CN101707666A - Adjusting method and device with high dynamic range - Google Patents

Abstract

The invention discloses an adjusting method with high dynamic range which comprises the following steps: obtaining the brightness range of images with low dynamic range according to the brightness of the images with high dynamic range, wherein the brightness range of the images with low dynamic range is the brightness range which can be displayed by a display device; and conducting linear mapping and histogram equalization on obtained results of the brightness range of the images with low dynamic range, and obtaining the images with low dynamic range. In the invention, high dynamic range adjustment technology for global mapping of single-frame images is more reasonable so as to improve the image quality, the details of bright and dark environments can be reasonably displayed simultaneously, algorithm is simple and practical, and discontinuous brightness caused by the fusion of local mapping and multi-frame images is avoided; and by providing users with the factors for controlling the image contrast and detail richness, the images are convenient for being adjusted to the effect which is more acceptable for human eyes.

Description

A kind of method of adjustment of high dynamic range and device

Technical field

The present invention relates to communication technical field, particularly relate to a kind of method of adjustment and device of high dynamic range.

Background technology

The brightness value that real scene represented has very broad dynamic range, starlight from the night sky is to the dazzling sun, the brightness amplitude that scene is sent has contained the dynamic range that surpasses nine orders of magnitude (10cd/m), wherein, the maximum of piece image gray scale and the ratio between the minimum value are called as dynamic range (Dynamic Range).

Automatic adjusting by eye pupil, starlight from the night sky is to the dazzling sun, the dynamic range that human eye can be differentiated object can reach 100000000: 1, even in same adaptation figure, do not need to regulate, the human visual system is the scene brightness of the about five number order magnitude range of perception (being the brightness range that human eye can be differentiated 10000: 1) simultaneously also, and promptly human eye can come the real world of perception by dynamic adjustment mechanism.

Development along with imaging technique and computer graphic image technology, high dynamic range (High DynamicRange, HDR) image can pass through the spectrum register instrument, perhaps, it is synthetic and obtain that several Same Scene have the image sequence of different exposure time, thereby make the high dynamic range technology begin to have increasing application in fields such as computer graphics, virtual realities.

Concrete, high dynamic range images can write down the visual detail information that is in the scene in the unusual bright area simultaneously, and be in the scene visual detail information in the unusual dark areas, and this visual detail information is easy to lose in common soft image, thereby makes high dynamic range images can more clearly write down the visual detail information in the scene.

As can be seen, in high dynamic range images, place bright in the scene can be very bright; Place dark in the scene can be very dark; The details of bright dark portion all clearly in the scene.

Yet, existing standard display device (for example, cathode-ray tube CRT display etc.) only can show the brightness of about two order of magnitude dynamic ranges, and the level that the luminance dynamic range of high dynamic range images can show considerably beyond present standard display device, in order to adapt to the present relative uniform images of standard display device output visually-perceptible with real scene, need be before showing above-mentioned high dynamic range images on the standard display device, high dynamic range images degree of comparing is compressed, promptly need high dynamic range images is converted to low dynamic range echograms, thereby make standard display device can clearly show the pairing image brightness of real scene.

In the prior art, the method for visualizing of HDR image (be about to high dynamic range images be converted to low dynamic range echograms) mainly is divided into two kinds, is respectively the method for visualizing of the HDR image of the method for visualizing of HDR image of global map and local mapping.

Concrete, in the method for visualizing of the HDR of global map image, each pixel in the HDR image is shone upon by the respective function (curve) of point-to-point between pixel; Promptly each pixel in the high dynamic range images and each pixel in the low dynamic range echograms are carried out the mapping of point-to-point according to respective function.

As can be seen, each pixel in the high dynamic range images and the mapping between each pixel in the low dynamic range echograms are man-to-man, and the pixel that value is identical in the high dynamic range images will be mapped as the pixel of identical low dynamic range echograms.It is fast that the method for visualizing of the HDR image of this global map has computational speed, can keep the advantage of good whole chiaroscuro effect.

In addition, in the method for visualizing of the HDR image that uses local mapping, do not need each pixel in the HDR image is carried out the mapping of point-to-point, local mapping algorithm is more flexible than global map algorithm, and owing to be not man-to-man each pixel in the HDR image to be shone upon in the local mapping process, thereby make the mapping result of pixel depend on this pixel space adjacent pixels.

