Recently,there has been a notable surge of interest in scientific research regarding spectral images.The potential of these images to revolutionize the digital photography industry,like aerial photography through Unma...Recently,there has been a notable surge of interest in scientific research regarding spectral images.The potential of these images to revolutionize the digital photography industry,like aerial photography through Unmanned Aerial Vehicles(UAVs),has captured considerable attention.One encouraging aspect is their combination with machine learning and deep learning algorithms,which have demonstrated remarkable outcomes in image classification.As a result of this powerful amalgamation,the adoption of spectral images has experienced exponential growth across various domains,with agriculture being one of the prominent beneficiaries.This paper presents an extensive survey encompassing multispectral and hyperspectral images,focusing on their applications for classification challenges in diverse agricultural areas,including plants,grains,fruits,and vegetables.By meticulously examining primary studies,we delve into the specific agricultural domains where multispectral and hyperspectral images have found practical use.Additionally,our attention is directed towards utilizing machine learning techniques for effectively classifying hyperspectral images within the agricultural context.The findings of our investigation reveal that deep learning and support vector machines have emerged as widely employed methods for hyperspectral image classification in agriculture.Nevertheless,we also shed light on the various issues and limitations of working with spectral images.This comprehensive analysis aims to provide valuable insights into the current state of spectral imaging in agriculture and its potential for future advancements.展开更多
Utilizing high-speed schlieren photography and particle-tracking-velocimetry,the wake flow of tethered houseflies is investigated.The high-speed schlieren photography is implemented on tethered houseflies inside an ai...Utilizing high-speed schlieren photography and particle-tracking-velocimetry,the wake flow of tethered houseflies is investigated.The high-speed schlieren photography is implemented on tethered houseflies inside an air container with a stable vertical temperature gradient to visualize the disturbed wake flow from the insects.The resulting photography images were then processed with the physics based optical flow method to derive the light-path averaged flow velocity.Additionally,the state of the art:Shake-the-Box system is implemented on a tethered housefly to measure the volumetric flow field in the wake of the insect,revealing interesting flow behavior and structures that can also be observed and correlated to the schlieren photography images.Comparing the dimensionless velocity magnitude of the wake flow from the two experiments,a good qualitative agreement is reached,suggesting the viability of high-speed schlieren photography in investigating the wake flow of small insects.Furthermore,the high-speed schlieren photography is successfully applied on a housefly that is taking off from the ground,visualizing the disturbed wake flow on the freely flying insect that is challenging to visualize with other methods.展开更多
Background:A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis.The choice of animal model is based on the measur...Background:A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis.The choice of animal model is based on the measurability of specific parameters or structures,the applicability of clinical measurement technologies,and the similarity to human eye function.Studies of eye pathology usually compare optical parameters between a healthy and altered state,so accurate baseline assessments are critical,but few reports have comprehensively examined the normal anatomical structures and physiological functions in these models.Methods:Three cynomolgus monkeys,six New Zealand rabbits,ten Sprague Dawley(SD)rats,and BALB/c mice were examined by fundus photography(FP),fundus fluorescein angiography(FFA),and optical coherence tomography(OCT).Results:Most retinal structures of cynomolgus monkey were anatomically similar to the corresponding human structures as revealed by FP,FFA,and OCT.New Zealand rabbits have large eyeballs,but they have large optic disc and myelinated retinal nerve fibers in their retinas,and the growth pattern of retinal vessels were also different to the human retinas.Unlike monkeys and rabbits,the retinal vessels of SD rats and BALB/c mice were widely distributed and clear.The OCT performance of them were similar with human beings except the macular.Conclusions:Monkey is a good model to study changes in retinal structure associated with fundus disease,rabbits are not suitable for studies on retinal vessel diseases and optic nerve diseases,and rats and mice are good models for retinal vascular diseases.These measures will help guide the choice of model and measurement technology and reduce the number of experimental animals required.展开更多
The eye is an immune-privileged and sensory organ in humans and animals.Anatomical,physiological,and pathobiological features share significant similarities across divergent species(1).Each compartment of the eye has ...The eye is an immune-privileged and sensory organ in humans and animals.Anatomical,physiological,and pathobiological features share significant similarities across divergent species(1).Each compartment of the eye has a unique structure and function.The anterior and posterior compartments of the eye contain endothelium(cornea),epithelium(cornea,ciliary body,iris),muscle(ciliary body),vitreous and neuronal(retina)tissues,which make the eye suitable to evaluate efficacy and safety of tissue specific drugs(2).展开更多
