Opencv remove small noise. You will see different functions like cv.

Opencv remove small noise adaptiveThreshold(): blockSize and C for many images. By understanding how different noise impacts images and how to handle it each of them can create more reliable and noise-tolerant algorithms that perform well in real-world conditions. erode () function works by sliding a kernel over the image. Remove very small clusters - considered to be noise. The project consists of 21 directories with approximately 100 frames each. I'm using python. The final PSNR . Feb 27, 2021 · Noise Reduction Model Here comes the project’s insightful part. The big yellow areas in the picture look alike. fastNlMeansDenoising (), cv. 1 day ago · 2D Convolution ( Image Filtering ) As in one-dimensional signals, images also can be filtered with various low-pass filters (LPF), high-pass filters (HPF), etc. It is a multi-stage algorithm and we will go through each stages. What you could do is try to Note we could have performed additional morph open after the adaptive threshold to remove the small particles of noise but the tradeoff is that it will remove vein details. Opening is an operation that combines erosion and dilation, and is used to remove small objects from the image and fill small gaps in the objects. Jan 16, 2025 · It is used to remove small white noises or detach connected objects. Every frame is unique. After the threshold, there should be an image left where the crystals (the white spots) are distinguished from the background (black). This is what is known as an opening operation. Find connected components (clusters) with statistics. medianBlur() function. It will be great , if you suggest the way. Mar 15, 2017 · I use OpenCV and Python and I want to remove the small connected object from my image. The goal of denoising techniques is to effectively remove unwanted noise while preserving Notifications You must be signed in to change notification settings Fork 0 Remove image noise by using techniques such as averaging filtering, median filtering, and adaptive filtering based on local image variance. Filter and remove small noise. Theory In earlier chapters, we have seen many image smoothing techniques like Gaussian Blurring, Median Blurring etc and they were good to some extent in removing small quantities of Feb 20, 2023 · Learn how to remove noise from images in OpenCV. Original image This is the code I tried for thinning (partially taken OpenCV Image Thresholding is a crucial technique in image processing, especially when aiming for accurate object detection. The puzzle piece images come from kaggle and piece edges are quite messy. , from camera artifacts). 6 days ago · In computer vision, converting grayscale images to black and white (binary) is a foundational step for tasks like object detection, segmentation, and feature extraction. Jan 17, 2022 · Background Remover with OpenCV – Method 1 To begin with, our first background remover focuses on how to clean up images with background noise. In the first case, global thresholding with a value of 127 is applied. Noise Reduction Since edge detection is susceptible to noise in the image, first step is to remove the noise in the image with a 5x5 Gaussian Feb 1, 2019 · I am new to image processing and is working on a project where I need to separate the images of the leaf form the background as a part of the project. I am a beginner in this type of programming and Im just wondering if you guys can help me denoise it? Apr 28, 2025 · These functions can be used to remove noise and improve the visual quality of an image. For example, it can be used to remove noise or separate connected objects. Apr 21, 2015 · I tried removing noise from the image shown below using Median Blur in OpenCV. dilate(dst, Apr 20, 2012 · The binary image has some small objects which I don't want. After segmentation with thresholding and watershed method I get this result After that I want to extracting textural features from the tumor area only, so I have to remove all noise and other objects outside the region of interst (the tumor) So like shown in image below, I What would be the best method to remove the internal noise ? Without loosing the contour of every objects on the top right. Jul 27, 2019 · Explore techniques to enhance the accuracy of OCR by preprocessing images with Python libraries such as OpenCV and pytesseract. Applying median blur BEFORE binarization may also help reduce small noise. floodFill (using OpenCV 4) returns a tuple of four elements. Source code or any related link/s are appreciated. Jan 8, 2013 · Goal In this chapter, we will learn about Concept of Canny edge detection OpenCV functions for that : cv. Sep 25, 2017 · As @Tetragramm mentioned, morphology will be faster than connected components. Jun 27, 2015 · I am not sure if this would work for you but you can make use of contourArea method to get contour area and filter out some small contours on a basis of that. We will be using a machine learning-trained noise reduction model. As they are overlapping, any filter I tried using remove the contour too. This tutorial will show you how to remove that noise and get better results. It replaces the pixel value with the minimum value of the overlapping region. ) to be detected correctly without too much noise. You will see different functions like cv2. Many times noise in your images is hurting your OCR. Based on this, we designed our background remover with the following strategy: Perform Gaussian Blur to remove noise Simplify our image by binning the pixels A good start could be a small median filter with a 3x3 kernel. Apr 30, 2025 · Whether you’re smoothing an image to remove noise or enhancing features for better detection, filtering techniques based on convolution are everywhere. 