CN109120910B - Method for compensating focusing of projector lens based on temperature detection - Google Patents
Method for compensating focusing of projector lens based on temperature detection Download PDFInfo
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- CN109120910B CN109120910B CN201811257843.4A CN201811257843A CN109120910B CN 109120910 B CN109120910 B CN 109120910B CN 201811257843 A CN201811257843 A CN 201811257843A CN 109120910 B CN109120910 B CN 109120910B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3141—Constructional details thereof
- H04N9/317—Convergence or focusing systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3179—Video signal processing therefor
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3191—Testing thereof
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- Transforming Electric Information Into Light Information (AREA)
- Automatic Focus Adjustment (AREA)
- Projection Apparatus (AREA)
Abstract
The invention discloses a method for compensating the focus of a projector lens based on temperature detection, which comprises the following steps: A. detecting the temperature in the projector according to a certain detection period in the starting state of the projector; B. comparing the temperature in the projector detected in the step A with each temperature gradient value in a temperature gradient value description table corresponding to the projector to obtain a temperature gradient value corresponding to the current temperature in the projector; C. judging whether the projector needs to adjust focusing according to the temperature gradient value description table, if so, entering the step D, otherwise, returning to the step A; D. and B, adjusting according to the adjustment instruction corresponding to the temperature gradient value of the current temperature in the projector recorded in the temperature gradient value description table, and returning to the step A. The method can realize the purpose of automatically compensating the focus of the projector according to the working state, and can effectively improve the speed of focus adjustment of the projector in use.
Description
Technical Field
The invention relates to the technical field of projectors, in particular to a method for compensating focusing of a projector lens based on temperature detection.
Background
In recent years, projectors have been popular in the market because of their advantages such as portability, large screen size, and flexible usage. However, a common phenomenon exists in a micro projector, a traditional projector, an ultra-short-focus projector, a laser television and the like: in the cold and hot states, the lens structure and the internal optical lens are affected by temperature and have slight deformation difference, so that the amplified picture effect is obviously different, and the most common and obvious problem is the difference of focusing effect. That is, in different working states, the focusing effect will be different, so that the user has to adjust the focusing frequently to enjoy the best viewing effect. This also severely impacts the user experience.
Although some parts of long-focus projectors are matched with an automatic focusing function and can theoretically perform focusing effect compensation in real time, most of the long-focus projectors adopt a method of taking pictures by using a camera and then comparing algorithms, the method is low in precision, and a specific picture is needed during automatic focusing, a lens focusing motor is adjusted back and forth for many times, so that the use experience of a user is influenced, and the method is basically not feasible. However, the existing short-focus and ultra-short-focus projectors basically do not apply an automatic focusing function, but most of them have an electric focusing option.
Disclosure of Invention
The present invention is directed to overcome the above-mentioned shortcomings in the background art, and provides a method for compensating the focus of a lens of a projector based on temperature detection, which can achieve the purpose of automatically compensating the focus of the projector according to the working state, and can effectively increase the speed of focus adjustment of the projector during use, and improve the satisfaction of users.
In order to achieve the technical effects, the invention adopts the following technical scheme:
a method for compensating the focus of a projector lens based on temperature detection comprises the following steps:
A. detecting the temperature in the projector according to a certain detection period in the starting state of the projector;
B. comparing the temperature in the projector detected in the step A with each temperature gradient value in a temperature gradient value description table corresponding to the projector to obtain a temperature gradient value corresponding to the current temperature in the projector;
C. judging whether the projector needs to adjust focusing according to the temperature gradient value description table, if so, entering the step D, otherwise, returning to the step A;
D. and B, adjusting according to the adjustment instruction corresponding to the temperature gradient value of the current temperature in the projector recorded in the temperature gradient value description table, and returning to the step A.
Furthermore, different projector types correspond to different temperature gradient value description tables, and a plurality of groups of temperature gradients, temperature ranges corresponding to the temperature gradients, and focusing adjustment directions and adjustment angles corresponding to the temperature gradients are recorded in the temperature gradient value description tables;
wherein, a temperature range corresponding to a group of temperature gradients is designated as a reference temperature, the focus of the projector is not required to be adjusted at the reference temperature, and the focus adjusting directions and adjusting angles corresponding to other temperature gradients are adjusted relative to the focus setting of the projector at the reference temperature; meanwhile, the focus setting of the projector is set according to the focus setting of the projector at the reference temperature before the projector is used.
