CN113989403A

CN113989403A - LED backlight source implementation method capable of highlighting body color

Info

Publication number: CN113989403A
Application number: CN202111304341.4A
Authority: CN
Inventors: 刘岸青; 魏敏晨; 李鹏
Original assignee: Shenzhne Chromatech Lighting Technology Co ltd
Current assignee: Shenzhen Aitushi Innovation Technology Co ltd
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2022-01-28

Abstract

The invention discloses a method for realizing an LED backlight source with prominent main body color, comprising the following steps of S1, transmitting detection information to an algorithm module by an optical detection device; step S2, the algorithm module judges the information of the dominant color hue area in the scene through the detection information; s3, extracting a main color sample of the main color according to the information of the main color tone area; s4, respectively calculating a first color coordinate of the main standard color sample under a reference light source and a second color coordinate of the main standard color sample under a target light source according to the main standard color sample; s5, calculating a primary color saturation vector according to the first and second color coordinates; s6: evaluating whether the direction of the saturation vector of the dominant color is towards the color enhancement direction and evaluating whether the saturation vectors of other hues are towards the color reduction direction; s7, outputting the current main target light source driving information when the main color saturation vector direction faces to the color enhancement direction; s8: the saturation vector direction of other hues is towards the color reduction direction; outputting other hue sub-target light source driving information; the driving device generates the total target spectrum based on the main and other hue sub target light source driving information S9.

Description

LED backlight source implementation method capable of highlighting body color

Technical Field

The invention relates to the field of spectrums, in particular to a method for realizing an LED backlight source with prominent body color.

Background

The appearance of various object colors by common white light sources such as fluorescent lamps and Light Emitting Diode (LED) light sources tends to be simultaneously intensified or weakened in comparison with natural light. In the same lighting scene, the colors either become brighter at the same time or become dimmer at the same time, failing to highlight a certain color. However, in film lighting, artwork lighting and special commercial lighting scenes, users often need to highlight one to two colors in the scene, namely, body colors, such as accent red, other colors are unchanged, accent green and blue, fade other colors, and the like.

The display of the object color is determined by the reflection spectrum of the object and the spectrum of the illumination source. Common white light sources such as fluorescent lamps and LEDs have spectral energy distributions in the red, green and blue bands, which allows similar characteristics to be exhibited by the colors of various colored objects: the various colors of an object under ordinary light sources are either simultaneously accentuated or simultaneously accentuated, as compared to the color of the object under daylight, as shown in fig. 1: FIG. 1 shows the spectrum of an LED white light source illuminated with a monochromatic object (Monser 5P 5/10 color chart) and reflected light, and it can be seen that when the LED white light is illuminated on the color chart, a portion of the wavelength bands of light (500 nm to 600nm in the figure) are partially absorbed, while other bands of light are reflected; the spectrum of the reflected light is different from that of the incident light, and the blue energy (400nm to 500nm band) of the reflected light accounts for a larger proportion than the true color of the object, and the color of the object is enhanced as a whole. The above is a spectral change analysis of a color sample, often with multiple colors in an illumination scene. In order to emphasize a specific color, the existing solutions are mainly the following two:

1. to match a particular light source to a body color, some fluorescent tubes, for example, have an accentuated effect on red and green, and a diminished effect on other colors.

2. Instead of using a white light source, a reddish light source is used for red enhancement, or a greenish light source is used for green enhancement. For example, the fresh market often uses a red lampshade, and uses reddish light to irradiate meat, so that the meat looks brighter.

The existing light source matching scheme has the following defects:

1. multiple attempts are required: different light sources are needed for matching different main body colors, and because various white light sources are designed not to design a luminous spectrum for highlighting a certain main body color but to simulate the color rendering effect of sunlight as much as possible and are designed according to a certain Color Rendering Index (CRI), the different light sources need to be matched for many times for highlighting a specific main body color, so that the requirement of real-time adjustment cannot be met, and the feasibility is low.