As can be seen, the result of local mapping tends to strengthen local less contrast more, and compresses relatively large contrast, thereby can keep all visual detail information.And in the process of the method for visualizing that uses the local HDR image that shines upon, because local mapping does not keep the pixel intensity size order in the former scene image, noise in various degree all occurs in the arithmetic result of local mapping, for example, near strong edge, the halo phenomenon will occur.And the computational complexity of the employed algorithm of local mapping is also than global map height.

Summary of the invention

The invention provides a kind of method of adjustment and device of high dynamic range, with contrast that guarantees image and the visual effect that color meets the people.

In order to achieve the above object, the present invention proposes a kind of method of adjustment of high dynamic range, may further comprise the steps:

According to the brightness range of the luminance acquisition low dynamic range echograms of high dynamic range images, the brightness range of described low dynamic range echograms is the brightness range that display device can show;

The result that obtains to the brightness range of described low dynamic range echograms carries out Linear Mapping and histogram equalization, and obtains low dynamic range echograms.

Wherein, the brightness range according to the luminance acquisition low dynamic range echograms of high dynamic range images comprises:

According to formula

$D\left(I\right)=(D_{\max }-D_{\min })*\frac{\log (I+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}{\log (I_{\max }+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}+D_{\min }$

Obtain the brightness range of low dynamic range echograms;

Wherein, described D (I) is the brightness of low dynamic range echograms;

Described D _Max, D _MinBe respectively the maximum and the minimum value of the display device brightness range that can show;

Described I is the brightness of high dynamic range images;

Described I _Max, I _MinBe respectively the maximum and the minimum value of the brightness of high dynamic range images;

Described τ is the brilliance control factor.

Wherein, the result that obtains of the brightness range of described low dynamic range echograms is carried out Linear Mapping and histogram equalization, and obtains low dynamic range echograms and specifically comprise:

Described D (I) Linear Mapping is divided into two sections of equal length, obtains mid point l _N/2And described D (I) histogram equalization cut apart, obtain emphasis e _N/2

According to formula

le _n/2＝l _n/2+β(e _n/2-l _n/2)

Obtain low dynamic range echograms;

Wherein, described le _N/2Be low dynamic range echograms;

Described β is the factor that control chart image contrast and details are enriched degree.

Wherein, when described high dynamic range images was coloured image, described method also comprised:

According to formula

L＝0.299R+0.587G+0.114B.

Obtain the brightness of high dynamic range images;

Wherein, described L is the brightness of high dynamic range images;

Described R is the GTG value of red brightness in the high dynamic range images;

Described G is the GTG value of high dynamic range images medium green colour brightness;

Described B is the GTG value of high dynamic range images Smalt brightness.

Wherein, after the described acquisition low dynamic range echograms, also comprise:

According to formula

$R_{\mathrm{out}}={\left(\frac{R_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$G_{\mathrm{out}}={\left(\frac{G_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$B_{\mathrm{out}}={\left(\frac{B_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

The brightness of image is carried out the triple channel color correction of RGB coloured image;

Wherein, R _OutRepresent the pairing output valve of red brightness, R _InRepresent the pairing input value of red brightness; G _OutRepresent the pairing output valve of green brightness, G _InRepresent the pairing input value of green brightness; B _OutRepresent the pairing output valve of blue brightness, B _InRepresent the pairing input value of blue brightness; L _OutThe pairing output valve of presentation video brightness, L _InThe pairing input value of presentation video brightness; γ is the factor.

The invention allows for a kind of adjusting device of high dynamic range, described device comprises:

Acquisition module is used for the brightness range according to the luminance acquisition low dynamic range echograms of high dynamic range images, and the brightness range of described low dynamic range echograms is the brightness range that display device can show;

Processing module, the result that obtains who is used for the brightness range of low dynamic range echograms that described acquisition module is obtained carries out Linear Mapping and histogram equalization, and obtains low dynamic range echograms.

Wherein, described acquisition module specifically is used for,

According to formula

$D\left(I\right)=(D_{\max }-D_{\min })*\frac{\log (I+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}{\log (I_{\max }+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}+D_{\min }$

Obtain the brightness range of low dynamic range echograms;

Wherein, described D (I) is the brightness of low dynamic range echograms;

Described D _Max, D _MinBe respectively the maximum and the minimum value of the display device brightness range that can show;

Described I is the brightness of high dynamic range images;

Described I _Max, I _MinBe respectively the maximum and the minimum value of the brightness of high dynamic range images;

Described τ is the brilliance control factor.

