecting mechanism according to the expected image distance;

the adjusting mechanism is used for constraining the reflecting mechanism at the calibration pose selected by the control module;

the control module controls the adjusting mechanism to generate variable non-contact constraint force on the reflecting mechanism according to the selected calibration pose so as to constrain the reflecting mechanism at the selected calibration pose; and based on the reflection light path formed by the reflection mechanism in different calibration poses, the path lengths of the variable imaging light paths between the optical module and the imaging surface are different from each other, and the position deviation of the projection position of the photosensitive surface is within a preset deviation tolerance range.

Optionally, the reflecting mechanism includes a swing mirror, the swing mirror tilts relative to the optical axis of the optical module at a calibration tilt angle selected from the tilt angle set, so as to form a calibration pose of the reflecting mechanism by using the tilt pose at the selected calibration tilt angle; the adjusting mechanism comprises magnetic attraction components which are arranged in pairs and used for generating variable magnetic attraction force which forms pose constraint on the reflecting mechanism between the magnetic attraction components, and the variable magnetic attraction force changes in response to the change of the coil electrifying current; the control module further realizes the selection of the calibration pose by selecting the calibration inclination angle from the inclination angle set, and controls the coil electrifying current of the magnetic attraction component according to the selected calibration inclination angle.

Optionally, the rotation fulcrum of the swing mirror is a fixed fulcrum arranged on the fixed bracket; the adjusting mechanism comprises a first permanent magnet element and a first electromagnetic element, wherein one of the first permanent magnet element and the first electromagnetic element is arranged on the swing mirror, and the other one of the first permanent magnet element and the first electromagnetic element is arranged on the fixing support and is arranged in a swing path of the swing mirror; the control module is further used for controlling the coil electrifying current of the first electromagnetic element according to the selected calibration inclination angle so as to drive the oscillating mirror to incline relative to the optical axis of the optical module at the selected calibration inclination angle by utilizing the first magnetic attraction force between the first electromagnetic element and the first permanent magnetic element.

Optionally, the light sensing surface of the imaging element is arranged parallel to the optical axis of the optical module, and the light sensing surface of the imaging element is deviated from the optical axis by a fixed lateral deviation distance H in a direction perpendicular to the optical axis; the rotation fulcrum of the oscillating mirror is arranged flush with the photosensitive surface of the imaging element in a direction perpendicular to the optical axis, and the rotation fulcrum of the oscillating mirror deviates from a reference projection position of the optical axis on the photosensitive surface by a fixed depth distance D in a direction parallel to the optical axis; the nominal tilt angles in the set of tilt angles include: in a manner that

And

at least two tilt angles within an angular tolerance range for the reference.

Optionally, the rotation fulcrum of the oscillating mirror is a movable fulcrum arranged on the translation bracket, wherein the moving direction of the translation bracket is parallel to the optical axis; the adjustment mechanism comprises a first permanent magnet element and a first electromagnetic element, and a second permanent magnet element, wherein: one of the first permanent magnetic element and the first electromagnetic element is arranged on the swing mirror, and the other one of the first permanent magnetic element and the first electromagnetic element is arranged on the translation bracket and is arranged in a swing path of the swing mirror; one of the second permanent magnetic element and the second electromagnetic element is arranged on the translation bracket, and the other permanent magnetic element is separated from the translation bracket and is arranged in the moving path of the translation bracket; the control module is further used for controlling the coil electrifying currents of the first electromagnetic element and the second electromagnetic element according to the selected calibrated inclination angle so as to drive the tilting mirror to incline relative to the optical axis of the optical module at the selected calibrated inclination angle by utilizing a first magnetic attraction force between the first electromagnetic element and the first permanent magnetic element and a second magnetic attraction force between the second electromagnetic element and the second permanent magnetic element.

Optionally, the light sensing surface of the imaging element is arranged parallel to the optical axis of the optical module, and the light sensing surface of the imaging element is deviated from the optical axis by a fixed offset distance H in a direction perpendicular to the optical axis; the rotation fulcrum of the oscillating mirror is arranged flush with the photosensitive surface of the imaging element in a direction perpendicular to the optical axis, and the rotation fulcrum of the oscillating mirror is arranged at a variable depth distance D in a direction parallel to the optical axis _adj A reference projection position on the photosensitive surface deviated from the optical axis; the nominal inclination angles in the inclination angle set comprise 45 degrees,

And

at least two of them, wherein the depth distance D is variable _adj There are at least two selectable distance values that vary in response to translation of the pivot point of rotation of the oscillating mirror.

Optionally, further comprising: the calibration mechanism is used for detecting the actual pose of the reflection mechanism under the constraint of the adjustment mechanism; when the pose deviation between the actual pose of the reflecting mechanism and the selected calibration pose exceeds a preset deviation threshold value, the control module is further used for controlling the adjusting mechanism to execute pose compensation with the pose deviation trend reduced.

Optionally, the verification mechanism comprises: a laser transmitter for transmitting laser to the reflecting mechanism; a sensor array for receiving the laser light retro-reflected from the reflecting mechanism; the control module further determines the actual pose of the reflecting mechanism under the constraint of the adjusting mechanism according to the sensing position of the retro-reflected laser on the sensor array.

Optionally, further comprising: and the distance measurement module is used for detecting the actual object distance of the shooting target relative to the optical module.

In another embodiment, an optical imaging apparatus is provided, which includes an optical lens having an optical module, an imaging element having a photosensitive surface, and an image distance adjusting apparatus as described in the above embodiments.

In another embodiment, a logistics code reading system is provided, which includes a material conveying mechanism, and the optical imaging device as described in the previous embodiment, wherein a lens field of view of the optical lens covers at least a part of a conveying range of the material conveying mechanism.

In another embodiment, there is provided an image distance adjusting method for optical imaging, including:

determining an expected image distance according to the focal length of the optical module and the actual object distance of the shooting target relative to the optical module;

selecting a calibration pose for the reflecting mechanism according to the expected image distance;

controlling the adjusting mechanism to generate a variable non-contact constraint force according to the selected calibration pose so that the adjusting mechanism utilizes the variable non-contact constraint force to constrain the reflecting mechanism at the selected calibration pose, and the reflecting mechanism forms a reflecting light path which is continuous with the straight light path between the straight light path of the optical module and the photosensitive surface of the imaging element outside the straight light path at the selected calibration pose;

based on the reflection light path formed by the reflection mechanism with different calibration poses, the path lengths of the variable imaging light paths between the optical module and the imaging surface are different from each other, and the position deviation of the projection position of the photosensitive surface is within a preset deviation tolerance range.

Optionally, selecting a calibration pose for the reflection mechanism according to the expected image distance includes: selecting a calibration dip angle from the dip angle set according to the expected image distance; when the swing mirror in the reflecting mechanism is in the selected calibration pose, the swing mirror inclines relative to the optical axis of the optical module by the selected calibration inclination angle; controlling the adjustment mechanism to produce the variable non-contact binding force comprises: and controlling the coil electrifying current of a magnetic component in the adjusting mechanism, wherein the magnetic component responds to the change of the coil electrifying current to generate variable magnetic attraction force on the reflecting mechanism.