2. The main body color has poor strengthening effect: white light sources have a limited degree of emphasis on a particular color and inevitably emphasize other non-body colors at the same time, which makes the body color not effectively highlighted. Fig. 2 shows the spectrum of the F32T8 fluorescent lamp tube, and fig. 3 shows the evaluation of the percentage enhancement/reduction of the color of 16 average color samples using IES-TM30 (see David, Aurelian et al, developments in the IES method for evaluating the color rendition of the light source, quick optical press 23.12(2015), numeral 1 representing a red color sample, numeral 6 representing a green color sample, numeral 12 representing a blue color sample, and the other numerals representing intermediate colors between the three, it can be seen that this tube, although yellow-green (corresponding to numerals 4-7) is enhanced, also reduces the red and blue-green (1-2, 8-11), but the maximum difference between the enhancement percentage and the reduction percentage is only 20% (5 vs. 10 color samples), which is not obvious in human eye identification and camera identification.

The existing non-white light source matching scheme has the following defects:

1. the protruding degree of the main body is uncontrollable: the corresponding color can be strengthened by wrapping colored filter paper on the white light exterior or using a colored luminescent light source, but the color strengthening degree is not controllable, and as a result, the object color is strengthened excessively and is beyond the comfortable range of human eye recognition. One example is to illuminate the meat with a reddish light source, although the meat is bright in color, the color is perceived by the consumer as false.

2. Different colored filter paper or colored light sources are matched for different main body colors, and the feasibility is low.

3. Colored light sources affect the comfort of the human eye and also affect the white balance settings of devices such as cameras, video cameras, etc., so that the color effect of an object cannot be truly captured by the human eye or the electronic device.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides a method for realizing an LED backlight source with prominent main body color.

The technical scheme of the invention is as follows: an LED backlight source realizing method for highlighting body color comprises the following steps:

step S1, the optical detection device transmits the detection information to the algorithm module;

step S2; the algorithm module judges the information of the dominant color hue region in the scene through the detection information;

step S3, extracting a main color sample of the main color according to the information of the main color tone area;

step S4, respectively calculating a first color coordinate of the main standard color sample under a reference light source and a second color coordinate of the main standard color sample under a target light source according to the main standard color sample;

step S5, calculating a primary color saturation vector of the primary color sample according to the first and second color coordinates;

step S6: evaluating whether the direction of the saturation vector of the dominant color is towards the color enhancement direction and evaluating whether the saturation vectors of other hues are towards the color reduction direction;

step S7, if the vector direction of the primary color saturation is towards the color enhancement direction, outputting the current driving information of the primary target light source;

step S8: if the saturation vector direction of other hues is toward the color-decreasing direction; outputting other hue sub-target light source driving information;

in step S9, the driving device generates the total target spectrum based on the main and other hue sub target light source driving information.

The preferable technical scheme is as follows: the detection information in step S1 includes spectral or RGB color information.

The preferable technical scheme is as follows: the reference light source in step S4 is obtained by the algorithm module based on the detection information in step S1.

The preferable technical scheme is as follows: step S6: evaluating whether the direction of the dominant color saturation vector is towards the color enhancement direction; if the color is not towards the color enhancement direction, the dominant difference value is obtained by subtracting the value of the dominant standard color wavelength range from the magnitude of the current dominant color saturation vector.

The preferable technical scheme is as follows: and according to the main difference value, obtaining the secondary driving information of the secondary target light source after the next iteration by optimizing the iteration parameters.

The preferable technical scheme is as follows: according to the secondary driving information, firstly, whether the ground color sample is white light needs to be judged, and the steps are as follows:

step S31: reading whether the ground color is white light or not according to the information of the ground color database;

step S32, if the ground color is white light, executing step S4;

step S33, if the ground color is not white light, step S31 is performed.

The preferable technical scheme is as follows: evaluating whether the saturation vectors of other hues are toward the color-decreasing direction in step S6; if the color is towards the color weakening direction, obtaining a secondary difference value by subtracting the size of the current other color saturation vectors from the wavelength range values of other color standard colors, obtaining the driving information of a secondary target light source of the next iteration by optimizing iteration parameters according to the secondary difference value, and continuously executing the step S4 to calculate a second secondary color coordinate under the target light source.

