Color Image Enhancement Techniques for Endoscopic images

Modern endoscopes play an important role in diagnosing various gastrointestinal (GI) tract related diseases. Although clinical findings of modern endoscopic imaging techniques are encouraging, there still remains much room for improvement of image quality. Of greatest concern, endoscopic images suffer from various degradations, such as specular highlights, non-uniform brightness and poor contrast. As a result, gastroenterologists often face difficulty in successfully identifying the subtle features, such as mucosal surface and structures, pit patterns, size and pattern of micro-vessels, tissue and vascular characteristics, superficial layer of mucosal and abnormal growths in endoscopic images. The improved visual quality of images can provide better diagnosis. This paper presents two proposed post-processing techniques for enhancing the subtle features of endoscopic images. The first proposed technique is named as endoscopic image enhancement based on adaptive sigmoid function and space-variant color reproduction (ASSVCR). It is achieved in two stages: image enhancement at gray level followed by color reproduction with the help of space variant chrominance mapping. Image enhancement is achieved by performing adaptive sigmoid function and uniform distribution of sigmoid pixels. Then color reproduction is used to generate new chrominance components. The second proposed technique is named as tri-scan. It is achieved in three stages: (1) Tissue and surface enhancement: a modified linear unsharp masking is used to sharpen the surface and edges of tissue and vascular characteristics, (2) Mucosa layer enhancement: an adaptive sigmoid function similar to the ASSVCR technique is employed on the R plane of the image to highlight the superficial layers of mucosa, (3) Color tone enhancement: the pixels are uniformly distributed to create a different color effect to highlight mucosa structures, superficial layers of mucosa and tissue characteristics. Both techniques are compared with other related works. Several performance metrics like focus value, statistic of visual representation, measurement of uniform distribution, color similarity test, color enhancement factor (CEF) and time complexity are used to assess the performance. The results showed improved performance compared to similar existing methods. In the post-processed images, we have observed that the ASSVCR can enhance and highlight pit patterns, tissue and vascular characteristics, mucosa structures and abnormal growths. It cannot highlight size and pattern of micro-vessels, and superficial layer of mucosa. In contrast, tri-scan can enhance and highlight all above mentioned features of endoscopic images

Experimental Evaluation and Analysis of LED Illumination Source for Endoscopy Imaging

The minimally invasive surgery uses a small instrument with camera and light to fit the tiny cut in the skin. The selection of the light depends on the power and driving current of the circuit. It can also help in the standardization of the camera and capture the tissues' true-colour image. This paper presents the LED source analysis used in the clinical endoscopes for surgery and the human body's medical examination. Initially, a LED source selection mechanism generating intense illuminance in a visible band is proposed. A low-cost prototype model is developed to analyze the wavelength and illuminance of three different LEDs types. An effect on variation in LED illumination is investigated by changing the distance between the Borescope and LED source. True-colour image generation and tissue contrast are more important in medical diagnostics. Therefore, a sigmoid function improving the whole contrast ratio of the captured image in real-time is presented. The results of spectrum and wavelength for a current variation are presented. Type 3 LED produces higher illumination (i.e., 395 Klux) and peak wavelength (i.e., 622.05 nm) than other LEDs, while type-2 LED has better FWHM for the blue colour spectrum. The modification in the sigmoid function enhances the image with 34.25 peak PSNR producing a true-colour image

Endoscopic image analysis using Deep Convolutional GAN and traditional data

One big challenge encountered in the medical field is the availability of only limited annotated datasets for research. On the other hand, medical image annotation requires a lot of input from medical experts. It is noticed that machine learning and deep learning are producing better results in the area of image classification. However, these techniques require large training datasets, which is the major concern for medical image processing. Another issue is the unbalanced nature of the different classes of data, leading to the under-representation of some classes. Data augmentation has emerged as a good technique to deal with these challenges. In this work, we have applied traditional data augmentation and Generative Adversarial Network (GAN) on endoscopic esophagus images to increase the number of images for the training datasets. Eventually we have applied two deep learning models namely ResNet50 and VGG16 to extract and represent the relevant cancer features. The results show that the accuracy of the model increases with data augmentation and GAN. In fact, GAN has achieved the highest accuracy, that is, 94% over non-augmented training set and traditional data augmentation for VGG16

Effects of rescaling bilinear interpolant on image interpolation quality

Rescaling bilinear (RB) interpolant's pixels is a novel image interpolation scheme. In the current study, we investigate the effects on the quality of interpolated images. RB determines the lower and upper bounds using the standard deviation of the four nearest pixels to find the new interval or range that will be used to rescale the bilinear interpolant's pixels. The products of the rescaled-pixels and corresponding distance-based-weights are added to estimate the new pixel value, to be assigned at the empty locations of the destination image. Effects of RB on image interpolation quality were investigated using standard full-reference and non-reference objective image quality metrics, particularly those focusing on interpolated images features and distortion similarities. Furthermore, variance and mean based metrics were also employed to further investigate the effects in terms of contrast and intensity increment or decrement. The Matlab based simulations demonstrated generally superior performances of RB compared to the traditional bilinear (TB) interpolation algorithm. The studied scheme's major drawback was a higher processing time and tendency to rely on the image type and/or specific interpolation scaling ratio to achieve superior performances. Potential applications of rescaling based bilinear interpolation may also include ultrasound scan conversion in cardiac ultrasound, endoscopic ultrasound, etc

Diseases of the Abdomen and Pelvis 2018-2021: Diagnostic Imaging - IDKD Book

Gastrointestinal disease; PET/CT; Radiology; X-ray; IDKD; Davo

Oral and Maxillofacial Surgery

Oral and maxillofacial surgery is a specialized branch of dentistry that deals with the surgical management of various head and neck pathologies. The specialty focuses on reconstructive surgery of the oro-facial region, surgery of facial trauma, the oral cavity and jaws, dental implants as well as cosmetic surgery. As such, surgeons in this field require extensive knowledge of not only these various surgical procedures but also head and neck anatomy. This book provides comprehensive information on both. Its goal is to educate oral and maxillofacial surgeons to enable them to treat a wide range of conditions and diseases using the most current surgical trends

Deep Learning in Medical Image Analysis

The accelerating power of deep learning in diagnosing diseases will empower physicians and speed up decision making in clinical environments. Applications of modern medical instruments and digitalization of medical care have generated enormous amounts of medical images in recent years. In this big data arena, new deep learning methods and computational models for efficient data processing, analysis, and modeling of the generated data are crucially important for clinical applications and understanding the underlying biological process. This book presents and highlights novel algorithms, architectures, techniques, and applications of deep learning for medical image analysis

New Techniques in Gastrointestinal Endoscopy

As result of progress, endoscopy has became more complex, using more sophisticated devices and has claimed a special form. In this moment, the gastroenterologist performing endoscopy has to be an expert in macroscopic view of the lesions in the gut, with good skills for using standard endoscopes, with good experience in ultrasound (for performing endoscopic ultrasound), with pathology experience for confocal examination. It is compulsory to get experience and to have patience and attention for the follow-up of thousands of images transmitted during capsule endoscopy or to have knowledge in physics necessary for autofluorescence imaging endoscopy. Therefore, the idea of an endoscopist has changed. Examinations mentioned need a special formation, a superior level of instruction, accessible to those who have already gained enough experience in basic diagnostic endoscopy. This is the reason for what these new issues of endoscopy are presented in this book of New techniques in Gastrointestinal Endoscopy