The role of color photography in the representation of architecture is a subject little investigated by architectural historiography.The link between the color values of architectural design and its visual transmissio...The role of color photography in the representation of architecture is a subject little investigated by architectural historiography.The link between the color values of architectural design and its visual transmission in the early phase of modernism was certainly problematic.Color photography had an undeniable impact on architectural color in practice:color photographs in books and periodicals published between the 1940s and 1960s clearly influenced the use of color in architectural design.展开更多
In recent years, with the development of social economy, college photography education career has been developing rapidly, but at the same time, some problems have appeared. In the construction of photography specialt...In recent years, with the development of social economy, college photography education career has been developing rapidly, but at the same time, some problems have appeared. In the construction of photography specialty, a series of problems, such as unreasonable course arrangement, outdated hardware facilities and imperfect teaching software system, are hindering the de-velopment of photography education in universities. Therefore, college educators should seriously sum up the problems existing in college photography education, and carry out photography teaching reasonably and scientifically.展开更多
Photography teaching is different from general culture teaching.There are obvious differences in teaching methods and teachers' teaching styles.To this end,photography teaching should be innovative,really interest...Photography teaching is different from general culture teaching.There are obvious differences in teaching methods and teachers' teaching styles.To this end,photography teaching should be innovative,really interested in students,love the photography course,and put photography knowledge into practice.At present,some photography teachers have some problems in the way of explai-ning photography knowledge,which makes it difficult for students to really grasp the practical knowledge of photography,and is not conducive to arousing students' interest in learning. The reason is that photography teachers do not attach importance to practical teaching.展开更多
It is always desirable to know the interior deformation pattern when a rock is subjected to mechanical load.Few experimental techniques exist that can represent fullfi eld three-dimensional(3D)strain distribution insi...It is always desirable to know the interior deformation pattern when a rock is subjected to mechanical load.Few experimental techniques exist that can represent fullfi eld three-dimensional(3D)strain distribution inside a rock specimen.And yet it is crucial that this information is available for fully understanding the failure mechanism of rocks or other geomaterials.In this study,by using the newly developed digital volumetric speckle photography(DVSP)technique in conjunction with X-ray computed tomography(CT)and taking advantage of natural 3D speckles formed inside the rock due to material impurities and voids,we can probe the interior of a rock to map its deformation pattern under load and shed light on its failure mechanism.We apply this technique to the analysis of a red sandstone specimen under increasing uniaxial compressive load applied incrementally.The fullfi eld 3D displacement fi elds are obtained in the specimen as a function of the load,from which both the volumetric and the deviatoric strain fi elds are calculated.Strain localization zones which lead to the eventual failure of the rock are identi fi ed.The results indicate that both shear and tension are contributing factors to the failure mechanism.展开更多
Bird photography is a popular and growing form of ecotourism that contributes to the economic growth of local communities,but its disturbance to bird reproduction remains understudied.We worked in a tropical forest of...Bird photography is a popular and growing form of ecotourism that contributes to the economic growth of local communities,but its disturbance to bird reproduction remains understudied.We worked in a tropical forest of southern China,which has experienced a sharp increase in the number of photographers in recent years.We compared nests that were photographed and those that were not,in their nest predation and parental feeding rates.Including nests of 42 species,the results demonstrate that the predation rate of nests that were not photographed(incubation stage:43.3%of 194 nests;nestling stage:34.5%of 110 nests)was significantly higher than that of photographed ones(incubation:2.4%of 83 nests;nestling:11.1%of 81 nests).Among different nest types,open cup nests in shrub and trees were most affected by photography,in both incubation and nestling stages.Of five factors investigated,including three natural factors(nest stage,structure and position),and two anthropogenic factors(photography and distance to forest edge),only photographic disturbance and nest structure had significant effects(open nests had higher predation).The feeding frequency at nests when photographers were present was not strongly different from when they were not present.Human activity therefore had no negative effects on the birds,but showed a positive effect on their nesting success,in terms of reducing nest predation rates.However,there needs to be further assessment of other aspects of nesting(e.g.,clutch size,duration of nestlings in nests),and other kinds of stress responses(e.g.,hormonal changes),before the total effect of bird photography can be understood.展开更多
