Effects of Depth-Based Object Isolation in Simulated Retinal Prosthetic Vision

Visual retinal prostheses aim to restore vision for blind individuals who suffer from outer retinal degenerative diseases, such as retinitis pigmentosa and age-related macular degeneration. Perception through retinal prostheses is very limited, but it can be improved by applying object isolation. We used an object isolation algorithm based on integral imaging to isolate objects of interest according to their depth from the camera and applied image processing manipulation to the isolated-object images. Subsequently, we applied a spatial prosthetic vision simulation that converted the isolated-object images to phosphene images. We compared the phosphene images for two types of input images, the original image (before applying object isolation), and the isolated-object image to illustrate the effects of object isolation on simulated prosthetic vision without and with multiple spatial variations of phosphenes, such as size and shape variations, spatial shifts, and dropout rate. The results show an improvement in the perceived shape, contrast, and dynamic range (number of gray levels) of objects in the phosphene image.

Simulating Visibility and Reading Performance in Low Vision

PurposeLow vision reduces text visibility and causes difficulties in reading. A valid low-vision simulation could be used to evaluate the accessibility of digital text for readers with low vision. We examined the validity of a digital simulation for replicating the text visibility and reading performance of low-vision individuals.MethodsLow-vision visibility was modeled with contrast sensitivity functions (CSFs) with parameters to represent reduced acuity and contrast sensitivity. Digital filtering incorporating these CSFs were applied to digital versions of the Lighthouse Letter Acuity Chart and the Pelli-Robson Contrast Sensitivity Chart. Reading performance (reading acuity, critical print size, and maximum reading speed) was assessed with filtered versions of the MNREAD reading acuity Chart. Thirty-six normally sighted young adults completed chart testing under normal and simulated low-vision conditions. Fifty-eight low-vision subjects (thirty with macular pathology and twenty-eight with non-macular pathology) and fifteen normally sighted older subjects completed chart testing with their habitual viewing. We hypothesized that the performance of the normally sighted young adults under simulated low-vision conditions would match the corresponding performance of actual low-vision subjects.ResultsWhen simulating low-vision conditions with visual acuity better than 1.50 logMAR (Snellen 20/630) and contrast sensitivity better than 0.15 log unit, the simulation adequately reduced the acuity and contrast sensitivity in normally sighted young subjects to the desired low-vision levels. When performing the MNREAD test with simulated low vision, the normally sighted young adults had faster maximum reading speed than both the Non-macular and Macular groups, by an average of 0.07 and 0.12 log word per minute, respectively. However, they adequately replicated the reading acuity as well as the critical print size, up to 2.00 logMAR of both low-vision groups.ConclusionA low-vision simulation based on clinical measures of visual acuity and contrast sensitivity can provide good estimates of reading performance and the accessibility of digital text for a broad range of low-vision conditions.

3D Reconstruction and Visual Simulation of Double-Flowered Plants Based on Laser Scanning

Flower plants have become a major difficulty in virtual plant research because of their rich external morphological structure and complex physiological processes. Computer vision simulation provides powerful tools for exploring powerful biological systems and operating laws. In this paper, Chrysanthemum and Chinese rose, double flowers as the symbolic flowers of Beijing, are chosen as the study subject. On the basis of maximizing the protection of flower growth structure, an effective method based on laser scanning for three-dimensional (3D) reconstruction and visual simulation of flower plants is proposed. This method uses laser technology to scan the sample and store it as point cloud data. After applying a series of image analysis and processing techniques such as splicing, denoising, repairing and color correction, the digital data optimized by the sample is obtained accurately and efficiently, and a highly realistic 3D simulation model of the plant is formed. The results of the research indicate that it is a convenient research method for the 3D reconstruction of flower plants and computer vision simulation of virtual plants. It also provides an effective way for in-depth study of scientific experiments and digital protection of rare and endangered plants.

Development of a portable community video surveillance system

In 2016, a crime rate has been evidently increasing particularly in Kuala Lumpur areas, including reports on house break-ins, car thefts, motorcycle thefts and robbery. One way of deterring such cases is by installing CCTV monitoring system in premises such as houses or shops, but this usually requires expensive equipment and installation fees. In this paper a cheaper alternative of a portable community video surveillance system running on Raspberry Pi 3 utilizing OpenCV is presented. The system will detect motion based on image subtraction algorithm and immediately inform users when intruders are detected by sending a live video feed to a Telegram group chat, as well as sound the buzzer alarm on the Raspberry Pi. Additionally, any Telegram group members can request images and recorded videos from the system at any time by sending a get request in Telegram which will be handled by Telegram Bot. This system uses the Pi NoIR camera module as the image acquisition device equipped with a 36 LED infrared illuminator for night vision capability. In addition to the Python language, OpenCV, a computer vision simulation from Intel is also used for image processing tasks. The performance analysis of the completed system is also presented computational complexity while offering improved flexibility. The performance time is also presented, where the whole process is run with a noticeable 3 seconds delay in getting the final output.

Uso de simulação da visão de daltônicos na avaliação da informação cromática contida em embalagens | The color blinds vision simulation in the evaluation of color information contained in packages

Deficiências cromáticas visuais, popularmente conhecidas como daltonismo, afetam a capacidade dos indivíduos para identificar e/ou diferenciar cores. Para compreender como a deficiência afeta a percepção de informações cromáticas em embalagens, este estudo utiliza ferramentas de simulação para obter imagens próximas ao modelo de visão das cores observado por estes indivíduos. Realizou-se a análise com três embalagens, selecionadas por conveniência, caracterizando-se como estudo exploratório descritivo, de abordagem qualitativa. Foram constatadas alterações nos níveis de RGB e HSB das cores analisadas, provocando ruído na compreensão das informações cromáticas, uma vez que ocorre a descaracterização as cores originalmente propostas.*****Color vision deficiency, popularly known as color blindness, affects a portion of the population. They affect the ability of individuals to differentiate between colors and, consequently, to interpret information associated with color-coding. Based on this problem, exploratory research was carried out, with a qualitative approach, in which we evaluated the perception of color information contained in packages. The strategy used was the technical analysis, performed by the researchers, using a color blindness simulator. Changes were observed in the levels of red, green and blue (RGB) images, with important modifications in the hue, saturation, and brightness (HSB), decharacterizing the original chromatic design. The use of color blindness simulation allowed the identification of possible noises and ambiguities in the packaging interface.

Understanding Visual Impairment and Its Impact on Patients: A Simulation-Based Training in Undergraduate Medical Education

Introduction: Simulation activities are valuable teaching aids for understanding about living with visual impairment (VI). Our medical students used low-vision simulation spectacles (Sim-specs) to enable learning about VI. Methods: Students made tea and filled dosette boxes using Sim-specs simulating central visual loss (age-related macular degeneration) and navigated using Sim-specs simulating peripheral visual loss (glaucoma). Facilitators recorded errors made for each task. Students completed questionnaires to grade the tasks’ difficulty on a 4-point Likert-type scale. The students also participated in focus groups to discuss how their approach to working with patients may change following this training. Results: In total, 252 out of 254 students participated. Central visual loss provided the greatest challenge when undertaking fine motor skilled activity (dosette box). Highest average number of errors made was for dosette box task (0.70 error), followed by navigation (0.59), then making tea task (0.34). Students scored the most difficult task on average as the dosette box task (3.23 Likert-type points), followed by navigation (2.97), then making tea task (2.63). Our students have shown learning in recognising the challenges of VI and have adapted their approach to patients. Conclusions: Simulation activities are valuable additions to the undergraduate curriculum. Such activities can potentially enable greater empathy for our visually impaired patients.