Optionally, controlling the coil energizing current of the magnetically attractive assembly in the adjustment mechanism comprises: controlling the coil electrifying current of a first electromagnetic element in the adjusting mechanism according to the selected calibration inclination angle so as to drive a swing mirror in the reflecting mechanism to incline relative to the optical axis of the optical module at the selected calibration inclination angle by utilizing a first magnetic attraction force between the first electromagnetic element and a first permanent magnetic element; one of the first permanent magnetic element and the first electromagnetic element is arranged on a swing mirror of the reflecting mechanism, the other one of the first permanent magnetic element and the first electromagnetic element is arranged on a fixed support of the reflecting mechanism and is arranged in a swing path of the swing mirror, and a rotating fulcrum of the swing mirror is a fixed fulcrum arranged on the fixed support.

Optionally, controlling the coil energizing current of the magnetically attractive assembly in the adjustment mechanism comprises: according to the coil electrifying current of the first electromagnetic element and the second electromagnetic element in the selected calibration position inclination angle system adjusting mechanism, driving a swing mirror in the reflecting mechanism to incline relative to the optical axis of the optical module at the selected calibration inclination angle by utilizing the first magnetic attraction between the first electromagnetic element and the first permanent magnetic element and the second magnetic attraction between the second electromagnetic element and the second permanent magnetic element; one of the first permanent magnetic element and the first electromagnetic element is arranged on a swing mirror of the reflecting mechanism, the other one of the first permanent magnetic element and the first electromagnetic element is arranged on a translation bracket of the reflecting mechanism and is arranged in a swing path of the swing mirror, one of the second permanent magnetic element and the second electromagnetic element is arranged on the translation bracket, the other one of the second permanent magnetic element and the second electromagnetic element is separated from the translation bracket and is arranged in a moving path of the translation bracket, a rotating fulcrum of the swing mirror is a movable fulcrum arranged on the translation bracket, and the moving direction of the translation bracket is parallel to an optical axis.

Optionally, further comprising: acquiring the actual pose of the reflecting mechanism detected by the checking mechanism under the constraint of the adjusting mechanism; and when the pose deviation between the actual pose of the reflecting mechanism and the selected calibration pose exceeds a preset deviation threshold value, controlling the adjusting mechanism to execute pose compensation with pose deviation reduction as a trend.

Optionally, the obtaining of the actual pose of the reflecting mechanism detected by the checking mechanism under the constraint of the adjusting mechanism includes: and determining the actual pose of the reflecting mechanism under the constraint of the adjusting mechanism according to the sensing position of the sensor array in the checking mechanism on the laser retroreflected from the reflecting mechanism, wherein the laser retroreflected from the reflecting mechanism is emitted by a laser emitter of the checking mechanism.

Optionally, further comprising: and acquiring the actual object distance of the shooting target detected by the distance measurement module relative to the optical module.

Based on the above-described embodiment, the photosensitive surface of the imaging element may be arranged outside the straight light path of the optical module, and a reflection light path may be formed between the straight light path of the optical module and the photosensitive surface of the imaging element by using the reflection mechanism. The reflection mechanism can be switchably constrained in any one of at least two calibration poses, and based on reflection light paths formed by the reflection mechanism in different calibration poses, the path lengths of variable imaging light paths equivalent to the image distance between the optical module and the imaging surface can be different from each other, but the position deviation of the projection position of the photosensitive surface is within a preset deviation tolerance range, so that the image distance can be adjusted by switching the calibration poses of the reflection mechanism, and the straight-through light path and the imaging element of the optical module do not need to be adjusted.

Further alternatively, switchable pose constraints of the reflective mechanism at different calibration poses may be used with variable non-contact constraining forces. The use of a variable non-contact restraining force may reduce wear compared to contact restraint such as mechanical transmissions, thereby reducing misalignment of adjustment accuracy due to wear and the rate of decay of service life. In particular, for multi-objective application scenarios such as logistics detection, the shooting targets often need to be frequently switched among a plurality of parcels, and the object distances of the shooting targets in each switching are different from each other with a high probability, thereby causing frequent adjustment of the image distance, wherein the abrasion caused by contact constraints such as mechanical transmission and the like in the scenario is further aggravated and seriously affects the adjustment precision and the service life, while the use of variable non-contact constraint force does not aggravate the reduction of the adjustment precision and the reduction of the service life.

Drawings

The following drawings are only schematic illustrations and explanations of the present invention, and do not limit the scope of the present invention:

FIG. 1 is a schematic diagram of an exemplary configuration of an optical imaging apparatus in one embodiment;

FIG. 2 is a schematic diagram of an exemplary structure of an image distance adjusting apparatus for optical imaging in the optical imaging apparatus shown in FIG. 1;

FIG. 3 is a schematic view of the image distance adjusting apparatus shown in FIG. 2 using the adjustment principle of non-contact constraint force;

fig. 4a and 4b are schematic diagrams illustrating a first example of the image distance adjusting apparatus shown in fig. 2 based on the adjustment principle shown in fig. 3;

FIG. 5 is a schematic view of a second example of the image distance adjusting apparatus shown in FIG. 2 based on the adjustment principle shown in FIG. 3;

FIG. 6 is a schematic diagram of a first expanded structure of the image distance adjusting apparatus shown in FIG. 2;

FIG. 7 is a schematic diagram of an example structure of the checking mechanism in the first expanded structure shown in FIG. 6;

FIG. 8 is a schematic diagram of a second expanded structure of the image distance adjusting apparatus shown in FIG. 2;

FIG. 9 is a schematic diagram of a third expanded structure of the image distance adjusting apparatus shown in FIG. 2;

FIG. 10 is a schematic diagram of an exemplary structure of a logistics code reading system using the optical imaging device shown in FIG. 1;

FIG. 11 is a schematic flow chart illustrating an exemplary method for image distance adjustment for optical imaging in another embodiment;

fig. 12 is a schematic diagram illustrating an optimization flow of the image distance adjusting method shown in fig. 11;

FIG. 13 is a flowchart illustrating an example of the image distance adjustment method shown in FIG. 11;

fig. 14 is an expanded flow diagram illustrating the self-checking mechanism introduced by the image distance adjusting method shown in fig. 11;

fig. 15 is an expanded flow diagram illustrating the self-ranging mechanism introduced in the image distance adjusting method shown in fig. 11.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and examples.

Fig. 1 is an exemplary structural diagram of an optical imaging apparatus in one embodiment. Fig. 2 is a schematic structural diagram of an exemplary image distance adjusting apparatus for optical imaging in the optical imaging apparatus shown in fig. 1. Referring to fig. 1, in the embodiment, the optical imaging apparatus may include an optical lens 10 having an optical module 100, an imaging device 20 having a photosensitive surface 200, and an image distance adjusting device 30.

The optical module 100 of the optical lens 10 may include a light transmitting element such as a lens, wherein the optical module 100 has a through light path transmitting in an optical axis direction, and the optical module 100 has a set focal length f.

The imaging element 20 may be a Device having photosensitive imaging capability, such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), wherein the photosensitive surface 200 of the imaging element 20 may be disposed outside the straight light path of the optical module 100, for example, the photosensitive surface 200 of the imaging element 20 may be disposed parallel to the optical axis of the optical module 100, and the photosensitive surface 200 of the imaging element 20 is deviated outside the straight light path of the optical module 100 in a direction perpendicular to the optical axis.

The image distance adjusting device 30 is used for adjusting the image distance between the optical module 100 and the photosensitive surface 200.