Through analyzing the concept,development history and works of gardening photography,unique status and charm of gardening photography in the field of photography art was explored.It was proposed that professional know...Through analyzing the concept,development history and works of gardening photography,unique status and charm of gardening photography in the field of photography art was explored.It was proposed that professional knowledge about gardening disciplines should be grasped,and the shoot targets shouid be fully investigated to present excellent works of gardening photography.In addition,photographers should have strong artistic sense,and be able to grasp the means of expressing image language,so that they will produce works with outstanding themes,proper light,concise composition,harmonious hue color and shadow tone.Sophisticated equipment and post processing skills are also needed.展开更多
Two speckle patterns are recorded using a video camera corresponding to undisplaced anddisplaced states intn the memory of a computer.After one pattern is added to another,the displacement ofthe measured points can be...Two speckle patterns are recorded using a video camera corresponding to undisplaced anddisplaced states intn the memory of a computer.After one pattern is added to another,the displacement ofthe measured points can be calculated by using the Fourier transform.The expression of displacement field isdeduced tbr non-uniform displacement,and as an example,a rotatanle disc is tested for illustration.The re-sults prove that the present method is promising.展开更多
Background:Digital hemispherical photography(DHP)is widely used to estimate the leaf area index(LAI)of forest plots due to its advantages of high efficiency and low cost.A crucial step in the LAI estimation of forest ...Background:Digital hemispherical photography(DHP)is widely used to estimate the leaf area index(LAI)of forest plots due to its advantages of high efficiency and low cost.A crucial step in the LAI estimation of forest plots via DHP is choosing a sampling scheme.However,various sampling schemes involving DHP have been used for the LAI estimation of forest plots.To date,the impact of sampling schemes on LAI estimation from DHP has not been comprehensively investigated.Methods:In this study,13 commonly used sampling schemes which belong to five sampling types(i.e.dispersed,square,cross,transect and circle)were adopted in the LAI estimation of five Larix principis-rupprechtii plots(25m×25 m).An additional sampling scheme(with a sample size of 89)was generated on the basis of all the sample points of the 13 sampling schemes.Three typical inversion models and four canopy element clumping index(Ωe)algorithms were involved in the LAI estimation.The impacts of the sampling schemes on four variables,including gap fraction,Ωe,effective plant area index(PAIe)and LAI estimation from DHP were analysed.The LAI estimates obtained with different sampling schemes were then compared with those obtained from litter collection measurements.Results:Large differences were observed for all four variable estimates(i.e.gap fraction,Ωe,PAIe and LAI)under different sampling schemes.The differences in impact of sampling schemes on LAI estimation were not obvious for the three inversion models,if the fourΩe algorithms,except for the traditional gap-size analysis algorithm were adopted in the estimation.The accuracy of LAI estimation was not always improved with an increase in sample size.Moreover,results indicated that with the appropriate inversion model,Ωe algorithm and sampling scheme,the maximum estimation error of DHP-estimated LAI at elementary sampling unit can be less than 20%,which is required by the global climate observing system,except in forest plots with extremely large LAI values(~>6.0).However,obtaining an LAI from DHP with an estimation error lower than 5%is impossible regardless of which combination of inversion model,Ωe algorithm and sampling scheme is used.Conclusion:The LAI estimation of L.principis-rupprechtii forests from DHP was largely affected by the sampling schemes adopted in the estimation.Thus,the sampling scheme should be seriously considered in the LAI estimation.One square and two transect sampling schemes(with sample sizes ranging from 3 to 9)were recommended to be used to estimate the LAI of L.principis-rupprechtii forests with the smallest mean relative error(MRE).By contrast,three cross and one dispersed sampling schemes were identified to provide LAI estimates with relatively large MREs.展开更多
With the popularity of smartphones,it is often easy to maliciously leak important information by taking pictures of the phone.Robust watermarking that can resist screen photography can achieve the protection of inform...With the popularity of smartphones,it is often easy to maliciously leak important information by taking pictures of the phone.Robust watermarking that can resist screen photography can achieve the protection of information.Since the screen photo process can cause some irreversible distortion,the currently available screen photo watermarks do not consider the image content well and the visual quality is not very high.Therefore,this paper proposes a new screen-photography robust watermark.In terms of embedding region selection,the intensity-based Scale-invariant feature transform(SIFT)algorithm used for the construction of feature regions based on the density of feature points,which can make it more focused on the key content of the image;in terms of embedding strength,the Just noticeable difference(JND)model is applied to limit the intensity of the watermark embedding according to the luminance and texture of the picture to balance robustness and invisibility;after embedding watermark,the coefficients in the neighborhood are again adjusted with optimal constraints to improve the accuracy of watermark extraction.After experiments,it is shown that the method we proposed can improve the correct rate of watermark extraction,the quality of the visual aspect of the watermarked picture is also improved.展开更多
