CN105578166A - Color temperature determination method and device - Google Patents

Abstract

The invention provides a color temperature determination method and device. The method comprises the following steps: making a statistic of white balance gain of any two primary colors of the primary colors of an image of a target gray object which is collected under at least three target light sources of different color temperatures, and determining a relation curve of the white balance gain and the color temperature, wherein the target light source is a light source which satisfies black-body radiation; mapping an other related color temperature line in an CIE chromaticity diagram to the relation curve of the white balance gain and the color temperature, so as to calibrate an other related color temperature line of a color temperature corresponding to the image of the target gray object collected under each target light source; and determining a color temperature of an image to be detected according to the white balance gain of the image to be detected and the other related color temperature line. By adopting the embodiment of the invention, the applicability and accuracy of color temperature determination can be improved.

Description

A kind of colour temperature defining method and device

Technical field

The present invention relates to technical field of image processing, particularly relate to a kind of colour temperature defining method and device.

Background technology

Colour temperature is the attribute representing that light source light spectrum forms, and spectrum intermediate waves component multi color temperature is high, the inclined blue-green of light, and long wavelength component multi color temperature is low, the inclined reddish yellow of image.

Be configured with the image modalities of imageing sensor by R (Red, red), G (Green, green), B (Blue, blue) photoelectric signal transformation of three passages realizes the collection of chromatic image, but the R that in environment, different-colour light source sends, G, B color component intensity is different, optic path is to R, G, the percent of pass of B tri-color components is different, and different electrooptical device is different to the conversion ratio of varying strength color component, the electrical signal intensity of the last chromatic image of image modalities and object own color is all likely caused to there are differences, as the white object in actual scene, partially yellow under low colour temperature environment, partially blue under high color temperature, and it is partially green to the image of green glow photosensitive property better electrooptical device output, namely the colors of image of image modalities collection affects by colour temperature, need to reduce to color according to colour temperature.Thus color temperature estimation has important function in image acquisition system.

Summary of the invention

The invention provides a kind of colour temperature defining method and device, to improve the applicability and accuracy that colour temperature determines.

According to the first aspect of the embodiment of the present invention, a kind of colour temperature defining method is provided, comprises:

Any white balance gains of two primary colours and the colour temperature of correspondence in the three primary colors of the image of the target grey object collected under the target light source of statistics at least three kinds of different-colours, and determine the relation curve of described white balance gains and colour temperature; Wherein, described target light source is the light source meeting black body radiation;

By in Commission Internationale De L'Eclairage's XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line;

According to the white balance gains of image to be detected and the correlated colour temperature line such as described, determine the colour temperature that described image to be detected is corresponding.

According to the second aspect of the embodiment of the present invention, a kind of colour temperature determining device is provided, comprises:

Statistic unit, for the white balance gains of any two primary colours in the three primary colors of the image of target grey object that collect under adding up the target light source of at least three kinds of different-colours; Wherein, described target light source is the light source meeting black body radiation;

First determining unit, for determining the relation curve of described white balance gains and colour temperature;

Demarcate unit, for by Commission Internationale De L'Eclairage's XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line;

Second determining unit, for according to the white balance gains of image to be detected and the correlated colour temperature line such as described, determines the colour temperature that described image to be detected is corresponding.

The application embodiment of the present invention, the white balance gains of any two primary colours in the three primary colors of the image of the target grey object collected under the target light source by statistics at least three kinds of different-colours, determine the relation curve of this white balance gains and colour temperature, and by XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line, and then according to the white balance gains of image to be detected and etc. correlated colour temperature line, determine the colour temperature that image to be detected is corresponding, when light source in IMAQ scene does not meet black body radiation, still can carry out colour temperature exactly to determine, improve applicability and accuracy that colour temperature determines.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of a kind of colour temperature defining method that the embodiment of the present invention provides;

Fig. 2 A is the relation curve schematic diagram of a kind of white balance gains of providing of the embodiment of the present invention and colour temperature;

Fig. 2 B is the schematic diagram of relation curve in three dimensional coordinate space of a kind of white balance gains of providing of the embodiment of the present invention and colour temperature;

Fig. 2 C be in a kind of XYZ chromaticity diagram etc. the schematic diagram of correlated colour temperature line;

Fig. 2 D is the schematic diagram that a kind of relation curve to white balance gains and colour temperature that the embodiment of the present invention provides carries out interpolation;

Fig. 2 E is the schematic diagram of the correlated colour temperature lines such as a kind of demarcation of providing of the embodiment of the present invention;

Fig. 3 is the schematic flow sheet of the another kind of colour temperature defining method that the embodiment of the present invention provides;

Fig. 4 is the structural representation of a kind of colour temperature determining device that the embodiment of the present invention provides;

Fig. 5 is the structural representation of the another kind of colour temperature determining device that the embodiment of the present invention provides;

Fig. 6 is the structural representation of the another kind of colour temperature determining device that the embodiment of the present invention provides;

Fig. 7 is the structural representation of the another kind of colour temperature determining device that the embodiment of the present invention provides.