Wherein, described processing module specifically is used for,

Described D (I) Linear Mapping is divided into two sections of equal length, obtains mid point l _N/2And described D (I) histogram equalization cut apart, obtain emphasis e _N/2

According to formula

le _n/2＝l _n/2+β(e _n/2-l _n/2)

Obtain low dynamic range echograms;

Wherein, described le _N/2Be low dynamic range echograms;

Described β is the factor that control chart image contrast and details are enriched degree.

Wherein, when described high dynamic range images is coloured image,

Described acquisition module also is used for,

According to formula

L＝0.299R+0.587G+0.114B.

Obtain the brightness of high dynamic range images;

Wherein, described L is the brightness of high dynamic range images;

Described R is the GTG value of red brightness in the high dynamic range images;

Described G is the GTG value of high dynamic range images medium green colour brightness;

Described B is the GTG value of high dynamic range images Smalt brightness.

Wherein, described processing module also is used for,

According to formula

$R_{\mathrm{out}}={\left(\frac{R_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$G_{\mathrm{out}}={\left(\frac{G_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$B_{\mathrm{out}}={\left(\frac{B_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

The brightness of image is carried out the triple channel color correction of RGB coloured image;

Wherein, R _OutRepresent the pairing output valve of red brightness, R _InRepresent the pairing input value of red brightness; G _OutRepresent the pairing output valve of green brightness, G _InRepresent the pairing input value of green brightness; B _OutRepresent the pairing output valve of blue brightness, B _InRepresent the pairing input value of blue brightness; L _OutThe pairing output valve of presentation video brightness, L _InThe pairing input value of presentation video brightness; γ is the factor.

Compared with prior art, the present invention has the following advantages:

The high dynamic range adjustment technology of the single-frame images global map that the present invention proposes more rationally, make picture quality increase, can reasonably show simultaneously that the details of bright dark situation and algorithm are simple and practical and it is discontinuous to have avoided local mapping and multiple image to merge the brightness that causes; By the factor that provides user's control chart image contrast and details to enrich degree, be convenient to be adjusted to the effect that human eye is more accepted.

Description of drawings

In order to be illustrated more clearly in the present invention or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in the present invention or the description of the Prior Art below, apparently, accompanying drawing in describing below only is accompanying drawings more of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the method for adjustment flow chart of a kind of high dynamic range of the present invention's proposition;

Fig. 2 is the method for adjustment flow chart of the high dynamic range of proposition under a kind of concrete application scenarios of the present invention;

Fig. 3 (A) and Fig. 3 (B) are respectively high dynamic range images and the adjusted low dynamic range echograms before adjusting;

Fig. 4 is the adjusting device structure chart of a kind of high dynamic range of the present invention's proposition.

Embodiment

Below in conjunction with the accompanying drawing among the present invention, the technical scheme among the present invention is clearly and completely described, obviously, described only is a part of the present invention, rather than whole.Based on the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other invention that is obtained under the creative work prerequisite.

Core concept of the present invention is by using the high dynamic range adjustment technology of single-frame images global map, and by adaptive overall brightness adjustment, histogram adjustment and color correction, high dynamic range images is become a width of cloth low dynamic range echograms, guaranteed the very bright and unusual visual detail at dark areas place in the image to greatest extent, and can make the contrast of image and the visual effect that color meets the people by parameter control among the present invention, make that then picture quality improves greatly.

As shown in Figure 1, the method for adjustment of a kind of high dynamic range that proposes for the present invention said method comprising the steps of:

Step 101, according to the brightness range of the luminance acquisition low dynamic range echograms of high dynamic range images, the brightness range of described low dynamic range echograms is the brightness range that display device can show.

Step 102 is carried out Linear Mapping and histogram equalization to the result that obtains of the brightness range of described low dynamic range echograms, and is obtained low dynamic range echograms.

In the present invention, the brightness range according to the luminance acquisition low dynamic range echograms of high dynamic range images specifically comprises:

According to formula

$D\left(I\right)=(D_{\max }-D_{\min })*\frac{\log (I+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}{\log (I_{\max }+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}+D_{\min }$

Obtain the brightness range of low dynamic range echograms;

Wherein, described D (I) is the brightness of low dynamic range echograms;

Described D _Max, D _MinBe respectively the maximum and the minimum value of the display device brightness range that can show;

Described I is the brightness of high dynamic range images;

Described I _Max, I _MinBe respectively the maximum and the minimum value of the brightness of high dynamic range images;

Described τ is the brilliance control factor.