Definition of architectural photography and features of the discipline in the new era were introduced. It was proposed that consummate photography and photographic equipment were prerequisites of architectural photogr...Definition of architectural photography and features of the discipline in the new era were introduced. It was proposed that consummate photography and photographic equipment were prerequisites of architectural photography, and architectural photographers had to learn architectural cultures and also intentions of architects. In addition, the ways of shooting should be determined by uses of the photos, and rich photographic languages applied to appreciate the buildings.展开更多
Both garden and photographic art creation pursue the expression of artistic conception.By analyzing the connotation of artistic conception of photographic art,the interaction between garden and photography are analyze...Both garden and photographic art creation pursue the expression of artistic conception.By analyzing the connotation of artistic conception of photographic art,the interaction between garden and photography are analyzed,and the artistic conception beauty of garden photography is discussed from three aspects:composition,color,and light and shadow expression.Moreover,artistic conception expression skills such as inspiration capture and deepening experience are put forward,in order to provide the reference for lovers of garden photography.展开更多
This paper aims to provide a quantitative method that employs image processing in the assessment of surface roughness based on digital photograph field surveys, as in previous studies employing the outdoor integrated ...This paper aims to provide a quantitative method that employs image processing in the assessment of surface roughness based on digital photograph field surveys, as in previous studies employing the outdoor integrated digital photography and image processing (O-IDIP) method. Digital photographs were taken on two different days under contrasting outdoor lighting conditions (overcast versus clear sky). Images were captured mounted on a tripod close up to the surface of a 380-year-old wall located at the University of Oxford Botanic Garden in the City of Oxford, UK. Sampling points were established at regular intervals along the border wall and encompassed sections facing west, north, and east, respectively along the survey. Two photographs were taken with a digital camera at each sampling point, one containing a color chart used to calibrate outdoor lighting conditions across images, which was excluded from the other photographic pair. Histogram-based quantification was performed based on images converted to Lab Color mode. The 10-step calibration procedure presented in this paper required more adjustments of contrast. However, more adjustments were not required under a clear sky. Std Dev L measurements were used to establish categories in a simple 3-point roughness index, namely the surface roughness index (SRI). The results denote that pitting did not affect surface roughness measurements. The study shows that it is possible to use Std Dev L measurements to quantify surface roughness on a comparative basis.展开更多
In this paper,the tilt photography data acquisition and three-dimensional modeling of the Tashkurgan MS5.5 earthquake in Xinjiang are conducted using the tilt photography system of the Rotor UAV. The three-dimensional...In this paper,the tilt photography data acquisition and three-dimensional modeling of the Tashkurgan MS5.5 earthquake in Xinjiang are conducted using the tilt photography system of the Rotor UAV. The three-dimensional model is used to interpret the earthquake damage on buildings in the mega-earthquake area in order to acquire different-level house damage in the Kuzirun village disaster area. In addition,the characteristics of seismic damage on typical buildings are analyzed. The results show that the main collapsed houses in the mega-earthquake area are sand-stone buildings,of which about 39% are sand-stone buildings. Several brick-wood buildings and brick-concrete buildings are seriously damaged,while the buildings with frame structures are mainly slightly damaged,and the houses near the macro-epicenter of the earthquake are all in good conditions. Three-dimensional tilt photography technology can vividly display the scene of earthquake disaster,and can provide significant demonstration in building damage degree together with detailed analysis of disaster situation.展开更多
During the Victorian Age,when the results of ambitious engineering radically transformed the principles of construction,photography proved to be a faithful and indispensable witness.This is plainly seen in the magnifi...During the Victorian Age,when the results of ambitious engineering radically transformed the principles of construction,photography proved to be a faithful and indispensable witness.This is plainly seen in the magnificent enterprise to build the railway bridge over the Forth River,accurately captured by the lens of the photographer and engineer Evelyn George Carey,whose excellent work to record those events is without equal.His almost daily annotations were free from symbolic meaning and monumental tendencies:it was the bridge itself that held the most important role.In the form of an experiment it was decided to illustrate the principle of the cantilever at the Royal Institution in 1887.It was during that particular circumstance that Carey produced the famous photographic image of the Human Cantilever.Carey presents to the observer an encyclopaedic array of representations and helps to truly visualise engineering.展开更多
This article begins with the construction and meaning of conceptual photography, analyzes its aesthetic attitude,and proposes that the reading experience of conceptual photography works through expression of meaning a...This article begins with the construction and meaning of conceptual photography, analyzes its aesthetic attitude,and proposes that the reading experience of conceptual photography works through expression of meaning and howto embody its spiritual connotation in the creative process, and “watch” the conceptual photography works becomethe act of interpreting a kind of figurative object, which makes the aesthetic experience of photography works fullyrealized.展开更多