2 days ago · Goal In this chapter, We will learn different morphological operations like Erosion, Dilation, Opening, Closing etc. We often encounter challenges with shadows obscuring objects, leading to inaccurate segmentation. Jan 8, 2013 · Goal In this chapter, You will learn about Non-local Means Denoising algorithm to remove noise in the image. To detect horizontal lines, we create a special horizontal kernel and morph open to detect horizontal contours. Apr 20, 2012 · The binary image has some small objects which I don't want. Jun 30, 2016 · You can use fastNlMeansDenoising or fastNlMeansDenoisingColored function in OpenCV to remove gaussian white noise or colored noise respectively. LPF helps in removing noise, blurring images, etc. If I read you correctly, noise removal is needed to find your psb contours to remove perspective distortion. 17 hours ago · In this blog, we’ll walk through a step-by-step pipeline to automatically detect and remove small unwanted objects from chest X-ray images using Python libraries: **OpenCV** (for image processing) and **scikit-image** (for advanced region analysis). 3 days ago · This function expected to be applied to grayscale images. This can be used to remove noise from the image or separate touching objects. May 7, 2025 · In the following image which is edges of some coins detected by Canny, I want to remove the extra edges detected inside the coins. Example code as below: threshold_area = 10000 #threshold area contours, hierarchy = cv2. The erosion removes those islands while the dilation grows back the larger objects to their original sizes. x and Python I have an image like this: Its an HSV thresholded output of a BGR image. The first image is the original image. Sep 30, 2021 · In this tutorial, we have used a machine-learning algorithm to denoise a noisy image by making use of Python as the programming language. Canny in 1986. You might run the risk of removing dots / punctuation as well. You can refer to my problem here enter link description here My original image is i want the output image as: 2 days ago · Goal In this chapter, We will learn different morphological operations like Erosion, Dilation, Opening, Closing etc. It is normally performed on binary images. e. erode (), cv. , noise, reflections, or tiny colored regions) that can interfere with detecting the primary object. 4 days ago · Several morphological filtering operations like closing and opening are done to remove unwanted noise. See how noise filtering improves the result. Feb 17, 2025 · Introduction Morphological transformations are image processing techniques used to enhance or clean up images. I'm using python and OpenCV May 15, 2021 · Erosion is useful for removing small blobs (or, noise) in an image or disconnecting two connected objects. The Non-local Means Denoise Algorithm selects a pixel, takes a Jun 21, 2022 · Topic Replies Views Activity Noise reduction C++ imgproc 0 485 May 4, 2022 Remove unwanted contours with irregular shapes Python 1 3320 December 30, 2021 Discard tiny elements detected with findContours C++ imgproc 1 360 June 8, 2021 Removing noise on the asphalt pavement Python 1 182 August 30, 2023 Opencv how to make edges more visible Python Jun 17, 2025 · Python OpenCV Morphological operations are one of the Image processing techniques that processes image based on shape. By the end, you’ll have a reproducible workflow to clean chest X-rays effectively. The idea I used is to findContours and then add a Mar 9, 2020 · I have tried Hough transform for circles, but the dots are too small (10x10 px aprox. The first thing that comes to my mind is to create a custom 5x5 or 7x7 or 9x9 filter that identifies small isolated blobs, but I never had the need to use such Jan 8, 2013 · This function expected to be applied to grayscale images. Generally this type of noise will only affect a small number of image pixels. Feb 20, 2023 · Learn how to remove noise from images in OpenCV. Sep 18, 2025 · Goal In this chapter, You will learn about Non-local Means Denoising algorithm to remove noise in the image. The purpose of this operation is to remove small islands of noise while (trying to) maintain the areas of the larger objects in your image. Nov 13, 2025 · How to Remove Noise in Images with OpenCV and Python: Adaptive Gaussian Thresholding for Black Text on White