CN103413337A - Color fog generation method based on human-machine interaction - Google Patents

Abstract

Disclosed is a color fog generation method based on human-machine interaction. An atmospheric scattering model and simple human-machine interaction are used for operation on a foggy image. Modules of dark primary color image extraction, atmospheric light estimation, transmissivity conversion, optimization compensation and color fog generation are included. a dark primary color image is obtained through a method based on dark primary color priori; the atmospheric light is estimated and a rough transmissivity diagram is obtained based on a local minimum derivation; a guided filter (guided filter) approach is used for optimization of the transmissivity diagram and sky compensation; index corresponding relationship between transmissivities is then used for calculation of different transmissivities; and the atmospheric light is set with different colors to change fog generation so that a foggy image in a color fog scene is obtained. The method can be used for color fog generation on a foggy image, thereby greatly reducing the complexity of fog visual effects and increasing versatility.

Description

A kind of colored mist effect generation method based on man-machine interactively

Technical field

The present invention relates to computer vision field, be specifically related to a kind of colored mist effect generation method based on man-machine interactively.

Background technology

Visual effect is the combination of color and relation thereof, and the same with drawing is the manifestation mode of visual art.In recent decades, visual effect develops and many branches, and has been widely used in a plurality of fields such as video display field, field of play, animation field.And be requisite part in video display game performance visual effect as the mist of natural scene important component part.But, due to the complicacy of mist effect simulation itself, for the generation of mist effect, always can be subject to the restriction of the algorithm of software own and operating personnel's technology.How can be convenient under the condition of interactive operation, scene is made to mist effect simulation preferably, be at present in the problem that need to solve aspect mist effect visual effect.

Current, for the processing of the visual effect of mist effect, mainly concentrate on this field of 3D scene.The mist effect of utilizing basic atmospheric scattering physical model to carry out scene generates, and has obtained certain effect.But itself can expend a large amount of internal memories these methods, and and be not suitable for the mist effect simulation of 2D scene.

The mist effect that is image for the 2D scene generates, and does not have at present too many research.Current, for the processing that the mist image is arranged, mainly concentrate on this field of demist.And some powerful business softwares have higher requirement for the software relevant knowledge of user own, and complicated operation, versatility do not possessed.A kind of digital filter method of effect of mist based on dark primary passage priori, be based on simple physical model and data and calculate, and just can carry out the effective ways that the simulation of mist effect comprises the demist operation to the mist image is arranged.Yet the method has just been considered the mist effect simulation in natural situation, only can generate white mist effect, does not make further expansion for the visual effect aspect of mist effect.

Summary of the invention

The invention provides a kind of colored mist effect generation method based on man-machine interactively, the deficiencies in the prior art have been made up, the method only needs succinct man-machine interactively, simple physical model and data are calculated, just can generate there being the mist image to carry out colored mist effect, greatly reduce the complicacy that obtains mist effect visual effect, increased its versatility.

The technical solution used in the present invention:

A kind of colored mist effect generation method based on man-machine interactively, adopt the atmospheric scattering model, and utilize simple man-machine interactively, operates the mist image is arranged.

A kind of colored mist effect generation method based on man-machine interactively, comprise the modules such as the extraction of dark primary image, the estimation of atmosphere light, transmissivity conversion, Optimization Compensation, the generation of colored mist effect, and its step is as follows:

The first step, the dark primary image extracts

A moving window is set on image, obtains pixel value in the RGB minimum value of pixel in this window this window and be set to this minimum value; Then window be take to 1 pixel as unit moves, until handle whole image, obtain single pass dark primary image.

Second step, atmosphere light is estimated

By the method that atmosphere light is estimated, obtain atmosphere light.0.1% the brightest point (being the point of gray-scale value maximum) in the dark primary image is taken out, and using the pixel in the source images of its correspondence position as a set o (x), get the three-channel pixel maximal value of RGB in o (x), according to scattering law, it is carried out to the coefficient correction, formula is as follows:

$I\max =\underset{y\∈o\left(x\right)}{\max }\left(H\left(y\right)\right)---\left(1\right)$

Wherein H is source images, and Imax is the value of atmosphere light.