Referring to fig. 2, in this embodiment, the image distance adjusting device may include a reflection mechanism 31, a control module 32, and an adjusting mechanism 33.

The reflecting mechanism 31 may include a variable-attitude reflecting mirror surface, and the reflecting mechanism 31 may be configured to form a reflecting optical path subsequent to the direct transmission optical path between the direct transmission optical path of the optical block 100 and the photosensitive surface 200 of the imaging element 20 located outside the direct transmission optical path. Accordingly, the partial through optical path from the optical module 100 to the reflection mechanism 31 and the reflection optical path from the reflection mechanism 31 to the light sensing surface 300 sequentially form an imaging optical path, and the path length of the imaging optical path is equivalent to the image distance.

The control module 32 may comprise a component having data processing capability, such as a processor, and the control module 31 may be configured to determine the desired image distance S according to the focal length f of the optical module 100 and the actual object distance of the shooting target relative to the optical module 100 _IMG . For example, according to the focal length f of the optical module 100 and the actual object of the shooting target relative to the optical module 100Distance S _OBJ Determined desired image distance S _IMG The following expression may be satisfied:

the control module 32 may also be used to vary the desired image distance S _IMG For example, the control module 32 may select a calibration pose for the reflecting mechanism 31 from at least two predetermined calibration poses.

The adjustment mechanism 33 may be used to constrain the reflecting mechanism 31 in the calibration pose selected by the control module 32.

Based on the reflection light paths formed by the reflection mechanism 31 in different calibration poses, the imaging light path between the optical module 100 and the imaging surface 200 is variable, the path lengths of the variable imaging light paths may be different from each other, and the position deviation at the projection position of the photosensitive surface 200 is within a preset deviation tolerance range.

Moreover, based on the reflection light path formed by the calibration pose selected by the control module 32 by the reflection mechanism 31, the definition of an image obtained under the imaging conditions of the focal length of the optical module and the actual object distance of a shooting target relative to the optical module can be not lower than the preset expected definition.

When the calibration pose is selected, the control module 32 can select the desired image distance S _IMG And a calibration tilt angle for the reflecting mechanism 31 is selected from at least two calibration poses in a look-up table manner in accordance with a preset correspondence with the calibration poses. Alternatively, when the optical imaging apparatus supports manual adjustment, the control module 32 may record manual adjustment records for different actual object distances, and may query, as the selected calibration pose, one of the at least two calibration poses that is closest to the historical pose in the manual adjustment records, according to the manual adjustment record that falls within the same object distance interval as the current actual object distance.

As can be seen from the above, based on this embodiment, the path length of the variable imaging optical path equivalent to the image distance can be adjusted by switching the calibration posture at which the reflection mechanism 31 is located, and it is not necessary to adjust neither the position of the optical block 100 nor the position of the photosensitive surface 200 of the imaging element 20.

For the posture adjustment of the reflecting mechanism 31, the adjusting mechanism 33 may adopt a contact type transmission manner to realize the restraint. However, contact-type mechanical transmissions cause wear and, as a result, increase in wear as the time of use increases, and therefore, the precision of adjustment decreases and the service life decreases more rapidly.

In particular, in an application scenario of multi-target large-span movement such as logistics detection, the shooting targets often need to be switched frequently among a plurality of parcels, and the object distances of the shooting targets switched at each time are different from each other with a large probability, so that the image distance has to be adjusted frequently in order to obtain a clear image with a proper image distance. In this manner, wear of the contact transmission is further increased, and the reduction in the adjustment accuracy and the reduction in the service life are further accelerated.

To this end, as a preferable mode, the adjusting mechanism 33 may realize the posture adjustment of the reflecting mechanism 31 by generating the non-contact constraint force, that is:

the adjustment mechanism 33 may further be used to generate a variable non-contact restraining force on the reflection mechanism 31;

the control module 32 may be further configured to control the adjustment mechanism 33 to generate a variable non-contact restraining force to restrain the reflection mechanism 31 in a selected one of the at least two calibration poses according to the selected calibration pose.

Fig. 3 is a schematic view illustrating an adjustment principle of the image distance adjusting apparatus shown in fig. 2 using a non-contact constraint force. Referring to fig. 3, the magnetic attraction is selected as the non-contact constraint force:

the reflection mechanism 31 may include a swing mirror 310, and the at least two calibration poses of the reflection mechanism 31 may include at least two tilt poses of the swing mirror 310, wherein the swing mirror 310 is tilted with respect to the optical axis of the optical module 100 at a calibration tilt angle selected from the set of tilt angles at each tilt pose, that is, the swing mirror 310 is tilted with respect to the optical axis of the optical module at the calibration tilt angle selected from the set of tilt angles to form the calibration pose of the reflection mechanism 31 with the tilt pose at the selected calibration tilt angle;

the adjustment mechanism 33 may include

magnetic attraction members

331 and 332, and a variable magnetic attraction force that forms a posture constraint on the reflection mechanism may be generated between the

magnetic attraction members

331 and 332, and the variable magnetic attraction force may be changed in response to a change in the coil energization current of the

magnetic attraction member

331 or 332.

Based on the above structure, the control module 32 can further select the calibration pose by selecting the calibration tilt angle from the tilt angle set, and can further control the coil current of the

magnetic attraction component

331 or 332 according to the selected calibration tilt angle.

When the calibration pose is expressed by the calibration inclination angle, the control module 32 can control the image distance S according to the expected image distance _IMG And a calibration pose for the reflecting mechanism 31 is selected from at least two calibration dip angles in a look-up table manner in accordance with a preset correspondence between the calibration dip angles. Alternatively, when the optical imaging apparatus supports manual adjustment, the control module 32 may record manual adjustment records for different actual object distances, and may query, as the selected calibration tilt angle, one calibration tilt angle that is closest to the historical tilt angle in the manual adjustment records in at least two calibration poses according to the manual adjustment records that fall within the same object distance interval as the current actual object distance.

In addition, the control module 32 can also control the coil current of the

magnetic component

331 or 332 according to the preset corresponding relationship between the calibration inclination angle and the current value.

In order to more clearly understand the principle of performing the posture adjustment of the reflection mechanism 31 using the non-contact restraining force, the following description will be given with reference to two examples.

Fig. 4a and 4b are schematic diagrams of a first example of the image distance adjusting apparatus shown in fig. 2 based on the adjustment principle shown in fig. 3. Referring to fig. 4a and 4b, in a first example:

the rotation fulcrum P of the swing mirror 310 may be a fixed fulcrum arranged at the fixed bracket 311, for example, the swing mirror 310 may be mounted at the fixed bracket 311 through a component such as a bearing to form a fixed rotation fulcrum P at the bearing, and the fixed bracket 311 may also perform a limit constraint on the swing angle range of the swing mirror 310, for example, the swing angle range may be constrained within a range not exceeding 10 °, and may even be constrained within a smaller range such as 5 ° or 2 °;

the adjusting mechanism 33 may include a first permanent magnetic element 331a and a first electromagnetic element 332a, wherein, in fig. 4, the first permanent magnetic element 331a is installed on the fixing bracket 311 and disposed in the swing path of the swing mirror 310, and the first electromagnetic element 332a is installed on the swing mirror 310 as an example, but it can be understood that the installation positions of the first permanent magnetic element 331a and the first electromagnetic element 332a may be reversed, that is, one of the first permanent magnetic element 331a and the first electromagnetic element 332a may be installed on the swing mirror 310, and the other may be installed on the fixing bracket 311 and disposed in the swing path of the swing mirror 310;

the control module 32 may be further configured to control the coil current of the first electromagnetic element 332a according to the selected calibration inclination angle (i.e. the calibration pose) to drive the tilting mirror 310 to tilt with respect to the optical axis of the optical module 100 at the selected calibration inclination angle by using the first magnetic attraction between the first electromagnetic element 332a and the first permanent magnetic element 331 a.

