Implementasi Metode Gaussian dan Median Filtering dalam Penghilangan Noise pada Citra

Meningkatnya angka kriminalitas menjadikan salah satu faktor dipasangnya CCTV pada beberapa sudut area oleh beberapa lembaga sebagai bentuk pengawasan, salah satunya yang telah dilakukan oleh Kementerian Perhubungan Republik Indonesia. Pengawasan melalui CCTV sering kali menghadapi gangguan, seperti hasil citra ber-noise yang menghambat proses pengidentifikasian suatu objek yang tertangkap CCTV. Oleh karena itu, penulis mencoba untuk melakukan implementasi metode Gaussian Filtering dan Median Filtering sebagai upaya dalam menghilangkan noise pada citra yang dihasilkan oleh CCTV. Implementasi yang akan dilakukan pada penelitian ini diawali dengan melakukan input data yang berupa citra hasil screen capture CCTV, kemudan dilakukan konversi dari citra berwarna menjadi citra greyscale. Tahap selanjutnya adalah melakukan penghilangan noise menggunakan metode Gaussian Filtering dan Median Filtering. Mean Square Error (MSE) dan Peak Signal to Noise Ratio (PSNR) digunakan dalam pengujian. Dapat disimpulkan dari penelitian ini, Median Filtering lebih efektif dalam melakukan penghilangan noise dari pada Gaussian Filtering. Hal ini dibuktikan dari 20 percobaan penghilangan noise menggunakan Median Filtering, 80% citra yang diproses menghasilkan nilai PSNR yang lebih besar daripada nilai PSNR citra dengan noise dan mengartikan jika citra yang diproses mendekati citra asli (citra tanpa noise). Sedangkan dari dari 20 percobaan penghilangan noise menggunakan Gaussian Filtering hanya 50% citra yang diproses menghasilkan nilai PSNR yang lebih besar daripada nilai PSNR citra dengan noise. Selanjutnya, untuk nilai standar deviasi terbaik penghilangan noise pada citra adalah ketika ada pada nilai 2 dengan rerata persentase penurunan noise sebesar 1,73%. Kata Kunci: CCTV, Citra, Pengolahan Citra, Noise, Gaussian Filtering, Median Filtering.

Unstructured Noise Removal for Industrial Sensor Imaging Unit by Hybrid Adaptive Median Algorithm

Thermal noise is the most common type of contamination in digital image acquisition operations, and is caused by the temperature condition of the industrial sensor devices used in the process. When it comes to picture improvement, removing noise from the image is one of the most crucial steps. However, in image processing, it is more critical to retain the characteristics of the original picture while eliminating the noise. Thermal noise removal is a challenging problem in image denoising. This article provides a strategy based on a Hybrid Adaptive Median (HAM) filtering approach for removing thermal noise from the image output of an industrial sensor. The demonstration of this proposed approach's ability, is to successfully detect and reduce thermal noise. In addition, this study examines an adaptive hybrid adaptive median filtering approach that has significant computational advantages, making it highly practical. Finally, this research report on experiments shows the high-quality industrial sensor imaging systems that have been successfully implemented in the real world.

An Improved Image Filtering Algorithm for Mixed Noise

In recent years, image filtering has been a hot research direction in the field of image processing. Experts and scholars have proposed many methods for noise removal in images, and these methods have achieved quite good denoising results. However, most methods are performed on single noise, such as Gaussian noise, salt and pepper noise, multiplicative noise, and so on. For mixed noise removal, such as salt and pepper noise + Gaussian noise, although some methods are currently available, the denoising effect is not ideal, and there are still many places worthy of improvement and promotion. To solve this problem, this paper proposes a filtering algorithm for mixed noise with salt and pepper + Gaussian noise that combines an improved median filtering algorithm, an improved wavelet threshold denoising algorithm and an improved Non-local Means (NLM) algorithm. The algorithm makes full use of the advantages of the median filter in removing salt and pepper noise and demonstrates the good performance of the wavelet threshold denoising algorithm and NLM algorithm in filtering Gaussian noise. At first, we made improvements to the three algorithms individually, and then combined them according to a certain process to obtain a new method for removing mixed noise. Specifically, we adjusted the size of window of the median filtering algorithm and improved the method of detecting noise points. We improved the threshold function of the wavelet threshold algorithm, analyzed its relevant mathematical characteristics, and finally gave an adaptive threshold. For the NLM algorithm, we improved its Euclidean distance function and the corresponding distance weight function. In order to test the denoising effect of this method, salt and pepper + Gaussian noise with different noise levels were added to the test images, and several state-of-the-art denoising algorithms were selected to compare with our algorithm, including K-Singular Value Decomposition (KSVD), Non-locally Centralized Sparse Representation (NCSR), Structured Overcomplete Sparsifying Transform Model with Block Cosparsity (OCTOBOS), Trilateral Weighted Sparse Coding (TWSC), Block Matching and 3D Filtering (BM3D), and Weighted Nuclear Norm Minimization (WNNM). Experimental results show that our proposed algorithm is about 2–7 dB higher than the above algorithms in Peak Signal-Noise Ratio (PSNR), and also has better performance in Root Mean Square Error (RMSE), Structural Similarity (SSIM), and Feature Similarity (FSIM). In general, our algorithm has better denoising performance, better restoration of image details and edge information, and stronger robustness than the above-mentioned algorithms.

Digital Video Image Preprocessing Algorithm Based on Embedded System

To solve the massive noise contained in the images acquired under low illumination, we designed a digital video image Preprocessing device with the denoising function. Based on the embedded CPU and operating system, video images are acquired by the camera. The noise contained in the video images is filtered by the improved median filtering algorithm and wavelet image denoising. Subsequently, the images are transmitted through USB and network interface, and the storage function of image files is implemented. The device can remove the noise contained in videos effectively, which is conducive to performing more advanced processing on the images.

Research on 3D crack segmentation of CT images of oil rock core

In this paper, we propose a framework for CT image segmentation of oil rock core. According to the characteristics of CT image of oil rock core, the existing level set segmentation algorithm is improved. Firstly, an algorithm of Chan-Vese (C-V) model is carried out to segment rock core from image background. Secondly the gray level of image background region is replaced by the average gray level of rock core, so that image background does not affect the binary segmentation. Next, median filtering processing is carried out. Finally, an algorithm of local binary fitting (LBF) model is executed to obtain the crack region. The proposed algorithm has been applied to oil rock core CT images with promising results.