Further, each data in the temperature gradient value specification table is determined by:
s1, setting a temperature range from a ℃ to b ℃ (the temperature does not include a ℃ and includes b ℃) as a reference temperature, starting a projector and adjusting focusing in an environment with the environment temperature in the temperature range; and the temperature gradient corresponding to the reference temperature is A;
s2, using the projector set in the previous step, and immediately detecting the temperature c inside the projector when the focusing effect of the projector is obviously changed and exceeds a normal range;
if c is larger than b, taking b-c ℃ (b ℃ is not included and c ℃) as a temperature range corresponding to the A +1 gradient, adjusting the focus of the projector, and recording the adjustment direction and angle as the focus adjustment direction and adjustment angle corresponding to the temperature gradient; the direction and the angle of the adjustment are set as a reference by the focus of the projector at a reference temperature;
if c is less than a, taking c-a ℃ (not including c ℃ but including a ℃) as a temperature range corresponding to the A-1 gradient, adjusting the focus of the projector, and recording the adjustment direction and angle as the focus adjustment direction and adjustment angle corresponding to the temperature gradient, wherein the adjustment direction and angle are set as the reference by the focus of the projector at the reference temperature;
and S3, repeating the step S2 until the temperature in the projector exceeds the allowable use temperature range of the projector.
Further, when the focusing is adjusted, the projector is specifically adjusted to the pixel number less than or equal to 1.5, and if the pixel number is greater than or equal to 2.0, the focusing effect of the projector is judged to be obviously changed and exceeds the normal range;
the pixel number is Ld/L, Ld is the line width actually projected by a single-pixel image under a fixed projection size, and L is the width of a single pixel.
Further, the temperature in the projector is the temperature in the projector shell.
Further, in the step a, the temperature inside the machine may be detected by a digital temperature sensor.
Compared with the prior art, the invention has the following beneficial effects:
in the method for compensating the focus of the lens of the projector based on temperature detection, the aim of automatically compensating the focus of the projector can be fulfilled by detecting the temperature of the lens part when the projector works, and for most of the projectors with electric focusing at present, including middle and long focus projectors, short focus projectors and ultra-short focus projectors, the method can realize dynamic compensation of the focusing effect along with the temperature through a simple algorithm by only increasing little or even no cost, has high precision, does not disturb the use experience of a user, and has strong practical value.
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FIG. 1 is a flow chart illustrating a method for compensating for projector lens focus based on temperature sensing in an embodiment of the present invention.
Detailed Description
The invention will be further elucidated and described with reference to the embodiments of the invention described hereinafter.
Example (b):
the first embodiment is as follows:
as shown in fig. 1, a method for compensating for focusing of a lens of a projector based on temperature detection needs to test different models of projectors, especially different lens batch models, before the method is used specifically, and generate a temperature gradient value specification table corresponding to the projector of the model.
During testing, a reference temperature is first set, for example, in this embodiment, a general room temperature of 20-25 ℃ is set as the reference temperature, and a temperature gradient corresponding to the reference temperature is a 4 th temperature gradient, and the projector is turned on and the focus is adjusted at the room temperature, and the projector is continuously used for projection.
Specifically, for example, after the projector is adjusted at the reference temperature, the projector continues projection operation, when the temperature in the projector rises to a certain value, so that the focusing effect of the projector obviously changes beyond the normal range, the current temperature in the projector is immediately detected, in this embodiment, the detected temperature is a ℃ (a >25), 25 ℃ -a ℃ is taken as the temperature range of the 5 th temperature gradient, at this time, the focusing is adjusted, and the adjustment direction and angle of the specific focusing motor are recorded as the focusing adjustment direction and adjustment angle corresponding to the temperature gradient.
The projector continues projection work, when the temperature in the projector rises to a certain value, so that the focusing effect of the projector obviously changes again and exceeds the normal range, the temperature in the projector is immediately detected, the temperature measured in the embodiment is b ℃ (b > a), the temperature from a ℃ to b ℃ is used as the temperature range of the 6 th temperature gradient, at the moment, the focusing is well adjusted, and the adjustment direction and the angle of the specific focusing motor relative to the reference temperature are recorded and used as the focusing adjustment direction and the adjustment angle corresponding to the temperature gradient.
Specifically, during testing, a definition test chart is input into the projector, the actual projected line width of a single-pixel image under a fixed projection size is measured as Ld, and the width of a single pixel is measured as L, then: and the Defocus pixel number is Ld/L. When the focusing is adjusted, the focusing effect is specifically adjusted to the Defocus pixel number is less than or equal to 1.5, and when the Defocus pixel number is greater than or equal to 2.0, the focusing effect is judged to be obviously changed and exceeds the normal range.
And the rest can be done in the same way, so that different temperature gradients are set in the use temperature range specified by the projector, and the adjustment directions and angles of the focusing motors corresponding to the different temperature gradients are recorded. The same method can also be used to set the temperature gradient and record the adjustment angle when the temperature is low in the working environment.
Preferably, multiple sets of projectors of the same batch can be selected for testing in practice, and finally, the adjustment directions and angles of the focusing motors corresponding to the temperature gradients are determined by integrating data.