The result that obtains to the brightness range of described low dynamic range echograms carries out Linear Mapping and histogram equalization, and obtains low dynamic range echograms and specifically comprise:

Described D (I) Linear Mapping is divided into two sections of equal length, obtains mid point l _N/2And described D (I) histogram equalization cut apart, obtain emphasis e _N/2

According to formula

le _n/2＝l _n/2+β(e _n/2-l _n/2)

Obtain low dynamic range echograms;

Wherein, described le _N/2Be low dynamic range echograms;

Described β is the factor that control chart image contrast and details are enriched degree.

When described high dynamic range images is coloured image, in the method provided by the invention, also comprise:

According to formula

L＝0.299R+0.587G+0.114B.

Obtain the brightness of high dynamic range images;

Wherein, described L is the brightness of high dynamic range images;

Described R is the GTG value of red brightness in the high dynamic range images;

Described G is the GTG value of high dynamic range images medium green colour brightness;

Described B is the GTG value of high dynamic range images Smalt brightness.

Further, after the described acquisition low dynamic range echograms, also comprise:

According to formula

$R_{\mathrm{out}}={\left(\frac{R_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$G_{\mathrm{out}}={\left(\frac{G_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$B_{\mathrm{out}}={\left(\frac{B_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

The brightness of image is carried out the triple channel color correction of RGB coloured image;

Wherein, R _OutRepresent the pairing output valve of red brightness, R _InRepresent the pairing input value of red brightness; G _OutRepresent the pairing output valve of green brightness, G _InRepresent the pairing input value of green brightness; B _OutRepresent the pairing output valve of blue brightness, B _InRepresent the pairing input value of blue brightness; L _OutThe pairing output valve of presentation video brightness, L _InThe pairing input value of presentation video brightness; γ is the factor.

As can be seen, the method that the application of the invention provides has the following advantages:

The high dynamic range adjustment technology of the single-frame images global map that the present invention proposes more rationally, make picture quality increase, can reasonably show simultaneously that the details of bright dark situation and algorithm are simple and practical and it is discontinuous to have avoided local mapping and multiple image to merge the brightness that causes; By the factor that provides user's control chart image contrast and details to enrich degree, be convenient to be adjusted to the effect that human eye is more accepted.

For the method for adjustment of high dynamic range provided by the present invention more clearly is described, the present invention is given unnecessary details in detail below in conjunction with a kind of concrete application scenarios.

As shown in Figure 2, this method may further comprise the steps:

Step 201, obtain the brightness of high dynamic range images. wherein, when needs are converted to low dynamic range echograms with high dynamic range images, and it is final by (for example using display device, standard display device such as CRT monitor) when showing, need get access to the brightness of this high dynamic range images earlier, this acquisition process is existing obtain manner, repeats no more among the present invention.

Step 202 is carried out adaptive brightness adjustment to the brightness of high dynamic range images, promptly needs the luminance compression of high dynamic range images is arrived the brightness range of low dynamic range echograms.Wherein, the brightness range of this low dynamic range echograms is the brightness range that display device can show, promptly by using above-mentioned standard display device such as CRT monitor can show brightness in the brightness range of this low dynamic range echograms.

Concrete, in this step, include but not limited to use formula 1 to compress to the mode of the brightness range of low dynamic range echograms the luminance compression of high dynamic range images, obtain the brightness range of low dynamic range echograms then.

$D\left(I\right)=(D_{\max }-D_{\min })*\frac{\log (I+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}{\log (I_{\max }+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}+D_{\min }$ (formula 1)

In formula 1, D (I) is the brightness of low dynamic range echograms; D _Max, D _MinBe respectively the maximum and the minimum value of the display device brightness range that can show; I is the brightness of high dynamic range images; I _Max, I _MinBe respectively the maximum and the minimum value of the brightness of high dynamic range images; τ is the brilliance control factor, can select arbitrarily according to the actual needs; As can be seen, as τ → ∞, D (I)=I.

In formula (1), by the value of control τ, the maximum and the minimum value that the brightest scene and the darkest scene of high dynamic range images can be mapped to display device respectively.The value of τ is more little, and the ratio in the image of low side after mapping of true high dynamic range images is big more.

Step 203 is carried out Linear Mapping and histogram equalization to the brightness range of the low dynamic range echograms that gets access to.