The preferable technical scheme is as follows: the colors in the color reduction and color enhancement refer to the standard color wavelength range values based on the dominant color or other colors, the color reduction direction refers to the direction of saturation vector of the hue into the standard color wavelength range values, and the color enhancement direction refers to the direction of saturation vector of the hue out of the standard color wavelength range values.

The invention achieves the following beneficial effects: the invention provides a lighting method for highlighting a body color, which can automatically identify the body color in a scene, adjust a light-emitting spectrum in real time, strengthen the body color and weaken other colors so as to achieve the purpose of highlighting the body color. The invention also provides a lighting device corresponding to the method, and the process is realized.

1. The invention solves the problem that the main body has uncontrollable or low degree of protrusion, and can quantitatively set the degree of color protrusion of the main body in the system.

2. The invention solves the problem of matching the main body color, can manually set or automatically detect the main body color of the scene, and the system automatically adjusts the luminous spectrum to strengthen the main body color. The method and the system can use the same light source to meet different main body color requirements of different scenes, do not need to match multiple light sources, and have strong feasibility.

3. The invention solves the problem of non-white light. The invention can highlight the main body color and ensure that the light-emitting equipment still emits white light, thereby not influencing the white balance judgment of human eyes and electronic equipment and really showing the object color.

Drawings

FIG. 1 shows the spectrum of the illuminated object (Monserl 5P 5/10 color chart) and the reflected light of the LED white light source of the present invention.

FIG. 2 is a spectrum of the F32T8 fluorescent lamp tube of the present invention;

FIG. 3 is a graphical representation of the percent color enhancement/reduction of the spectrum of an F32T8 fluorescent lamp tube using the IES-TM30 method according to the present invention for 16 average color samples;

FIG. 4 is a schematic diagram of a white light source implementation system highlighting body colors according to the present invention;

FIG. 5 shows different overall emission spectra of the light emitting module of the present invention under different driving settings;

FIG. 6 is a schematic diagram of an algorithm module of the present invention;

FIG. 7 is a reflectance spectrum of a portion of the color samples (IES 01-IES 10) in the IES-TM-30 standard of the present invention;

FIG. 8 is a 16 mean color saturation vector diagram of the present invention;

FIG. 9 is a diagram of the spectrum of outdoor daylight and a standard color wavelength range value indicator;

FIG. 10 is a graph showing the spectrum of a green accent fluorescent lamp light and a standard color wavelength range value indicator;

FIG. 11 is a graph of the spectrum of green accent LED light and a standard color wavelength range value indicator;

FIG. 12 is a graph of spectra and corresponding standard color wavelength range value indicators for yellow and violet enhanced light sources;

FIG. 13 is a schematic representation of the spectra of red and green accentuated light sources and the corresponding standard color wavelength range value indicators;

FIG. 14 is a schematic representation of the spectrum of a green-enhanced light source and the corresponding standard color wavelength range value indicator;

FIG. 15 is a graph of the spectrum of a yellow-enhanced light source and the corresponding standard color wavelength range value index.

Detailed Description

To facilitate an understanding of the present invention by those skilled in the art, specific embodiments thereof are described below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As shown in fig. 6, the present invention provides a method for implementing an LED backlight source with a prominent body color, which includes the following steps:

step S32, if the ground color is white light, executing step S4;

step S33, if the ground color is not white light, step S31 is performed.