Background In today’s digital age, images containing text—such as scanned documents, invoices, or OCR inputs—are ubiquitous. May 21, 2015 · What you're doing is an erosion first followed by a dilation. Closing is the opposite of opening, and is used to remove small holes in the objects and connect small gaps between objects. Theory In earlier chapters, we have seen many image smoothing techniques like Gaussian Blurring, Median Blurring etc and they were good to some extent in removing small quantities of [Question] Why sometimes when image is small (not too much) OpenCV find contours function gets wrong values, like triangle can be detected as triangle + rectangle at same shape, And how to fix it? : r/opencv r/opencv Current search is within r/opencv Remove r/opencv filter and expand search to all of Reddit Oct 28, 2020 · So in short, I would like to remove the background noise, so that only the information i'm interested in stays in the image. I already use this knowledge and filter dots based on the distance from the line. Theory Morphological transformations are some simple operations based on the image shape. g. This guide provides step-by-step instructions and examples to handle text recognition challenges, especially in complex images with overlays. You do not need converting original image into gray: www. Consider it as tidying up the image—removing unwanted specks while preserving the essentials. - anadi45/Image-Noise-Remover Jan 21, 2016 · I am doing a image processing project which is about the noise removal. See here for a description of the different types. To remove small islands of noise (also known as "salt and pepper" noise) in an image using Python and OpenCV, you can use morphological operations like erosion and dilation. I've already done Morphological Opening on the original image and the current one. Jun 1, 2023 · OpenCV provides a range of algorithms for image processing, including denoising techniques that aim to remove the noise from an image while preserving its essential features. Since widths of all the edges are the same, I think I can't use er Jan 10, 2018 · You can remove the noises by removing small connected components that might improve the accuracy. Canny in It is a multi-stage algorithm and we will go through each stages. fastNlMeansDenoisingColored () etc. However, real-world images are rarely perfect: noise, occlusion, low lighting, or sensor limitations can fragment these contours Jan 6, 2019 · I have images that are noised with some random lines like the following one: I want to apply on them some preprocessing in order to remove the unwanted noise ( the lines that distort the writing) so May 4, 2022 · Hello, I have an assignment project, I would like to remove the small white pixels and stay with the bird, I have tried filtering using the morphological method but the result is still not good. Advanced usage of this functions can be manual denoising of colored image in different colorspaces. You are adding extra noise without reducing it back. Create a rectangular kernel with cv2. Basics Most of you will have some old degraded photos at your home with some black spots, some strokes etc on it. Dec 13, 2016 · It may remove small noise, both black and white, while preserving colors (image will stil be binary) and, with posssible small errors, shapes. how to get rid of these small Denoising Noise remove from an image applying Denoising using OpenCV C++ Denoising: Denoising or noise reduction is the process of removing noise from signals obtained from analog or digital devices. In short, noise removal at a pixel was local to its neighbourhood. In this blog, we’ll walk through a step-by-step guide using OpenCV, a powerful computer vision library, to achieve this. It is one of the best noise reduction… Nov 22, 2020 · I have been at this all day, how to we remove the small back noise in the red circle? I would need it to work on other samples of pictures like this. I wish to remove (or diminish) the tiny reflections somehow, acros Jun 10, 2024 · Discover effective noise reduction techniques in OpenCV for enhancing image quality. 1 day ago · To solve this, we need to detect table lines, remove them cleanly, and eliminate noise before feeding the image to OCR. Does your bwareaopen get rid of this, or are you doing further processing to remove it? Aug 11, 2025 · searchWindowSize: Size of the window to search for similar patches. In the third case, the image is first filtered with a 5x5 gaussian kernel to remove the noise, then Otsu thresholding is applied. May 22, 2014 · DISCLAIMER: I can NOT use morphological (i. " - wiki - Noise reduction. It's easy to see where there are tiny reflections scattered throughout. In those techniques, we took a small neighbourhood around a pixel and did some operations like gaussian weighted average, median of the values etc to replace the central element. 