Concrete, when the brightness range of the low dynamic range echograms that gets access to is adjusted, when the mode that only adopts Linear Mapping is low dynamic range echograms with the high dynamic range images Linear Mapping, can cause details disappearance and decrease of contrast; And when only adopting the histogram equalization technology that the high dynamic range images histogram equalization is low dynamic range echograms, the visual effect of the image after may causing shining upon is not fine.

So, in the present invention,, between Linear Mapping and histogram equalization, seek a reasonably compromise by Linear Mapping and histogram equalization are integrated consideration, it is better to obtain visual effect, and details is abundant, the low dynamic range echograms that contrast is moderate.

Further, Linear Mapping is for to carry out the mapping of point-to-point according to respective function with each pixel in the high dynamic range images and each pixel in the low dynamic range echograms.Histogram equalization is from becoming the even distribution in whole tonal ranges between certain gray area of relatively concentrating the grey level histogram of original image.As can be seen, histogram equalization is redistributed image pixel value by image is carried out non-linear stretching, makes the pixel quantity in certain tonal range roughly the same, and the histogram distribution with given image changes over even distribution histogram distribution then.

The histogram equalization technology is a technology of utilizing image histogram that contrast is adjusted in the image processing field, by using the histogram equalization technology, can increase the local contrast of image, when the contrast of image useful data quite near the time, brightness can distribute on histogram better, can be used to strengthen local contrast then and does not influence whole contrast.

In this step, the brightness range of the low dynamic range echograms that gets access to is carried out Linear Mapping and histogram equalization specifically comprises:

(1) D (I) is partitioned into two sections (being similar to Linear Mapping) of equal length, and obtains intermediate point l _N/2Wherein, this cutting procedure is the processing procedure of corresponding Linear Mapping.

(2) D (I) histogram equalization is divided into two sections, and obtains another emphasis e _N/2Wherein, this cutting procedure is the processing procedure of corresponding histogram equalization technology.

(3) according to l _N/2And e _N/2, and adaptive equalization algorithm obtains low dynamic range echograms.

Among the present invention, carry out Linear Mapping and histogram equalization by brightness range to the low dynamic range echograms that gets access to, and the use adaptive equalization algorithm, can obtain low dynamic range echograms then, and finally can this low dynamic range echograms be shown to the user by using display device.

Concrete, this adaptive equalization algorithm as shown in Equation (2):

Le _N/2=l _N/2+ β (e _N/2-l _N/2) formula (2)

As can be seen, by using this adaptive equalization algorithm, the point that D (I) can be divided into two sections is le _N/2Wherein, β supplies user's control chart image contrast and details to enrich the factor of degree, can select according to the actual needs.

Among the present invention, by the use adaptive equalization algorithm, and the intermediate point l that comprehensively uses the Linear Mapping technology to obtain _N/2The mid point e that obtains with the histogram equalization technology _N/2, can obtain the le that adaptive equalization algorithm obtains _N/2Thereby, obtain optimum low dynamic range echograms.

Further, use in this step in the process of adaptive equalization algorithm, also need the two sections D (I) after cutting apart in the said process (1) are continued Linear Mapping in the implementations (1), and continue to be partitioned into two sections of equal length, obtain intermediate point l _N/2And, need continue histogram equalization in the implementations (2) to the two sections D (I) after cutting apart in the said process (2), and continue histogram equalization and be partitioned into two sections of equal length, obtain emphasis e _N/2And the middle process that obtains low dynamic range echograms of continuation implementation (3).

By that analogy, through n iteration, whole dynamic range will be split into N=2 ⁿIndividual segmentation, the pixel in same segmentation will be endowed identical display brightness value in low dynamic range echograms, promptly can obtain the whole structure of low dynamic range echograms, and finally be shown to the user by display device.

Need to prove, in the present invention,, promptly can realize high dynamic range images is adjusted into low dynamic range echograms, and finally be shown to the user by display device by using above-mentioned step 201-step 203.

But, be the situation of coloured image for high dynamic range images, in the method provided by the invention, can also comprise the steps:

Step 204 is carried out the color correction on the triple channel of RGB coloured image.

At high dynamic range images is under the situation of coloured image, the process of obtaining the brightness of high dynamic range images in the above-mentioned steps 201 is specially: obtain the brightness of high dynamic range images according to formula (3).

L=0.299R+0.587G+0.114B. (formula 3)

Concrete, in above-mentioned step 202 and step 203, be brightness with high dynamic range images to only occur on the luminance channel of image be that example describes, and for coloured image, the brightness calculation formula of correspondence is as shown in Equation (3).In formula (3), R is the GTG value of red brightness in the high dynamic range images; G is the GTG value of high dynamic range images medium green colour brightness; B is the GTG value of high dynamic range images Smalt brightness; L is the brightness of high dynamic range images.