Embodiment

Technical scheme in the embodiment of the present invention is understood better in order to make those skilled in the art person, and enable the above-mentioned purpose of the embodiment of the present invention, feature and advantage become apparent more, below in conjunction with accompanying drawing, technical scheme in the embodiment of the present invention is described in further detail.

Refer to Fig. 1, the schematic flow sheet of a kind of colour temperature defining method that Fig. 1 provides for the embodiment of the present invention, as shown in Figure 1, this colour temperature defining method can comprise the following steps:

The white balance gains of any two primary colours in the three primary colors of the image of the target grey object collected under the target light source of step 101, statistics at least three kinds of different-colours, and determine the relation curve of this white balance gains and colour temperature, wherein, this target light source is the light source meeting black body radiation.

In the embodiment of the present invention, said method can be applied to the image modalities (as camera, video camera etc.) being configured with imageing sensor (as digital image sensor).For ease of describe, below for the executive agent of said method for image modalities is described.

In the embodiment of the present invention, target grey object does not refer in particular to a certain fixing grey object, but can refer to arbitrary for etc. correlated colour temperature line model set up grey object; Wherein, grey refers to that saturation is the color of 0.

Preferably, this target grey object can be standard ash card.

In the embodiment of the present invention, image modalities can gather the view data of the target grey object under the light source (hereinafter referred to as target light source) meeting black body radiation of at least three kinds of different-colours, calculates the white balance gains of any two primary colours in three primary colours of the view data of the target grey object under the target light source of the variant colour temperature collected.

Wherein, the white balance gains of view data comprises the gain that image carries out R, G, B tri-components required for white balance correction: RGain (R gain), GGain (G gain), BGain (B gain), as the optional execution mode of one, the gain of these three components can pass through following formulae discovery respectively:

$RGain=\frac{avgG\left(i\right)}{avgR\left(i\right)}$

$GGain=\frac{avgG\left(i\right)}{avgG\left(i\right)}=1.0$

$BGain=\frac{avgG\left(i\right)}{avgB\left(i\right)}$

Wherein, the mean value of R, G, B tri-components of each pixel in the view data of the target grey object that avgR (i), avgG (i), avgB (i) collect under being respectively each colour temperature target light source, i represents the target light source of different-colour.

Wherein, due in this embodiment, G gain is steady state value, therefore, respectively according to the white balance gains of the R component in the three primary colors of the image of the target grey object collected and B component, can determine corresponding white balance gains and the relation curve of colour temperature.

But what deserves to be explained is, in embodiments of the present invention, the account form of the white balance gains of above-mentioned three primary colors is only the concrete example of one of the technical scheme that the embodiment of the present invention provides, instead of limiting the scope of the present invention.Such as, in embodiments of the present invention, the gain of three components can also respectively by following formulae discovery:

$RGain=\frac{avgR\left(i\right)}{avgR\left(i\right)}=1.0$

$GGain=\frac{avgR\left(i\right)}{avgG\left(i\right)}$

$BGain=\frac{avgR\left(i\right)}{avgB\left(i\right)}$

Correspondingly, in this case, because R gain is steady state value, therefore, respectively according to the white balance gains of the G component in the three primary colors of the image of target grey object collected and B component, corresponding white balance gains and the relation curve of colour temperature can be determined.

In like manner, also can according to the white balance gains of the G component in the three primary colors of the image of the target grey object collected and R component in the embodiment of the present invention, determine corresponding white balance gains and the relation curve of colour temperature, its specific implementation does not repeat them here.

For convenience of description, below with the white balance gains according to the R component in the three primary colors of the image of target grey object collected and B component, determine that the relation curve of corresponding white balance gains and colour temperature is that example is described.

In the embodiment of the present invention, the colour temperature of target light source can be measured by colour temperature measurement device (as colour temperature meter).

In the embodiment of the present invention, in three primary colours of the image of the target grey object that image modalities collects under counting on the target light source of variant colour temperature any two primary colours (being described for R component and B component in the embodiment of the present invention) white balance gains after, the relation curve of this white balance gains and colour temperature can be determined.