Also, in the first example as shown in fig. 4a and 4 b:

the photosensitive surface 200 of the imaging element 20 is arranged parallel to the optical axis of the optical module 100, and the photosensitive surface 200 of the imaging element 20 is deviated from the optical axis by a fixed lateral deviation distance H in a direction perpendicular to the optical axis;

the rotation fulcrum P of the oscillating mirror 310 is disposed flush with the light-sensing surface 200 of the imaging element 20 in a direction perpendicular to the optical axis of the optical module 100, and the rotation fulcrum P of the oscillating mirror 310 is deviated from the reference projection position M of the optical axis at the light-sensing surface 200 by a fixed depth distance D (e.g., greater than or less than a fixed lateral deviation distance H) in a direction parallel to the optical axis. Here, the reference projection position M may be regarded as a central position of the lens field of view of the optical lens 10 in a desired projection area of the photosensitive surface 200.

That is, the reference projection position M is spaced apart from the optical axis by a fixed lateral offset distance H, and the rotation fulcrum P is spaced apart from the reference projection position M by a fixed depth distance D.

Fig. 4a also shows a state where the oscillating mirror 310 is tilted at three different nominal tilt angles α 0 to α 2, and the intersection points of the oscillating mirror 310 with the optical axis when tilted at the nominal tilt angles α 0 to α 2 are respectively marked as R0 to R2. The lengths of the imaging optical paths from the optical module 100 to the reference projection position M via the intersection points R0, R1, and R2 are different from each other.

Through a triangle (i is any positive integer of 1-2) imaginary with the intersection point Ri, the rotation fulcrum P and the reference projection position M as a vertex in fig. 4a, ═ PRiM ═ α i ═ RiPM can be determined, and the distance MRi between the intersection point Ri and the reference projection position M is equal to the fixed depth distance D, so that sin (180 ° -2 × α i) can be derived as the ratio of the fixed lateral deviation distance H to the fixed depth distance D, and thus the calibration inclination angles α 1 and α 2 can satisfy:

and

the actual projection position M 'corresponding to the calibration inclination angle α 0 has a positional deviation within a deviation tolerance range with respect to the reference projection position M, and at this time, a right-angle triangle imaginary by taking a connecting line between the actual projection position M' and the intersection point R0 as a hypotenuse may be an isosceles right-angle triangle, and at this time, the calibration inclination angle α 0 may be 45 °.

The nominal inclination α 0 can also be expressed as

Or

Where Δ D is the deviation of the actual projection position M' from the reference projection position M.

If the deviation Δ D of the actual projection position M 'from the reference projection position M is ignored, i.e. the distance MR0 between the intersection point R0 and the reference projection position M is considered to be equal to the fixed depth distance D, then the actual projection position M' is also ignoredThe nominal inclination angle α 0 can be considered to approximately satisfy

And

in addition, the calibrated dip angles in the dip angle set can further comprise other approximate values based on the constraint condition that the position deviation of the actual projection position compared with the reference projection position M does not exceed the deviation tolerance range

And

optionally calibrating the inclination angle.

It can thus be considered that the nominal inclination in the set of inclinations is included in

And

at least two tilt angles within an angular tolerance range for the reference.

The tilting state of the tilting mirror 310 is switched between the nominal tilt angles α 1 and α 2, and can be driven by the first magnetic attraction force between the first electromagnetic element 332a and the first permanent magnetic element 331 a.

Fig. 4b also shows a state where the oscillating mirror 310 is tilted at two different nominal tilt angles α 1 and α 2, and the intersection points of the oscillating mirror 310 with the optical axis when tilted at the nominal tilt angles α 1 and α 2 are respectively marked as R1 and R2. Wherein the path lengths of the imaging optical paths from the optical block 100 to the reference projection position M via the intersection points R1 and R2, respectively, are different from each other.

By using a triangle imaginary with the intersection point R1, the rotation fulcrum P, and the reference projection position M as a vertex in fig. 4b, and another triangle imaginary with the intersection point R2, the rotation fulcrum P, and the reference projection position M as a vertex in fig. 4b, it can be determined that ═ PRiM ═ α i ═ RiPM (i is any positive integer from 1 to 2), and the distance MRi between the intersection point Ri and the reference projection position M can be equal to the fixed depth distance D, from which it can be derived:

sin (180-2 x α i) is the ratio of the fixed lateral offset H to the fixed depth D, to derive a nominal inclination α 1 which may be

The nominal inclination angle α 2 may be

At this time, it can be considered that the nominal inclination angles in the inclination angle set may include:

and

i.e. the set of tilt angles used in the situation as shown in fig. 4b, can be considered as a subset of the set of tilt angles used in the situation as shown in fig. 4 b.

In comparison with fig. 4a, it can be considered that fig. 4b eliminates the positional deviation of the projection position of the variable imaging optical path on the photosensitive surface 200 at the expense of the calibration inclination angle (i.e., the calibration pose), i.e., in exchange for the consistency of the projection position of the variable imaging optical path on the photosensitive surface 200.

In practical use, the requirement of the application scene for the number of calibration poses and the consistency severity of the projection positions can be comprehensively considered, and one of the two modes shown in fig. 4a and fig. 4b can be selected.

Fig. 5 is a schematic view of a second example of the image distance adjusting apparatus shown in fig. 2 based on the adjustment principle shown in fig. 3. Referring to fig. 5, in a second example:

the rotation fulcrum P of the oscillating mirror 310 is a movable fulcrum arranged at the translation bracket 312, wherein the moving direction of the translation bracket 312 is parallel to the optical axis, for example, the oscillating mirror 310 may be mounted at the translation bracket 312 through a component such as a bearing to form the rotation fulcrum P following the translation bracket 312 in the direction parallel to the optical axis at the bearing, and the translation bracket 312 may also perform limit constraint on the oscillating angle range of the oscillating mirror 310, for example, the oscillating angle range may be constrained within a range not exceeding 10 °, and may even be constrained within a smaller range such as 5 ° or 2 °;

the adjusting mechanism 33 may include a first permanent magnetic element 331a and a first electromagnetic element 332a, wherein, in fig. 5, the first permanent magnetic element 331a is installed on the fixing bracket 311 and disposed in the swing path of the swing mirror 310, and the first electromagnetic element 332a is installed on the swing mirror 310 as an example, but it can be understood that the installation positions of the first permanent magnetic element 331a and the first electromagnetic element 332a may be reversed, that is, one of the first permanent magnetic element 331a and the first electromagnetic element 332a may be installed on the swing mirror 310, and the other may be installed on the fixing bracket 311 and disposed in the swing path of the swing mirror 310;

the adjusting mechanism 33 may further include a second permanent magnet element 331b and a second permanent magnet element 332b, wherein, in fig. 5, the second permanent magnet element 331b is separated from the translating bracket 312 and disposed in the moving path of the translating bracket 312, and the second electromagnetic element 332b is mounted on the translating bracket 312, but it is understood that the positions of the second permanent magnet element 331b and the second permanent magnet element 332b may be reversed, that is, one of the second permanent magnet element 331b and the second electromagnetic element 332b is mounted on the translating bracket 312, and the other is separated from the translating bracket 312 and disposed in the moving path of the translating bracket 312;

the control module 32 may be further configured to control the coil energizing currents of the first electromagnetic element 332a and the second electromagnetic element 332b according to the selected calibration inclination angle (i.e., the calibration pose) so as to drive the tilting mirror 310 to tilt with respect to the optical axis of the optical module 100 at the selected calibration inclination angle by using a first magnetic attraction force between the first electromagnetic element 332a and the first permanent magnetic element 331a and a second magnetic attraction force between the second electromagnetic element 332b and the second permanent magnetic element 331 b.