After a temperature gradient value description table corresponding to a batch of models of projectors is established, the temperature gradient value description table can be directly applied to the actual use of the batch of models of projectors. The projector is default set to be the focusing setting at the reference temperature when leaving the factory, and the specific steps are as follows:
the method comprises the following steps: detecting the temperature in the projector according to a certain period in the starting state of the projector;
specifically, the period may be set according to a specific use condition, for example, the detection frequency may be set according to the speed of temperature rise in the machine in different machine types and different working environments;
step two: comparing the temperature detected in the step one with the temperature range corresponding to each temperature gradient value in the temperature gradient value description table to obtain the temperature gradient of the current temperature;
step three: and judging whether the focusing needs to be adjusted according to the temperature gradient value description table:
if the adjustment is needed, presetting an adjustment direction and an angle according to a temperature gradient value description table, sending an instruction of rotating a certain angle to a certain direction to a focusing motor, and then returning to the first step; if no adjustment is needed, directly returning to the step one.
Specifically, the method for determining whether the focus needs to be adjusted is to compare the detected temperature value with the temperature gradient specification table to determine whether the detected temperature value exceeds the temperature gradient range in which the previous detection is performed. For example, the 4 th temperature gradient is 25-30 ℃, the 5 th temperature gradient is 30-35 ℃, if the last detected temperature is 27 ℃, the temperature of the lens part detected this time is 31 ℃, and the temperature exceeds the first temperature gradient, then the focusing adjustment is determined to be needed, and if the detected temperature is 29 ℃, the adjustment is not needed.
Preferably, in the present embodiment, the internal temperature is detected by a digital temperature sensor.
Example two
A method for compensating the focus of a projector lens based on temperature detection is provided, which is particularly directed to a projector of A model.
Before the A-type projection production is carried out, taking the room temperature of 20-25 ℃ as a reference temperature, starting the projector at room temperature and adjusting the focusing, measuring the detection temperature of a lens part to be 30 ℃ until the focusing effect of the projector is obviously changed and exceeds a normal range, adjusting the focusing at the moment, and recording the adjustment direction and angle of a focusing motor to rotate 2 degrees clockwise relative to the initial position;
the projector continues to work until the focusing effect of the projector changes significantly and exceeds the normal range, the temperature of the lens part is measured to be 35 ℃, the focusing is adjusted at the moment, and the adjustment direction and angle of the focusing motor are recorded to be clockwise 4 degrees relative to the initial position.
And setting different temperature gradients by analogy, and recording the adjustment directions and angles of the focusing motors corresponding to the different temperature gradients. An illustrative table of temperature gradient values was obtained as follows:
specifically, the temperature range of each temperature gradient in the above table includes an upper limit and a lower limit, and for example, in the temperature range of 35 ℃ to 45 ℃ of the 1 st temperature gradient, 45 ℃ falls within the temperature range of the temperature gradient, and 35 ℃ does not fall within the temperature range of the temperature gradient. And writing the data corresponding to the table into a projector focusing adjustment program.
Starting the projector, initializing, resetting the focus according to an initial position, carrying out first temperature detection, comparing a temperature gradient value description table at the first temperature detection of 24 ℃, and judging that the focus does not need to be adjusted because the temperature is still in a temperature gradient range where the initialization reset is positioned when the temperature is more than 20 ℃ and less than 24 ℃ and less than 25 ℃; then, detection is carried out according to a period of 5min, secondary detection is carried out after 5min, the detection temperature is 27 ℃, the temperature is in a 3 rd temperature gradient range and exceeds a 4 th temperature gradient range, focusing adjustment is judged to be needed, an adjustment instruction is sent out, and the focusing motor is adjusted to the position 2 degrees clockwise from the initial position and stopped; carrying out third detection after 5min, wherein the detection temperature is 29 ℃, the detection temperature does not exceed the 3 rd temperature gradient range of the last detection, and the judgment is that the focusing is not required to be adjusted; the focusing is dynamically compensated according to the detected temperature in the cycle.
Therefore, in the method for compensating the focus of the lens of the projector based on temperature detection, the aim of automatically compensating the focus of the projector can be fulfilled by detecting the temperature of the lens part when the projector works, and for most of the projectors with electric focusing at present, including middle and long focus projectors, short focus projectors and ultra-short focus projectors, the method can realize dynamic compensation of the focusing effect along with the temperature through a simple algorithm only by increasing little or even no cost, has high precision, does not disturb the use experience of a user, and has strong practical value.
It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.