At high dynamic range images is under the situation of coloured image, and through the adjustment process in above-mentioned steps 202 and the step 203, the brightness of image has obtained mapping, in this step, need proofread and correct the color on the triple channel of RGB coloured image.

Concrete, the mode that color is proofreaied and correct is respectively shown in formula (4), formula (5) and formula (6).

$R_{\mathrm{out}}={\left(\frac{R_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$ (formula 4)

$G_{\mathrm{out}}={\left(\frac{G_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$ (formula 5)

$B_{\mathrm{out}}={\left(\frac{B_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$ (formula 6)

In above-mentioned formula (4), formula (5) and formula (6), R _OutRepresent the pairing output valve of red brightness, R _InRepresent the pairing input value of red brightness; G _OutRepresent the pairing output valve of green brightness, G _InRepresent the pairing input value of green brightness; B _OutRepresent the pairing output valve of blue brightness, B _InRepresent the pairing input value of blue brightness; L _OutThe pairing output valve of presentation video brightness, L _InThe pairing input value of presentation video brightness; γ is the factor, can adjust according to the actual needs, repeats no more among the present invention.

Wherein, the step among the present invention can also be adjusted according to the actual needs.

Shown in Fig. 3 (A) and Fig. 3 (B), be respectively high dynamic range images and adjusted low dynamic range echograms before adjusting; As can be seen, the method that the application of the invention provides has the following advantages:

By using the high dynamic range adjustment technology of single-frame images global map, and by adaptive overall brightness adjustment, histogram adjustment and color correction, high dynamic range images is become a width of cloth low dynamic range echograms, guaranteed the very bright and unusual visual detail at dark areas place in the image to greatest extent, and can make the contrast of image and the visual effect that color meets the people by parameter control among the present invention, make that then picture quality improves greatly.

In sum, the high dynamic range adjustment technology of the single-frame images global map that proposes of the present invention more rationally, make picture quality increase, can reasonably show simultaneously that the details of bright dark situation and algorithm are simple and practical and it is discontinuous to have avoided local mapping and multiple image to merge the brightness that causes; By the factor that provides user's control chart image contrast and details to enrich degree, be convenient to be adjusted to the effect that human eye is more accepted.

As shown in Figure 4, be the adjusting device of a kind of high dynamic range proposed by the invention, described device comprises:

Acquisition module 41 is used for the brightness range according to the luminance acquisition low dynamic range echograms of high dynamic range images, and the brightness range of described low dynamic range echograms is the brightness range that display device can show.

Concrete, described acquisition module 41 specifically is used for,

According to formula

$D\left(I\right)=(D_{\max }-D_{\min })*\frac{\log (I+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}{\log (I_{\max }+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}+D_{\min }$

Obtain the brightness range of low dynamic range echograms;

Wherein, described D (I) is the brightness of low dynamic range echograms;

Described D _Max, D _MinBe respectively the maximum and the minimum value of the display device brightness range that can show;

Described I is the brightness of high dynamic range images;

Described I _Max, I _MinBe respectively the maximum and the minimum value of the brightness of high dynamic range images;

Described τ is the brilliance control factor.

Processing module 42, the result that obtains who is used for the brightness range of low dynamic range echograms that described acquisition module 41 is obtained carries out Linear Mapping and histogram equalization, and obtains low dynamic range echograms.

Concrete, described processing module 42 specifically is used for,

Described D (I) Linear Mapping is divided into two sections of equal length, obtains mid point l _N/2And described D (I) histogram equalization cut apart, obtain emphasis e _N/2

According to formula

le _n/2＝l _n/2+β(e _n/2-l _n/2)

Obtain low dynamic range echograms;

Wherein, described le _N/2Be low dynamic range echograms;

Described β is the factor that control chart image contrast and details are enriched degree.

Among the present invention, when described high dynamic range images was coloured image, described acquisition module 51 also was used for,

According to formula

L＝0.299R+0.587G+0.114B.

Obtain the brightness of high dynamic range images;

Wherein, described L is the brightness of high dynamic range images;

Described R is the GTG value of red brightness in the high dynamic range images;

Described G is the GTG value of high dynamic range images medium green colour brightness;

Described B is the GTG value of high dynamic range images Smalt brightness.

