METHOD AND SYSTEM FOR FIXING INITIAL BRIGHTNESS LEVEL OF LIGHT FIXTURE, AND LIGHT FIXTURE SYSTEM

Abstract

A method for fixing an initial brightness level of lights is provided. Gamma correction is performed on the light based on a dynamic Gamma curve. When a user adjusts brightness of the light based on the dynamic Gamma curve, a dynamic Gamma curve image is valid all the time when a set current brightness level n changes from 0 to N, and when x>0, the dynamic Gamma curve image is continuous, and accordingly, brightness of the light continuously changes gradually. Further, by calculating an initial brightness PWM critical duty ratio D of light sources, the dynamic Gamma curve is customized according to the light, so that an initial brightness level position of the light sources in the same model is fixed and unified.

Claims

1. A method for fixing an initial brightness level of a light fixture, comprising steps of: performing a Gamma correction on the light fixture based on a dynamic Gamma curve, wherein the dynamic Gamma curve is $G\left(x\right)=\{\begin{array}{cc}0& \left(x=0\right)\\ \left(1-b\right)x^{\gamma }+b& \left(0<x\le 1,0<b<1\right)\end{array};$ in which, G(x) is the dynamic Gamma curve, x=n/N, n is a current brightness level set by a user, N is a maximum brightness level of the light fixture, γ is a current Gamma value set by the user, and b is a current initial brightness PWM threshold.

2. The method according to claim 1, wherein the current initial brightness PWM threshold b is: $b=G_0\left(x\right).Math.\frac{f}{f_0}\left(0\le x\le 1\right);$ in which, G.sub.0(x) is a function of an original Gamma curve of the light fixture, x=n.sub.0/N, n.sub.0 is an original initial brightness level of the light fixture, N is the maximum brightness level of the light fixture, f.sub.0 is an original refresh rate when the light fixture adopts the original Gamma curve G.sub.0(x), and f is a current refresh rate set by the user.

3. The method according to claim 2, wherein, the function of the original Gamma curve of the light fixture is set to be G.sub.0(x)=x.sup.γ.sup.0, (0≤x≤1), wherein γ.sub.0 is an original Gamma value set by the user.

4. The method according to claim 3, wherein the original Gamma value γ.sub.0 ranges from 2.0 to 2.4.

5. The method according to claim 2, wherein the original initial brightness level n.sub.0 and the original refresh rate f.sub.0 of the light fixture are acquired by the following method: setting the Gamma curve of the light fixture as the original Gamma curve G.sub.0(x); adjusting the light fixture of which the Gamma curve is the original Gamma curve to an initial brightness state; acquiring the original refresh rate f.sub.0 of the light fixture with the original Gamma curve in the initial brightness state; and acquiring the original initial brightness level n.sub.0 of the light fixture with the original Gamma curve in the initial brightness state.

6. The method according to claim 5, wherein, before adjusting the light fixture of which the Gamma curve is the original Gamma curve to the initial brightness state, the method further comprises: placing the light fixture in a dark room.

7. The method according to claim 5, wherein, the method of acquiring the original initial brightness level n.sub.0 of the light fixture comprises: respectively setting each Gamma curve of A sets of light fixtures in the same model as the original Gamma curve G.sub.0(x); respectively adjusting A sets of light fixtures of which the Gamma curve is the original Gamma curve to the initial brightness state, and acquiring an experimental initial brightness level n.sub.a of each light fixture in the initial brightness state, wherein a is ≥2, which is a positive integer; and the original initial brightness level n.sub.0 is a maximum value of the acquired A sets of experimental initial brightness levels n.sub.a.

8. The method according to claim 7, wherein, before adjusting the light fixture of which the Gamma curve is the original Gamma curve to the initial brightness state, the method further comprises: placing the light fixture in a dark room.