As the optional execution mode of one, determine the relation curve of white balance gains and colour temperature, can comprise the following steps:

11) white balance gains (i.e. RGain, BGain) of above-mentioned two primary colours of the image collected under the target light source, according to variant colour temperature and the colour temperature of correspondence, determine corresponding calibration point in respectively with the coordinate system of the white balance gains of these two primary colours (i.e. RGain and BGain) for transverse and longitudinal coordinate;

12), to calibration point carry out curve fitting, to determine the relation curve of described white balance gains and colour temperature.

In this embodiment, after the white balance gains of the image that image modalities collects under counting on the target light source of variant colour temperature, image modalities can according to RGain and BGain of the image collected under the target light source of variant colour temperature, taking RGain as abscissa, determining corresponding calibration point (or being called white balance correction position) in the BGain coordinate system that is ordinate, and each calibration point is carried out curve fitting, to determine the relation curve of white balance gains and colour temperature, its schematic diagram can as shown in Figure 2 A (wherein Tc is colour temperature); Wherein, the schematic diagram of relation curve in the three-dimensional system of coordinate being reference axis with RGain, BGain and colour temperature respectively of white balance gains and colour temperature can be as shown in Figure 2 B, the relation curve of the white balance gains shown in Fig. 2 A and colour temperature is the projection of relation curve shown in Fig. 2 B in the coordinate system being transverse and longitudinal coordinate with RGain and BGain respectively, based on the relation curve shown in Fig. 2 A, the correlated colour temperature line model such as to set up herein.

Step 102, by XYZ chromaticity diagram etc. correlated colour temperature line be mapped to the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line.

In the embodiment of the present invention, the white balance gains of the image of the target grey object that image modalities collects under determining the target light source of variant colour temperature is with after the relation curve of corresponding colour temperature, the colour temperature that the image of the target grey object collected under can demarcating each target light source is further corresponding etc. correlated colour temperature line, to set up the correlated colour temperature line models such as corresponding.

Concrete, can according to CIE (InternationalCommissiononillumination, Commission Internationale De L'Eclairage) 1960UCS chromatic diagram (a kind of standard chromatic diagram, hereinafter referred to as XYZ chromaticity diagram) in each colour temperature place etc. the slope of correlated colour temperature line, the colour temperature that the image of the target grey object collected under demarcating each target light source is corresponding etc. the slope of correlated colour temperature line.Wherein, in XYZ chromaticity diagram etc. correlated colour temperature line can as shown in Figure 2 C, the transverse and longitudinal coordinate of this XYZ chromaticity diagram is corresponding respectively with

Wherein, for the colour temperature be present in XYZ chromaticity diagram, by this colour temperature etc. the slope of correlated colour temperature line in XYZ chromaticity diagram, be defined as this colour temperature etc. the slope of correlated colour temperature line in the relation curve of above-mentioned white balance gains and colour temperature;

For the colour temperature be not present in XYZ chromaticity diagram, according to adjacent two colour temperatures of this colour temperature existed in XYZ chromaticity diagram etc. the slope of correlated colour temperature line in XYZ chromaticity diagram, determine this colour temperature etc. the slope of correlated colour temperature line in the relation curve of above-mentioned white balance gains and colour temperature; Wherein, in two colour temperatures adjacent with this colour temperature one higher than this colour temperature, another is less than this colour temperature; Monotonicity (namely along with the increase dullness of colour temperature increases or dullness reduces) is met etc. the slope of correlated colour temperature line and colour temperature size.

For example, suppose that XYZ chromaticity diagram comprises colour temperature 10000K, 6000K and 4000K, the colour temperature that the image of the target grey object collected under each target light source is corresponding is respectively 10000K, 7500K and 6000K, the colour temperature that the image of the target grey object then collected under target light source is corresponding be 10000K and 6000K etc. correlated colour temperature line slope can directly according to the colour temperature 10000K in above-mentioned chromatic diagram and 6000K etc. the slope of correlated colour temperature line determine, colour temperature 7500K etc. the slope of correlated colour temperature line then can determine according to the slope of two colour temperatures (10000K and 6000K) adjacent with this colour temperature (7500K) in XYZ chromaticity diagram.Such as, suppose colour temperature 10000K etc. angle corresponding to the slope of correlated colour temperature line in XYZ chromaticity diagram be A1, colour temperature 6000K etc. angle corresponding to the slope of correlated colour temperature line in XYZ chromaticity diagram be A2, then colour temperature 7500K etc. angle corresponding to the slope of correlated colour temperature line in XYZ chromaticity diagram can be: A2+ (A2-A1) * (7500K-6000K)/(10000K-6000K), and then, can according to the slope of this angle determination colour temperature 6000K in the relation curve of above-mentioned white balance gains and colour temperature.Wherein, the colour temperature such as 6000K, 7500K and 10000K etc. correlated colour temperature line increase all successively in the relation curve of XYZ chromaticity diagram and above-mentioned white balance gains and colour temperature.

