CN110868576A - Laser light source based imaging system, modulation method thereof and storage medium - Google Patents

Laser light source based imaging system, modulation method thereof and storage medium Download PDF

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CN110868576A
CN110868576A CN201810980759.9A CN201810980759A CN110868576A CN 110868576 A CN110868576 A CN 110868576A CN 201810980759 A CN201810980759 A CN 201810980759A CN 110868576 A CN110868576 A CN 110868576A
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projection image
image
projection
imaging system
light source
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郭祖强
鲁宁
李屹
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Shenzhen Appotronics Corp Ltd
Shenzhen Appotronics Technology Co Ltd
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Appotronics Corp Ltd
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Priority to PCT/CN2019/076653 priority patent/WO2020042570A1/en
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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
    • H04N9/315—Modulator illumination systems
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources
    • 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]
    • 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
    • H04N9/315—Modulator illumination systems
    • H04N9/3161—Modulator illumination systems using laser light sources
    • 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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Abstract

The invention discloses an imaging system based on a laser light source, a modulation method thereof and a storage medium. The modulation method of the imaging system comprises the steps of obtaining a first projection image of an illumination light field emitted by a laser light source in the imaging system after being modulated by a spatial light modulator in the imaging system, and obtaining a first image characteristic of the first projection image; and when the first projection image is judged to not meet the projection requirement, modulating projection light corresponding to the defective pixel in the first projection image according to the first image characteristic. By the modulation method of the imaging system, the modulation process of the imaging system is more convenient.

Description

Laser light source based imaging system, modulation method thereof and storage medium
Technical Field
The invention relates to the technical field of optical imaging systems, in particular to an imaging system based on a laser light source, a modulation method and a storage medium thereof.
Background
An optical modulator is generally provided in an optical imaging system, and an illumination light field emitted by a laser light source is modulated by the optical modulator to form a projection image, wherein the quality of the optical modulator directly affects the display effect of the projection image.
The optical modulator is generally composed of a plurality of reflective or transmissive optical components, a parameter or a state of each optical component affects a projected image, and when a reflectance or a transmittance of one optical component is different from that of another optical component, a luminance unevenness or a color unevenness of the projected image occurs, so that a display effect of the projected image is affected.
Disclosure of Invention
In view of the above, the present invention provides an imaging system based on a laser light source, a modulation method thereof and a storage medium, and the modulation method of the imaging system based on a laser light source of the present invention can make modulation in the imaging system more convenient.
In order to achieve the above object, the present invention provides a modulation method based on a laser light source imaging system, wherein the modulation method comprises:
acquiring a first projection image of an illumination light field emitted by a laser light source in the imaging system after passing through a spatial light modulator in the imaging system, and acquiring a first image characteristic of the first projection image;
judging whether the first projection image meets the projection requirement or not;
if the first projection image does not meet the projection requirement, determining a defective pixel from the first projection image according to the first image characteristic;
and modulating projection light corresponding to the defective pixel according to the first image characteristic.
In another aspect, the present invention provides an imaging system based on a laser light source, the imaging system comprising:
the system comprises a laser light source and a screen arranged on a light-emitting path of the laser light source, wherein a spatial light modulator is arranged between the laser light source and the screen, and an illuminating light field emitted by the laser light source forms a projection image on the screen after being modulated by the spatial light modulator;
the camera is used for shooting the projection image to obtain a first projection image;
and the processing terminal is used for acquiring the first projection image shot by the camera and executing the modulation method of the imaging system.
In another aspect, the present invention also proposes a storage medium storing program data executed to implement the modulation method of the imaging system described above; and/or a method of adjusting an imaging system as described above.
Has the advantages that: different from the prior art, the modulation method of the imaging system based on the laser light source obtains a first projection image obtained by modulating an illumination light field emitted by the laser light source in the imaging system by a spatial light modulator in the imaging system, and obtains a first image characteristic of the first projection image; when the first projection image is judged not to meet the projection requirement, the projection light corresponding to the defective pixel in the first projection image is modulated according to the first image characteristic, and other elements irrelevant to the projection light in the imaging system do not need to be modulated in the modulation process, so that the modulation process of the imaging system is more convenient.