9. The method according to claim 1, wherein the current Gamma value γ ranges from 2.0 to 2.4.

10. A system for fixing an initial brightness level of a light fixture, comprising: an adjusting module for performing Gamma correction on the light fixture based on a dynamic Gamma curve, wherein the dynamic Gamma curve is $G\left(x\right)=\{\begin{array}{cc}0& \left(x=0\right)\\ \left(1-b\right)x^{\gamma }+b& \left(0<x\le 1,0<b<1\right)\end{array};$ in which, G(x) is the dynamic Gamma curve, x=n/N, n is a current brightness level set by a user, N is a maximum brightness level of the light fixture, γ is a current Gamma value set by the user, and b is a current initial brightness PWM threshold.

11. A light fixture system, comprising a light source and a control unit connected to each other, wherein the dynamic Gamma curve according to claim 1 is pre-set in the control unit, and the control unit is configured to receive a current brightness level input by a user, and output a current PWM duty ratio corresponding to the current brightness level to the light source according to the dynamic Gamma curve, so that the light source emits light according to the current PWM duty ratio.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 is a graph showing the relationship between current and brightness of an LED light source in the prior art.

[0040] FIG. 2 is a schematic diagram of a left-shifted Gamma curve according to the present invention.

[0041] FIG. 3 is a schematic diagram of an upward-shifted Gamma curve according to the present invention.

[0042] FIG. 4 is a schematic diagram of a dynamic Gamma curve according to the present invention.

[0043] FIG. 5 is a structural diagram of a light fixture system according to the present invention.

DETAILED DESCRIPTION

[0044] The accompanying drawings are only for illustrative descriptions and cannot be understood as a limitation to the patent. In order to better illustrate the following embodiments, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent a size of an actual product; and it is understandable for those skilled in the art that some well-known structures in the accompanying drawings and their descriptions may be omitted.

Embodiment 1

[0045] A method for fixing an initial brightness level of a light fixture, in which Gamma correction is performed on the light fixture based on a dynamic Gamma curve, the dynamic Gamma curve is as follows:

[00004]$G\left(x\right)=\{\begin{array}{cc}0& \left(x=0\right)\\ \left(1-b\right)x^{\gamma }+b& \left(0<x\le 1,0<b<1\right)\end{array};$

[0046] wherein, G(x) is a Gamma curve, x=n/N, n is a current brightness level set by a user, N is a maximum brightness level of the light fixture, γ is a current Gamma value set by the user, and b is a current initial brightness PWM threshold, n and N are both positive integers.

[0047] In order to fix the initial brightness level of the light fixture, the Gamma curve of the light fixture can be set to the dynamic Gamma curve according to the present embodiment. Gamma correction is performed on the light fixture based on the dynamic Gamma curve of the present embodiment.

[0048] The dynamic Gamma curve of the present embodiment is transformed from an original Gamma curve. Specifically, a dotted line in FIG. 2 is a 2.2Gamma curve y=x.sup.2.2 in the prior art, passing through an origin (0, 0) and (1, 1). An x axis represents normalization of the brightness level of the light fixture, referred to x=n/N, where N is the maximum brightness level of the light fixture, n is the current brightness level set by the user, 0≤n≤N, so 0≤x≤1. A y axis represents a PWM duty ratio, 0≤y≤1, and the greater the PWM duty ratio, the higher the brightness of the light fixture.

[0049] It can be understood that in order to achieve continuous adjustment of brightness of the light fixture, the Gamma curve is required to be continuous when 0≤x≤1, and 0≤y≤1. Simultaneously, in order to solve the problem that the light fixture does not emit light until an input current of the light fixture reaches a threshold current, the transformed Gamma curve should intersect with a positive half axis of the y axis with an intercept of b (b>0), which is the current initial brightness PWM threshold. The transformed Gamma curve passes through a point (0, b).

[0050] As shown in FIG. 2 and FIG. 3, if the 2.2Gamma curve y=x.sup.2.2 in the prior art (as shown by dashed lines in FIG. 2 and FIG. 3) is directly translated leftwards by x.sub.0 or upwards by b, y=(x+x.sub.0).sup.2.2 (as shown by a solid line in FIG. 2) or y=x.sup.2.2+b (as shown by a solid line in FIG. 3) is obtained. Although it is possible to make the Gamma curve intersect with the positive half axis of the y axis, the directly translated and transformed Gamma curve does not pass through a point (1, 1), its image would go beyond a range of 0≤x≤1, and 0≤y≤1, so that a brightness adjusting requirement of the light fixture when x is large cannot be met. Therefore, after translated, the Gamma curve is also needed to be aligned for stretching transformation to make the image of the Gamma curve not beyond the range of 0≤x≤1, and 0≤y≤1.