Also, in the second example shown in fig. 5:

the rotation fulcrum P of the oscillating mirror 310 is arranged flush with the light-sensing surface 200 of the imaging element 20 in a direction perpendicular to the optical axis of the optical module 100, and the rotation fulcrum P of the oscillating mirror 310 is arranged at a variable depth distance D in a direction parallel to the optical axis _adj (e.g., greater than or equal to or less than a fixed offset distance H) from the reference projected position M of the optical axis on the photosensitive surface 200. Here, the reference projection position M may be considered as a central position of the lens field of view of the optical lens 10 in a desired projection area of the photosensitive surface 200.

That is, the reference projection position M is spaced apart from the optical axis by a fixed lateral offset distance H, and the rotation fulcrum P is spaced apart from the reference projection position M by a variable depth distance D _adj And (4) spacing.

Fig. 5 also shows a state where the oscillating mirror 310 is tilted at three different nominal tilt angles α 0 to α 2, and the intersection points of the oscillating mirror 310 with the optical axis when tilted at the nominal tilt angles α 0 to α 2 are respectively marked as R0 to R2. The lengths of the imaging optical paths from the optical module 100 to the reference projection position M via the intersection points R0, R1, and R2 are different from each other.

The angle PRjM ═ Rj ═ RjPM can be determined by a triangle (j is any positive integer of 0 to 2) imaginary with the intersection point Ri, the rotation fulcrum P, and the reference projection position M as vertices in fig. 5, and the distance MRj between the intersection point Rj and the reference projection position M and the variable depth distance D can be determined _adj Equality, from which it can be deduced that sin (180-2 x α j) is a fixed offset H and a variable depth D _adj So as to deduce that the calibrated inclination angles alpha 0-alpha 2 can all satisfy:

or

The nominal inclination angle alpha 0 corresponds to the variable depth distance D _adj In the case where the fixed offset distance H is equal, the right triangle formed with the line between the reference projection position M and the intersection point R0 as the hypotenuse may be an isosceles right triangle, and at this time,

and

the same and all 45 degrees, that is, the calibration inclination angle alpha 0 can be 45 degrees;

the nominal inclination angles alpha 1 and alpha 2 correspond to the variable depth distance D _adj Taking the case where the distance between the pivot point P and the reference projection position M is equal to the distance between the pivot point P and the intersection point R1, which is different from the case of the fixed yaw distance H, in the right-angled triangle formed with the connecting line between the reference projection position M and the intersection point R1 as the hypotenuse, the angle at the reference projection position M is twice the nominal inclination angle α 1, and therefore, the nominal inclination angle α 1 may be the same as the nominal inclination angle α 1

Similarly, the nominal inclination α 2 may be determined as a right triangle formed by the hypotenuse of the line connecting the reference projection position M and the intersection point R2

It can thus be considered that the nominal inclination in the set of inclinations comprises 45 °,

and

at least two of them.

Wherein the depth distance D is variable _adj Having at least two selectable distance values that vary in response to translation of the pivot of rotation of the oscillating mirror, by presetting the selectable distancesThe angle and the number of the calibration dip angles in the dip angle set can be determined according to the value and the number of the deviation values. Variable depth distance D _adj The position of the rotation fulcrum P is also shifted correspondingly in the direction parallel to the optical axis, depending on the distance value of (b).

For example, each additional optional distance, equal to the fixed offset distance H, can be increased to satisfy the requirement

And

a pair of calibrated inclinations.

I.e. variable depth distance D _adj When the distance is substituted into the different distance values,

and

different nominal tilt angles may be indicated.

In this way it is possible to obtain,

and

should be understood to include at least one tilt angle cluster that is a selectable distance different from the fixed offset distance H.

The switching of the tilting state of the oscillating mirror 310 between the nominal tilt angles set according to the above principle can be driven by the first magnetic attraction force between the first electromagnetic element 332a and the first permanent magnetic element 331 a.

The rotation fulcrum P is at a variable depth distance D _adj Between positions at which different selectable distance values are taken, there is a positional deviation in a direction parallel to the optical axis. Such positional deviation may be produced in response to translation of the translation support 312. Moreover, the translation of the translation bracket 312 can be performed by one of the second electromagnetic element 332b and the second permanent magnetic element 331bIs driven by the second magnetic attraction force.

The second example shown in fig. 5 may provide more selectable nominal tilt angles (i.e., nominal poses) while ensuring consistency than the way in which the projected positions of the variable imaging beam paths on the photosensitive surface 200 are consistent as shown in fig. 4b in the first example.

Fig. 6 is a schematic diagram of a first expanded structure of the image distance adjusting device shown in fig. 2. Referring to fig. 6, if the adjusting mechanism 33 uses a non-contact constraining force to constrain the pose of the reflecting mechanism 31, considering that the non-contact constraint is easily interfered by an uncertain factor and is misaligned, the pose constraint effect can be verified, and closed-loop feedback compensation can be performed based on the verification result, in this case, on the basis of the structure shown in fig. 2, the image distance adjusting apparatus may further include a verifying mechanism 34 for detecting the actual pose (for example, the actual tilt angle) of the reflecting mechanism 31 under the constraint of the adjusting mechanism 33. For example, the verification mechanism 34 can perform non-contact detection on the actual posture of the reflection mechanism 31 under the constraint of the adjustment mechanism 33.

The actual pose detected by the verification mechanism 34 may be fed back to the control module 32, so that, when the pose deviation of the actual pose of the reflection mechanism 31 from the calibrated pose selected by the control module 32 exceeds a predetermined deviation threshold (e.g., the angle deviation between the actual tilt angle and the selected calibrated tilt angle exceeds a predetermined angle threshold), the control module 32 may be further configured to control the adjustment mechanism 33 to perform pose compensation that tends to reduce the pose deviation (e.g., by adjusting the coil energization current of the first solenoid 332a, or adjusting the coil energization currents of the first solenoid 332a and the second solenoid 332b at the same time).

Fig. 7 is a schematic structural diagram of an example of the checking mechanism in the first extended structure shown in fig. 6. Referring to fig. 7, when the checking mechanism 34 performs non-contact detection on the actual posture of the reflecting mechanism 31 under the constraint of the adjusting mechanism 33, the checking mechanism 34 may include:

a laser transmitter 341 for transmitting laser light to the reflection mechanism 31;

a sensor array 342 for receiving the laser light reflected back from the reflection mechanism 31;

wherein, the control module 32 can further determine the actual pose of the reflecting mechanism 31 under the constraint of the adjusting mechanism 33 according to the sensing position of the retro-reflected laser on the sensor array 342.