Drawings
FIG. 1 is a schematic flow chart of a first embodiment of a modulation method based on a laser light source imaging system according to the present invention;
FIG. 2 is a schematic flow chart diagram illustrating one embodiment of step S14 in FIG. 1;
FIG. 3 is a schematic flow chart diagram illustrating another embodiment of step S14 in FIG. 1;
FIG. 4 is a schematic flow chart of a second embodiment of the modulation method based on the laser light source imaging system according to the present invention;
FIG. 5 is a schematic flow chart of a third embodiment of a modulation method based on a laser light source imaging system according to the present invention;
FIG. 6 is a schematic flow chart of a fourth embodiment of the modulation method based on the laser light source imaging system according to the present invention;
FIG. 7 is a schematic block diagram of an embodiment of an imaging system of the present invention;
FIG. 8 is a schematic structural diagram of another embodiment of the imaging system of the present invention;
FIG. 9 is a schematic structural diagram of an embodiment of a storage medium according to the present invention.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
In order to make the technical solutions of the present invention better understood, those skilled in the art will now describe the present invention in further detail with reference to the accompanying drawings and detailed description. It is to be understood that the described embodiments are merely some embodiments of the invention, and not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative effort belong to the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic flowchart illustrating a modulation method based on a laser source imaging system according to a first embodiment of the present invention. As shown in fig. 1, the modulation method of the present embodiment may include the following steps:
in step S11, a first projection image is obtained in which the illumination light field emitted from the laser light source in the imaging system passes through the spatial light modulator in the imaging system, and a first image characteristic of the first projection image is obtained.
In the imaging system, an illuminating light field emitted by a laser light source is modulated by a spatial light modulator to form a modulated light field, and the modulated light field passes through a lens in the imaging system to form a first projection image on a screen; the spatial light modulator in this embodiment may be a Digital micromirror array (DMD), a transmissive liquid crystal panel, or a reflective liquid crystal panel; and the imaging system may be a Digital Light Processing (DLP) projection system or a Liquid Crystal Display (LCD) projection system.
Furthermore, a modulation light path composed of a plurality of optical devices can be used behind the laser light source, the modulation light path homogenizes the illumination light field emitted by the laser light source, and a light homogenizing device such as a square rod or a compound eye can be used in the homogenization process; in addition, the illumination light emitted by the laser light source may be uniformized in another manner. The homogenized illumination light field is modulated by the spatial light modulator to form a first projection image on the screen.
In this embodiment, a camera is used to photograph a first projection image on a screen, and the photographed first projection image is transmitted to a processing terminal, where the processing terminal may obtain a corresponding first image characteristic from the first projection image, and the first image characteristic is an image characteristic of the first projection image formed by modulating an illumination light field emitted by a laser light source by a spatial light modulator, so that the first image characteristic may reflect a performance of the spatial light modulator, and further determine whether the spatial light modulator meets an image projection requirement, in other words, the performance of the spatial light modulator may be detected by analyzing the first image characteristic, and the spatial light modulator may be modulated according to a detection condition.
In step S12, it is determined whether the first projection image satisfies a projection requirement.
And comparing the acquired first image characteristic with a preset image characteristic requirement to judge whether the first image characteristic meets the image characteristic requirement or not, and obtaining a corresponding judgment result. If the first image characteristic does not meet the image characteristic requirement, determining that the first projection does not want to meet the projection requirement, and further performing a subsequent step of modulating image light corresponding to the first projection image so as to avoid poor display effect of the projection image obtained in the laser light source-based imaging system. If the judgment result is that the first projection image does not meet the projection requirement, continuing to execute the step S13; if the first projection image meets the projection requirement, the modulation step is not required to be continuously executed, and the process is ended.
In step S13, a defective pixel is determined from the first projection image based on the first image characteristic.
If the determination result of step S12 is that the first projection image does not satisfy the projection requirement, the first projection image may have a non-uniform image distribution, in other words, the first projection image may have a uniform brightness distribution and/or a non-uniform color distribution of some pixels, and the pixels having the uniform brightness distribution and/or the non-uniform color distribution are used as defective pixels, and the defective pixels are determined in the first projection image, where determining the defective pixels may include determining at least a display characteristic of the defective pixels and a position of the defective pixels in the first projection image.
In step S14, the projection light corresponding to the defective pixel is modulated according to the first image characteristic.
In this embodiment, when the determination result is that the first projection image does not satisfy the projection requirement, the projection light corresponding to the defective pixel is adjusted according to the first image characteristic, so that the display characteristic of the defective pixel and the display characteristics of other pixels tend to be consistent. The modulation process does not need to modulate other elements of the imaging system which are not related to the projection light, so that the modulation process of the imaging system is more convenient.
Further, in an embodiment, the spatial light modulator may be modulated by means of electronic rectification compensation according to the phenomenon of non-uniformity of the first projected image; as shown in fig. 2, at this time, step S14 may include the steps of:
in step S14a1, a modulation amount difference between the modulation amount of the spatial light modulator for the defective pixel and the modulation amount for the other pixels of the first projection image is acquired.