[0051] As shown in FIG. 4, according to a preferred embodiment, according to that the image of the transformed Gamma curve needs to always pass through the point (1, 1) and the point (0, b), and the dynamic Gamma curve obtained after transformation (as shown by a solid line in FIG. 4) is:

[00005]$G\left(x\right)=\{\begin{array}{cc}0& \left(x=0\right)\\ \left(1-b\right)x^{\gamma }+b& \left(0<x\le 1,0<b<1\right)\end{array};$

[0052] wherein γ is a current Gamma value set by the user.

[0053] When x=0, G(x)=0, its physical meaning is that when the current brightness level n set by the user is 0, that is, when x=0, the PWM duty ratio is 0, and the light fixture does not emit light.

[0054] Based on the above-mentioned dynamic Gamma curve, when the user adjusts brightness of the light fixture, a dynamic Gamma curve image is valid all the time when the set current brightness level n changes from 0 to N, and when x>0, the dynamic Gamma curve image is continuous, and accordingly, the brightness of the light fixture continuously changes gradually.

[0055] The current initial brightness PWM threshold b according to an embodiment is specifically as follows:

[00006]$b=G_0\left(x\right).Math.\frac{f}{f_0}\left(0\le x\le 1\right);$

[0056] wherein, G.sub.0(x) is a function of an original Gamma curve of the light fixture, x=n.sub.0/N, no is an original initial brightness level of the light fixture, N is the maximum brightness level of the light fixture, f.sub.0 is an original refresh rate when the light fixture adopts the original Gamma curve G.sub.0(x), and f is a current refresh rate set by the user.

[0057] The current initial brightness PWM threshold b will change with a change of the current refresh rate f set by the user, and at the same time, the original initial brightness level n.sub.0, the maximum brightness level N and the original refresh rate f.sub.0 will be different for light fixtures in different models. Therefore, the Gamma curve obtained based on transformation of the current initial brightness PWM threshold b is the dynamic Gamma curve, the dynamic Gamma curve can adapt to the light fixtures in different models and can be customized according to different light fixtures, and the initial brightness level of the same light fixture is fixed and unchanged under any current refresh rate f.

[0058] The function of the original Gamma curve of the light fixture is set to be G.sub.0(x)=x.sup.γ.sup.0, (0≤x≤1), wherein γ.sub.0 is an original Gamma value set by the user.

[0059] In combination with the function of the original Gamma curve, it can be obtained:

[00007]$b={\left(\frac{n_0}{N}\right)}^{{\gamma }_0}.Math.\frac{f}{f_0};$

[0060] wherein n.sub.0 is the original initial brightness level of the light fixture, N is the maximum brightness level of the light fixture, f.sub.0 is the original refresh rate when the light fixture adopts the original Gamma curve G.sub.0(x), f is the current refresh rate set by the user, and γ.sub.0 is the original Gamma value set by the user.

[0061] A derivation process of the dynamic Gamma curve is described as follows.

[0062] For the light fixture of which the Gamma curve is the original Gamma curve, in an initial brightness state (namely, the brightness level is the original initial brightness level n.sub.0), and the refresh rate is the original refresh rate f.sub.0, x=n.sub.0/N is substituted into the original Gamma curve G.sub.0=x.sup.γ0(0≤x≤1) an original critical duty ratio D.sub.0 when the light fixture is at the initial brightness level is thus acquired:

[00008]$D_0=G\left(\frac{n_0}{N}\right)={\left(\frac{n_0}{N}\right)}^{{\gamma }_0};$

[0063] the original critical duty ratio D.sub.0 is a PWM duty ratio when the light fixture of which the Gamma curve is the original Gamma curve starts to emit light.