Fig. 8 is a schematic diagram of a second expanded structure of the image distance adjusting device shown in fig. 2. Referring to fig. 8, if the pixel adjusting device needs to integrate the function of detecting the actual object distance, the image distance adjusting device may further include a distance measuring module 35 for detecting the actual object distance of the shooting target relative to the optical module 100 based on the structure shown in fig. 2. And, the actual object distance detected by the distance measuring module 35 can be fed back to the control module 32.

Alternatively, the distance measurement module 35 may detect the actual object distance by non-contact detection. For example, the ranging module 35 may implement detection of the actual object distance based on Time of flight (TOF).

The ranging module 35 that detects the actual object distance based on TOF may include a TOF controller, a light pulse emitter and a TOF sensor. Wherein:

the optical pulse transmitter may transmit an optical pulse in response to a trigger of the TOF control;

the TOF sensor can sense a returned reflected wave of the light pulse after reaching the shooting target;

the TOF controller can measure the converted distance of the shooting target with respect to the TOF optical path of the ranging module 35 according to the time of flight from the emission of the light pulse to the reception of the reflected wave and the propagation speed of the reflected wave.

When the distance measuring module 35 is mounted on the optical lens 10, and the optical pulse transmitter and the TOF sensor are arranged at positions aligned with the optical module 100 in the optical axis direction, the converted distance of the photographing target with respect to the TOF optical path of the distance measuring module 35 may be equal to or approximately equal to the actual object distance. At this time, the control module 32 may determine the actual object distance of the shooting target relative to the optical module 100 according to the TOF optical path converted distance fed back by the TOF controller in the ranging module 35.

Fig. 9 is a schematic diagram of a third expanded structure of the image distance adjusting device shown in fig. 2. Referring to fig. 9, as a preferred combination, the image distance adjusting apparatus may further include a verification mechanism 34 and a distance measuring module 35 on the basis of the structure shown in fig. 2.

Fig. 10 is a schematic diagram of an exemplary structure of a logistics code reading system using the optical imaging device shown in fig. 1. Referring to fig. 10, in this embodiment, a logistics code reading system may include a material conveying mechanism 50, and an optical imaging device 60 (which may be used as a code reading camera) having a structure as shown in fig. 1, wherein a lens field of view of an optical lens 10 of the optical imaging device 60 covers at least a portion of a conveying range of the material conveying mechanism 50. In fig. 10, the optical imaging device 60 includes the distance measuring module 35 as an example, but it is understood that the distance measuring module 35 may be replaced by an auxiliary detection device independent from the optical imaging device 60. As can be seen from fig. 10, when the material conveying mechanism 50 continuously conveys a plurality of materials (e.g., packages) 500, each material 500 is sequentially photographed and imaged by the optical imaging device 60 as a photographic target. Since the actual object distance of each object 500 is uncertain when it is photographed, the image distance can be adjusted to an image distance suitable for the current actual object distance in time by adjusting the image distance.

Fig. 11 is an exemplary structural diagram of an image distance adjusting method for optical imaging in another embodiment. Referring to fig. 11, in this embodiment, an image distance adjusting method for optical imaging may include:

s1110: determining an expected image distance according to the focal length of the optical module and the actual object distance of the shooting target relative to the optical module;

s1120: selecting a calibration pose for the reflecting mechanism according to the expected image distance;

s1130: and controlling the adjusting mechanism to restrict the reflecting mechanism at the selected calibration pose according to the selected calibration pose, so that the reflecting mechanism forms a reflecting light path which is continuous with the straight-through light path between the straight-through light path of the optical module and the photosensitive surface of the imaging element positioned outside the straight-through light path at the selected calibration pose.

And based on the reflection optical path formed by the reflection mechanism in the calibration pose selected in S1120, the image definition obtained under the imaging conditions of the focal length of the optical module and the actual object distance of the shooting target relative to the optical module is not lower than the preset expected definition.

When the calibration pose is selected, S1120 may select one calibration pose for the reflection mechanism from at least two calibration poses in a lookup table according to a preset correspondence between the expected image distance and the calibration pose. Alternatively, when the optical imaging apparatus supports manual adjustment, the image distance adjustment method in this embodiment may further include the step of recording manual adjustment records for different actual object distances, and S1120 may query, as the selected calibration pose, one of the at least two calibration poses that is closest to the historical pose in the manual adjustment records, based on the manual adjustment records that fall within the same object distance interval as the current actual object distance.

Based on the above flow, the path length of the variable imaging optical path equivalent to the image distance can be adjusted by switching the calibration pose where the reflection mechanism is located, and the position of the optical module and the position of the photosensitive surface of the imaging element do not need to be adjusted.

Fig. 12 is a schematic view of an optimization flow of the image distance adjusting method shown in fig. 11. In order to avoid wear caused by contact mechanical transmission, and further reduction of adjustment precision and accelerated service life attenuation caused by the wear, the adjusting structure can implement non-contact constraint on the reflecting mechanism. In order to support non-contact constraint on the reflection mechanism, referring to fig. 12, the image distance adjustment method in this embodiment may be modified to include the following steps:

s1210: determining an expected image distance according to the focal length of the optical module and the actual object distance of the shooting target relative to the optical module;

s1220: selecting a calibration pose for the reflecting mechanism according to the expected image distance;

s1230: and controlling the adjusting mechanism to generate variable non-contact constraint force according to the selected calibration pose, so that the adjusting mechanism utilizes the variable non-contact constraint force to constrain the reflecting mechanism at the selected calibration pose, and forming a reflecting light path which is continuous with the straight light path between the straight light path of the optical module and the photosensitive surface of the imaging element which is positioned outside the straight light path at the selected calibration pose.

Where S1230 may be regarded as an extension of S1130 shown in fig. 11.

Based on the reflection light path formed by the reflection mechanism in the calibration pose selected in S1220, the image definition obtained under the imaging conditions of the focal length of the optical module and the actual object distance of the photographic target relative to the optical module is not lower than the preset expected definition. The manner of selecting the calibration pose in S1220 may be substantially the same as S1120 shown in fig. 11.

Fig. 13 is a flowchart illustrating an example of the image distance adjusting method shown in fig. 11. If magnetic attraction is selected as the non-contact constraint force, referring to fig. 13, an example process of performing non-contact pose constraint on the reflection mechanism may include:

s1310: and determining the expected image distance according to the focal length of the optical module and the actual object distance of the shooting target relative to the optical module.

S1320: selecting a calibration inclination angle from the inclination angle set according to the expected image distance; when the swing mirror in the reflecting mechanism is in the selected calibration pose, the swing mirror is inclined relative to the optical axis of the optical module by the selected calibration inclination angle.

Therein, S1320 may be regarded as an extension of S1220 as shown in fig. 12.

S1330: and controlling the coil electrifying current of a magnetic component in the adjusting mechanism, wherein the magnetic component generates variable magnetic attraction force on the reflecting mechanism in response to the change of the coil electrifying current, so that the adjusting mechanism restrains the reflecting mechanism at the selected calibration pose by using the variable non-contact restraining force, and a reflecting light path which is continuous with the straight light path is formed between the straight light path of the optical module and the light sensing surface of the imaging element outside the straight light path at the selected calibration pose.

Therein, S1330 can be regarded as an extension of S1230 as shown in fig. 12.