It is understood that the modulation amount of the spatial light modulator may be classified into reflectivity or transmissivity according to the properties of the spatial light modulator. In an imaging system, when the modulation amount of a spatial light modulator for each pixel is the same, the brightness distribution and/or the color distribution of a projected image formed on a screen are uniform, and if the modulation amount of one or several of a plurality of reflective sub-elements or transmissive sub-elements constituting the spatial light modulator is different from the modulation amount of the other reflective sub-elements or transmissive sub-elements, the color and/or the brightness of some pixels in an obtained image are different from those of the other pixels, resulting in a phenomenon that the brightness distribution and/or the color distribution of the image are non-uniform.
In this embodiment, based on the information of the position, the display characteristic, and the like of the defective pixel obtained in step S13, the modulation amount of the defective pixel by the spatial light modulator and the modulation amount difference between the modulation amounts of the defective pixel and the other pixels by the spatial light modulator can be obtained.
In step S14a2, the spatial light modulator is modulated according to the modulation amount difference.
According to the above description, for the first projection image, because the difference of the modulation amounts of the spatial light modulator for the defective pixel and the other pixels exists, at this time, the modulation amount of the spatial light modulator for the defective pixel and the modulation amount of the other pixels can be made the same by modulating the modulation amount of the spatial light modulator for the defective pixel, that is, the modulation amount of the spatial light modulator for the defective pixel can be changed according to the difference of the modulation amounts of the spatial light modulator for the defective pixel and the modulation amount of the spatial light modulator for the defective pixel, so that the modulation amount of the spatial light modulator for the defective pixel and the modulation amount of the spatial light modulator for the other pixels are made to be the same.
In this embodiment, the modulation amount may be a brightness modulation amount, and correspondingly, the modulation amount difference is a brightness modulation amount difference; at this time, the spatial light modulator is modulated according to the modulation amount difference, and the brightness of the projection light corresponding to the defective pixel is modulated.
In this embodiment, the modulation amount of the defective pixel by the spatial light modulator may be a first modulation amount, and the modulation amount of the other pixels may be a second modulation amount, and then the difference between the first modulation amount and the second modulation amount is the modulation amount difference between the modulation amounts of the other pixels of the first projection image. Further, the modulation quantity of the sub-element corresponding to the defective pixel in the spatial light modulator is changed to be equal to the modulation quantity of other pixels by adding or subtracting the modulation quantity difference value on the basis of the first modulation quantity, so that the projection image of the imaging system is modulated, and the projection image with better display quality is obtained.
Further, in another embodiment, the spatial light modulator may be modulated according to the first image characteristic using a method of pre-modulation of the illumination light field; in this case, referring to fig. 3, the step S14 may include the following steps:
in step S14b1, the illumination light field is divided according to the position of the defective pixel, and an area illumination light field in which the defective pixel is generated after the division is obtained.
The embodiment divides the illumination light field emitted by the laser light source, and according to the position of the defective pixel in the first projection image, the area illumination light field generating the defective pixel can be determined from the divided multiple area illumination light fields, so as to modulate the area illumination light field generating the defective pixel in the subsequent steps.
In step S14b2, the modulation region illuminates the light field.
The area illumination light field in which the defective pixel is generated is obtained, that is, the area illumination light field corresponding to the defective pixel can be modulated.
The method for modulating the area illumination light field in this embodiment includes a light emitter array method or a method of adding a light modulator in front of the spatial light modulator, and this embodiment is not particularly limited.
Further, in this embodiment, the first image characteristic may include a brightness characteristic and a color characteristic, and the corresponding determining that the first projection image does not satisfy the projection requirement may include that the brightness distribution of the first projection image does not satisfy the brightness distribution requirement and/or that the color distribution of the first projection image does not satisfy the color distribution requirement. Thus, according to the first embodiment of the modulation method based on the laser light source imaging system shown in fig. 1 to 3, further improvements can be made according to the specific case where the first projection image does not satisfy the projection requirements.
Referring to fig. 4, fig. 4 is a schematic flowchart of a modulation method based on a laser source imaging system according to a second embodiment of the present invention, which is an embodiment of the modulation method of the imaging system when the first projection image does not satisfy the projection requirement and the brightness distribution of the first projection image does not satisfy the brightness distribution requirement. As shown in fig. 4, the modulation method of the present embodiment may include the following steps:
in step S21, a first projection image is obtained in which the illumination light field emitted from the laser light source in the imaging system passes through the spatial light modulator in the imaging system, and a first image characteristic of the first projection image is obtained.
Step S21 in this embodiment is the same as step S11 shown in fig. 1, and is not repeated here.
In step S22, an illuminance value of each pixel in the first projection image, an average value of illuminance of the first projection image, and an illuminance difference contrast value of the first projection image are acquired according to the first image characteristics.