Step 103, according to the white balance gains of image to be detected and etc. correlated colour temperature line, determine the colour temperature that image to be detected is corresponding.

In the embodiment of the present invention, any two field picture that image to be detected can collect for image modalities.

When image modalities needs to determine colour temperature corresponding to image to be detected, image modalities can calculate the white balance gains of this image to be detected, and according to the white balance gains of this image to be detected and the correlated colour temperature line such as above-mentioned, determine the colour temperature that this image to be detected is corresponding.Wherein, the colour temperature that image to be detected is corresponding is the colour temperature of image modalities light source of residing scene when gathering this image to be detected.

As the optional execution mode of one, in above-mentioned steps 103, according to the white balance gains of image to be detected and etc. correlated colour temperature line, determine the colour temperature that image to be detected is corresponding, can comprise the following steps:

21), according to the white balance gains (i.e. RGain and BGain) of above-mentioned two primary colours of image to be detected, the target location that the determination in the coordinate system being transverse and longitudinal coordinate with the white balance gains of these two primary colours (RGain and BGain) is respectively corresponding;

22), according to the distance of target location to the correlated colour temperature lines such as adjacent two, and this adjacent two etc. colour temperature corresponding to correlated colour temperature line, determine the colour temperature that image to be detected is corresponding; Wherein, this adjacent two etc. correlated colour temperature line be positioned at the both sides of described target location.

In this embodiment, for any two field picture collected, image modalities can carry out white balance process to this image, to obtain RGain and BGain of this image, and then taking RGain as abscissa, in the BGain coordinate system that is ordinate, determining corresponding target location.

Further, image modalities can travel through the correlated colour temperature lines such as above-mentioned, obtains the correlated colour temperature lines such as corresponding adjacent two, this target location, is namely positioned at both sides, target location, and with the correlated colour temperature lines such as immediate two of this target location.Image modalities can calculated target positions to the distance of the correlated colour temperature lines such as these adjacent two, and then according to the distance of this target location to the correlated colour temperature lines such as these adjacent two, and the colour temperature that the correlated colour temperature line such as these adjacent two is corresponding, determine the colour temperature that image to be detected is corresponding.

As the optional execution mode of one, in embodiments of the present invention, according to the distance of target location to the correlated colour temperature lines such as adjacent two, and this adjacent two etc. colour temperature corresponding to correlated colour temperature line, determine the colour temperature that image to be detected is corresponding, can realize especially by following formula:

$TcCur=TcLf+\frac{distLf}{distLf+distRt}(TcRt-TcLf)$

Wherein, TcCur is the colour temperature that image to be detected is corresponding, TcLf, TcRt are the colour temperature that the correlated colour temperature line such as these adjacent two is corresponding, and TcRt > TcLf, distLf and distRt are respectively the distance of target location to the correlated colour temperature lines such as these adjacent two.

In the embodiment of the present invention, after image modalities determines the colour temperature that the image that collects is corresponding, can carry out color rendition correction according to this colour temperature, its specific implementation embodiment of the present invention repeats no more.

What deserves to be explained is, in embodiments of the present invention, described by step 101 ~ step 102 etc. the demarcation mode of correlated colour temperature line can only perform once in whole flow process, based on these correlated colour temperature line parameters, image modalities can perform arbitrarily step 103 repeatedly, namely image modalities can adopt always these correlated colour temperature line parameters to subsequent acquisition to image carry out colour temperature and determine.And do not need to carry out colour temperature when determining at every turn, all redefine an inferior correlated colour temperature line.

Further, when considering that the hardware units such as the filter that image modalities adopts are different, the colour temperature of the image collected may also can be distinct, therefore, for arbitrary money image modalities, need the different hardware device (as the hardware unit that filter etc. can have an impact to the colour temperature of the image collected) used for this image modalities to demarcate the correlated colour temperature lines such as different, its specific implementation does not repeat them here.

Visible, in the method flow shown in Fig. 1, the white balance gains of image of the target grey object collected under the target light source by statistics at least three kinds of different-colours and the relation curve of corresponding colour temperature, and by XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of this white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line, and then when needing the colour temperature determining image to be detected, can according to the white balance gains of image to be detected and etc. correlated colour temperature line, determine the colour temperature of this image to be detected, when light source in IMAQ scene does not meet black body radiation, still can carry out colour temperature exactly to determine, improve applicability and accuracy that colour temperature determines.