As a contemporary fashion photographer and international visual artist,Chen Man has become one of the most influential photographers with heravant-garde in sights and creative personalities.Her works not only show a s...As a contemporary fashion photographer and international visual artist,Chen Man has become one of the most influential photographers with heravant-garde in sights and creative personalities.Her works not only show a strong Chinese style,but also show the charm of modern fashion.This paper starts with the Chinese elements in Chen Man’s photography works,analyzes the application of Chinese traditional aesthetics theory in Chen Man’s photography,explores the expressions and characteristics of the collision between Chinese tradition and Western modernity in her works,and hopes to give inspiration for the development of current Chinese fashion photography.展开更多
文摘Recently,there has been a notable surge of interest in scientific research regarding spectral images.The potential of these images to revolutionize the digital photography industry,like aerial photography through Unmanned Aerial Vehicles(UAVs),has captured considerable attention.One encouraging aspect is their combination with machine learning and deep learning algorithms,which have demonstrated remarkable outcomes in image classification.As a result of this powerful amalgamation,the adoption of spectral images has experienced exponential growth across various domains,with agriculture being one of the prominent beneficiaries.This paper presents an extensive survey encompassing multispectral and hyperspectral images,focusing on their applications for classification challenges in diverse agricultural areas,including plants,grains,fruits,and vegetables.By meticulously examining primary studies,we delve into the specific agricultural domains where multispectral and hyperspectral images have found practical use.Additionally,our attention is directed towards utilizing machine learning techniques for effectively classifying hyperspectral images within the agricultural context.The findings of our investigation reveal that deep learning and support vector machines have emerged as widely employed methods for hyperspectral image classification in agriculture.Nevertheless,we also shed light on the various issues and limitations of working with spectral images.This comprehensive analysis aims to provide valuable insights into the current state of spectral imaging in agriculture and its potential for future advancements.
基金The Shake-the-Box system used for the particle tracking velocimetry experiment was funded by National Science Foundation(CMMI-1919726)to Y.Liu.
文摘Utilizing high-speed schlieren photography and particle-tracking-velocimetry,the wake flow of tethered houseflies is investigated.The high-speed schlieren photography is implemented on tethered houseflies inside an air container with a stable vertical temperature gradient to visualize the disturbed wake flow from the insects.The resulting photography images were then processed with the physics based optical flow method to derive the light-path averaged flow velocity.Additionally,the state of the art:Shake-the-Box system is implemented on a tethered housefly to measure the volumetric flow field in the wake of the insect,revealing interesting flow behavior and structures that can also be observed and correlated to the schlieren photography images.Comparing the dimensionless velocity magnitude of the wake flow from the two experiments,a good qualitative agreement is reached,suggesting the viability of high-speed schlieren photography in investigating the wake flow of small insects.Furthermore,the high-speed schlieren photography is successfully applied on a housefly that is taking off from the ground,visualizing the disturbed wake flow on the freely flying insect that is challenging to visualize with other methods.
基金This study was funded by Science and Technology Projects of Guangdong Province(Nos.2019A030317002,2017A030303013,2013B060300003).
文摘Background:A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis.The choice of animal model is based on the measurability of specific parameters or structures,the applicability of clinical measurement technologies,and the similarity to human eye function.Studies of eye pathology usually compare optical parameters between a healthy and altered state,so accurate baseline assessments are critical,but few reports have comprehensively examined the normal anatomical structures and physiological functions in these models.Methods:Three cynomolgus monkeys,six New Zealand rabbits,ten Sprague Dawley(SD)rats,and BALB/c mice were examined by fundus photography(FP),fundus fluorescein angiography(FFA),and optical coherence tomography(OCT).Results:Most retinal structures of cynomolgus monkey were anatomically similar to the corresponding human structures as revealed by FP,FFA,and OCT.New Zealand rabbits have large eyeballs,but they have large optic disc and myelinated retinal nerve fibers in their retinas,and the growth pattern of retinal vessels were also different to the human retinas.Unlike monkeys and rabbits,the retinal vessels of SD rats and BALB/c mice were widely distributed and clear.The OCT performance of them were similar with human beings except the macular.Conclusions:Monkey is a good model to study changes in retinal structure associated with fundus disease,rabbits are not suitable for studies on retinal vessel diseases and optic nerve diseases,and rats and mice are good models for retinal vascular diseases.These measures will help guide the choice of model and measurement technology and reduce the number of experimental animals required.