The illuminance value of an image is the luminous flux of visible light received by a unit area on the image, and is also a characteristic quantity of the image brightness, where the brightness value is the illuminance value/beam angle, and in this embodiment, the first projection image is formed by an illumination light field emitted from the same lens, and therefore the beam angle is the same for the first projection image.
Whether the brightness distribution of the first projected image satisfies the projection requirement may be determined by the illuminance value of the first projected image. In addition, the illumination average value of the first projection image is obtained through calculation of the illumination value of each pixel in the first projection image and the number of the pixels, and the illumination average value represents the brightness distribution condition of the first projection image. The illumination contrast value is a commonly used parameter for determining whether the overall brightness distribution of the image is uniform.
Therefore, in the present embodiment, when it is determined that the luminance distribution of the first projection image does not satisfy the luminance distribution condition, the illuminance value and the number of pixels in each pixel of the first projection image are obtained, that is, the illuminance average value of the first projection image is obtained through calculation, and further the illuminance difference contrast value of the first projection image is obtained through calculation according to the illuminance value, the number of pixels, and the illuminance average value of the first projection image.
In this embodiment, the illumination difference contrast value of the first projection image may be calculated according to the following formula:
Figure BDA0001778475970000071
where N is the number of pixels in the first projection image, xkRepresenting the illumination value of each pixel in the first projection image, μ beingAverage value of illumination of a projected image.
In step S23, it is determined whether or not the illuminance value of each pixel, the average value of the illuminance of the first projection image, and the illuminance difference contrast value satisfy the luminance distribution condition.
In this embodiment, a brightness distribution condition is preset, and the illuminance value of each pixel, the illuminance average value of the first projection image, and the illuminance difference contrast value obtained in step S22 are compared with the preset brightness distribution condition, so as to determine whether the brightness distribution of the first projection image satisfies the brightness distribution in the image characteristic requirement. If the judgment result is that the brightness distribution of the first projection image meets the brightness distribution in the image characteristic requirement, ending the process; and if the judgment result is that the brightness distribution of the first projection image does not meet the brightness distribution in the image characteristic requirement, continuing to execute the subsequent steps.
In the embodiment, whether the first projection image has the local uneven brightness is judged by comparing the illumination value of each pixel with the average illumination value, and whether the first projection image has the overall uneven brightness is judged by the contrast value of illumination difference.
Specifically, the obtained illumination value of each pixel is compared with the average illumination value of the first projection image, if the absolute value of the difference between the illumination value of each pixel and the average illumination value is smaller than a first preset difference value, it is indicated that the first projection image has no local brightness unevenness, and if the absolute value of the difference between the illumination value of one or more pixels in the first projection image and the average illumination value is greater than or equal to the first preset difference value, it is indicated that the brightness of the one or more pixels has a large brightness difference with respect to other pixels, and the first projection image has a local brightness unevenness at the one or more pixels.
Further, comparing the calculated illumination difference contrast value with a second preset difference value, and if the illumination difference contrast value is smaller than the second preset difference value, determining that the first projection image has no integral brightness unevenness; and if the illumination difference contrast value is larger than or equal to the second preset difference value, the first projection image is considered to have the phenomenon of overall uneven brightness.
In other words, the luminance distribution conditions of the present embodiment include: the absolute value of the difference value between the illumination value of each pixel and the illumination average value is smaller than a first preset difference value, and the illumination difference contrast value is smaller than a second preset difference value; that is, the luminance distribution of the first projection image is considered to satisfy the luminance distribution condition only when both conditions are satisfied, and the luminance distribution of the first projection image is considered not to satisfy the luminance distribution condition as long as any one of the conditions is not satisfied. In this embodiment, the first preset difference and the second preset difference may be set according to an actual situation, and this embodiment is not particularly limited. In general, the second preset difference may be 2%, and of course, the second preset difference may also be set to a value of 3%, 5%, or 7%, etc. according to actual situations.
In step S24, a luminance difference value between the luminance of the defective pixel in the first projection image and the luminance of the other pixels in the first projection image is acquired.
When the determination result in the step S23 is that the illuminance value of the pixel, the average illuminance value of the first projection image, and the illuminance difference contrast value do not satisfy the brightness distribution condition, the defect pixel in the first projection image is further obtained by using the first image characteristic, where the defect pixel refers to a pixel in the first projection image with uneven brightness distribution, and the position of the defect pixel and the brightness difference value between the defect pixel and another pixel can be obtained according to the above steps.
In step S25, the area illumination light field is modulated according to the brightness difference value.
In this embodiment, the area illumination light field corresponding to the defective pixel is adjusted according to the brightness difference value between the defective pixel and the other pixels, so that the brightness of the defective pixel and the brightness of the other pixels tend to be consistent, and the first projection image meets the projection requirement.