Corresponding, described processing module 42 also is used for,

According to formula

$R_{\mathrm{out}}={\left(\frac{R_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$G_{\mathrm{out}}={\left(\frac{G_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$B_{\mathrm{out}}={\left(\frac{B_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

The brightness of image is carried out the triple channel color correction of RGB coloured image;

Wherein, R _OutRepresent the pairing output valve of red brightness, R _InRepresent the pairing input value of red brightness; G _OutRepresent the pairing output valve of green brightness, G _InRepresent the pairing input value of green brightness; B _OutRepresent the pairing output valve of blue brightness, B _InRepresent the pairing input value of blue brightness; L _OutThe pairing output valve of presentation video brightness, L _InThe pairing input value of presentation video brightness; γ is the factor.

Wherein, each module of apparatus of the present invention can be integrated in one, and also can separate deployment.Above-mentioned module can be merged into a module, also can further split into a plurality of submodules.

As seen, the device that the application of the invention provides has the following advantages:

By using the high dynamic range adjustment technology of single-frame images global map, and by adaptive overall brightness adjustment, histogram adjustment and color correction, high dynamic range images is become a width of cloth low dynamic range echograms, guaranteed the very bright and unusual visual detail at dark areas place in the image to greatest extent, and can make the contrast of image and the visual effect that color meets the people by parameter control among the present invention, make that then picture quality improves greatly.

In sum, the high dynamic range adjustment technology of the single-frame images global map that proposes of the present invention more rationally, make picture quality increase, can reasonably show simultaneously that the details of bright dark situation and algorithm are simple and practical and it is discontinuous to have avoided local mapping and multiple image to merge the brightness that causes; By the factor that provides user's control chart image contrast and details to enrich degree, be convenient to be adjusted to the effect that human eye is more accepted.

Through the above description of the embodiments, those skilled in the art can be well understood to the present invention and can realize by hardware, also can realize by the mode that software adds necessary general hardware platform.Based on such understanding, technical scheme of the present invention can embody with the form of software product, it (can be CD-ROM that this software product can be stored in a non-volatile memory medium, USB flash disk, portable hard drive etc.) in, comprise that some instructions are with so that a computer equipment (can be personal computer, server, perhaps network equipment etc.) is carried out method of the present invention.

The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be looked protection scope of the present invention.

It will be appreciated by those skilled in the art that the module in the device among the embodiment can be distributed in the device of embodiment according to the embodiment description, also can carry out respective change and be arranged in the one or more devices that are different from present embodiment.The module of the foregoing description can be merged into a module, also can further split into a plurality of submodules.

The invention described above sequence number is not represented the quality of embodiment just to description.

More than disclosed only be several specific embodiment of the present invention, still, the present invention is not limited thereto, any those skilled in the art can think variation all should fall into protection scope of the present invention.

Claims (10)

1. the method for adjustment of a high dynamic range is characterized in that, may further comprise the steps:

According to the brightness range of the luminance acquisition low dynamic range echograms of high dynamic range images, the brightness range of described low dynamic range echograms is the brightness range that display device can show;

The result that obtains to the brightness range of described low dynamic range echograms carries out Linear Mapping and histogram equalization, and obtains low dynamic range echograms.

2. the method for claim 1 is characterized in that, comprises according to the brightness range of the luminance acquisition low dynamic range echograms of high dynamic range images:

According to formula

$D\left(I\right)=(D_{\max }-D_{\min })*\frac{\log (I+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}{\log (I_{\max }+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}+D_{\min }$

Obtain the brightness range of low dynamic range echograms;

Wherein, described D (I) is the brightness of low dynamic range echograms;

Described D _Max, D _MinBe respectively the maximum and the minimum value of the display device brightness range that can show;

Described I is the brightness of high dynamic range images;

Described I _Max, I _MinBe respectively the maximum and the minimum value of the brightness of high dynamic range images;

Described τ is the brilliance control factor.

3. method as claimed in claim 2 is characterized in that, the result that obtains of the brightness range of described low dynamic range echograms is carried out Linear Mapping and histogram equalization, and obtains low dynamic range echograms and specifically comprise:

Described D (I) Linear Mapping is divided into two sections of equal length, obtains mid point l _N/2And described D (I) histogram equalization cut apart, obtain emphasis e _N/2

According to formula

le _n/2＝l _n/2+β(e _n/2-l _n/2)

Obtain low dynamic range echograms;

Wherein, described le _N/2Be low dynamic range echograms;

Described β is the factor that control chart image contrast and details are enriched degree.

