A high-precision multi-path light mixing method and a lamp

Abstract

The application discloses a high-precision multi-path light mixing method and a lamp, and the high-precision multi-path light mixing method comprises the following steps: S1: acquiring light source basic parameters of each channel of a light source, wherein the light source basic parameters of each channel of the light source comprise color coordinates and luminous flux of each channel; S2: solving contribution degrees of each channel according to the number of channels, the color coordinates of each channel and target color coordinates; S3: obtaining duty cycles of each channel by using the contribution degrees of each channel, luminous flux and brightness for normalization; and S4: performing nonlinear calibration on the duty cycles of each channel. A lamp is provided, and light mixing is performed by using the high-precision multi-path light mixing method. Under the condition of compatible double-color and three-color light mixing calculation, the application provides a simple method for solving duty cycle calculation of light mixing of more than four colors, is suitable for a low-power MCU, and can reduce cost and power consumption.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of LED light mixing, and particularly relates to a high-precision multi-path light mixing method and a lamp. BACKGROUND

[0002] The multi-color LED light mixing technology used by the existing lamp needs to apply different light mixing algorithms according to the number of LED channels: when double-color light mixing, two channels usually correspond to two white light LEDs with different color temperatures, at this time, all the color coordinates that can be obtained by light mixing exist on the line formed by the color coordinates of the two white light channels, and according to the principle of three stimulus values, the current duty cycle required by each channel to achieve the target color coordinate can be solved; when three-color light mixing, three channels usually correspond to R, G and B color LEDs, at this time, all the color coordinates that can be obtained by light mixing exist in the triangular region formed by the color coordinates of R, G and B, and the duty cycle of each channel can be directly obtained by using the Grassmann formula; when four-color light mixing, four channels usually correspond to R, G, B and W, and the color coordinates that can be obtained by light mixing also exist in the triangular region formed by the color coordinates of R, G and B, but due to the existence of W, the triangular region is divided into three smaller triangles, and when calculating the current duty cycle, it is necessary to first determine in which small triangle the target color coordinate falls, and then calculate the duty cycle of the color channel corresponding to the vertex of the small triangle according to the Grassmann formula; when five-color light mixing, five channels usually correspond to R, G, B, CW and WW, and the color coordinates that can be obtained by light mixing also exist in the triangular region formed by the color coordinates of R, G and B, but due to the existence of two color temperatures W, the triangular region can be divided into five smaller triangles, and when calculating the current duty cycle, it is necessary to first determine in which small triangle the target color coordinate falls, and then calculate the duty cycle of the color channel corresponding to the vertex of the small triangle according to the Grassmann formula.

[0003] In the traditional method, when the light source of the lamp is replaced, it is necessary to reselect the above light mixing algorithm model; when four or more colors are mixed, additional computing power is required to select three channels for three-way problem solving, which requires high computing power of hardware and has high cost and power consumption. SUMMARY

[0004] In order to solve the above problems in the prior art, the application provides a high-precision multi-path light mixing method and a lamp, which provides a simple method for solving the duty cycle calculation of four or more colors under the condition of compatible double-color and three-color light mixing calculation, is suitable for low-power MCU, can reduce cost and power consumption, and overcomes the shortcomings of the prior art.

[0005] In order to achieve the above purpose, the application adopts the following technical scheme:

[0006] According to a first aspect of the present application, a high-precision multi-channel light mixing method is provided, comprising the following steps:

[0007] S1: obtaining light source basic parameters of each channel, including color coordinates and luminous flux of each channel;

[0008] S2: solving the contribution degree of each channel according to the number of channels, the color coordinates of each channel, and the target color coordinates;

[0009] S3: normalizing the duty cycle of each channel using the contribution degree of each channel, luminous flux, and brightness;

[0010] S4: nonlinear calibration of the duty cycle of each channel. All the above calculation steps assume that the luminous flux of each channel LED is linearly related to the duty cycle, and in fact it is nonlinearly related. After nonlinear calibration of the duty cycle of each channel, the calibrated measured color coordinates are closer to the target color coordinates, and the target color point can be more accurately reproduced.

[0011] Preferably, the S1 needs to obtain the color coordinates and luminous flux of each channel of the light source through an integrating sphere or other photoelectric equipment.

[0012] Preferably, the calculation method for solving the contribution degree of each channel in S2 is:

[0013]

[0014] Where x c , y c represent the target color coordinates, i represents the number of channels, x 1～i , y 1～i represent the color coordinates of each channel, and f 1～i represents the contribution degree of each channel. The color coordinates are substituted into the above parameter equation to solve.