According to the LED backlight source implementation method for highlighting the main body color, the white light source implementation system for highlighting the main body color is divided into three modules: the system comprises an optical detection module, an algorithm module and a light-emitting device module; the optical detection module receives object optical information including, but not limited to, an object luminescence spectrum, object red, green, blue tristimulus values, and the like. The optical module transmits information into the algorithm module, calculates driving information of the light-emitting device, such as driving current and the like, and outputs the driving information to the light-emitting device module, and the light-emitting device module emits corresponding spectrum according to the driving information calculated by the algorithm module. The light emitting device module consists of a plurality of driving circuits, a plurality of light emitting modules and a single light mixing module. The driving circuit drives each light-emitting module independently through the driving current output by the calculation of the algorithm module, so that the light-emitting modules emit light, and the light-emitting spectrum is fully mixed through the light-mixing module to emit light integrally. Because the current of each driving circuit is independently adjustable, and the luminous intensity of each luminous module is also independently adjustable, the proportion of each luminous module in the whole luminous spectrum is also adjustable, and as a result, the energy distribution of the whole luminous spectrum is adjustable. Fig. 5 shows different overall emission spectra of 4 light-emitting modules under different driving settings.

The light emitting module in fig. 4 includes, but is not limited to, various types of colored and white LEDs, various types of conventional light sources with adjustable current, such as fluorescent lamps, metal halide lamps, etc.

Fig. 6 shows the working principle of the algorithm module. The optical detection device passes the detected spectral or RGB color information to the algorithm module, which determines the body color hue in the scene from this information. If the spectrum is input, the algorithm module can obtain hue region information of the body color according to the following method:

(1) firstly, XYZ tristimulus values corresponding to the spectrum are calculated

Wherein S (lambda) is the energy distribution of the spectrum, lambda is the wavelength, and the unit is nanometer (nm),

is a color matching function. The upper and lower limits of integration are visible light bands: 380 nm-780 nm.

(2) The color coordinates (a, b) in the color space are calculated from the tristimulus values XYZ:

wherein:

xn, Yn, Zn are the tristimulus values of the reference light source. If the D65 light source is used as the reference light source, the tristimulus value is

X_n＝95.047，

Y_n＝100.000，

Z_n＝108.883

(3) And judging the color belongs to which hue region according to the color coordinates (a, b). The hue region is divided into 16 regions in total, i.e., 16 hues. This can be achieved by looking up the IES-TM30 standard, see reference [1] David, Aurelian et al, developments in the IES method for assessing light source color rendering, optical bulletin 23.12 (2015): 15888-15906.

After obtaining the hue region of the main body color, the algorithm module completes the definition of the main body color. And calculating the color temperature of the ambient light according to the ambient light information acquired by the optical detection module, and acquiring the spectrum of the reference light source by adopting the sunlight with the same color temperature as the reference light source according to the color temperature. This process can be implemented by solar spectral database extraction.

Meanwhile, the algorithm module randomly generates the current of each driving circuit, thereby generating the light emission spectrum of the current target light source, see fig. 5. The algorithm module evaluates the current spectrum to determine that it is white light. This can be achieved by calculating the color deviation value Duv. If Duv is small enough, the current spectrum is considered as white light and output; otherwise, the light emission spectrum is regenerated until white light is obtained.

After obtaining the light emission spectra of the reference light source and the current target light source, the color coordinates (a, b) of each color sample in the IES-TM30 standard under the irradiation of the two light sources are respectively calculated. 99 color samples are defined in the IES-TM30 standard and are respectively located in 16 color domains, so the following steps need to be respectively and repeatedly calculated for the 99 color samples. The reflectance spectrum is first calculated:

S_r，i(λ)＝S(λ)R_i(λ)

wherein S_r，i(λ) is the reflection spectrum of the ith IES-TM30 color sample, S (λ) is the reference light source spectrum or the target light source spectrum, and R is calculated respectively_i(λ) is the reflection spectrum of the color sample in the ith IES-TM-30 standard. FIG. 6 shows the reflectance spectra of part of the color samples (IES 01-IES 10) in the IES-TM-30 standard. To obtainAfter the reflection spectrum, the color coordinates (a, b) of the reflection spectrum are calculated, the calculation method being described in detail above.

TABLE I enhanced color and enhanced ratio of various light sources

The reinforcement factor refers to the difference between the maximum reinforcement ratio and the maximum reduction ratio

Compared with the light source matching technology, the invention has the following advantages:

1. the object color enhancement range is large. Both artificial light sources of fig. 10 and 11, although green-enhanced, are small in magnitude. The light sources of the present invention in fig. 12-15 have a large range of values for the standard color wavelength range with an enhancement factor of 2-3 times that of other light sources.

