Projector TMR motor focusing method and projector

Abstract

The invention relates to a projector TMR motor focusing method and a projector, and the method comprises the steps: placing the projector at a position corresponding to a calibration distance, controlling a motor to move from an initial position to a right boundary position, and then starting to move leftwards from the right boundary; taking the motor position corresponding to the peak value of the projection definition corresponding to each motor position in the leftward movement process as a calibration position corresponding to the calibration distance, and controlling the motor to return to the calibration position; controlling the motor to move rightward and rightward from the calibration position, and storing a corresponding relation between the position of the motor and the projection distance after each movement; forming a calibration table by corresponding relations between all motor positions and projection distances; and acquiring the current actual projection distance of the projector, searching the corresponding motor position from the calibration table according to the projection distance, and controlling the motor to move to the position. According to the invention, rapid focusing of the projector based on the TMR motor is realized.

Description

Technical Field

[0001] The present invention relates to the field of projection technology, and in particular to a focusing method for a TMR motor of a projector and a projector. Background Art

[0002] With the development of projection technology, projection has gradually become a widely used multimedia display means. However, in actual use, whether the projection image is clear depends on the focusing alignment and control methods, and there are also requirements for the overall temperature rise control and scheme selection. However, for portable small-sized projectors, it is very difficult to control the temperature. Therefore, there is an urgent need for a focusing scheme with less influence from temperature. In this focusing scheme, the focusing position will not be affected by the temperature change causing the motor position change. On the one hand, it is necessary to exclude the temperature influence as much as possible, and on the other hand, it is necessary to ensure that the position movement is fixed.

[0003] Using a motor with a feedback signal can accurately provide the motor position, and the TMR (Tunnel MagnetoResistance) series motors are a good choice. Compared with the previous method of judging the position by an optocoupler, in small-sized portable projections, it has always been very difficult to control the heat dissipation. The position of the optocoupler will change due to the different operating temperatures inside the projector, which will affect the motor position movement and cause changes during calibration. Therefore, choosing a TMR motor from the scheme is a prerequisite for ensuring clear pure tof focusing. However, in the calibration and control of the TMR motor, due to the lack of the feedback starting point and ending point of the optocoupler, it is easy to cause the problem that the motor reaches the limit and gets stuck during manual calibration. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a focusing method for a TMR motor of a projector and a projector.

[0005] The specific solutions are as follows:

[0006] A focusing method for a TMR motor of a projector includes a TMR motor calibration process and a TMR motor focusing process;

[0007] (1) TMR motor calibration process;

[0008] S1: After placing the projector at the position corresponding to the calibration distance, initialize the direction of the TMR motor in the projector;

[0009] S2: Control the TMR motor to move from the initial position to the preset right boundary position, and then control the TMR motor to move left from the right boundary. Determine the clarity peak value based on the clarity of the projection images corresponding to different motor positions during the leftward movement, and use the motor position corresponding to the clarity peak value as the target position;

[0010] S3: Store the obtained target position as the calibration position corresponding to the calibrated distance, and control the TMR motor to return to the calibration position;

[0011] S4: Control the TMR motor to move right from the calibration position. After each movement, calculate the corresponding projection distance based on the number of movement steps relative to the calibration position after the movement, and store the correspondence between the motor position after the movement and the projection distance; return to the calibration position after moving N steps to the right;

[0012] S5: Control the TMR motor to move left from the calibration position. After each movement, calculate the corresponding projection distance based on the number of movement steps relative to the calibration position after the movement, and store the correspondence between the motor position after the movement and the projection distance; return to the calibration position after moving M steps to the left;

[0013] S6: Compose the correspondence between all motor positions and projection distances into a calibration table;

[0014] (2) TMR motor focusing process;

[0015] Obtain the current actual projection distance of the projector, look up the corresponding motor position from the calibration table according to this projection distance, and control the motor to move to this position.

[0016] Further, the method for initializing the direction of the TMR motor in the projector is: set the direction of the TMR motor to the positive direction.

[0017] Further, before initializing the direction of the TMR motor in the projector, it also includes: obtaining the actual projection distance through a distance sensor, and calculating whether the difference between the actual projection distance and the calibrated distance is within the set error range. If so, continue with the subsequent steps; otherwise, reset the position of the projector until it meets the requirements within the error range.