文摘The eye is an immune-privileged and sensory organ in humans and animals.Anatomical,physiological,and pathobiological features share significant similarities across divergent species(1).Each compartment of the eye has a unique structure and function.The anterior and posterior compartments of the eye contain endothelium(cornea),epithelium(cornea,ciliary body,iris),muscle(ciliary body),vitreous and neuronal(retina)tissues,which make the eye suitable to evaluate efficacy and safety of tissue specific drugs(2).
文摘The role of color photography in the representation of architecture is a subject little investigated by architectural historiography.The link between the color values of architectural design and its visual transmission in the early phase of modernism was certainly problematic.Color photography had an undeniable impact on architectural color in practice:color photographs in books and periodicals published between the 1940s and 1960s clearly influenced the use of color in architectural design.
文摘In recent years, with the development of social economy, college photography education career has been developing rapidly, but at the same time, some problems have appeared. In the construction of photography specialty, a series of problems, such as unreasonable course arrangement, outdated hardware facilities and imperfect teaching software system, are hindering the de-velopment of photography education in universities. Therefore, college educators should seriously sum up the problems existing in college photography education, and carry out photography teaching reasonably and scientifically.
文摘Photography teaching is different from general culture teaching.There are obvious differences in teaching methods and teachers' teaching styles.To this end,photography teaching should be innovative,really interested in students,love the photography course,and put photography knowledge into practice.At present,some photography teachers have some problems in the way of explai-ning photography knowledge,which makes it difficult for students to really grasp the practical knowledge of photography,and is not conducive to arousing students' interest in learning. The reason is that photography teachers do not attach importance to practical teaching.
基金financially supported by National Basic Research Program of China (973 Program) (No. 2010CB732002)National Natural Science Foundation of China (Nos. 51374211, 51374215)+1 种基金National Key Foundation for Exploring Scientific Instrument of China (No. 2013YQ240803)Fundamental Research Funds for the Central Universities (No. 2009QM02)
文摘It is always desirable to know the interior deformation pattern when a rock is subjected to mechanical load.Few experimental techniques exist that can represent fullfi eld three-dimensional(3D)strain distribution inside a rock specimen.And yet it is crucial that this information is available for fully understanding the failure mechanism of rocks or other geomaterials.In this study,by using the newly developed digital volumetric speckle photography(DVSP)technique in conjunction with X-ray computed tomography(CT)and taking advantage of natural 3D speckles formed inside the rock due to material impurities and voids,we can probe the interior of a rock to map its deformation pattern under load and shed light on its failure mechanism.We apply this technique to the analysis of a red sandstone specimen under increasing uniaxial compressive load applied incrementally.The fullfi eld 3D displacement fi elds are obtained in the specimen as a function of the load,from which both the volumetric and the deviatoric strain fi elds are calculated.Strain localization zones which lead to the eventual failure of the rock are identi fi ed.The results indicate that both shear and tension are contributing factors to the failure mechanism.
基金supported by the National Natural Science Foundation of China(Grant No.31870370)the Graduate Education Innovation Program of Guangxi(No.YCSW2020023)。
文摘Bird photography is a popular and growing form of ecotourism that contributes to the economic growth of local communities,but its disturbance to bird reproduction remains understudied.We worked in a tropical forest of southern China,which has experienced a sharp increase in the number of photographers in recent years.We compared nests that were photographed and those that were not,in their nest predation and parental feeding rates.Including nests of 42 species,the results demonstrate that the predation rate of nests that were not photographed(incubation stage:43.3%of 194 nests;nestling stage:34.5%of 110 nests)was significantly higher than that of photographed ones(incubation:2.4%of 83 nests;nestling:11.1%of 81 nests).Among different nest types,open cup nests in shrub and trees were most affected by photography,in both incubation and nestling stages.Of five factors investigated,including three natural factors(nest stage,structure and position),and two anthropogenic factors(photography and distance to forest edge),only photographic disturbance and nest structure had significant effects(open nests had higher predation).The feeding frequency at nests when photographers were present was not strongly different from when they were not present.Human activity therefore had no negative effects on the birds,but showed a positive effect on their nesting success,in terms of reducing nest predation rates.However,there needs to be further assessment of other aspects of nesting(e.g.,clutch size,duration of nestlings in nests),and other kinds of stress responses(e.g.,hormonal changes),before the total effect of bird photography can be understood.
