Spectrum decomposition in Gaussian scale space for uneven illumination image binarization

Although most images in industrial applications have fewer targets and simple image backgrounds, binarization is still a challenging task, and the corresponding results are usually unsatisfactory because of uneven illumination interference. In order to efficiently threshold images with nonuniform illumination, this paper proposes an efficient global binarization algorithm that estimates the inhomogeneous background surface of the original image constructed from the first k leading principal components in the Gaussian scale space (GSS). Then, we use the difference operator to extract the distinct foreground of the original image in which the interference of uneven illumination is effectively eliminated. Finally, the image can be effortlessly binarized by an existing global thresholding algorithm such as the Otsu method. In order to qualitatively and quantitatively verify the segmentation performance of the presented scheme, experiments were performed on a dataset collected from a nonuniform illumination environment. Compared with classical binarization methods, in some metrics, the experimental results demonstrate the effectiveness of the introduced algorithm in providing promising binarization outcomes and low computational costs.

Hybrid quasi-3D optimization of grid architecture for single junction photovoltaic converters

A numerical study of metal front contacts grid spacing for photovoltaic (PV) converter of relatively small area is presented. The model is constructed based on Solcore, an open-source Python-based library. A three-step-process is developed to create a hybrid quasi-3D model. The grid spacing under various operating conditions was assessed for two similar p–n and n–p structures. The key target was finding optimal configuration to achieve the highest conversion efficiency at different temperatures and illumination profiles. The results show that the n–p structure yields wider optimal spacing range and the highest output power. Also, it was found that temperature increase and illumination nonuniformity results in narrower optimal spacing for both structure architectures. Analyzing the current–voltage characteristics, reveals that resistive losses are the dominant loss mechanism bringing restriction in terms of ability to handle nonuniform illumination.

Compatibility of Enhancement and Segmentation of Digital Image Processing in Medical Applications

The proposed work is an attempt to investigate the compatibility of enhancement and segmentation within the digital image processing framework in the medical field. The correction nonuniform illumination enhancement technique and marker-controlled watershed segmentation method were conducted in order to calculate the red blood cells in digital images of blood samples. Twenty-five patients at Medical City Teaching Hospital in Baghdad participated in this study. The attained outcomes of the two mentioned methods were compared with the real results, which were obtained by a digital camera coupled with a high technology microscope. The comparison illustrated large matching between two proposed techniques and real outcomes throughout very short computation time in spite of limited features of the used computer and available MATLAB environment.

Experimental Characterisation of Photovoltaic Modules with Cells Connected in Different Configurations to Address Nonuniform Illumination Effect

Most concentrating systems that are being used for photovoltaic (PV) applications do not illuminate the PV module uniformly which results in power output reduction. This study investigated the electrical performance of three PV modules with cells connected in different configurations to address nonuniform illumination effect. PV module 1 is the standard module consisting of 11 solar cells connected in series whereas PV module 2 is a proposed design with 11 cells in three groups and each group consists of different cells in series connections. PV module 3 is also a new design with 11 cells in two groups and each group consists of different cells connected in series. The new PV modules were designed in such a way that the effect of nonuniform illumination should affect a group of cells but not the entire PV module, leading to high power output. The PV modules were tested under three different intensities: uniform, low nonuniform, and high nonuniform illumination. When the PV modules were tested at uniform illumination, the total maximum power output of PV module 1 was higher than that of PV module 2 and PV module 3 by about 7%. However, when the PV modules were tested at low nonuniform illumination, the total maximum power output of PV module 2 was higher than that of PV module 1 and PV module 3 by about 4% and 7%, respectively. This difference increased to about 12% for PV module 3 and 17% for PV module 1 when the modules were tested at high nonuniform illumination. Therefore, the best PV module design in addressing nonuniform illumination effect in solar collectors is PV module 2. In practical situation this implies that manufacturers of PV modules should consider designing modules with groups of cells in series connection instead of all cells being connected in series.