Frontal Lighting Research Articles

Defect Inspection Using Modified YoloV4 on a Stitched Image of a Spinning Tool.

In Industry 4.0, automation is a critical requirement for mechanical production. This study proposes a computer vision-based method to capture images of rotating tools and detect defects without the need to stop the machine in question. The study uses frontal lighting to capture images of the rotating tools and employs scale-invariant feature transform (SIFT) to identify features of the tool images. Random sample consensus (RANSAC) is then used to obtain homography information, allowing us to stitch the images together. The modified YOLOv4 algorithm is then applied to the stitched image to detect any surface defects on the tool. The entire tool image is divided into multiple patch images, and each patch image is detected separately. The results show that the modified YOLOv4 algorithm has a recall rate of 98.7% and a precision rate of 97.3%, and the defect detection process takes approximately 7.6 s to complete for each stitched image.

Quantitative High-speed Assessment of Droplet and Aerosol From an Eye After Impact With an Air-puff Amid COVID-19 Scenario

To quantify aerosol and droplets generated during noncontact tonometry (NCT) and assess the spread distance of the same. This was an experimental study on healthy human volunteers (n=8 eyes). In an experimental setup, NCT was performed on eyes (n=8) of human volunteers under normal settings, with a single and 2 drops of lubricant. High-speed shadowgraphy, frontal lighting technique, and fluorescein analysis were used to detect the possible generation of any droplets and aerosols. Mathematical computation of the spread of the droplets was then performed. In a natural setting, there was no droplet or aerosol production. Minimal splatter along with droplet ejection was observed when 1 drop of lubricant was used before NCT. When 2 drops of lubricant were instilled, a significant amount of fluid ejection in the form of a sheet that broke up into multiple droplets was observed. Some of these droplets traversed back to the tonometer. Droplets ranging from 100 to 500 µm in diameter were measured. There was no droplet generation during NCT performed in a natural setting. However, NCT should be avoided in conditions with high-tear volume (natural or artificial) as it would lead to droplet spread and tactile contamination.

Icons of Depression

Icons of Depression Alix Beeston (bio) One especially striking image included in walker Evans's American Photographs, the photographic book published by the Museum of Modern Art to accompany a retrospective of Evans's work in the fall of 1938, foregrounds the terms of its representation of life in the United States during the Depression. Depicting a found object in a shallow picture plane, “Torn Movie Poster, 1930” (Figure 1) aligns the flat surface of a Hollywood film poster with the flat surface of the photographic image. Evans typically employs a head-on viewing angle and stark but unobtrusive frontal lighting in his photographs, which are, in turn, conceived as unsentimental, unmotivated objects. But “Torn Movie Poster” recasts this notion of his “bare-faced” aesthetic—to borrow a description from the essay that the writer and art critic Lincoln Kirstein contributed to the 1938 book (198). Evans confers mystery upon the original poster image by the framing of this photograph in American Photographs. Extricated from its spatial, geographical, and commercial contexts, the poster's dramatic substance is redirected, transposing the question of what, exactly, so terrifies the woman in the image into a metatextual key. Since each photograph in the book is positioned on the recto page, with the verso side left blank but for the relevant plate number, the woman's startled gaze appears to be directed at the photographic frame itself: the clean expanse of white space that faces and encases the woman. Through an austere, minimalistic poetics of negation, Evans visualizes the limits of his photographed nation. Evans's image of the Hollywood movie poster is at pains to disclose its own status as an image. It depicts a woman who is already playing a role, whose pose of white, middle-class femininity is as contrived and hyperbolic as her stance of panicked victimhood in the poster. The woman is both scared and scarred, her apparent vulnerability to the damages of the photographic frame—and of the Hollywood typology of the innocent white female victim—ingrained in the corrugated surface of the poster. Resembling both falling tears and lacerations, the rippled [End Page 1] Click for larger view View full resolution Figure 1. Walker Evans, “Torn Movie Poster, 1930.” © Walker Evans Archive, The Metropolitan Museum of Art. Digital image © The Museum of Modern Art. Licensed by SCALA/Art Resource, New York [End Page 2] creases on the faces of the couple supplement the large rip in the poster that slashes open the woman's forehead. Since the surface of the poster and the surface of the image are collapsed into each other, these textual traces of dilapidation signify as the wounds of representation itself. The deep gorge in the woman's face produces a “beautiful convulsion” of the real that Rosalind Krauss identifies in surrealist photography in the 1920s and 1930s (“Photography” 35).1 Its chaotic, foliated layering of rips and tears are the signs of signification. “Torn Movie Poster” offers a means for re-conceptualizing one of the archetypal images of the Great Depression: the portrait in American Photographs with the caption, “Alabama Cotton Tenant Farmer Wife, 1936” (Figure 2). This portrait is a slight variation on the iconic photograph of Allie Mae Burroughs, the wife of a tenant farmer featured under the pseudonym Annie Mae Gudger in Let Us Now Praise Famous Men, the 1941 documentary book in which Evans collaborated with the writer James Agee (Figure 3). In the sequence of American Photographs, the woman in the movie poster is cordoned off from but still proximate to “Alabama Cotton Tenant Farmer Wife,” which appears immediately after “Torn Movie Poster,” as well as a range of other female figures. In this sense, in symbolizing the wounds of representation, the weathered, marred surface of the movie poster also registers the emplacement of the Hollywood icon as an image in series with other images. A detailed reading of American Photographs—particularly its serial figurations of the white woman—demonstrates its status as an indispensable precursor to Agee and Evans's 1941 documentary work. Indeed, Agee completed the major revisions of his 400-page contribution to Praise in 1939, as the generally positive reviews of Evans's...