4. as each described method of claim 1-3, it is characterized in that when described high dynamic range images was coloured image, described method also comprised:

According to formula

L＝0.299R+0.587G+0.114B.

Obtain the brightness of high dynamic range images;

Wherein, described L is the brightness of high dynamic range images;

Described R is the GTG value of red brightness in the high dynamic range images;

Described G is the GTG value of high dynamic range images medium green colour brightness;

Described B is the GTG value of high dynamic range images Smalt brightness.

5. method as claimed in claim 4 is characterized in that, after the described acquisition low dynamic range echograms, also comprises:

According to formula

$R_{\mathrm{out}}={\left(\frac{R_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$G_{\mathrm{out}}={\left(\frac{G_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$B_{\mathrm{out}}={\left(\frac{B_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

The brightness of image is carried out the triple channel color correction of RGB coloured image;

Wherein, R _OutRepresent the pairing output valve of red brightness, R _InRepresent the pairing input value of red brightness; G _OutRepresent the pairing output valve of green brightness, G _InRepresent the pairing input value of green brightness; B _OutRepresent the pairing output valve of blue brightness, B _InRepresent the pairing input value of blue brightness; L _OutThe pairing output valve of presentation video brightness, L _InThe pairing input value of presentation video brightness; γ is the factor.

6. the adjusting device of a high dynamic range is characterized in that, described device comprises:

Acquisition module is used for the brightness range according to the luminance acquisition low dynamic range echograms of high dynamic range images, and the brightness range of described low dynamic range echograms is the brightness range that display device can show;

Processing module, the result that obtains who is used for the brightness range of low dynamic range echograms that described acquisition module is obtained carries out Linear Mapping and histogram equalization, and obtains low dynamic range echograms.

7. device as claimed in claim 6 is characterized in that,

Described acquisition module specifically is used for,

According to formula

$D\left(I\right)=(D_{\max }-D_{\min })*\frac{\log (I+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}{\log (I_{\max }+\mathrm{\τ})-\log (I_{\min }+\mathrm{\τ})}+D_{\min }$

Obtain the brightness range of low dynamic range echograms;

Wherein, described D (I) is the brightness of low dynamic range echograms;

Described D _Max, D _MinBe respectively the maximum and the minimum value of the display device brightness range that can show;

Described I is the brightness of high dynamic range images;

Described I _Max, I _MinBe respectively the maximum and the minimum value of the brightness of high dynamic range images;

Described τ is the brilliance control factor.

8. device as claimed in claim 7 is characterized in that,

Described processing module specifically is used for,

Described D (I) Linear Mapping is divided into two sections of equal length, obtains mid point l _N/2And described D (I) histogram equalization cut apart, obtain emphasis e _N/2

According to formula

le _n/2＝l _n/2+β(e _n/2-l _n/2)

Obtain low dynamic range echograms;

Wherein, described le _N/2Be low dynamic range echograms;

Described β is the factor that control chart image contrast and details are enriched degree.

9. as each described device of claim 6-8, it is characterized in that, when described high dynamic range images is coloured image,

Described acquisition module also is used for,

According to formula

L＝0.299R+0.587G+0.114B.

Obtain the brightness of high dynamic range images;

Wherein, described L is the brightness of high dynamic range images;

Described R is the GTG value of red brightness in the high dynamic range images;

Described G is the GTG value of high dynamic range images medium green colour brightness;

Described B is the GTG value of high dynamic range images Smalt brightness.

10. device as claimed in claim 9 is characterized in that,

Described processing module also is used for,

According to formula

$R_{\mathrm{out}}={\left(\frac{R_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$G_{\mathrm{out}}={\left(\frac{G_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

$B_{\mathrm{out}}={\left(\frac{B_{\mathrm{in}}}{L_{\mathrm{in}}}\right)}^{\mathrm{\γ}}{L}_{\mathrm{out}},$

The brightness of image is carried out the triple channel color correction of RGB coloured image;

Wherein, R _OutRepresent the pairing output valve of red brightness, R _InRepresent the pairing input value of red brightness; G _OutRepresent the pairing output valve of green brightness, G _InRepresent the pairing input value of green brightness; B _OutRepresent the pairing output valve of blue brightness, B _InRepresent the pairing input value of blue brightness; L _OutThe pairing output valve of presentation video brightness, L _InThe pairing input value of presentation video brightness; γ is the factor.

Images