Further, when the defective pixel is determined, the illumination spot corresponding to the defective pixel may be calculated through the area illumination light field generating the defective pixel. It can be understood that the size and intensity of the illumination spot corresponding to the defective pixel are different from those of the illumination spots corresponding to other pixels, resulting in the generation of the defective pixel. Therefore, after the illumination spot corresponding to the defective pixel is found, the size and the light intensity of the illumination spot corresponding to the defective pixel can be adjusted according to the brightness difference value between the defective pixel and the other pixels obtained in step S24, so as to adjust the phenomenon of uneven brightness of the first projection image.
The above modulation process is exemplified: when the illumination light field emitted by the laser light source is a uniform illumination light field, the brightness of the illumination light field is a, the ratio of light received by the lens after the spatial light modulator reflects (or transmits) light by other pixels except for the defective pixel is b, and then the brightness obtained by the projected image is a x b; at this time, since the defective pixel has an abnormality, the ratio of the illumination light field corresponding to the defective pixel received by the lens is changed to c, and therefore the amount by which the luminance of the illumination light field corresponding to the defective pixel needs to be adjusted is (b/c) × a, and further the luminance of the point corresponding to the defective pixel in the projected image is (b/c) × a ═ b, which is the same as that of the other pixels, that is, the uneven luminance distribution of the projected image is eliminated by modulating the laser light source.
Referring to fig. 5, fig. 5 is a schematic flowchart of a modulation method based on a laser source imaging system according to a third embodiment of the present invention, and this embodiment is an embodiment of the modulation method of the imaging system when the first projection image does not satisfy the projection requirement and the color distribution of the first projection image does not satisfy the color distribution requirement. As shown in fig. 5, the modulation method of the present embodiment may include the following steps:
in step S31, a first projection image is obtained in which the illumination light field emitted from the laser light source in the imaging system passes through the spatial light modulator in the imaging system, and a first image characteristic of the first projection image is obtained.
Step S31 in this embodiment is the same as step S11 shown in fig. 1, and is not repeated here.
In step S32, the color coordinates of each pixel of the first projection image are calculated based on the first image characteristics.
The color coordinate is a coordinate of a color, and the color coordinate is a coordinate point of the color on the chromaticity diagram, and the color can be accurately represented by the coordinate.
The color coordinates of a pixel are related to the color tristimulus value of the pixel by the following relationship:
Figure BDA0001778475970000101
Figure BDA0001778475970000102
wherein x is the abscissa of the color coordinate of the pixel, and y is the ordinate of the color coordinate of the pixel; x, Y, Z are the tristimulus values of red, green and blue among the tristimulus values of the pixel's color, respectively.
As can be seen from the above formula, calculating the color coordinates of each pixel in the first projection image requires obtaining the color tristimulus value of each pixel first. In this embodiment, three primary color image signal values (R, G, B) of each pixel in the first projection image are obtained through the first projection image, where the three primary color image signal values of each pixel are the gray scale of the pixel, and the maximum value is 255; further, coordinates of three primary colors of an image captured by a camera capturing the first projection image are obtained from a color gamut of the camera (the color coordinates of the three primary colors are determined by the color gamut of the camera, not the color coordinates of the three primary colors in the first projection image), wherein the color coordinate of red is (x) in colorR，yR) The color coordinate of green is (x)G，yG) And the color coordinate of blue is (x)B，yB) The tristimulus values of red, green and blue among the tristimulus values of the colors of the pixels in the first projection image can be calculated according to the following formula:
Figure BDA0001778475970000103
y in the above formulaR、YG、YBCan be as followsThe following formula is calculated:
Figure BDA0001778475970000104
wherein, XW、YW、ZWTri-color stimulus values for white light.
According to the formula, the color tristimulus value (X, Y, Z) of each pixel in the first projection image can be calculated, and the color coordinate (X, Y) of each pixel can be further calculated.
In step S33, it is determined whether the difference between the color coordinates of each pixel and the color coordinates of the light source is greater than a third preset difference.
The color coordinate of each pixel in the first projection image may represent the color of the corresponding pixel, and numerically represents the position of the color of each pixel in the chromaticity diagram, and the first projection image is formed by the illumination light field emitted by the laser light source, and if the color distribution of the first projection image is uniform, the color coordinate of each pixel in the first projection image should theoretically approach the color coordinate of the laser light source, so that the embodiment compares the color coordinate of each pixel calculated in step S32 with the color coordinate of the laser light source, and determines the relationship between the difference between the color coordinate of each pixel and the color coordinate of the laser light source and the third preset difference.