In the above example process of representing the calibration pose by the calibration tilt angle, S1320 may select one calibration tilt angle for the reflection mechanism from at least two calibration tilt angles in a lookup table according to the preset corresponding relationship between the expected image distance and the calibration tilt angle. Alternatively, when the optical imaging apparatus supports manual adjustment, the example process may further include the step of recording manual adjustment records for different actual object distances, and S1320 may query, as the selected calibration tilt, one of the at least two calibration poses that is closest to the historical tilt in the manual adjustment records, based on the manual adjustment records that fall within the same object distance interval as the current actual object distance.

In addition, in S1330, the coil current of the

magnetic attraction assembly

331 or 332 may be controlled according to the preset corresponding relationship between the calibration inclination angle and the current value.

If the example process is applied to the first example shown in fig. 4a and 4b, S1330 may specifically include:

controlling the coil electrifying current of a first electromagnetic element in the adjusting mechanism according to the selected calibration pose so as to drive a swing mirror in the reflecting mechanism to incline relative to an optical axis of the optical module at the selected calibration inclination angle by utilizing a first magnetic attraction force between the first electromagnetic element and a first permanent magnetic element;

one of the first permanent magnetic element and the first electromagnetic element is arranged on a swing mirror of the reflecting mechanism, the other one of the first permanent magnetic element and the first electromagnetic element is arranged on a fixed support of the reflecting mechanism and is arranged in a swing path of the swing mirror, and a rotating fulcrum of the swing mirror is a fixed fulcrum arranged on the fixed support.

If the example process is applied to the second example shown in fig. 5, S1330 may specifically include:

controlling coil electrifying currents of a first electromagnetic element and a second electromagnetic element in the adjusting mechanism according to the selected calibration pose so as to drive a swing mirror in the reflecting mechanism to incline relative to an optical axis of the optical module at the selected calibration inclination angle by utilizing a first magnetic attraction force between the first electromagnetic element and the first permanent magnetic element and a second magnetic attraction force between the second electromagnetic element and the second permanent magnetic element;

the first permanent magnetic element and the second electromagnetic element are arranged on the translation bracket, the other permanent magnetic element and the second electromagnetic element are separated from the translation bracket and are arranged in the moving path of the translation bracket, the rotating fulcrum of the swing mirror is a movable fulcrum arranged on the translation bracket, and the moving direction of the translation bracket is parallel to the optical axis.

Fig. 14 is an expanded flow diagram illustrating the self-checking mechanism introduced in the image distance adjusting method shown in fig. 11. Referring to fig. 14, when the position and orientation constraint of the reflection mechanism is checked, the image distance adjusting method in this embodiment may include:

s1410: and determining the expected image distance according to the focal length of the optical module and the actual object distance of the shooting target relative to the optical module.

S1420: and selecting a calibration pose for the reflecting mechanism according to the expected image distance.

S1430: and according to the selected calibration pose, controlling the adjusting mechanism to restrict the reflecting mechanism to the selected calibration pose, so that the reflecting mechanism forms a reflecting light path which is continuous with the straight-through light path between the straight-through light path of the optical module and the photosensitive surface of the imaging element positioned outside the straight-through light path at the selected calibration pose.

S1440: and acquiring the actual pose of the reflecting mechanism detected by the checking mechanism under the constraint of the adjusting mechanism.

For example, for the example configuration shown in fig. 7, S1440 may determine the actual pose of the reflecting mechanism under the constraint of the adjustment mechanism based on the sensed position of the sensor array in the verification mechanism on the laser light retroreflected from the reflecting mechanism emitted by the laser emitter of the verification mechanism.

S1450: and when the pose deviation between the actual pose of the reflecting mechanism and the selected calibration pose exceeds a preset deviation threshold value, controlling the adjusting mechanism to execute pose compensation with pose deviation reduction as a trend.

For example, when the magnetic attraction force is adjusted by the coil current of the magnetic attraction assembly in the adjustment mechanism, S1450 may control and compensate the coil current of the magnetic attraction assembly in the adjustment mechanism.

Fig. 15 is an expanded flow diagram illustrating the self-ranging mechanism introduced in the image distance adjusting method shown in fig. 11. Referring to fig. 15, when a distance measurement mechanism for a shooting target is introduced, the image distance adjusting method in this embodiment may include:

s1500: and acquiring the actual object distance of the shooting target detected by the distance measurement module relative to the optical module.

For example, when the distance measurement module detects the actual object distance based on the TOF, S1500 may determine the actual object distance of the shooting target relative to the optical module according to the converted distance of the TOF optical path measured by the distance measurement module based on the TOF.

S1510: and determining the expected image distance according to the focal length of the optical module and the actual object distance of the shooting target relative to the optical module.

S1520: and selecting a calibration pose for the reflecting mechanism according to the expected image distance.

S1530: and according to the selected calibration pose, controlling the adjusting mechanism to restrict the reflecting mechanism to the selected calibration pose, so that the reflecting mechanism forms a reflecting light path which is continuous with the straight-through light path between the straight-through light path of the optical module and the photosensitive surface of the imaging element positioned outside the straight-through light path at the selected calibration pose.

In addition, it is understood that:

the steps in the extended flow as shown in fig. 14 or fig. 15 may be embodied as corresponding steps in the optimization flow as shown in fig. 12 or the example flow as shown in fig. 13; and the number of the first and second electrodes,

the extended flows shown in fig. 14 and fig. 15 may be integrated into one flow, for example, S1500 in the flow shown in fig. 15 is added before S1410 in the flow shown in fig. 14, or S1440 to S1450 in the flow shown in fig. 14 is added after S1530 in the flow shown in fig. 15.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. An image distance adjusting apparatus for optical imaging, comprising:

2. The image distance adjusting apparatus according to claim 1,

the reflecting mechanism comprises a swing mirror, the swing mirror inclines relative to the optical axis of the optical module at a calibration inclination angle selected from the inclination angle set, so that the calibration pose of the reflecting mechanism is formed by utilizing the inclined pose at the selected calibration inclination angle;

the adjusting mechanism comprises magnetic attraction components which are arranged in pairs and used for generating variable magnetic attraction force which forms pose constraint on the reflecting mechanism between the magnetic attraction components, and the variable magnetic attraction force changes in response to the change of the coil electrifying current;

the control module further realizes the selection of the calibration pose by selecting the calibration inclination angle from the inclination angle set, and controls the coil electrifying current of the magnetic attraction component according to the selected calibration inclination angle.

3. The image distance adjusting apparatus according to claim 2,

the rotating fulcrum of the swing mirror is a fixed fulcrum arranged on the fixed bracket;

the adjusting mechanism comprises a first permanent magnetic element and a first electromagnetic element, wherein one of the first permanent magnetic element and the first electromagnetic element is arranged on the swing mirror, and the other one of the first permanent magnetic element and the first electromagnetic element is arranged on the fixing support and is arranged in a swing path of the swing mirror;

the control module is further used for controlling the coil electrifying current of the first electromagnetic element according to the selected calibration inclination angle so as to drive the swing mirror to incline relative to the optical axis of the optical module at the selected calibration inclination angle by utilizing the first magnetic attraction force between the first electromagnetic element and the first permanent magnetic element.