Refer to Fig. 3, the schematic flow sheet of the another kind of colour temperature defining method that Fig. 3 provides for the embodiment of the present invention, as shown in Figure 3, this colour temperature defining method can comprise the following steps:

The R component of image of the target grey object collected under the target light source of step 301, statistics at least three kinds of different-colours and the white balance gains of B component.

RGain, BGain of image of the target grey object collected under step 302, target light source according to variant colour temperature and the colour temperature of correspondence, determine corresponding calibration point in respectively with the coordinate system of RGain and BGain for transverse and longitudinal coordinate.

Step 303, calibration point to be carried out curve fitting, to determine the relation curve of white balance gains and colour temperature.

In the embodiment of the present invention, the associated description in the method flow that the specific implementation of step 301 ~ step 303 can be shown in Figure 1, the embodiment of the present invention does not repeat them here.

Step 304, interpolation is carried out, to increase the quantity of the calibration point on the relation curve of white balance gains and colour temperature to the calibration point in the relation curve of white balance gains and colour temperature.

In the embodiment of the present invention, when considering that calibration point is very few in the relation curve of white balance gains and colour temperature, in follow-up flow process according to each calibration point corresponding etc. correlated colour temperature line determine the colour temperature of image to be detected time accuracy rate can be lower, thus, after the relation curve determining white balance gains and colour temperature, can carry out interpolation to the calibration point on this relation curve, to increase the quantity of the calibration point on this relation curve, its schematic diagram can be as shown in Figure 2 D.

Should be realized that, when white balance gains and the quantity of calibration point corresponding with the white balance gains of image that collects under each target light source in the relation curve of colour temperature are enough, namely during the kind of target light source enough (kind as target light source exceedes predetermined threshold value), also can not carry out the interpolation of calibration point, and directly carry out the process of subsequent step.

Step 305, by XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, to demarcate with white balance gains the correlated colour temperature line such as corresponding with each calibration point on the relation curve of colour temperature.

In the embodiment of the present invention, after calibration point in the relation curve to white balance gains and colour temperature carries out interpolation, image modalities (can comprise the calibration point corresponding with the white balance gains of image that collects under each target light source to white balance gains with each calibration point on the relation curve of colour temperature, and by the newly-increased calibration point of interpolation) the correlated colour temperature line such as to carry out and demarcate, its schematic diagram can be as shown in Figure 2 E.

Wherein, colour temperature for correspondence is present in the calibration point in XYZ chromaticity diagram, by colour temperature corresponding for this calibration point etc. the slope of correlated colour temperature line in XYZ chromaticity diagram, be defined as this calibration point corresponding etc. the slope of correlated colour temperature line in the relation curve of white balance gains and colour temperature;

Colour temperature for correspondence is not present in the calibration point in XYZ chromaticity diagram, according to adjacent two colour temperatures of the colour temperature corresponding with this calibration point existed in XYZ chromaticity diagram etc. the slope of correlated colour temperature line in XYZ chromaticity diagram, determine this calibration point corresponding etc. the slope of correlated colour temperature line in the relation curve of white balance gains and colour temperature; Wherein, in two colour temperatures that the colour temperature corresponding with this calibration point is adjacent one higher than colour temperature corresponding to this calibration point, another is less than colour temperature corresponding to this calibration point; Monotonicity is met etc. the slope of correlated colour temperature line and colour temperature size.

Step 306, according to the white balance gains of image to be detected and etc. correlated colour temperature line, determine the colour temperature that image to be detected is corresponding.

In the embodiment of the present invention, the specific implementation of step 306 can see the associated description in above-mentioned steps 103, and the embodiment of the present invention does not repeat them here.

It should be noted that, in embodiments of the present invention, if the outermost of the correlated colour temperature lines such as target location is in, namely there is not the correlated colour temperature lines such as adjacent two of being positioned at both sides, target location, then can by connect recently target location etc. colour temperature corresponding to correlated colour temperature line be defined as colour temperature corresponding to image to be detected, or determine with other strategy the colour temperature that image to be detected is corresponding further, the embodiment of the present invention does not limit this.

By describing above and can finding out, in the technical scheme that the embodiment of the present invention provides, the white balance gains of any two primary colours in the three primary colors of the image of the target grey object collected under the target light source by statistics at least three kinds of different-colours, determine the relation curve of this white balance gains and colour temperature, and by XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line, and then according to the white balance gains of image to be detected and etc. correlated colour temperature line, determine the colour temperature that image to be detected is corresponding, when light source in IMAQ scene does not meet black body radiation, still can carry out colour temperature exactly to determine, improve applicability and accuracy that colour temperature determines.