2. The object body which can be strengthened is complete in color. While conventional light sources and LEDs generally only provide standard color wavelength range values for green and red, the light source of the present invention can provide enhancements for a variety of different colors, as well as 2 colors.

3. Is continuously adjustable. The method and the system can use the same device to strengthen different main body colors, and the light source matching technology needs to be replaced for many times because the spectrum is not adjustable, so different light sources are tried.

Compared with the non-white light source technology, the invention has the following advantages:

1. the light source is still white and the visual comfort is high, and the white balance setting of electronic equipment such as a camera and a video camera is not influenced. Table 2 shows that the color deviation (Duv) of different luminescent spectra obtained by the method of the present invention is small compared to non-white light at each color temperature, indicating that the colors of these spectra are closer to natural white light. (generally Duv <0.007 is considered white light)

2. The spectrum is fully automatically adjusted without replacing the filter element or replacing the light source.

3. The object color enhancement amplitude is controllable, and color effect distortion caused by excessive object color enhancement can be avoided.

Kind of light source	Absolute color deviation (Duv)
		Sunlight	<0.0001
Common fluorescent lamp	<0.007
		General LED	<0.007
Non-white light source	>0.02
		Light source of the invention	<0.003

The above-described embodiments of the present invention do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for realizing an LED backlight source with prominent body color is characterized by comprising the following steps: the method comprises the following steps:

step S1: the optical detection equipment transmits detection information to the algorithm module;

step S2: the algorithm module judges the information of the dominant color hue region in the scene through the detection information;

step S3: extracting a main color sample of the main color according to the information of the main color tone area;

step S4: respectively calculating a first color coordinate of the main standard color sample under a reference light source and a second color coordinate of the main standard color sample under a target light source according to the main standard color sample;

step S5: calculating a main color saturation vector of the main color sample according to the first and second color coordinates;

step S7: if the vector direction of the primary color saturation points to the color enhancement direction, outputting current primary target light source driving information;

step S9: the driving device generates a total target spectrum based on the main and other hue sub target light source driving information.

2. The method of claim 2, wherein the method further comprises: the detection information in step S1 includes spectral or RGB color information.

3. The method of claim 2, wherein the method further comprises: the reference light source in step S4 is obtained by the algorithm module based on the detection information in step S1.

4. The method of claim 1, wherein the method comprises: step S6: evaluating whether the direction of the dominant color saturation vector is towards the color enhancement direction; if the color is not towards the color enhancement direction, the dominant difference value is obtained by subtracting the value of the dominant standard color wavelength range from the magnitude of the current dominant color saturation vector.

5. The method of claim 5, wherein the method further comprises: and according to the main difference value, obtaining the secondary driving information of the secondary target light source after the next iteration by optimizing the iteration parameters.

6. The method of claim 5, wherein the method further comprises: according to the secondary driving information, firstly, whether the ground color sample is white light needs to be judged, and the steps are as follows:

step S32, if the ground color is white light, executing step S4;

step S33, if the ground color is not white light, step S31 is performed.

7. The method of claim 1, wherein the method comprises: evaluating whether the saturation vectors of other hues are toward the color-decreasing direction in step S6; if the color is towards the color weakening direction, obtaining a secondary difference value by subtracting the size of the current other color saturation vectors from the wavelength range values of other color standard colors, obtaining the driving information of a secondary target light source of the next iteration by optimizing iteration parameters according to the secondary difference value, and continuously executing the step S4 to calculate a second secondary color coordinate under the target light source.

8. The method for realizing the LED backlight source with the prominent body colors according to any one of claims 1, 4 and 7, wherein the method comprises the following steps: the colors in the color reduction and color enhancement refer to the standard color wavelength range values based on the dominant color or other colors, the color reduction direction refers to the direction of saturation vector of the hue into the standard color wavelength range values, and the color enhancement direction refers to the direction of saturation vector of the hue out of the standard color wavelength range values.