[0018] Further, in step S2, the following steps are executed during the leftward movement:

[0019] S201: Take a photo after each movement, obtain the clarity of the photo image, and write the current motor position and clarity into the mapping table for storing the correspondence between the motor position and the clarity in sequence;

[0020] S202: Determine whether there are two consecutive decreases in clarity in the current mapping table. If so, enter S203; otherwise, enter S204;

[0021] S203: Extract the 5 most recently written sharpness levels in the mapping table, and determine whether the difference between the maximum and minimum values of these 5 sharpness levels is less than the set first difference threshold. If so, proceed to S204; otherwise, based on these 5 sharpness levels, perform curve fitting with the motor position as the abscissa and the sharpness level as the ordinate, and use the abscissa value corresponding to the peak position in the fitted curve as the target position, then proceed to S3.

[0022] S204: Determine whether the difference between the current motor position and the preset left boundary position is less than the second difference threshold. If so, end and return a calibration anomaly; otherwise, control the TMR motor to move left once, and then return to S201.

[0023] Further, after the step S3 controls the TMR motor to return to the calibration position, it also includes: taking a photo at the calibration position, obtaining the sharpness level of the photo, and determining whether the sharpness level meets the requirements. If so, continue with the subsequent steps; otherwise, end and return a calibration anomaly.

[0024] Further, the method for determining that the TMR motor returns to the calibration position is: the difference between the current motor position and the calibration position is less than the third difference threshold.

[0025] Further, it also includes calculating the left turning deadband steps and the right turning deadband steps of the TMR motor; when performing focusing, first determine whether there is a left turn or a right turn. If so, first move the corresponding left turning deadband steps or right turning deadband steps, and then move towards the found motor position.

[0026] The calculation method for the left turning deadband steps is: when step S4 returns to the calibration position after moving N steps to the right, count the number of steps N1 to return to the calibration position, and set the difference between N1 and N as the left turning deadband steps.

[0027] The calculation method for the right turning deadband steps is: when step S5 returns to the calibration position after moving M steps to the left, count the number of steps M1 to return to the calibration position, and set the difference between M1 and M as the left turning deadband steps.

[0028] Further, all the motor positions in the calibration table are arranged in order from left to right, and interpolation processing is performed between each motor position.

[0029] Further, after step S6, it also includes setting the left limit value and the right limit value of the motor position according to the maximum and minimum values of the motor positions corresponding to the calibration table, where the left limit value is less than the minimum value of the motor position, and the right limit value is greater than the maximum value of the motor position; controlling the motor to move and determining whether it can move to the positions corresponding to the left limit value and the right limit value. If so, it is determined that the calibration is qualified; otherwise, it is determined that the calibration is unqualified.

[0030] A projector includes a TMR motor, a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method described above in the embodiments of the present invention are implemented.

[0031] With the above technical solution, the present invention realizes fast focusing of the projector based on the TMR motor. Description of the Drawings

[0032] Figure 1 The flowchart of the TMR motor calibration process in the first embodiment of the present invention is shown. Detailed Embodiments

[0033] To further illustrate the embodiments, the present invention provides drawings. These drawings are a part of the disclosure of the present invention, mainly used to illustrate the embodiments, and can be combined with the relevant descriptions in the specification to explain the operating principle of the embodiments. With reference to these contents, those of ordinary skill in the art should be able to understand other possible embodiments and the advantages of the present invention.

[0034] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0035] Embodiment 1:

[0036] The embodiment of the present invention provides a method for focusing the TMR motor of a projector, including a TMR motor calibration process and a TMR motor focusing process.

[0037] (1) TMR motor calibration process (as Figure 1 shown)

[0038] S1: After placing the projector at the position corresponding to the calibration distance, initialize the direction of the TMR motor in the projector.

[0039] The distance value is the distance between the optical lens of the projector and the screen or wall to be projected. In this embodiment, the calibration is set to 1 meter, and in other embodiments, it can also be set to other values, which will not be limited here.