[0064] The reason that the initial brightness level of the light fixture changes with the refresh rate is a change of effective action time t of the current. Therefore, the initial brightness level can be fixed merely by fixing the effective action time t of the current when the light fixture starts to emit light under any current refresh rate f.

[0065] In order to fix the effective action time t of the current, let t=D.sub.0T.sub.0=DT, wherein, T=1/f, T.sub.0=1/f.sub.0, in combination with a relational expression of the original critical duty ratio D.sub.0, it is obtained by substitution that:

[00009]${\left(\frac{n_0}{N}\right)}^{{\gamma }_0}.Math.\frac{1}{f_0}=D\frac{1}{f};$

[0066] the critical duty ratio D of the light fixture at the initial brightness level under any current refresh rate f is obtained:

[00010]$D={\left(\frac{n_0}{N}\right)}^{{\gamma }_0}.Math.\frac{f}{f_0};$

[0067] the critical duty ratio D is the PWM duty ratio when the light fixture starts to emit light under any current refresh rate f.

[0068] It can be seen from the above equation that the critical duty ratio D of the light fixture changes with the current refresh rate f.

[0069] It can be understood that if a fixed Gamma curve is used, then if the critical duty ratio D (y-axis coordinate) changes, an x-axis coordinate corresponding to the critical duty ratio D will also change, and according to x=n/N, the initial brightness level n will also change, resulting in uncertainty of the initial brightness level n under different refresh rates.

[0070] The current initial brightness PWM threshold b is set as the critical duty ratio D, the dynamic Gamma curve which changes dynamically with the change of the current refresh rate f is obtained, the dynamic Gamma curve image passes through a point (0, D), and the physical meaning of the point is that, for the light fixture under any refresh rate, as long as the brightness level is adjusted as the initial brightness level, the critical duty ratio D can be reached, so that the light fixture can emit light, achieving effect of fixing the initial brightness level.

[0071] In order to achieve that the light fixture does not emit light when x=0 for the Gamma, the dynamic Gamma curve is sub-sectioned when x=0, and the obtained final dynamic Gamma curve is:

[00011]$G\left(x\right)=\{\begin{array}{cc}0& \left(x=0\right)\\ \left(1-{\left(\frac{n_0}{N}\right)}^{{\gamma }_0}.Math.\frac{f}{f_0}\right)x^{\gamma }+{\left(\frac{n_0}{N}\right)}^{{\gamma }_0}.Math.\frac{f}{f_0}& \left(0<x\le 1\right)\end{array};$

[0072] wherein, G(x) is the Gamma curve, x=n/N, n is the current brightness level set by the user, N is the maximum brightness level of the light fixture, γ is the current Gamma value set by the user, γ.sub.0 is the original Gamma value set by the user, f is the current refresh rate set by the user, n.sub.0 is the original initial brightness level of the light fixture, f.sub.0 is the original refresh rate of the light fixture, and n, n.sub.0 and N are all positive integers.

[0073] The current Gamma value γ and the current refresh rate f can be set by the user according to the current usage scenario.

[0074] Gamma correction is performed on the light fixture based on the above-mentioned dynamic Gamma curve such that a controller for controlling the brightness of the light fixture receives the current brightness level n input by the user, and outputs a corresponding PWM duty ratio to a driver according to the dynamic Gamma curve, so that the driver controls the brightness of the light fixture according to the corresponding PWM duty ratio.

[0075] For the light fixture under any set current refresh rate f, the light fixture is turned off at a brightness level 0 and starts to emit light at a brightness level 1. When the brightness level is adjusted from the 1st level to the Nth level, the light fixture emits light all the time without a loss of the brightness level. By arbitrarily changing the current refresh rate f, a position of the initial brightness level can still be dynamically maintained.

[0076] A general formula of the dynamic Gamma curve G(x) is still in the form of a power function when 0<x≤1, thus conforming to the perception rule of human eyes on brightness. Furthermore, the dynamic Gamma curve customized according to the light fixture is more proper and natural than the original Gamma curve.