Claims (4)
1. A method for compensating the focus of a projector lens based on temperature detection is characterized by comprising the following steps:
A. detecting the temperature in the projector according to a certain detection period in the starting state of the projector;
B. comparing the temperature in the projector detected in the step A with each temperature gradient value in a temperature gradient value description table corresponding to the projector to obtain a temperature gradient value corresponding to the current temperature in the projector;
C. judging whether the projector needs to adjust focusing according to the temperature gradient value description table, if so, entering the step D, otherwise, returning to the step A;
D. b, adjusting according to an adjusting instruction corresponding to the temperature gradient value of the current temperature in the projector recorded in the temperature gradient value description table, and returning to the step A;
different projector types correspond to different temperature gradient value description tables, and a plurality of groups of temperature gradients, temperature ranges corresponding to the temperature gradients, focusing adjustment directions and adjustment angles corresponding to the temperature gradients are recorded in the temperature gradient value description tables;
wherein, a temperature range corresponding to a group of temperature gradients is designated as a reference temperature, the focus of the projector is not required to be adjusted at the reference temperature, and the focus adjusting directions and adjusting angles corresponding to other temperature gradients are adjusted relative to the focus setting of the projector at the reference temperature; meanwhile, the focus setting of the projector is set according to the focus setting of the projector at the reference temperature before the projector is used;
the data in the temperature gradient value specification table are determined by the following method:
s1, setting a temperature range from a ℃ to b ℃ (the temperature does not include a ℃ and includes b ℃) as a reference temperature, starting a projector and adjusting focusing in an environment with the environment temperature in the temperature range; and the temperature gradient corresponding to the reference temperature is A;
s2, using the projector set in the previous step, and immediately detecting the temperature c inside the projector when the focusing effect of the projector is obviously changed and exceeds a normal range;
if c is larger than b, taking b-c ℃ (b ℃ is not included and c ℃) as a temperature range corresponding to the A +1 gradient, adjusting the focus of the projector, and recording the adjustment direction and angle as the focus adjustment direction and adjustment angle corresponding to the temperature gradient; the direction and the angle of the adjustment are set as a reference by the focus of the projector at a reference temperature;
if c is less than a, taking c-a ℃ (not including c ℃ but including a ℃) as a temperature range corresponding to the A-1 gradient, adjusting the focus of the projector, and recording the adjustment direction and angle as the focus adjustment direction and adjustment angle corresponding to the temperature gradient, wherein the adjustment direction and angle are set as the reference by the focus of the projector at the reference temperature;
and S3, repeating the step S2 until the temperature in the projector exceeds the allowable use temperature range of the projector.
2. The method as claimed in claim 1, wherein the method for compensating the focus of the projector lens based on temperature detection is specifically to adjust the projector to a pixel number of less than or equal to 1.5 when adjusting the focus, and if the pixel number is greater than or equal to 2.0, it is determined that the focus effect of the projector has changed significantly and is out of a normal range;
the pixel number is Ld/L, Ld is the line width actually projected by a single-pixel image under a fixed projection size, and L is the width of a single pixel.
3. The method of claim 1, wherein the temperature inside the projector is a temperature inside a housing of the projector.
4. The method of claim 1, wherein the temperature in the projector lens is detected by a digital temperature sensor in step a.
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| CN201811257843.4A CN109120910B (en) | 2018-10-26 | 2018-10-26 | Method for compensating focusing of projector lens based on temperature detection |
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| CN201811257843.4A CN109120910B (en) | 2018-10-26 | 2018-10-26 | Method for compensating focusing of projector lens based on temperature detection |
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| CN113596421B (en) * | 2019-10-31 | 2024-05-14 | 峰米(北京)科技有限公司 | Thermal defocus compensation method, storage medium and projection equipment |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201600544U (en) * | 2010-01-11 | 2010-10-06 | 中国华录·松下电子信息有限公司 | Automatic focusing system of projector |
| CN107942601A (en) * | 2017-12-25 | 2018-04-20 | 天津天地伟业电子工业制造有限公司 | A kind of stepper motor lens focus method based on temperature-compensating |
| CN108259869A (en) * | 2018-02-26 | 2018-07-06 | 神画科技（深圳）有限公司 | A kind of projector and its temperature-compensation method of keystone |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5621212B2 (en) * | 2009-04-21 | 2014-11-12 | セイコーエプソン株式会社 | projector |
| CN104834162A (en) * | 2015-04-17 | 2015-08-12 | 神画科技（深圳）有限公司 | Thermal focus losing automatic compensation projector |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201600544U (en) * | 2010-01-11 | 2010-10-06 | 中国华录·松下电子信息有限公司 | Automatic focusing system of projector |
| CN107942601A (en) * | 2017-12-25 | 2018-04-20 | 天津天地伟业电子工业制造有限公司 | A kind of stepper motor lens focus method based on temperature-compensating |
| CN108259869A (en) * | 2018-02-26 | 2018-07-06 | 神画科技（深圳）有限公司 | A kind of projector and its temperature-compensation method of keystone |
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