[0040] Before initializing the direction of the TMR motor in the projector in this embodiment, it further includes: obtaining the actual projection distance through a distance sensor (TOF), and calculating whether the difference between the actual projection distance and the calibration distance is within the set error range (set to plus or minus 50 millimeters in this embodiment). If so, continue with the subsequent steps; otherwise, reset the position of the projector until it meets the error range.

[0041] The direction of the TMR motor is its magnetic direction, including positive or negative. When it is positive, the value increases when the motor moves to the right and decreases when it moves to the left; when it is negative, the value decreases when the motor moves to the right and increases when it moves to the left. The way to initialize the direction of the TMR motor in this embodiment is: set the direction of the TMR motor to positive.

[0042] S2: After controlling the TMR motor to move from the initial position to the preset right boundary position, then control the TMR motor to move left from the right boundary, determine the clarity peak value based on the clarity of the projection image corresponding to different motor positions during the leftward movement, and use the motor position corresponding to the clarity peak value as the target position.

[0043] In one implementation, the following steps are performed during the leftward movement:

[0044] S201: Take a photo after each movement (in this embodiment, it is achieved by controlling an industrial camera to take a photo of the projection screen or the projection wall), and obtain the clarity of the photo image (achieved by an existing clarity calculation algorithm), and write the current motor position and clarity in sequence (that is, according to the leftward movement order, the first leftward movement is written in the first row, the second leftward movement is written in the second row, and so on) into the mapping table for storing the correspondence between the motor position and the clarity.

[0045] The first row in the mapping table records the motor position and the clarity of the captured image after the first leftward movement, the second row records the motor position and the clarity of the captured image after the second leftward movement, and so on.

[0046] S202: Determine whether there is a situation where the clarity decreases continuously twice in the current mapping table. If so, enter S203; otherwise, enter S204.

[0047] A decrease in clarity means that the clarity is smaller than the clarity written last time. The situation of continuous decrease in clarity twice is like the clarity in the nth row is less than the clarity in the n - 1th row, and the clarity in the n - 1th row is less than the clarity in the n - 2th row, where n represents the current number of leftward movements.

[0048] S203: Extract the 5 most recently (newest) written clarities in the mapping table (that is, the (n - 4)th row to the nth row), and determine whether the difference between the maximum value and the minimum value of these 5 clarities is less than the set first difference threshold (set to 0.5 in this embodiment). If so, enter S204; otherwise, based on these 5 clarities, perform curve fitting with the motor position (recorded by the variable tmr_adc in this embodiment) as the abscissa and the clarity as the ordinate, and use the abscissa value corresponding to the peak (wave peak) position in the fitting curve as the target position, and enter S3.

[0049] S204: Determine whether the difference between the current motor position and the preset left boundary position is less than the second difference threshold (set to the step size of the TMR motor in this embodiment). If so, end and return calibration anomaly; otherwise, control the TMR motor to move left once, and return to S201.

[0050] To improve efficiency, in this embodiment, setting the above-mentioned one-time left movement to two steps to the left.

[0051] The left boundary position and the right boundary position are set according to empirical values, that is, the peak value calculated later should be between these two positions. In this embodiment, the right boundary position is set to the position five steps to the right from the initial position; the left marker position is set to the position of the initial position - 100.

[0052] In another embodiment, the operation of determining the clarity peak based on the clarity of the projection images corresponding to different motor positions during the left movement can be judged by the human eye, that is, continuously judge the clarity of the projection image after movement by the human eye during the left movement, and record the motor position at this time as the target position when observing the appearance of the peak.

[0053] S3: Store the obtained target position as the calibration position corresponding to the calibration distance, and control the TMR motor to return to the calibration position.

[0054] Since the clearest positions at different projection distances are different, therefore, this embodiment further includes finding the motor positions corresponding to the clear points at different projection distances through subsequent steps according to the calibration position corresponding to the calibration distance.

[0055] After controlling the TMR motor to return to the calibration position in this embodiment, it further includes: taking a photo at the calibration position, obtaining the clarity of the photo image, and judging whether the clarity meets the requirements (judged manually or compared with the set clarity threshold). If so, continue with the subsequent steps; otherwise, end and return calibration anomaly (the clarity after calibration cannot meet the requirements).

[0056] The method for judging that the TMR motor returns to the calibration position in this embodiment is: the difference between the current motor position (tmr_adc) and the calibration position is less than the third difference threshold (set to 6 in this embodiment).