[0077] According to some embodiments, the original initial brightness level n.sub.0 and the original refresh rate f.sub.0 of the light fixture are acquired according to the following method: [0078] setting the Gamma curve of the light fixture as the original Gamma curve G.sub.0(x); [0079] adjusting the light fixture of which the Gamma curve is the original Gamma curve to the initial brightness state. [0080] acquiring the original refresh rate f.sub.0 of the light fixture with the original Gamma curve in the initial brightness state; [0081] acquiring the original initial brightness level n.sub.0 of the light fixture with the original Gamma curve in the initial brightness state.

[0082] In the embodiments, preferably, there are various method for acquiring the original initial brightness level n.sub.0 of the light fixture with the original Gamma curve in the initial brightness state.

[0083] Due to errors of industrial manufacturing, different light fixtures in the same model may have a slight difference, thus, when the original initial brightness level n.sub.0 is acquired, it needs to reduce the errors. As one embodiment, by testing a plurality of light fixtures, the original initial brightness level n.sub.0 is acquired. The method of acquiring the original initial brightness level n.sub.0 of the light fixture specifically comprises: [0084] respectively setting each Gamma curve of A sets of light fixtures in the same model as the original Gamma curve G.sub.0(x); [0085] respectively adjusting the A sets of light fixtures of which the Gamma curve is the original Gamma curve to the initial brightness state, and acquiring an experimental initial brightness level n.sub.a of each light fixture in the initial brightness state, wherein A is ≥2, which is a positive integer;

[0086] the original initial brightness level n.sub.0 is a maximum value of the acquired A sets of experimental initial brightness levels n.sub.a.

[0087] Taking the maximum value of the plurality of experimental initial brightness levels n.sub.a as the original initial brightness level n.sub.0, the value is accurate, and it can be guaranteed that when the brightness level of the light fixture reaches the initial brightness level, the critical duty ratio D is large enough so that the light fixture can emit light.

[0088] As another embodiment, in order to reduce a number of test light fixtures, only one light fixture may be tested, and the experimental initial brightness level n.sub.1 of the light fixture obtained by testing may be directly increased by several levels. Specifically, acquiring the original initial brightness level n.sub.0 of the light fixture in the present embodiment specifically comprises: adjusting the light fixture of which the Gamma curve is the original Gamma curve to the initial brightness state, and acquiring the experimental initial brightness level n.sub.1 of the light fixture in the initial brightness state;

[0089] n.sub.0=n.sub.1+m, m≥1, and m is a positive integer.

[0090] In the embodiment, preferably, m=3, that is, n.sub.0=n.sub.1+3.

[0091] In the embodiment, it is not needed to perform experiments on the multiple light fixtures, which is simple and fast in operation.

[0092] It can be understood that n.sub.a and n.sub.1 are both positive integers.

[0093] Before adjusting the light fixture of which the Gamma curve is the original Gamma curve to the initial brightness state, the method further comprises: placing the light fixture in a dark room.

[0094] By placing the light fixture in the dark room, the initial brightness state of the light fixture can be determined more accurately, so that the subsequently obtained original initial brightness level n.sub.0 is more accurate.

[0095] In a preferred embodiment, the original Gamma value γ.sub.0 ranges from 2.0 to 2.4, and preferably, the current Gamma value γ ranges from 2.0 to 2.4.

[0096] In a preferred embodiment, the original Gamma value γ.sub.0 may be 2.0 or 2.2 or 2.4, etc. the current Gamma value γ may be 2.0 or 2.2 or 2.4, etc. and the maximum brightness level N of the light fixture may be 100 or 255 or 65535, etc.

[0097] In the embodiment, preferably, the light fixture includes an LED light source.

Embodiment 2

[0098] A system for fixing an initial brightness level of light fixtures is further provided according to one embodiment, including:

[0099] an adjusting module for performing Gamma correction on the light fixture based on a dynamic Gamma curve, the dynamic Gamma curve is as follows:

[00012]$G\left(x\right)=\{\begin{array}{cc}0& \left(x=0\right)\\ \left(1-b\right)x^{\gamma }+b& \left(0<x\le 1,0<b<1\right)\end{array};$

[0100] wherein, G(x) is a Gamma curve, x=n/N, n is a current brightness level set by a user, N is a maximum brightness level of the light fixture, γ is a current Gamma value set by the user, and b is a current initial brightness PWM threshold.