[0015] Further preferably, in response to the number of channels being 2, if the target color point is within the color gamut range, the equation in S2 is simplified as:

[0016]

[0017] The above simplified form shows that x c =f1x1+f2x2+...+f i x i and y c =f1y1+f2y2+...+f i y i The equivalent relationship under the condition of two channels, where k1x c and k2y c are x c and y cThe equation has a unique solution:

[0018] Further preferably, in response to the number of channels being 3, the equation in S2 is in the form of:

[0019]

[0020] The equation has a unique solution:

[0021] Further preferably, in response to the number of channels being 4 or more, the above equation can be rewritten in the following form, i.e. the calculation method for solving the contribution degree of each channel is:

[0022]

[0023] Let

[0024] Simplified as:

[0025] A·x=b

[0026] The above matrix equation can be solved by Lagrange method or sequential quadratic programming method, etc. If Lagrange method is used, the solution is:

[0027] x=A T (AA T ) -1 b

[0028] The sequential quadratic programming method is to approximate the objective function with a quadratic function at each step of iteration, and approximate the general constraint with linear constraint, and construct a series of quadratic programming to approximate the original problem.

[0029] Preferably, when the solution of S2 contains a negative number, the complementary color of the channel corresponding to the negative number is used to participate in the light mixing, specifically including setting the solution to 0 and re-solving the equation of S2. This step indicates that the complementary color of the channel corresponding to the negative number needs to be used to participate in the light mixing in order to achieve the target color coordinate.

[0030] Preferably, after obtaining the contribution degree of each channel that meets the condition, in order to compensate for the different luminous fluxes of different channels, the duty cycle of each channel is obtained by normalization, and the contribution degree of each channel is substituted into the following equation:

[0031]

[0032] Where, D i represents the duty cycle of the i-th channel, Y i represents the luminous flux of the i-th channel, and L represents the luminance. The unit solid angle luminous flux is the luminous intensity, and the unit area luminous intensity is the luminance.

[0033] All the above calculation steps assume that the LED luminous flux of each channel is linearly related to the duty cycle, and in fact it is nonlinearly related, so the following nonlinear calibration is needed:

[0034] The duty cycle obtained according to S3 is D i , let the calibrated duty cycle be D * , the nonlinear relationship satisfies Y=aD 2 +bD+c, where a, b and c are all coefficients of the nonlinear relationship, then the relationship between the actual duty cycle and the calculated duty cycle satisfies:

[0035] Y i D i =aD *2 +bD * +c

[0036] Solve D * as the final output duty cycle.

[0037] According to the second aspect of the present application, a lamp is proposed, which uses the high-precision multi-channel light mixing method as described above to mix light.

[0038] Compared with the prior art, the beneficial results of the present application are:

[0039] The present application provides a high-precision multi-channel light mixing method and a lamp, under the condition of compatible two-color and three-color light mixing calculation, a simple method is provided to solve the duty cycle calculation method of four or more number of light mixing, when the light source scheme of the lamp is changed, there is no need to change the light mixing algorithm model again, when the number of channels is four or more, there is no need to consume additional computing power to select three channels to solve the three-way problem, there is no need to select the light source again, the method can directly solve the duty cycle required to reach the target color coordinate by substituting the basic parameters of the light source, greatly reducing the required computing power, which can be used in low-power MCUs, and has the advantages of reducing cost and power consumption. BRIEF DESCRIPTION OF DRAWINGS

[0040] The accompanying drawings are included to provide a further understanding of embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and serve the purpose of explaining the principles of the application. Other embodiments and many of the intended advantages of the application will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings. Other features, objects, and advantages of the application will become apparent from the detailed description of the non-limiting embodiments made by reference to the drawings:

[0041] Figure 1 is a flowchart of a high-precision multi-channel light mixing method according to an embodiment of the present application;

[0042] Figure 2is a specific flow chart of a high-precision multi-channel light mixing method according to a specific embodiment of the present application;

[0043] Figure 3 is a data chart before and after calibration according to a specific embodiment of the present application. DETAILED DESCRIPTION

[0044] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended for the purpose of interpretation of the related application, and are not limiting of the application. In addition, it should be noted that only the parts related to the application are shown in the accompanying drawings for the purpose of description.

[0045] For the convenience of those skilled in the art, the present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0046] As shown in the accompanying drawings, Figure 1 a high-precision multi-channel light mixing method comprises the following steps:

[0047] S1: obtaining light source basic parameters of each channel of the light source, the light source basic parameters of each channel of the light source including color coordinates and luminous flux of each channel.

[0048] Preferably, the light source basic parameters of each channel of the light source are obtained by an integrating sphere or other photoelectric equipment.

[0049] S2: solving the contribution degree of each channel according to the number of channels, the color coordinates of each channel and the target color coordinates.