The 3rd step, the transmissivity conversion

According to step (1), obtain the rgb value of atmosphere light, then, in conjunction with dark primary passage priori principle and atmospheric scattering model formation (4), (5), derive and obtain transmissivity derivation formula (6), specific as follows:

t(x)=e ^-βd(x) （2）

I(x)=J(x)t(x)+A(1-t(x)) （3）

Wherein t is transmissivity, and e is natural constant, and β is transmission coefficient, and d is distance, and I is source images, and J is without the mist image, and A is atmosphere light.

Derivation transmissivity derivation formula:

$t\left(x\right)=1-\frac{I^{\mathrm{dark}}\left(x\right)}{A}---\left(4\right)$

I wherein ^DarkFor dark primary figure, A is atmosphere light, and t is the rough transmissivity figure obtained.

The 4th step, Optimization Compensation

Use the method for guiding filtering (guided filter) to be optimized this transmissivity figure.After optimization, it is carried out to the sky compensation, the aberration of the bright areas such as the inapplicable sky of correction dark primary passage priori principle, by the method for man-machine interactively, obtain sky compensation threshold alpha, this threshold value, as the cut off value of distinguishing the bright areas such as sky and actual scenery, is utilized the sky compensation formula:

T=2 α-t (5) carries out the sky compensation to transmissivity figure, the transmissivity figure that obtains revising.

The 5th step, colored mist effect generates

Set the visibility under different mist effect scenes, when variable concentrations mist image reached maximum visibility simultaneously, their transmissivity was identical, derived according to formula (4):

$t_n\left(x\right)=t_h{\left(x\right)}^{D{\mathrm{vis}}_h{/\mathrm{Dcis}}_n}---\left(6\right)$

T wherein _n(x) and t _h(x) be respectively the transmissivity of simulate fog image and source images, Dvis _hAnd Dvis _nBe respectively the source images of man-machine interactively setting and the visibility of simulate fog image.

Again the scene under different mist effects is connected, and the atmosphere light value A that participates in calculating is carried out to different man-machine interactivelies.As follows alternately:

The first, original color mist generates

Atmosphere light value A is set as to the color-values of artificial appointment.Namely

A(R,G,B)=Set(R,G,B) （7）

Wherein Set is the artificial color value of setting.

The second, the color mist of laterally/vertical partition generates

The image that is m*n by size is divided into laterally/longitudinally W zone, is m for each size _W* n/m*n _WZone, all set different color-values.

A _W(R,G,B)=Set _W(R,G,B) （8）

A wherein _WFor atmosphere light value corresponding to each zone, Set _WFor artificial each regional color value of setting.

The third, the color mist of laterally/vertical partition gradual change generates

Image is divided into to laterally/longitudinally W zone, is m for each size _W* n/m*n _WZone, all set different color-values.And the A value is done to corresponding gradual change operation.

$A_W(R,G,B)=\frac{(m_W-\mathrm{\δi})}{m_W}{\mathrm{Set}}_{W1}(R,G,B)+\frac{\mathrm{\δi}}{m_W}{\mathrm{Set}}_{W2}(R,G,B)---\left(9\right)$

$A_W(R,G,B)=\frac{(n_W-\mathrm{\ηj})}{n_W}{\mathrm{Set}}_{W1}(R,G,B)+\frac{\mathrm{\ηj}}{n_W}{\mathrm{Set}}_{W2}(R,G,B)---\left(10\right)$

The horizontal and vertical A value gradual change operation of correspondence respectively of two formula.A wherein _WFor atmosphere light value corresponding to each zone, Set _W1, Set _W2For two groups of color values of the artificial participation gradual change operation of setting, i and j mean the horizontal stroke/ordinate of corresponding pixel points, and δ and η mean respectively control variable/functional value arbitrarily.

Formula according to formula (3) derivation:

N(x)=(H(x)t _n(x)-A(t _n(x)-t _h(x)))/t _h(x) （11）

Wherein N (x) is required simulate fog image, and H (x) is source images, t _n(x) and t _h(x) be respectively the transmissivity of simulate fog image and source images, A is atmosphere light.By the transmissivity figure that the mist scene is arranged obtained, source images, the transmissivity figure of source images, and calculate by the atmosphere light value substitution formula (11) that interactive computing generates the image that colored mist effect generates.Finally again image is carried out to suitable exposure and modify to improve its visual effect.