[0057] S4: Control the TMR motor to move right from the calibration position. After each movement, calculate the corresponding projection distance based on the number of movement steps relative to the calibration position after movement, and store the corresponding relationship between the motor position after movement and the projection distance; return to the calibration position after moving N steps to the right.

[0058] S5: Control the TMR motor to move leftward from the calibration position. After each movement, calculate the corresponding projection distance based on the number of movement steps relative to the calibration position after the movement, and store the corresponding relationship between the motor position after the movement and the projection distance; return to the calibration position after moving leftward by M steps.

[0059] S6: Compose the corresponding relationships between all motor positions and projection distances into a calibration table.

[0060] In this embodiment, combined with the characteristics of the TMR motor, when moving rightward, the corresponding projection distance is relatively small, and when moving leftward, the corresponding projection distance increases. Set N = 10 and M = 2. After each rightward or leftward movement, record the corresponding tmr_adc value as the motor position. All motor positions in the calibration table are arranged in the order from left to right, and interpolation processing is performed between each motor position to expand the data volume and improve the accuracy of subsequent focusing.

[0061] This embodiment further includes left and right limit tests after step S6, that is, according to the maximum and minimum values of the motor positions corresponding to the calibration table, set the left limit value and right limit value of the motor position. Among them, the left limit value is less than the minimum value of the motor position (in this embodiment, it is the minimum value - 10), and the right limit value is greater than the maximum value of the motor position (in this embodiment, it is the maximum value + 40); control the motor to move and determine whether it can move to the positions corresponding to the left limit value and the right limit value. If so (both the left limit value and the right limit value can be moved to), it is determined that the calibration is qualified; otherwise, it is determined that the calibration is unqualified.

[0062] (2) TMR motor focusing process

[0063] Obtain the current actual projection distance of the projector through a distance sensor, find the corresponding motor position from the calibration table according to this projection distance, and control the motor to move to this position.

[0064] Furthermore, considering that when the motor changes direction, the direction change includes left turn (changing from moving rightward to moving leftward) and right turn (changing from moving leftward to moving rightward), and there will be a dead zone (i.e., idling) phenomenon in the TMR motor. Since focusing often requires turning, therefore, to improve the focusing speed, this embodiment also includes: calculating the left turn dead zone steps and right turn dead zone steps of the TMR motor; when focusing, first determine whether there is a left turn or a right turn. If so, first move the corresponding left turn dead zone steps or right turn dead zone steps, and then move to the found motor position.

[0065] The calculation method of the left turn dead zone steps is: when step S4 returns to the calibration position after moving rightward by N steps, count the number of steps N1 to return to the calibration position, and set the difference between N1 and N as the left turn dead zone steps.

[0066] The calculation method of the right turning dead band steps is as follows: When step S5 returns to the calibration position after moving left by M steps, count the number of steps M1 for returning to the calibration position, and set the difference between M1 and M as the left turning dead band steps.

[0067] Embodiment 2:

[0068] The present invention also provides a projector, including a TMR motor, a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above method embodiment of Embodiment 1 of the present invention are implemented.

[0069] Although the present invention is specifically shown and described in combination with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present invention in terms of form and details without departing from the spirit and scope of the present invention defined by the appended claims, and all of them are within the protection scope of the present invention.

Claims

1. A projector TMR motor focusing method, characterized in that: Including TMR motor calibration process and TMR motor focusing process; (1) TMR motor calibration process; S1: After placing the projector at a position corresponding to the calibration distance, the direction of the TMR motor in the projector is initialized; S2: After controlling the TMR motor to move from the initial position to the preset right boundary position, the TMR motor is then controlled to move leftward from the right boundary, and a clarity peak is determined based on the clarity of the projection image corresponding to different motor positions during the leftward movement, and the motor position corresponding to the clarity peak is used as the target position; S3: storing the target position as the calibration position corresponding to the calibration distance, and controlling the TMR motor to return to the calibration position; S4: Control the TMR motor to move rightward from the calibration position. After each movement, calculate the corresponding projection distance based on the number of movement steps relative to the calibration position after the movement, and store the corresponding relationship between the motor position after the movement and the projection distance; return to the calibration position after moving rightward N steps; S5: Control the TMR motor to move leftward from the calibration position, and after each movement, calculate the corresponding projection distance based on the number of movement steps relative to the calibration position after the movement, and store the corresponding relationship between the motor position after the movement and the projection distance; Move leftward M steps and then return to the calibration position; S6: forming a calibration table of the correspondence between all motor positions and projection distances; (2) TMR motor focusing process; The actual current projection distance of the projector is obtained, and the corresponding motor position is found from the calibration table according to the projection distance, and the motor is controlled to move to the position.