[0050] First, the number of channels is set to the to-be-solved parameter, the contribution degree of each channel f 1～i The specific calculation method for solving the contribution degree of each channel is:

[0051]

[0052] wherein x c , y c represent the target color coordinates, i represents the number of channels, x 1～i , y 1～i represent the color coordinates of each channel, and f 1～i represents the contribution degree of each channel, and the color coordinates are substituted into the above parameter equation to solve.

[0053] Further preferably, in response to the number of channels being 2, if the target color point is within the color gamut range, the equation in S2 is simplified as:

[0054]

[0055] The simplified form shows that x c =f1x1+f2x2+...+fi x i With y c = f1y1 + f2y2 +... + f i y i In the equivalent relationship under two-channel conditions, where k1x c and k2y c are common multiples of x c and y c , k1, k2 are constants, the equation has a unique solution:

[0056] Further preferably, in response to the channel number being 3, the equation in S2 is in the form of:

[0057]

[0058] The equation has a unique solution:

[0059] Further preferably, in response to the channel number being 4 or more, the above equation can be rewritten in the following form, i.e. the calculation method for solving the contribution degree of each channel is:

[0060]

[0061] Let

[0062] Simplified as:

[0063] A·x = b

[0064] Solve the above matrix equation by Lagrange method or sequential quadratic programming method, etc. If Lagrange method is used, the solution is:

[0065] x = A T (AA T ) -1 b

[0066] The sequential quadratic programming method is to approximate the objective function with a quadratic function at each step of iteration, and approximate the general constraint with linear constraint, and construct a series of quadratic programming to approximate the original problem.

[0067] When the solution of S2 contains negative numbers, the complementary color of the channel corresponding to the negative number is used to participate in light mixing, specifically including setting the solution to 0 and re-solving the equation of S2.

[0068] S3: Normalize each channel duty cycle using the contribution degree, luminous flux and brightness of each channel.

[0069] After obtaining the contribution degree of each channel satisfying the condition, in order to compensate for the different luminous fluxes of different channels and simultaneously perform normalization to obtain the duty cycle of each channel, the contribution degree of each channel is substituted into the following equation:

[0070]

[0071] where i represents the number of channels, y 1～i represents the color coordinates of each channel, f 1～i represents the contribution degree of each channel, D i represents the duty cycle of the i-th channel, Y i represents the luminous flux of the i-th channel, L represents luminance, the luminous intensity per unit solid angle is luminous intensity, and the luminous intensity per unit area is luminance.

[0072] S4: Nonlinear calibration is performed on the duty cycle of each channel.

[0073] All the above calculation steps assume that the LED luminous flux and duty cycle of each channel are linearly related, and in fact they are nonlinearly related, so the following nonlinear calibration is needed:

[0074] The duty cycle obtained according to S3 is D i , let the calibrated duty cycle be D * , the nonlinear relationship satisfies Y=aD 2 +bD+c, where a, b, and c are coefficients of the nonlinear relationship, then the relationship between the actual duty cycle and the calculated duty cycle satisfies:

[0075] Y i D i =aD *2 +bD * +c

[0076] Solving D * is the final output duty cycle.

[0077] Example 1: Verification based on A667-B bulb lamp.

[0078] In one specific embodiment, Figure 2 a specific flowchart of a high-precision multi-channel light mixing method according to one specific embodiment of the present application is shown, as Figure 2 shown, the specific flowchart includes:

[0079] First, the basic parameters of each channel of the light source are obtained, including the color coordinates and luminous flux in the CIE1931 color space, and the basic parameters of the light source based on the bulb lamp are as follows:

[0080] Light source color x y Y (1 m) R 0.6789 0.3177 40.725 G 0.1505 0.7051 134.95 B 0.1521 0.0457 32.79 W 0.514 0.4385 781.57

[0081] The color coordinates in CIE1931 color space and the target color coordinates are substituted into the following parameter equation ① to solve the channel contribution degree, and the parameter equation ① is as follows:

[0082]

[0083] Wherein, x c , y c represent the target color coordinates, i represents the channel number, x 1～i , y 1～i represent the channel color coordinates, and f 1～i represents the channel contribution degree.

[0084] As an example, when the channel number is 2, if the target color point is within the color gamut range, the parameter equation ① is simplified as:

[0085]

[0086] Wherein, k1x c and k2y c are common multiples of x c and y c , k1 and k2 are constants, and the parameter equation ① has a unique solution:

[0087] Another example is that when the channel number is 3, the parameter equation ① is in the form of:

[0088]

[0089] The parameter equation ① has a unique solution:

[0090] In other examples, when the channel number is 4 or more, the parameter equation ① is rewritten in the following form:

[0091]

[0092] Let

[0093] Simplified as:

[0094] A·x=b

[0095] Solved by Lagrange method:

[0096] x=A T (AA T ) -1 b

[0097] Then, it is judged whether the contribution degrees of all channels are all greater than or equal to 0, if not, the negative solution is set to 0, the equation 1 is solved again, the color coordinates in the CIE1931 color space and the target color coordinates are substituted into the parameter equation 1 to solve, and it is judged again whether the contribution degrees of all channels are all greater than or equal to 0; if yes, the brightness L is introduced to compensate for different luminous fluxes of different channels, normalization is carried out, and the duty cycles of all channels are output.