The present invention is based on the physical model of general atmospheric scattering, employing is asked for the dark primary image based on the method for dark primary priori, estimate atmosphere light and obtain rough transmissivity figure according to the derivation of local minimum, utilize the method that guides filtering (guided filter) to be optimized transmissivity figure and carry out the sky compensation, and then utilize the index corresponding relation between transmissivity to calculate different transmissivities, and atmosphere light is carried out to different color settings change the mist effect and generate, thereby obtain colored mist effect scene the mist image arranged.

The accompanying drawing explanation

Accompanying drawing is method workflow diagram of the present invention.

101 source images, 102 dark primary images, 103 rough transmissivity images, the 104 transmissivity images of optimizing, the transmissivity image after 105 sky compensation, the transmissivity image of 106 simulate fog images, 107 colored mist effect images.

Embodiment

For making purpose of the present invention, technical scheme and advantage clearer, below in conjunction with accompanying drawing and instantiation, the present invention is described in further details.These examples are only illustrative, and are not limitation of the present invention.

The present invention proposes a kind of colored mist effect generation method based on man-machine interactively, the concrete implementation step of the method: at first, load source images 101, principle according to atmospheric scattering model dark primary passage priori, set up the single channel image of a blank, adopt the window area of 15*15 size, source images 101 is carried out to computing, get pixel RGB minimum value in window, and pixel value in should zone using this minimum value as the single channel image, the pixel of take is carried out identical operation as unit moves this window, until handle whole source images 101, the single channel image obtained is the dark primary image 102 of source images,

Then, 0.1% the brightest point (being the point of gray-scale value maximum) in dark primary image 102 is taken out, and using the pixel in the source images of its correspondence position as a set, get the three-channel pixel maximal value of RGB in this set, according to scattering law, it is carried out to the coefficient correction, according to formula (1), calculate atmosphere light, then according to formula (4), calculate rough transmissivity Figure 103, rough transmissivity figure is optimized to the transmissivity Figure 104 be optimized by the method for guiding filtering (guided filter);

Then, according to the image situation, utilize formula (5) to carry out the transmissivity Figure 105 after sky compensation (being 0.1 if there is no day dummy section threshold value is set) is compensated to the transmissivity figure optimized.The maximum visibility of definition source images and the image that needs simulation, then manually determine interaction schemes, the atmosphere light value is set, utilize formula (6) substitution source images and need the maximum visibility of the image of simulating and transmissivity Figure 106 that the transmissivity figure after compensation obtains the simulate fog image, to utilize the atmosphere light (annotate: used herein is formula (9)) after calculate formula (7)/(8)/(9)/(10), source images, the transmissivity substitution formula (11) of source images and simulate fog image, and suitable its result being modified with exposure, obtain final colored mist effect synthetic image 107.

Finally, can be written into different images, adopt different interaction schemes, generate different colored mist effects.

Accompanying drawing is the atlas of the different mist effects of simulation.From left to right, be followed successively by from top to bottom source images, original color mist effect generates figure, and the color mist of horizontal partition generates figure, and the color mist of vertical partition generates figure, and the color mist of horizontal partition gradual change generates figure, and the color mist of vertical partition gradual change generates figure.

Claims (1)

1. the colored mist effect generation method based on man-machine interactively, is characterized in that following steps,

The first step, dark primary image are extracted: a moving window is set on image, obtains pixel value in the RGB minimum value of pixel in this window this window and be set to this minimum value; Then window be take to 1 pixel as unit moves, until handle whole image, obtain single pass dark primary image;

Second step, the method of using atmosphere light to estimate obtains atmosphere light: 0.1% the brightest point in the dark primary image is taken out, and using the pixel in the source images of its correspondence position as a set o (x), get the three-channel pixel maximal value of RGB in o (x), according to scattering law, it is carried out to the coefficient correction, formula is as follows:

$I\max =\underset{y\∈o\left(x\right)}{\max }\left(H\left(y\right)\right)---\left(1\right)$

Wherein H is source images, and Imax is the value of atmosphere light;