文摘Through analyzing the concept,development history and works of gardening photography,unique status and charm of gardening photography in the field of photography art was explored.It was proposed that professional knowledge about gardening disciplines should be grasped,and the shoot targets shouid be fully investigated to present excellent works of gardening photography.In addition,photographers should have strong artistic sense,and be able to grasp the means of expressing image language,so that they will produce works with outstanding themes,proper light,concise composition,harmonious hue color and shadow tone.Sophisticated equipment and post processing skills are also needed.
文摘Two speckle patterns are recorded using a video camera corresponding to undisplaced anddisplaced states intn the memory of a computer.After one pattern is added to another,the displacement ofthe measured points can be calculated by using the Fourier transform.The expression of displacement field isdeduced tbr non-uniform displacement,and as an example,a rotatanle disc is tested for illustration.The re-sults prove that the present method is promising.
基金the National Science Foundation of China(Grant Nos.41871233,41371330 , 41001203).
文摘Background:Digital hemispherical photography(DHP)is widely used to estimate the leaf area index(LAI)of forest plots due to its advantages of high efficiency and low cost.A crucial step in the LAI estimation of forest plots via DHP is choosing a sampling scheme.However,various sampling schemes involving DHP have been used for the LAI estimation of forest plots.To date,the impact of sampling schemes on LAI estimation from DHP has not been comprehensively investigated.Methods:In this study,13 commonly used sampling schemes which belong to five sampling types(i.e.dispersed,square,cross,transect and circle)were adopted in the LAI estimation of five Larix principis-rupprechtii plots(25m×25 m).An additional sampling scheme(with a sample size of 89)was generated on the basis of all the sample points of the 13 sampling schemes.Three typical inversion models and four canopy element clumping index(Ωe)algorithms were involved in the LAI estimation.The impacts of the sampling schemes on four variables,including gap fraction,Ωe,effective plant area index(PAIe)and LAI estimation from DHP were analysed.The LAI estimates obtained with different sampling schemes were then compared with those obtained from litter collection measurements.Results:Large differences were observed for all four variable estimates(i.e.gap fraction,Ωe,PAIe and LAI)under different sampling schemes.The differences in impact of sampling schemes on LAI estimation were not obvious for the three inversion models,if the fourΩe algorithms,except for the traditional gap-size analysis algorithm were adopted in the estimation.The accuracy of LAI estimation was not always improved with an increase in sample size.Moreover,results indicated that with the appropriate inversion model,Ωe algorithm and sampling scheme,the maximum estimation error of DHP-estimated LAI at elementary sampling unit can be less than 20%,which is required by the global climate observing system,except in forest plots with extremely large LAI values(~>6.0).However,obtaining an LAI from DHP with an estimation error lower than 5%is impossible regardless of which combination of inversion model,Ωe algorithm and sampling scheme is used.Conclusion:The LAI estimation of L.principis-rupprechtii forests from DHP was largely affected by the sampling schemes adopted in the estimation.Thus,the sampling scheme should be seriously considered in the LAI estimation.One square and two transect sampling schemes(with sample sizes ranging from 3 to 9)were recommended to be used to estimate the LAI of L.principis-rupprechtii forests with the smallest mean relative error(MRE).By contrast,three cross and one dispersed sampling schemes were identified to provide LAI estimates with relatively large MREs.
基金This work is supported by the National Key R&D Program of China under grant 2018YFB1003205by the National Natural Science Foundation of China under grant U1836208,U1836110+1 种基金by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)fundby the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)fund,China.
文摘With the popularity of smartphones,it is often easy to maliciously leak important information by taking pictures of the phone.Robust watermarking that can resist screen photography can achieve the protection of information.Since the screen photo process can cause some irreversible distortion,the currently available screen photo watermarks do not consider the image content well and the visual quality is not very high.Therefore,this paper proposes a new screen-photography robust watermark.In terms of embedding region selection,the intensity-based Scale-invariant feature transform(SIFT)algorithm used for the construction of feature regions based on the density of feature points,which can make it more focused on the key content of the image;in terms of embedding strength,the Just noticeable difference(JND)model is applied to limit the intensity of the watermark embedding according to the luminance and texture of the picture to balance robustness and invisibility;after embedding watermark,the coefficients in the neighborhood are again adjusted with optimal constraints to improve the accuracy of watermark extraction.After experiments,it is shown that the method we proposed can improve the correct rate of watermark extraction,the quality of the visual aspect of the watermarked picture is also improved.