Refer to Fig. 4, be the structural representation of a kind of colour temperature determining device that the embodiment of the present invention provides, wherein, this colour temperature determining device can be applied to the image modalities in said method embodiment, and as shown in Figure 4, this colour temperature determining device can comprise:

Statistic unit 410, for the white balance gains of any two primary colours in the three primary colors of the image of target grey object that collect under adding up the target light source of at least three kinds of different-colours; Wherein, described target light source is the light source meeting black body radiation;

First determining unit 420, for determining the relation curve of described white balance gains and colour temperature;

Demarcate unit 430, for by XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line;

Second determining unit 440, for according to the white balance gains of image to be detected and the correlated colour temperature line such as described, determines the colour temperature that described image to be detected is corresponding.

See also Fig. 5, the structural representation of the another kind of colour temperature determining device that Fig. 5 provides for the embodiment of the present invention, on basis embodiment illustrated in fig. 4, in the colour temperature determining device shown in Fig. 5, the first determining unit 420 can comprise:

First determines subelement 421, for the described white balance gains of two primary colours and the colour temperature of correspondence of the image according to the target grey object collected under the target light source of variant colour temperature, in respectively with the coordinate system of the white balance gains of these two primary colours for transverse and longitudinal coordinate, determine corresponding calibration point;

Fitting unit 422, for carrying out curve fitting to described calibration point, to determine the relation curve of described white balance gains and colour temperature.

See also Fig. 6, the structural representation of the another kind of colour temperature determining device that Fig. 6 provides for the embodiment of the present invention, on basis embodiment illustrated in fig. 5, the colour temperature determining device shown in Fig. 6 can also comprise:

Interpolating unit 450, carries out interpolation for the calibration point in the relation curve to described white balance gains and colour temperature, to increase the quantity of the calibration point on the relation curve of described white balance gains and colour temperature;

Correspondingly, described demarcation unit 430, can specifically for being present in the calibration point in described XYZ chromaticity diagram for the colour temperature of correspondence, by colour temperature corresponding for this calibration point etc. the slope of correlated colour temperature line in described XYZ chromaticity diagram, be defined as this calibration point corresponding etc. the slope of correlated colour temperature line in the relation curve of described white balance gains and colour temperature; Colour temperature for correspondence is not present in the calibration point in described XYZ chromaticity diagram, according to adjacent two colour temperatures of the colour temperature corresponding with this calibration point existed in described XYZ chromaticity diagram etc. the slope of correlated colour temperature line in described XYZ chromaticity diagram, determine this calibration point corresponding etc. the slope of correlated colour temperature line in the relation curve of described white balance gains and colour temperature; Wherein, in two colour temperatures that the colour temperature corresponding with this calibration point is adjacent one higher than colour temperature corresponding to this calibration point, another is less than colour temperature corresponding to this calibration point; Monotonicity is met etc. the slope of correlated colour temperature line and colour temperature size.

See also Fig. 7, the structural representation of the another kind of colour temperature determining device that Fig. 7 provides for the embodiment of the present invention, on basis embodiment illustrated in fig. 4, in the colour temperature determining device shown in Fig. 7, the second determining unit 440 can comprise:

Second determines subelement 441, for the white balance gains of described two primary colours according to described image to be detected, and the target location that the determination in the coordinate system being transverse and longitudinal coordinate with the white balance gains of described two primary colours is respectively corresponding;

3rd determines subelement 442, for according to the distance of described target location to the correlated colour temperature lines such as adjacent two, and this adjacent two etc. colour temperature corresponding to correlated colour temperature line, determine the colour temperature that image to be detected is corresponding; Wherein, this adjacent two etc. correlated colour temperature line be positioned at the both sides of described target location.

In an alternative embodiment, described 3rd determines subelement 442, can specifically for being realized by following formula according to the distance of described target location to the correlated colour temperature lines such as adjacent two, and this adjacent two etc. colour temperature corresponding to correlated colour temperature line, determine the colour temperature that image to be detected is corresponding:

$TcCur=TcLf+\frac{distLf}{distLf+distRt}(TcRt-TcLf)$

Wherein, TcCur is the colour temperature that described image to be detected is corresponding, TcLf, TcRt are the colour temperature that the correlated colour temperature line such as these adjacent two is corresponding, and TcRt > TcLf, distLf and distRt are respectively the distance of described target location to the correlated colour temperature lines such as these adjacent two.

In said apparatus, the implementation procedure of the function and efficacy of unit specifically refers to the implementation procedure of corresponding step in said method, does not repeat them here.

