Digital dental photography. Part 6: camera settings

Photography in dentistry has revolutionized the diagnosis, treatment planning, marketing, and communication between the patient, dentist, and dental laboratory technicians. With the advancements digital photography has implied in dentistry, the craftsmanship of the practitioners is touching new grounds for education, self-improvement, and documentation. This article tries to solve the enigma of choosing the camera and its lens, the accessories that necessitate achieving professional-like results and also seeking the same results with the next big leap in accessible photography, the smartphone camera. This article intends to broaden the knowledge of the technicality behind digital photography and how the same can be used in dentistry to make a standpoint for the practitioners in their field.

Photography in dentistry has revolutionized diagnosis, treatment planning, marketing and communication between the patient, dentist and the dental lab technicians. With the advancements digital photography has implied on dentistry, the craftsmanship of the practitioners are touching new grounds for education, self-improvement and documentation. Through this article, we intend to broaden the knowledge on technicality behind digital photography and how the same can be used in dentistry. We have attempted to solve the enigma of choosing the camera and its lens and other accessories that are necessary to achieve professional results and have also highlighted about the next big leap in accessible photography, the smartphone camera.

The majority of pictures taken in the dental surgery are intra-oral and this article looks at the practicalities involved in full-arch, quadrant occlusal, lingual (or palatal) and lateral views, as well as magnified images, oral mucosa, enamel texture, dentine strata and shade analysis for artificial restorations. Additionally, the issue of cross-infection control is considered.

Probabilistic moving least squares with spatial constraints for nonlinear color transfer between images

Nowadays, research focusing on robotics, autonomous vehicles, and scene analysis shows a clear need for the ability to accurately reconstruct three-dimensional environments. One of the methods allowing to conduct such a reconstruction is to use a set of cameras and image processing techniques. This is a passive method. Despite being, in general, less accurate than its active counterparts, it offers significant advantages in numerous applications in which active systems cannot be deployed due to limited performance. This paper provides a theoretical analysis of the accuracy of estimating 3D positions of objects present at a given scene, based on images from a set of cameras. The analysis assumes a known geometrical configuration of the camera system. The important limiting factor in the considered scenario is the physical resolution of sensors - especially in the case of systems that are supposed to work in real time, with a high FPS rate, as the use of high-resolution cameras is difficult in such circumstances. In the paper, the influence of the geometric arrangement of the cameras is studied and important conclusions about the potential of three-camera configurations are drawn. The analysis performed and the formulas derived help predict the boundary accuracy values of any system using a digital camera. The results of an experiment that confirm the theoretical conclusions are presented as well.

When rendering photographs, it is important to preserve the gray tones despite variations in the ambient illumination. When the illuminant is known, white balancing that preserves gray tones can be performed in many different color spaces; the choice of color space influences the renderings of other colors. In this behavioral study, we ask whether users have a preference for the color space where white balancing is performed. Subjects compared images using a white balancing transformation that preserved gray tones, but the transformation was applied in one of the four different color spaces: XYZ, Bradford, a camera sensor RGB and the sharpened RGB color space. We used six scenes types (four portraits, fruit, and toys) acquired under three calibrated illumination environments (fluorescent, tungsten, and flash). For all subjects, transformations applied in XYZ and sharpened RGB were preferred to those applied in Bradford and device color space.

HP and Microsoft propose the addition of support for a standard color space, sRGB, within the Microsoft OS's, HP products and the Internet. The aim of this color space is to complement the current color management strategies by enabling a third method of handling color in the OS's and the Internet that utilizes a simple and robust device independent color definition that will provide good quality and backwards compatibility with minimum transmission and system overhead. Based on a colorimetric RGB color space well suited to Cathode Ray Tube (CRT) monitors, television, scanners, digital cameras, and printing systems, such a space can be supported with minimum cost to software and hardware vendors. Our intent here is to promote its adoption by showing the benefits of supporting a standard color space, the suitability of the standard color space we are proposing, describe some of the system issues and propose a methodology for its implementation on the Web.

The analysis of fish skin color in time lapse experiments is a wide field, since the color changes could be affected by different causes. The classical approach uses single point measurement in CIEL*a*b* color space. On the other hand the image acquisition by digital cameras allows to evaluate spatial statistic, in RGB color space. The reliability of the camera color accuracy as well as the software and method description for the automatic color evaluation, is of the concern of this article. Various fish species were subjected of the test. We performed transformations to other color space and using multivariate data statistics, namely principal component analysis, the relevant color space is seleted. The presented software solutions are available at http://www.auc.cz/software/.

Calibration of digital compact cameras for sky quality measures

Improving plant discrimination in image processing by use of different colour space transformations

Evaluation of using digital photography as a cost-effective tool for the rapid assessment of soil organic carbon at a regional scale

This study examines the implementation of an MnNH4P2O7 (ammonium manganese III pyrophosphate)-based coating on structural elements to obtain temperature information with color changes. Based on the MnNH4P2O7 material, a coating was prepared and deposited on cement mortar surfaces. Heat experiments were then conducted to evaluate the thermochromism on the fabricated samples. The coated samples exhibited a superior irreversible thermochromic property at 400 °C with a color change from dark violet to light grayish blue at the heated surface. The color changes were retrieved at each temperature using a digital camera, and the change in color properties was evaluated in the RGB and L*a*b* color spaces using image processing techniques. With increasing temperature from room temperature, the RGB values were almost constant until 200 °C. At higher temperatures, the color changes started to accelerate until 400 °C. The values showed a 167%, 567%, and 49% increase in R, G, and B values, respectively, at 400 °C. In the L*a*b* color space, when the temperature was increased from room temperature to 400 °C, the L*a*b* values showed an increase of 211%, a decrease of 94%, and an increase of 78%, respectively.

There is no accepted method to objectively assess the visual appearance of sunscreens on the skin. We present a method for sunscreen application, digital photography, and computer analysis to quantify the appearance of the skin after sunscreen application. Four sunscreen lotions were applied randomly at densities of 0.5, 1.0, 1.5, and 2.0mg/cm2 to areas of the back of 29 subjects. Each application site had a matched contralateral control area. High-resolution standardized photographs including a color card were taken after sunscreen application. After color balance correction, CIE L*a*b* color values were extracted from paired sites. Differences in skin appearance attributed to sunscreen were represented by ΔE, which in turn was calculated from the linear Euclidean distance within the L*a*b* color space between the paired sites. Sunscreen visibility as measured by median ΔE varied across different products and application densities and ranged between 1.2 and 12.1. The visibility of sunscreens varied according to product SPF, composition (organic vs inorganic), presence of tint, and baseline b* of skin (P<.05 for all). Standardized sunscreen application followed by digital photography and indirect computer-based colorimetry represents a potential method to objectively quantify visibility of sunscreen on the skin.

In this paper, we propose fast color interpolation methods for color filter array (CFA). The proposed methods exploit correlations among the three color components. It has been reported that the quality of color interpolation can be significantly improved by utilizing correlation among color components. However, the complexity of such methods may increase significantly compared to those methods which separately interpolate each color component. On the other hand, the major application of CFA is portable imaging devices such as digital cameras or mobile phones. For portable devices, power consumption is an important issue. In this paper, we propose high quality color interpolation methods with reduced complexity. Experimental results show that the proposed methods provide noticeable improvements without significantly increasing the system complexity.

A Study of Comparison between Window Glass and Mirror on Flatness Measurement in RCM LIPI