[0098] Based on the contribution degrees of all channels of the ball bubble lamp, the actual calculation data of the duty cycles before calibration are as follows:

[0099]

[0100] Finally, the output duty cycles of all channels are nonlinearly calibrated.

[0101] Based on the actual measured parameters before calibration of the ball bubble lamp, the actual calculation data of the duty cycles after calibration and the actual measured parameters after calibration are as shown in Figure 3 Figure 3 In the formula, SDCM represents a color tolerance, the SDCM refers to a difference between a calculated formula and a target standard, and is calculated under a single illumination light source, and the smaller the value is, the higher the accuracy is.

[0102] As can be seen from the embodiment 1, under the condition of compatible double-color and three-color mixed light calculation, the duty cycles of four or more numbers of mixed light can also be directly calculated by the high-precision multi-channel mixed light method and the lamp proposed in the application, without additional calculation power to select three channels to solve the three-channel problem, without the need to select the light source again; when the light source scheme of the lamp is changed, the mixed light algorithm model does not need to be selected again, the duty cycles required to reach the target color coordinates can be directly solved by substituting the basic parameters of the light source, the required calculation power is greatly reduced, the target color point can be accurately reproduced, the requirement for the calculation power of the hardware is low, the method can be applied to the MCU with low calculation power and low cost, and the purpose of reducing cost and power consumption is achieved.

[0103] The above description is only the preferred embodiment of the application and the explanation of the applied technical principles. It should be understood by those skilled in the art that the application range involved in the application is not limited to the technical solutions formed by the specific combinations of the above technical features, and also covers other technical solutions formed by the above technical features or equivalent features in any combination without departing from the above inventive concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features disclosed in the application (but not limited to) with similar functions.​

Claims

1. A high-precision multi-path light mixing method, characterized in that, The method comprises the following steps: S1: acquiring light source basic parameters of each channel of the light source, the light source basic parameters of each channel of the light source comprising color coordinates and luminous flux of each channel; S2: solving contribution degrees of each channel according to the number of channels, the color coordinates of each channel and target color coordinates; S3: obtaining duty cycles of each channel by normalization using the contribution degrees of each channel, luminous flux and brightness; S4: performing nonlinear calibration on the duty cycles of each channel; The calculation method for solving the contribution degrees of each channel in S2 is: wherein, represents a target color coordinate, i represents the number of channels, , represents a color coordinate of each channel, represents a contribution degree of each channel; The calculation method for obtaining the duty cycles of each channel by normalization in S3 is: wherein, Dpi represents the duty cycle of the i-th channel, Lpi represents the luminous flux of the i-th channel, L represents the luminance.

2. The high-precision multi-path light mixing method according to claim 1, characterized in that, The light source basic parameters of each channel of the light source are acquired by an integrating sphere in S1.

3. The high-precision multi-path light mixing method according to claim 1, characterized in that, In response to the number of channels being 2, if a target color point is within a color gamut range, the equation in S2 is simplified as: wherein is and a common multiple of 2 and 3, the equation has a unique solution: .

4. The high-precision multi-path light mixing method according to claim 1, characterized in that, In response to the number of channels being 3, the equation in S2 is in the form of: The equation has a unique solution: .

5. The high-precision multi-path light mixing method according to claim 1, characterized in that, In response to the number of channels being more than 4, the calculation method for solving the contribution degrees of each channel is: Let The solution is obtained by using the Lagrange method as: That is, the contribution degrees of each channel are obtained.

6. The high-precision multi-path light mixing method according to claim 1, wherein, When the solution of S2 contains a negative number, a complementary color of a channel corresponding to the negative number is used to participate in light mixing, specifically comprising setting the solution to 0, and re-solving the equation of S2.

7. The high-precision multi-path light mixing method according to claim 1, characterized in that, The method for performing nonlinear calibration on the duty cycles of each channel in S4 is: Wherein, the nonlinear relationship satisfies a, b and c are all coefficients of the nonlinear relationship, D represents the calibrated duty cycle, and the solved is the final output duty cycle.

8. A luminaire characterized by, The light is mixed by using the high-precision multi-channel light mixing method according to any one of claims 1-7.

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