For device embodiment, because it corresponds essentially to embodiment of the method, so relevant part illustrates see the part of embodiment of the method.Device embodiment described above is only schematic, the wherein said unit illustrated as separating component or can may not be and physically separates, parts as unit display can be or may not be physical location, namely can be positioned at a place, or also can be distributed in multiple network element.Some or all of module wherein can be selected according to the actual needs to realize the object of the present invention program.Those of ordinary skill in the art, when not paying creative work, are namely appreciated that and implement.

As seen from the above-described embodiment, the white balance gains of any two primary colours in the three primary colors of the image of the target grey object collected under the target light source by statistics at least three kinds of different-colours, determine the relation curve of this white balance gains and colour temperature, and by XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line, and then according to the white balance gains of image to be detected and etc. correlated colour temperature line, determine the colour temperature that image to be detected is corresponding, when light source in IMAQ scene does not meet black body radiation, still can carry out colour temperature exactly to determine, improve applicability and accuracy that colour temperature determines.

Those skilled in the art, at consideration specification and after putting into practice invention disclosed herein, will easily expect other embodiment of the present invention.The application is intended to contain any modification of the present invention, purposes or adaptations, and these modification, purposes or adaptations are followed general principle of the present invention and comprised the undocumented common practise in the art of the present invention or conventional techniques means.Specification and embodiment are only regarded as exemplary, and true scope of the present invention and spirit are pointed out by claim below.

Should be understood that, the present invention is not limited to precision architecture described above and illustrated in the accompanying drawings, and can carry out various amendment and change not departing from its scope.Scope of the present invention is only limited by appended claim.

Claims (10)

1. a colour temperature defining method, is characterized in that, comprising:

The white balance gains of any two primary colours in the three primary colors of the image of the target grey object collected under the target light source of statistics at least three kinds of different-colours, and determine the relation curve of described white balance gains and colour temperature; Wherein, described target light source is the light source meeting black body radiation;

By in Commission Internationale De L'Eclairage's XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line;

According to the white balance gains of image to be detected and the correlated colour temperature line such as described, determine the colour temperature that described image to be detected is corresponding.

2. method according to claim 1, is characterized in that, the described relation curve determining described white balance gains and colour temperature, comprising:

The described white balance gains of two primary colours of the image of the target grey object collected under the target light source according to variant colour temperature and the colour temperature of correspondence, determine corresponding calibration point in respectively with the coordinate system of the white balance gains of these two primary colours for transverse and longitudinal coordinate;

Described calibration point is carried out curve fitting, to determine the relation curve of described white balance gains and colour temperature.

3. method according to claim 2, is characterized in that, described described calibration point is carried out curve fitting after, also comprise:

Interpolation is carried out, to increase the quantity of the calibration point on the relation curve of described white balance gains and colour temperature to the calibration point in the relation curve of described white balance gains and colour temperature;

Described by XYZ chromaticity diagram etc. correlated colour temperature line be mapped to the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line, comprising:

Colour temperature for correspondence is present in the calibration point in described XYZ chromaticity diagram, by colour temperature corresponding for this calibration point etc. the slope of correlated colour temperature line in described XYZ chromaticity diagram, be defined as this calibration point corresponding etc. the slope of correlated colour temperature line in the relation curve of described white balance gains and colour temperature;

Colour temperature for correspondence is not present in the calibration point in described XYZ chromaticity diagram, according to adjacent two colour temperatures of the colour temperature corresponding with this calibration point existed in described XYZ chromaticity diagram etc. the slope of correlated colour temperature line in described XYZ chromaticity diagram, determine this calibration point corresponding etc. the slope of correlated colour temperature line in the relation curve of described white balance gains and colour temperature; Wherein, in two colour temperatures that the colour temperature corresponding with this calibration point is adjacent one higher than colour temperature corresponding to this calibration point, another is less than colour temperature corresponding to this calibration point; Monotonicity is met etc. the slope of correlated colour temperature line and colour temperature size.

4. method according to claim 1, is characterized in that, the described white balance gains according to image to be detected and the correlated colour temperature line such as described, determines the colour temperature that described image to be detected is corresponding, comprising:

According to the white balance gains of described two primary colours of described image to be detected, the target location that the determination in the coordinate system being transverse and longitudinal coordinate with the white balance gains of described two primary colours is respectively corresponding;

According to the distance of described target location to the correlated colour temperature lines such as adjacent two, and this adjacent two etc. colour temperature corresponding to correlated colour temperature line, determine the colour temperature that image to be detected is corresponding; Wherein, this adjacent two etc. correlated colour temperature line be positioned at the both sides of described target location.