[0101] The current initial brightness PWM threshold b is specifically as follows:

[00013]$b=G_0\left(x\right).Math.\frac{f}{f_0}\left(0\le x\le 1\right);$

[0102] wherein, G.sub.0(x) is a function of an original Gamma curve of the light fixture, x=n.sub.0/N, no is an original initial brightness level of the light fixture, N is the maximum brightness level of the light fixture, f.sub.0 is an original refresh rate when the light fixture adopts the original Gamma curve G.sub.0(x), and f is a current refresh rate set by the user.

[0103] The function of the original Gamma curve of the light fixture is set to be G.sub.0(x)=x.sup.γ.sup.0, (0≤x≤1), wherein γ.sub.0 is an original Gamma value set by the user.

[0104] Preferably, the original Gamma value γ.sub.0 ranges from 2.0 to 2.4.

[0105] The original initial brightness level n.sub.0 and the original refresh rate f.sub.0 of the light fixture are acquired by the following method: [0106] setting the Gamma curve of the light fixture as the original Gamma curve G.sub.0(x); [0107] adjusting the light fixture of which the Gamma curve is the original Gamma curve to an initial brightness state; [0108] acquiring the original refresh rate f.sub.0 of the light fixture with the original Gamma curve in the initial brightness state; [0109] acquiring the original initial brightness level n.sub.0 of the light fixture with the original Gamma curve in the initial brightness state.

[0110] As one embodiment, the method of acquiring the original initial brightness level n.sub.0 of the light fixture specifically comprises: [0111] respectively setting each Gamma curve of A sets of light fixtures in the same model as the original Gamma curve G.sub.0(x); [0112] respectively adjusting the A sets of light fixtures of which the Gamma curve is the original Gamma curve to the initial brightness state, and acquiring an experimental initial brightness level n.sub.a of each light fixture in the initial brightness state, wherein A is ≥2, which is a positive integer;

[0113] the original initial brightness level n.sub.0 is a maximum value of the acquired A sets of experimental initial brightness levels n.sub.a.

[0114] As another embodiment of the embodiment, the method of acquiring the original initial brightness level n.sub.0 of the light fixture specifically comprises: [0115] adjusting the light fixture of which the Gamma curve is the original Gamma curve to the initial brightness state, and acquiring an experimental initial brightness level n.sub.1 of the light fixture in the initial brightness state:

[0116] n.sub.0=n.sub.1+m, m≥1, and m is a positive integer.

[0117] Before adjusting the light fixture of which the Gamma curve is the original Gamma curve to the initial brightness state, the light fixture is placed in a dark room.

[0118] Preferably, the original Gamma value γ ranges from 2.0 to 2.4.

Embodiment 3

[0119] A computer-readable storage medium, on which a computer program is stored, is further provided, and when the computer program is executed by a processor, the method for fixing the initial brightness level of the light fixture according to Embodiment 1 is implemented.

Embodiment 4

[0120] As shown in FIG. 5, the present embodiment provides a light fixture system, including a light source and a control unit connected to each other. The dynamic Gamma curve according to Embodiment 1 is pre-set in the control unit.

[0121] The control unit is configured to receive a current brightness level input by a user, and outputs a current PWM duty ratio corresponding to the current brightness level to the light source according to the dynamic Gamma curve, so that the light source emits light according to the current PWM duty ratio.

[0122] In a preferred embodiment, the control unit may include a controller and a driver connected to each other, and the driver is further connected to the light source. When the light fixture system works, the controller receives the current brightness level input by the user, and outputs the current PWM duty ratio corresponding to the current brightness level to the driver according to the dynamic Gamma curve, so that the driver controls the light source to emit light according to the current PWM duty ratio.

[0123] Obviously, the above-mentioned embodiments of the present invention are merely embodiments to clearly illustrate the technical solution of the present invention, and are not intended to limit the specific embodiment of the present invention. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the claims of the present invention shall be included in the protection scope of the claims of the present invention.