If the difference value between the color coordinate of one or more pixels and the color coordinate of the laser light source is larger than or equal to a third preset difference value, the color distribution of the first projection image does not meet the color distribution condition, and the first projection image has a phenomenon of uneven color at the pixel, and the subsequent steps are continuously executed; if the difference between the color coordinate of each pixel and the color coordinate of the laser light source is smaller than the third preset difference, it indicates that the color distribution of the first projection image meets the color distribution condition, and the first projection image has no phenomenon of non-uniform color, and at this time, the process is ended.
In this embodiment, the first preset difference, the second preset difference, and the third preset difference may be set according to an actual situation, and this embodiment is not particularly limited.
In step S34, three primary-color image signal values of the image of the area illumination light field corresponding to the defective pixel before modulation are acquired according to the first image characteristics.
And acquiring three primary color image signal values of the area illumination light field corresponding to the defective pixel before adjustment, wherein the three primary color image signal values are gray levels of three primary colors of the image corresponding to the area illumination light field, the brightness of the three primary colors in the image is represented, and the maximum value is 255.
In step S35, three primary-color image signal values required for the image of the area illumination light field corresponding to the defective pixel are calculated.
The three primary color image signal values required by the image mean that when the image has no color non-uniformity, the three primary color image signal values of the image corresponding to the defective pixel, in other words, the three primary color image signal values of the image of the area illumination light field corresponding to the defective pixel need to be adjusted to the required three primary color image signal values, that is, the modulation of the color non-uniformity of the first projection image can be realized.
In step S36, a three primary color image signal difference value is calculated from the three primary color image signal values before modulation and the desired three primary color image signal values, and the light field is illuminated according to the three primary color image signal difference value modulation region.
And calculating to obtain three primary color image signal difference values according to the three primary color image signal values of the image corresponding to the defect pixel before adjustment obtained in the step S34 and the step S35 and the required three primary color image signal values. In this embodiment, the area illumination light field generating the defective pixel is modulated according to the calculated difference value of the three primary color image signals, and the three primary color image signal values of the image in which the modulated defective pixel is located are the required three primary color image signal values, so as to realize the adjustment of the color unevenness of the first projection image.
The modulation calculation process for the area illumination light field corresponding to the defective pixel in this embodiment is as follows:
calculating a color tristimulus value of a defective pixel on a first projection image photographed by a camera and color tristimulus values of other pixelsThe difference between the tristimulus color values is (Δ X, Δ Y, Δ Z), the tristimulus color value of the laser light source before modulation is (X ', Y ', Z '), and the tristimulus color value of the modulated illumination light is (X)0，Y0，Z0) Then, the color tristimulus value of the illumination light is calculated as:
X0＝X'+ΔX；Y0＝Y'+ΔY；Z0＝Z'+ΔZ；
under the color gamut of the imaging system, the obtained color coordinates of the corresponding three primary colors are respectively: (x)r，yr)、(xg，yg)、(xb，yb) The illumination light field of the laser light source can be calculated according to the following formula, namely the three primary color image signal values (r, g, b) are obtained:
Figure BDA0001778475970000121
wherein, Yr、Yg、YbThe value of (d) can be calculated by the following formula:
Figure BDA0001778475970000122
wherein, XW、YW、ZWTri-color stimulus values for white light.
By the method for adjusting the imaging system, the imaging system can be adjusted through the first image characteristic of the first projection image formed by the imaging system, so that the image characteristic of the first projection image meets the image characteristic requirement.
Further, it is also possible that the first projection image does not satisfy the projection requirement and the luminance distribution does not satisfy the luminance distribution requirement and the color distribution does not satisfy the color distribution requirement, and at this time, the modulation methods shown in fig. 4 and 5 may be combined to constitute a new embodiment.
Referring to fig. 6, fig. 6 is a schematic flow chart of a modulation method of an imaging system according to a fourth embodiment of the invention. As shown in fig. 6, the modulation method of the present embodiment may include the following steps:
in step S41, the imaging system of the laser light source is preprocessed.
Each optical device including the laser light source in the imaging system affects the image characteristics of the formed first projection image, so that the imaging system needs to be preprocessed before the spatial light modulator is detected to eliminate the effect of other optical devices in the imaging system except the spatial light modulator on the first image characteristics of the first projection image.
Further, in an embodiment, the pre-processing of the imaging system of the laser light source may be: and acquiring a second projection image which is not modulated by the element to be detected in the illumination light field emitted by the laser light source, wherein the imaging system is not provided with a spatial light modulator, the second projection image which is formed on the screen by the illumination light field emitted by the laser light source is not modulated by the spatial light modulator, and the image characteristics of the second projection image are only influenced by other optical devices in the imaging system except the spatial light modulator and are not influenced by the spatial light modulator. Further, when the image characteristics of the acquired second projection image are determined not to meet the image characteristic requirements, the image characteristics of the second projection image are recorded, so that after the spatial light modulator is placed in an imaging system of a laser light source in a subsequent step, the image characteristics of the second projection image can be removed from the original image characteristics of the acquired first projection image, and the first image characteristics of the first projection image can be obtained, and at the moment, the first image characteristics are only influenced by the spatial light modulator.