5. method according to claim 4, it is characterized in that, described according to the distance of described target location to the correlated colour temperature lines such as adjacent two, and this adjacent two etc. colour temperature corresponding to correlated colour temperature line, determine to realize the colour temperature that image to be detected is corresponding especially by following formula:

$TcCur=TcLf+\frac{distLf}{distLf+distRt}(TcRt-TcLf)$

Wherein, TcCur is the colour temperature that described image to be detected is corresponding, TcLf, TcRt are the colour temperature that the correlated colour temperature line such as these adjacent two is corresponding, and TcRt > TcLf, distLf and distRt are respectively the distance of described target location to the correlated colour temperature lines such as these adjacent two.

6. a colour temperature determining device, is characterized in that, comprising:

Statistic unit, for the white balance gains of any two primary colours in the three primary colors of the image of target grey object that collect under adding up the target light source of at least three kinds of different-colours; Wherein, described target light source is the light source meeting black body radiation;

First determining unit, for determining the relation curve of described white balance gains and colour temperature;

Demarcate unit, for by Commission Internationale De L'Eclairage's XYZ chromaticity diagram etc. correlated colour temperature line be mapped in the relation curve of described white balance gains and colour temperature, with colour temperature corresponding to the image of the target grey object collected under demarcating each target light source etc. correlated colour temperature line;

Second determining unit, for according to the white balance gains of image to be detected and the correlated colour temperature line such as described, determines the colour temperature that described image to be detected is corresponding.

7. device according to claim 6, is characterized in that, described first determining unit, comprising:

First determines subelement, for the described white balance gains of two primary colours and the colour temperature of correspondence of the image according to the target grey object collected under the target light source of variant colour temperature, in respectively with the coordinate system of the white balance gains of these two primary colours for transverse and longitudinal coordinate, determine corresponding calibration point;

Fitting unit, for carrying out curve fitting to described calibration point, to determine the relation curve of described white balance gains and colour temperature.

8. device according to claim 7, is characterized in that, described device also comprises:

Interpolating unit, carries out interpolation for the calibration point in the relation curve to described white balance gains and colour temperature, to increase the quantity of the calibration point on the relation curve of described white balance gains and colour temperature;

Described demarcation unit, specifically for demarcating the calibration point be present in for the colour temperature of correspondence in described XYZ chromaticity diagram, by colour temperature corresponding for this calibration point etc. the slope of correlated colour temperature line in described XYZ chromaticity diagram, be defined as this calibration point corresponding etc. the slope of correlated colour temperature line in the relation curve of described white balance gains and colour temperature; Colour temperature for correspondence is not present in the calibration point in described XYZ chromaticity diagram, according to adjacent two colour temperatures of the colour temperature corresponding with this calibration point existed in described XYZ chromaticity diagram etc. the slope of correlated colour temperature line in described XYZ chromaticity diagram, determine this calibration point corresponding etc. the slope of correlated colour temperature line in the relation curve of described white balance gains and colour temperature; Wherein, in two colour temperatures that the colour temperature corresponding with this calibration point is adjacent one higher than colour temperature corresponding to this calibration point, another is less than colour temperature corresponding to this calibration point; Monotonicity is met etc. the slope of correlated colour temperature line and colour temperature size.

9. device according to claim 6, is characterized in that, described second determining unit comprises:

Second determines subelement, for the white balance gains of described two primary colours according to described image to be detected, and the target location that the determination in the coordinate system being transverse and longitudinal coordinate with the white balance gains of described two primary colours is respectively corresponding;

3rd determines subelement, for according to the distance of described target location to the correlated colour temperature lines such as adjacent two, and this adjacent two etc. colour temperature corresponding to correlated colour temperature line, determine the colour temperature that image to be detected is corresponding; Wherein, this adjacent two etc. correlated colour temperature line be positioned at the both sides of described target location.

10. device according to claim 9, it is characterized in that, described 3rd determines subelement, specifically for being realized according to the distance of described target location to the correlated colour temperature lines such as adjacent two by following formula, and this adjacent two etc. colour temperature corresponding to correlated colour temperature line, determine the colour temperature that image to be detected is corresponding:

$TcCur=TcLf+\frac{distLf}{distLf+distRt}(TcRt-TcLf)$

Wherein, TcCur is the colour temperature that described image to be detected is corresponding, TcLf, TcRt are the colour temperature that the correlated colour temperature line such as these adjacent two is corresponding, and TcRt > TcLf, distLf and distRt are respectively the distance of described target location to the correlated colour temperature lines such as these adjacent two.