The 3rd step, transmissivity conversion: step (1) obtains the rgb value of atmosphere light, then, in conjunction with dark primary passage priori principle and atmospheric scattering model formation (4), (5), derives and obtain transmissivity derivation formula (6), specific as follows:

t(x)=e ^-βd(x) （2）

I(x)=J(x)t(x)+A(1-t(x)) （3）

Wherein t is transmissivity, and e is natural constant, and β is transmission coefficient, and d is distance, and I is source images, and J is without the mist image, and A is atmosphere light;

Derivation transmissivity derivation formula:

$t\left(x\right)=1-\frac{I^{\mathrm{dark}}\left(x\right)}{A}---\left(4\right)$

I wherein ^DarkFor dark primary figure, A is atmosphere light, and t is the rough transmissivity figure obtained;

The 4th step, use the method for guiding filtering to be optimized compensation to this transmissivity figure: the aberration of the bright areas such as the inapplicable sky of correction dark primary passage priori principle, by the method for man-machine interactively, obtain sky compensation threshold alpha, this threshold value, as the cut off value of distinguishing the bright areas such as sky and actual scenery, is utilized the sky compensation formula:

t=2α-t （5）

Transmissivity figure is carried out to the sky compensation, the transmissivity figure that obtains revising.

The 5th step, colored mist effect generates: set the visibility under different mist effect scenes, when variable concentrations mist image reached maximum visibility simultaneously, their transmissivity was identical, derived according to formula (4):

$t_n\left(x\right)=t_h{\left(x\right)}^{D{\mathrm{vis}}_h{/\mathrm{Dvis}}_n}---\left(6\right)$

T wherein _n(x) and t _h(x) be respectively the transmissivity of simulate fog image and source images, Dvis _hAnd Dvis _nBe respectively the source images of man-machine interactively setting and the visibility of simulate fog image;

Again the scene under different mist effects is connected, and the atmosphere light value A that participates in calculating is carried out to different man-machine interactivelies; As follows alternately:

The first, original color mist generates: atmosphere light value A is set as to the color-values of artificial appointment, namely

A(R,G,B)=Set(R,G,B) （7）

Wherein Set is the artificial color value of setting.

The second, the color mist of laterally/vertical partition generates: the image that is m*n by size is divided into laterally/longitudinally W zone, is m for each size _W* n/m*n _WZone, all set different color-values;

A _W(R,G,B)=Set _W(R,G,B) （8）

A wherein _WFor atmosphere light value corresponding to each zone, Set _WFor artificial each regional color value of setting.

The third, the color mist of laterally/vertical partition gradual change generates: image is divided into to laterally/longitudinally W zone, is m for each size _W* n/m*n _WZone, all set different color-values.And the A value is done to corresponding gradual change operation;

$A_W(R,G,B)=\frac{(m_W-\mathrm{\δi})}{m_W}{\mathrm{Set}}_{W1}(R,G,B)+\frac{\mathrm{\δi}}{m_W}{\mathrm{Set}}_{W2}(R,G,B)---\left(9\right)$

$A_W(R,G,B)=\frac{(n_W-\mathrm{\ηj})}{n_W}{\mathrm{Set}}_{W1}(R,G,B)+\frac{\mathrm{\ηj}}{n_W}{\mathrm{Set}}_{W2}(R,G,B)---\left(10\right)$

The horizontal and vertical A value gradual change operation of correspondence respectively of two formula.A wherein _WFor atmosphere light value corresponding to each zone, Set _W1, Set _W2For two groups of color values of the artificial participation gradual change operation of setting, i and j mean the horizontal stroke/ordinate of corresponding pixel points, and δ and η mean respectively control variable/functional value arbitrarily.

Formula according to formula (3) derivation:

N(x)=(H(x)t _n(x)-A(t _n(x)-t _h(x)))/t _h(x) （11）

Wherein N (x) is required simulate fog image, and H (x) is source images, and tn (x) and th (x) are respectively the transmissivity of simulate fog image and source images, and A is atmosphere light; By the transmissivity figure that the mist scene is arranged obtained, source images, the transmissivity figure of source images, and calculate by the atmosphere light value substitution formula (11) that interactive computing generates the image that colored mist effect generates.

Images