Further, in another embodiment, the pre-processing of the imaging system of the laser light source may be: and when the image characteristics of the acquired second projection image are determined not to meet the image characteristic requirements, modulating other optical devices except the spatial light modulator in the imaging system according to the second image characteristics. Thus, after the spatial light modulator is placed in the imaging system of the laser light source in the subsequent step, the original image characteristic of the obtained first projection image is not affected by other optical devices except the spatial light modulator, and at this time, the original image characteristic of the first projection image is the first image characteristic.
In this embodiment, other optical devices in the imaging system include a laser light source, a modulation optical path, and/or a lens.
In step S42, a first projection image is obtained, in which the illumination light field emitted from the laser light source in the imaging system is modulated by the spatial light modulator in the imaging system, and a first image characteristic of the first projection image is obtained.
In step S43, it is determined whether the first projection image satisfies a projection requirement.
In step S44, a defective pixel is determined from the first projection image based on the first image characteristic.
In step S45, the projection light corresponding to the defective pixel is modulated according to the first image characteristic.
In this embodiment, the steps S42 to S45 may be the same as the steps S11 to S14 shown in fig. 1, and specifically, the modulation method of the projection light corresponding to the defective pixel in step S45 may further refer to the modulation methods shown in fig. 2 and 3.
Further, the steps S44 and S45 may refer to the modulation methods of steps S22 to S25 shown in fig. 4, or refer to the modulation methods of steps S32 to S35 shown in fig. 5, in accordance with whether the first projection image does not satisfy the projection requirement as the luminance distribution of the first projection image does not satisfy the luminance distribution requirement or the first projection image does not satisfy the color distribution requirement.
Further, referring to fig. 7, fig. 7 is a schematic structural diagram of an embodiment of an imaging system of the present invention. As shown in fig. 7, the imaging system 100 of the present embodiment includes a laser light source 101, and a screen 105 disposed on a light exit path of the laser light source 101, a spatial light modulator 103 is disposed between the laser light source 101 and the screen 105, and an illumination light field emitted from the laser light source 101 is modulated by the spatial light modulator 103, and then forms a projection image on the screen 105 through a lens 104. The camera 106 is configured to shoot the projection image to obtain a first projection image. The processing terminal 107 is connected to the camera 106, and is configured to acquire the first projection image captured by the camera 106 and execute the first to fourth embodiments of the modulation method of the imaging system of the laser light source shown in fig. 1 to 6, and for details of the modulation method of the imaging system, please refer to the descriptions of the first to fourth embodiments of the modulation method of the imaging system shown in fig. 1 to 6, which are not described herein again.
Further, referring to fig. 7, the imaging system 100 of this embodiment may further include a modulation optical path 102 formed by a plurality of optical devices, where the modulation optical path 102 is disposed between the laser light source 101 and the spatial light modulator 103 and is used to homogenize the illumination light field emitted by the laser light source 101, and the homogenization process may use a light uniformizing device, such as a square rod or a compound eye, or may use other methods to homogenize the illumination light emitted by the laser light source 101. The homogenized illumination light field is modulated by the spatial light modulator 103 to form a first projection image on the screen 105.
Further, referring to fig. 8, fig. 8 is a schematic structural diagram of an imaging system according to another embodiment of the present invention. As shown in fig. 8, the imaging system 200 of the present embodiment includes a laser light source 201, and a screen 205 disposed on a light exit path of the laser light source 201, a spatial light modulator 203 is disposed between the laser light source 201 and the screen 205, and an illumination light field emitted from the laser light source 201 is modulated by the spatial light modulator 203, and then forms a projection image on the screen 205 through a lens 204. The camera 206 is used for shooting the projection image to obtain a first projection image. The processing terminal 207 is connected to the camera 206, and is configured to acquire the first projection image captured by the camera 206 and execute the first to fourth embodiments of the modulation method of the imaging system shown in fig. 1 to 6, for details of the modulation method of the imaging system, please refer to the descriptions of the first to fourth embodiments of the modulation method of the imaging system shown in fig. 1 to 6, which are not described herein again.
In addition, the imaging system 200 of the present embodiment may further include a modulation optical path 202 formed by a plurality of optical devices, where the modulation optical path 202 is disposed between the laser light source 201 and the spatial light modulator 203, and is used to homogenize the illumination light field emitted by the laser light source 201, and the homogenization process may use a light homogenizing device, such as a square rod or a compound eye, and in addition, may also use other methods to homogenize the illumination light emitted by the laser light source 201. The homogenized illumination field is modulated by the spatial light modulator 203 to form a first projection image on the screen 205.