4. The image distance adjusting apparatus according to claim 3,

the light sensing surface of the imaging element is arranged in parallel to the optical axis of the optical module, and deviates from the optical axis by a fixed offset distance H in the direction perpendicular to the optical axis;

the rotating fulcrum of the oscillating mirror is arranged flush with the photosensitive surface of the imaging element in the direction vertical to the optical axis, and the rotating fulcrum of the oscillating mirror deviates from the reference projection position of the optical axis on the photosensitive surface by a fixed depth distance D in the direction parallel to the optical axis;

the calibrated dip in the dip set comprises: in a manner that

And

at least two tilt angles within an angular tolerance range for the reference.

5. The image distance adjusting apparatus according to claim 2,

the rotating fulcrum of the oscillating mirror is a movable fulcrum arranged on the translation bracket, wherein the moving direction of the translation bracket is parallel to the optical axis;

the adjustment mechanism comprises a first permanent magnet element and a first electromagnetic element, and a second permanent magnet element, wherein: one of the first permanent magnetic element and the first electromagnetic element is arranged on the swing mirror, and the other one of the first permanent magnetic element and the first electromagnetic element is arranged on the translation bracket and is arranged in a swing path of the swing mirror; one of the second permanent magnetic element and the second electromagnetic element is arranged on the translation bracket, and the other permanent magnetic element is separated from the translation bracket and is arranged in the moving path of the translation bracket;

the control module is further used for controlling the coil electrifying currents of the first electromagnetic element and the second electromagnetic element according to the selected calibration inclination angle so as to drive the swing mirror to incline relative to the optical axis of the optical module at the selected calibration inclination angle by utilizing the first magnetic attraction between the first electromagnetic element and the first permanent magnetic element and the second magnetic attraction between the second electromagnetic element and the second permanent magnetic element.

6. The image distance adjusting apparatus according to claim 5,

the photosensitive surface of the imaging element is arranged in parallel to the optical axis of the optical module, and deviates from the optical axis by a fixed offset distance H in the direction vertical to the optical axis;

the rotation fulcrum of the oscillating mirror is arranged flush with the photosensitive surface of the imaging element in the direction perpendicular to the optical axis, and the rotation fulcrum of the oscillating mirror is arranged at a variable depth distance D in the direction parallel to the optical axis _adj A reference projection position on the photosensitive surface deviated from the optical axis;

the nominal inclination angles in the inclination angle set comprise 45 degrees,

And

wherein the variable depth distance D _adj There are at least two selectable distance values that vary in response to translation of the pivot point of rotation of the oscillating mirror.

7. The image distance adjusting apparatus according to claim 1, further comprising:

the calibration mechanism is used for detecting the actual pose of the reflection mechanism under the constraint of the adjustment mechanism;

when the pose deviation between the actual pose of the reflecting mechanism and the selected calibration pose exceeds a preset deviation threshold value, the control module is further used for controlling the adjusting mechanism to execute pose compensation with the pose deviation trend reduced.

8. The image distance adjusting apparatus according to claim 7, wherein the verification mechanism comprises:

a laser transmitter for transmitting laser to the reflection mechanism;

a sensor array for receiving the laser light retro-reflected from the reflecting mechanism;

and the control module further determines the actual pose of the reflecting mechanism under the constraint of the adjusting mechanism according to the sensing position of the retro-reflected laser on the sensor array.

9. The image distance adjusting apparatus according to claim 1, further comprising:

and the distance measurement module is used for detecting the actual object distance of the shooting target relative to the optical module.

10. An optical imaging apparatus comprising an optical lens having an optical module, an imaging element having a photosensitive surface, and the image distance adjusting apparatus according to any one of claims 1 to 9.

11. A logistics code reading system, comprising a material conveying mechanism, and the optical imaging device according to claim 10, wherein the lens field of view of the optical lens covers at least a part of the conveying range of the material conveying mechanism.

12. An image distance adjusting method for optical imaging, comprising:

controlling the adjusting mechanism to generate variable non-contact constraint force according to the selected calibration pose so that the adjusting mechanism utilizes the variable non-contact constraint force to constrain the reflecting mechanism at the selected calibration pose, and the reflecting mechanism forms a reflecting light path which is continuous with the straight light path between the straight light path of the optical module and the photosensitive surface of the imaging element which is positioned outside the straight light path at the selected calibration pose;

13. The image distance adjusting method according to claim 12,

the reflection mechanism comprises the following components according to the expected image distance: selecting a calibration inclination angle from the inclination angle set according to the expected image distance; when the swing mirror in the reflecting mechanism is in the selected calibration pose, the swing mirror inclines relative to the optical axis of the optical module by the selected calibration inclination angle;

controlling the adjustment mechanism to produce the variable non-contact binding force comprises: and controlling the coil electrifying current of a magnetic component in the adjusting mechanism, wherein the magnetic component responds to the change of the coil electrifying current to generate variable magnetic attraction force on the reflecting mechanism.

14. The image distance adjusting method according to claim 13, wherein controlling the coil current of the magnetic attraction assembly in the adjusting mechanism comprises:

controlling the coil electrifying current of a first electromagnetic element in the adjusting mechanism according to the selected calibration inclination angle so as to drive a swing mirror in the reflecting mechanism to incline relative to the optical axis of the optical module at the selected calibration inclination angle by utilizing a first magnetic attraction force between the first electromagnetic element and a first permanent magnetic element;

15. The image distance adjusting method according to claim 13, wherein controlling the coil current of the magnetic attraction assembly in the adjusting mechanism comprises:

according to the coil electrifying current of the first electromagnetic element and the second electromagnetic element in the selected calibration position inclination angle system adjusting mechanism, driving a swing mirror in the reflecting mechanism to incline relative to the optical axis of the optical module at the selected calibration inclination angle by utilizing the first magnetic attraction between the first electromagnetic element and the first permanent magnetic element and the second magnetic attraction between the second electromagnetic element and the second permanent magnetic element;

one of the first permanent magnetic element and the first electromagnetic element is arranged on a swing mirror of the reflecting mechanism, the other one of the first permanent magnetic element and the first electromagnetic element is arranged on a translation bracket of the reflecting mechanism and is arranged in a swing path of the swing mirror, one of the second permanent magnetic element and the second electromagnetic element is arranged on the translation bracket, the other one of the second permanent magnetic element and the second electromagnetic element is separated from the translation bracket and is arranged in a moving path of the translation bracket, a rotating fulcrum of the swing mirror is a movable fulcrum arranged on the translation bracket, and the moving direction of the translation bracket is parallel to an optical axis.

16. The image distance adjusting method according to claim 12, further comprising:

acquiring the actual pose of the reflecting mechanism detected by the checking mechanism under the constraint of the adjusting mechanism;

and when the pose deviation between the actual pose of the reflecting mechanism and the selected calibration pose exceeds a preset deviation threshold value, controlling the adjusting mechanism to execute pose compensation with pose deviation reduction as a trend.

17. The image distance adjusting method according to claim 12, wherein acquiring the actual pose of the reflection mechanism detected by the verification mechanism under the constraint of the adjustment mechanism comprises:

and determining the actual position of the reflecting mechanism under the constraint of the adjusting mechanism according to the sensing position of the sensor array in the checking mechanism on the laser reflected from the reflecting mechanism, wherein the laser reflected from the reflecting mechanism is emitted by the laser emitter of the checking mechanism.

18. The image distance adjusting method according to claim 12, further comprising:

and acquiring the actual object distance of the shooting target detected by the distance measurement module relative to the optical module.