文摘Definition of architectural photography and features of the discipline in the new era were introduced. It was proposed that consummate photography and photographic equipment were prerequisites of architectural photography, and architectural photographers had to learn architectural cultures and also intentions of architects. In addition, the ways of shooting should be determined by uses of the photos, and rich photographic languages applied to appreciate the buildings.
文摘Both garden and photographic art creation pursue the expression of artistic conception.By analyzing the connotation of artistic conception of photographic art,the interaction between garden and photography are analyzed,and the artistic conception beauty of garden photography is discussed from three aspects:composition,color,and light and shadow expression.Moreover,artistic conception expression skills such as inspiration capture and deepening experience are put forward,in order to provide the reference for lovers of garden photography.
文摘This paper aims to provide a quantitative method that employs image processing in the assessment of surface roughness based on digital photograph field surveys, as in previous studies employing the outdoor integrated digital photography and image processing (O-IDIP) method. Digital photographs were taken on two different days under contrasting outdoor lighting conditions (overcast versus clear sky). Images were captured mounted on a tripod close up to the surface of a 380-year-old wall located at the University of Oxford Botanic Garden in the City of Oxford, UK. Sampling points were established at regular intervals along the border wall and encompassed sections facing west, north, and east, respectively along the survey. Two photographs were taken with a digital camera at each sampling point, one containing a color chart used to calibrate outdoor lighting conditions across images, which was excluded from the other photographic pair. Histogram-based quantification was performed based on images converted to Lab Color mode. The 10-step calibration procedure presented in this paper required more adjustments of contrast. However, more adjustments were not required under a clear sky. Std Dev L measurements were used to establish categories in a simple 3-point roughness index, namely the surface roughness index (SRI). The results denote that pitting did not affect surface roughness measurements. The study shows that it is possible to use Std Dev L measurements to quantify surface roughness on a comparative basis.
基金sponsored by the National Key R&D Program(2017YFC150090501)Seismological Science and Technology Spark Program(XH20052)。
文摘In this paper,the tilt photography data acquisition and three-dimensional modeling of the Tashkurgan MS5.5 earthquake in Xinjiang are conducted using the tilt photography system of the Rotor UAV. The three-dimensional model is used to interpret the earthquake damage on buildings in the mega-earthquake area in order to acquire different-level house damage in the Kuzirun village disaster area. In addition,the characteristics of seismic damage on typical buildings are analyzed. The results show that the main collapsed houses in the mega-earthquake area are sand-stone buildings,of which about 39% are sand-stone buildings. Several brick-wood buildings and brick-concrete buildings are seriously damaged,while the buildings with frame structures are mainly slightly damaged,and the houses near the macro-epicenter of the earthquake are all in good conditions. Three-dimensional tilt photography technology can vividly display the scene of earthquake disaster,and can provide significant demonstration in building damage degree together with detailed analysis of disaster situation.
文摘During the Victorian Age,when the results of ambitious engineering radically transformed the principles of construction,photography proved to be a faithful and indispensable witness.This is plainly seen in the magnificent enterprise to build the railway bridge over the Forth River,accurately captured by the lens of the photographer and engineer Evelyn George Carey,whose excellent work to record those events is without equal.His almost daily annotations were free from symbolic meaning and monumental tendencies:it was the bridge itself that held the most important role.In the form of an experiment it was decided to illustrate the principle of the cantilever at the Royal Institution in 1887.It was during that particular circumstance that Carey produced the famous photographic image of the Human Cantilever.Carey presents to the observer an encyclopaedic array of representations and helps to truly visualise engineering.
文摘This article begins with the construction and meaning of conceptual photography, analyzes its aesthetic attitude,and proposes that the reading experience of conceptual photography works through expression of meaning and howto embody its spiritual connotation in the creative process, and “watch” the conceptual photography works becomethe act of interpreting a kind of figurative object, which makes the aesthetic experience of photography works fullyrealized.
文摘As a contemporary fashion photographer and international visual artist,Chen Man has become one of the most influential photographers with heravant-garde in sights and creative personalities.Her works not only show a strong Chinese style,but also show the charm of modern fashion.This paper starts with the Chinese elements in Chen Man’s photography works,analyzes the application of Chinese traditional aesthetics theory in Chen Man’s photography,explores the expressions and characteristics of the collision between Chinese tradition and Western modernity in her works,and hopes to give inspiration for the development of current Chinese fashion photography.