A Framework for Making Face Detection Benchmark Databases

The images in face detection benchmark databases are mostly taken by consumer cameras, and thus are constrained by popular preferences, including a frontal pose and balanced lighting conditions. A good face detector should consider beyond such constraints and work well for other types of images, for example, those captured by a surveillance camera. To overcome such constraints, a framework is proposed to transform a mother database, originally made for benchmarking face recognition, to daughter datasets that are good for benchmarking face detection. The daughter datasets can be customized to meet the requirements of various performance criteria; therefore, a face detector can be better evaluated on desired datasets. The framework is composed of two phases: 1) intrinsic parametrization and 2) extrinsic parametrization. The former parametrizes the intrinsic variables that affect the appearance of a face, and the latter parametrizes the extrinsic variables that determine how faces appear on an image. Experiments reveal that the proposed framework can generate not just data that are similar to those available from popular benchmark databases, but also those that are hardly available from existing databases. The datasets generated by the proposed framework offer the following advantages: 1) they can define the performance specification of a face detector in terms of the detection rates on variables with different variation scopes; 2) they can benchmark the performance on one single or multiple variables, which can be difficult to collect; and 3) their ground truth is available when the datasets are generated, avoiding the time-consuming manual annotation.

Use of a Lighted Reading Magnifier for Cavity Photographing

Sir: Photographs are an essential part of the plastic surgeon's life, as they capture and display the objective changes that have been created and allow for a platform of discussion under more objective circumstances.1–5 Photographing hollow areas including the oral cavity necessitates special equipment. A ring flash is a circle-shaped electronic flash unit that fits around a lens and provides shadowless, uniform frontal lighting, which is especially useful in close-up (macro) photography and in photographing cavities. Currently, digital photography is popular, being reasonably inexpensive and much improved in quality. Digital photography offers multiple advantages in terms of quality, and easy image storage and retrieval. In contrast, with the widespread use of digital cameras today, it has been quite tricky to photograph hollow areas of the body, including orifices such as the oral cavity. This is because many digital cameras are not equipped with classic ring flashes, and the required digital photography equipment for this purpose can be quite expensive. For better quality photographs of the hollow areas including oral mucosa and palate, we put together an arrangement to give the ring flash effect while photographing with a digital camera. The simple placement of a lighted reading magnifier before the patient while taking the picture creates better lighting without shadows and a detailed close-up image. We believe that surgeons, especially those dealing with the oral cavity and other orifices, will benefit from this simple and very affordable arrangement while collecting photographic data (Figs. 1 and 2).Fig. 1.: A lighted reading magnifier placed between the patient and the camera for taking an intraoral picture.Fig. 2.: A detailed, clear photograph of the intraoral cavity taken with a lighted reading magnifier.Billur Sezgin, M.D. Selahattin Ozmen, M.D. Department of Plastic, Reconstructive, and Aesthetic Surgery and Hand Surgery Gazi University Faculty of Medicine Ankara, Turkey DISCLOSURE Neither of the authors has any disclosures of commercial associations or financial relationships.