2. The projector TMR motor focusing method according to claim 1, characterized in that: The way to initialize the direction of the TMR motor in the projector is to set the direction of the TMR motor to the forward direction.

3. The projector TMR motor focusing method according to claim 1, characterized in that: Before initializing the direction of the TMR motor in the projector, it also includes: obtaining the actual projection distance through the distance sensor, and calculating whether the difference between the actual projection distance and the calibrated distance is within the set error range. If so, continue with the subsequent steps; otherwise, reset the position of the projector until it is within the error range.

4. The projector TMR motor focusing method according to claim 1, characterized in that: Step S2 performs the following steps in the process of moving to the left: S201: taking a photo after each movement, obtaining the definition of the photographed image, and sequentially writing the current motor position and definition into a mapping table for storing the corresponding relationship between the motor position and the definition; S202: Determine whether there are two consecutive cases of clarity reduction in the current mapping table. If yes, proceed to S203; otherwise, proceed to S204; S203: extract the five most recently written sharpnesses in the mapping table, and determine whether the difference between the maximum and minimum values ​​of the five sharpnesses is less than the set first difference threshold value. If yes, proceed to S204; otherwise, based on the five sharpnesses, curve fitting is performed with the motor position as the horizontal coordinate and the sharpness as the vertical coordinate, and the horizontal coordinate value corresponding to the peak position in the fitting curve is used as the target position, and proceed to S3; S204: Determine whether the difference between the current motor position and the preset left boundary position is less than a second difference threshold. If so, end and return to calibration exception; otherwise, control the TMR motor to move left once and return to S201.

5. The projector TMR motor focusing method according to claim 1, characterized in that: After controlling the TMR motor to return to the calibration position, step S3 also includes: taking a picture at the calibration position, obtaining the clarity of the photographed image, and judging whether the clarity meets the requirements. If so, continue with the subsequent steps; otherwise, end and return to the calibration exception.

6. The projector TMR motor focusing method according to claim 1, characterized in that: The method for determining whether the TMR motor returns to the calibration position is: the difference between the current motor position and the calibration position is less than the third difference threshold.

7. The projector TMR motor focusing method according to claim 1, characterized in that: It also includes calculating the number of left-turn idle steps and right-turn idle steps of the TMR motor; when focusing, first determine whether there is a left turn or a right turn, and if so, first move the corresponding left-turn idle steps or right-turn idle steps, and then move to the found motor position; The calculation method of the number of steps of the left turn idle stroke is as follows: in step S4, when returning to the calibration position after moving rightward N steps, the number of steps N1 of returning to the calibration position is counted, and the difference between N1 and N is set as the number of steps of the left turn idle stroke; The calculation method of the number of right turn idle steps is as follows: in step S5, when returning to the calibration position after moving M steps to the left, the number of steps M1 returning to the calibration position is counted, and the difference between M1 and M is set as the number of left turn idle steps.

8. The projector TMR motor focusing method according to claim 1, characterized in that: All motor positions in the calibration table are arranged in order from left to right, and interpolation is performed between each motor position.

9. The projector TMR motor focusing method according to claim 1, characterized in that: After step S6, the method also includes setting the left limit value and the right limit value of the motor position according to the maximum value and the minimum value of the motor position corresponding to the calibration table, wherein the left limit value is smaller than the minimum value of the motor position and the right limit value is larger than the maximum value of the motor position; controlling the motor to move and determining whether it can move to the positions corresponding to the left limit value and the right limit value, and if so, determining that the calibration is qualified; otherwise, determining that the calibration is unqualified.

10. A projector, characterized in that: The method comprises a TMR motor, a processor, a memory and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 9 when executing the computer program.

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