Further, referring to fig. 8, the imaging system 200 of this embodiment further includes a hardware processing circuit 208, where the hardware processing circuit 208 is respectively connected to the processing terminal 207, the laser light source 201, and the spatial light modulator 203, and is configured to execute the first to fourth embodiments of the adjusting method of the imaging system of the laser light source shown in fig. 1 to 6 when the processing terminal 207 determines that the spatial light modulator 203 does not meet the projection requirement, which is not described herein again.
Further, the present invention also discloses an embodiment of a storage medium, in which the storage medium stores program data, as shown in fig. 9, the storage medium 300 may include at least one storage block 31, and the program data is stored in at least one storage block 31 or stored in a part of the storage blocks 31. The program data can be executed to implement the first to fourth embodiments of the modulation method of the imaging system as shown in fig. 1 to 6, which will not be described herein again.
The storage medium in this embodiment may be a device such as a usb disk, a network disk, a storage hard disk, a terminal, and a server with a storage function.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (10)

1. A modulation method based on a laser light source imaging system is characterized by comprising the following steps:
acquiring a first projection image of an illumination light field emitted by a laser light source in the imaging system after passing through a spatial light modulator in the imaging system, and acquiring a first image characteristic of the first projection image;
judging whether the first projection image meets the projection requirement or not;
if the first projection image does not meet the projection requirement, determining a defective pixel from the first projection image according to the first image characteristic;
and modulating projection light corresponding to the defective pixel according to the first image characteristic.
2. The adjustment method according to claim 1, wherein the modulating the projection light corresponding to the defective pixel according to the first image characteristic comprises:
acquiring a modulation amount difference between the modulation amount of the spatial light modulator on the defective pixel and the modulation amount on other pixels of the first projection image;
and modulating the spatial light modulator according to the modulation amount difference value, so that the modulation amount of the spatial light modulator on the defective pixel is the same as the modulation amount on other pixels of the first projection image.
3. The adjustment method according to claim 1, wherein the modulating the projection light corresponding to the defective pixel according to the first image characteristic comprises:
dividing the illumination light field according to the position of the defective pixel to obtain a region illumination light field which generates the defective pixel after division;
modulating the area illumination light field to make the first projection image meet projection requirements.
4. The adjustment method according to claim 3, wherein said modulating said area illumination light field comprises:
acquiring brightness difference values between the brightness of the defective pixel in the first projection image and the brightness of other pixels in the first projection image;
modulating the area illumination light field according to the brightness difference value.
5. The adjustment method according to claim 3, wherein said modulating said area illumination light field comprises:
acquiring three primary color image signal values of an image of an area illumination light field corresponding to the defective pixel before modulation;
calculating three primary color image signal values required by the image of the area illumination light field corresponding to the defective pixel;
and calculating three primary color image signal differences according to the three primary color image signal values before modulation and the required three primary color image signal values, and modulating the area illumination light field according to the three primary color image signal differences.
6. The modulation method according to claim 1,
before the acquiring a first projection image of an illumination light field emitted by a laser light source in the imaging system after passing through a spatial light modulator in the imaging system, the method further includes:
preprocessing the laser light source imaging system to exclude the influence of other optical elements than the spatial light modulator on the first projection image.
7. The modulation method according to claim 1,
the judging whether the first projection image meets the projection requirement includes:
acquiring an illumination value of each pixel in the first projection image, an illumination average value of the first projection image and an illumination difference contrast value of the first projection image;
judging whether the illumination value of each pixel, the illumination average value of the first projection image and the illumination difference contrast value meet the brightness distribution condition or not;
wherein the brightness distribution condition includes: the absolute value of the difference between the illumination value of each pixel and the illumination average value is smaller than a first preset difference, and the illumination difference contrast value is smaller than a second preset difference.
8. The modulation method according to claim 6,
the judging whether the first projection image meets the projection requirement includes:
calculating a color coordinate of each pixel of the first projection image;
and judging whether the difference value between the color coordinate of each pixel and the color coordinate of the laser light source is larger than a third preset difference value.
9. A laser light source based imaging system, comprising:
the system comprises a laser light source and a screen arranged on a light-emitting path of the laser light source, wherein a spatial light modulator is arranged between the laser light source and the screen, and an illuminating light field emitted by the laser light source forms a projection image on the screen after being modulated by the spatial light modulator;
the camera is used for shooting the projection image to obtain a first projection image;
a processing terminal for acquiring the first projection image and executing the imaging system modulation method of any one of claims 1 to 8.
10. A storage medium holding program data executed to implement the imaging system modulation method of any one of claims 1 to 8.
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