The Effects of Dressing Room Lighting on Consumers’ Perceptions of Self and Environment

A positive experience in a retail store dressing room is a key part of the purchase decision process. Poor atmospherics can negatively affect the shopping experience and result in lost sales. Even though the importance of dressing room lighting has been acknowledged, no empirical studies have been done in this area. The purpose of this study was to examine the effects of dressing room lighting direction on states of arousal and pleasure, and on shopper self–evaluation and dressing room assessment. In this field study conducted at a local area boutique, 60 female participants between the ages of 18 and 35 years were randomly assigned to one of two dressing rooms; overhead and frontal lighting. The participants were asked to shop for a few different outfits, try them on, and complete the questionnaires in the dressing room. Data were analyzed using independent sample t–tests, revealing statistical significances for dimensions of self–evaluation ( p = 0.003) and dressing room evaluation ( p = 0.002). The quantitative results indicate that dressing room lighting direction has a specifically strong effect on facial shadowing and perceived roominess, for which frontal lighting is superior. Qualitatively, the results indicate that though some prefer overhead lighting, frontal lighting is generally preferred for self– and dressing room evaluations. Designers may consider using frontal lighting instead of overhead lighting unless they can use both to achieve the most universally acceptable shopper experience.

LIGHTING POSITION AND JUDGMENTS OF DISTANCE OF SHADOW-CASTING OBJECTS

Participants recruited on the web performed in two experiments in which they viewed eight pictures of the same two rods in the exact same positions with shadows generated by a light source located at eight positions around the rods. In Exp. 1, participants judged how much shadows projected to the front, back, and sides of the rods facilitated the correct perception of the actual distance of the rods relative to each other. In Exp. 1 (n: 52), frontal lighting facilitated judgments more than lighting from the rear, but frontal and side lighting did not differ in facultative effects. In Exp. 2 (n: 72), Judgments of rods depicted with shadows were relative to a judgment of the rods depicted without shadows (raw scores were the value of the judgment of the shadowless rods subtracted from the value of the judgment of each of the eight sets of rods). Again, frontal lighting was more facilitative than rear lighting and frontal lighting did not differ from side lighting. However, when the average of each participant's backlighting judgments was compared with his judgment of the shadowless rods, shadows generated by backlighting were more facilitative than none.

Shadows as sources of cues for distance of shadow-casting objects.

Shadows are neglected sources of information about shadow-casting objects' distance (location). In an experiment using real shadows, participants judged the distance of two rods, either with shadows (illumination from the left) or without shadows. Without shadows, a thin rod raised slightly above the surface was incorrectly judged to be more distant than a thick rod, but with shadows the thin rod was accurately judged to be closer. For judgments to be correct, shadows had to overwhelm competing height and stimulus-size cues. Exp. II involved nonoverlapping shadows produced by a light placed in front of the rods. Again, without shadows the thin-elevated rod was incorrectly judged to be more distant, but with shadows it was correctly judged to be closer. Exp. III involved two sets of thick and thin elevated rods and frontal lighting. Judgments were accurate when shadows were present but inaccurate when shadows were absent. Experiments conducted through the American Psychological Society Web-research site replicated results of Exp. I, II, and III. A final Web experiment replicated results of the others, but with shadows produced by illumination from the right. Three properties of shadows--angles, interposition, and positioning--are possible sources of distance information associated with cast shadows.

LIGHTING AND ENVIRONMENTAL CONTROL IN THE SACRISTY OF THE MONASTERY OF OUR LADY OF GUADALUPE IN CACERES

"LIGHTING AND ENVIRONMENTAL CONTROL IN THE SACRISTY OF THE MONASTERY OF OUR LADY OF GUADALUPE IN CACERES." Studies in Conservation, 39(sup1), p. 27