5 days ago · In computer vision and image processing, analyzing 2D images often involves detecting and interpreting continuous curves or contours—think of object boundaries in medical scans, product edges in industrial inspection, or geographic features in satellite imagery. OpenCV provides a function cv. In this tutorial, we’ll learn how to apply erosion, dilation, opening, and closing using OpenCV in Python. getStructuringElement() and then perform morphological operations to remove noise. I'm new in the world of image processing. erosion followed by dilate), the size of the larger objects will be preserved whilst the noise will be removed. I am trying to crop the roots alone. Theory In earlier chapters, we have seen many image smoothing techniques like Gaussian Blurring, Median Blurring etc and they were good to some extent in removing small quantities of Apr 10, 2020 · I am even more new to opencv, but came across a code which might help you. It was developed by John F. Iterate the clusters, and delete clusters with large width and large height. drawContours() Perform OCR. thank you. 4) Search the maximum contour. learnopencv Remove small black spots (black color) & noise And make numbers, for example 0, 2, 6, 8, 9 etc & text NA, more complete, sharp & readable Please advise & suggest, thanks a lot Im very new to Opencv but somehow Im able to load and display image, please refer this image for more clarity on what I mean: Remove noise from threshold image opencv python Asked 8 years, 9 months ago Modified 3 years, 1 month ago Viewed 60k times Jun 18, 2022 · Is there some kind of filter that I can remove these noises circled in red in my image? I want to process different type of image to extract actual text from noisy image . Noise is generally considered to be a random variable with zero mean. Feb 9, 2015 · This blog post will show you how to remove contours (according to some criterion) from an image using Python and OpenCV. Canny () Theory Canny Edge Detection is a popular edge detection algorithm. What are the best image processing techniques that I can use to remove these noisy edges without Jun 26, 2018 · Hi all, I am running this in OpenCV 3. For colored images look at fastNlMeansDenoisingColored. It needs two inputs, one is our original image, second May 19, 2016 · May I ask, how should I remove noise via either adaptiveThreshold () function or the erode () and dilate () functions without causing the crack to become thinner or wider? May 19, 2016 · May I ask, how should I remove noise via either adaptiveThreshold () function or the erode () and dilate () functions without causing the crack to become thinner or wider? Tool made using Python and OpenCV to remove periodic noise in frequency domain. The image on this page is a real world image. 2) Convert the image into the binary 3) Apply erosion and dilation operation on the mask. I have attached input and output images. Background noise can very a lot, and I have images where I know that only the background noise is in there and nothing else. However, a common challenge is filtering out small, irrelevant "blobs" (e. I suggest as an adaptive threshold to use a closing (on the input grey-value image) with a structuring element just large enough to remove all the text. Jan 8, 2011 · Goal In this chapter, You will learn about Non-local Means Denoising algorithm to remove noise in the image. Example input image I have tried median blurring and removing small connected Apr 13, 2017 · I always find it weird for people to use dilation filters, but no following erode filters. 2, Raspberry pi 3/3b/4 #Date: 12th December, 2019 import cv2 as cv import numpy as np img = cv. Moreover, the ima Apr 8, 2019 · How to remove small noise (several irregular small shapes) from image opencv Asked 5 years, 11 months ago Modified 2 years, 6 months ago Viewed 409 times Nov 7, 2025 · Removing these small connected objects is critical to "clean" the image, improving downstream tasks like object counting, shape analysis, or feature extraction. In this project, we are denoising the Video clip or Image using OpenCV. Next apply edge detection on the image, make sure that noise is sufficiently removed as ED is susceptible to it. Performing Video and Image Noise Reduction using OpenCV. The median filter effectively eliminates these noisy pixels while preserving the edges and structures of the image. but my code results still have little stains. edit flag offensive delete link more add a comment Sep 24, 2020 · Processing image for reducing noise with OpenCV in Python Asked 4 years, 9 months ago Modified 4 years, 9 months ago Viewed 3k times May 24, 2022 · How to remove noise from an image in opencv (see the input picture)? I want to achieve that in the output I will get white background and black text only. Aug 26, 2022 · Are there any methods or functions to remove small contours given an already thresholded image through OpenCV in Python? My aim is only letting the rectangles and soon separate these overlapped ones: 1 day ago · Goal In this chapter, You will learn about Non-local Means Denoising algorithm to remove noise in the image. 1) Input 2) Output image. Jan 8, 2013 · The input image is a noisy image. There is a property of noise. When viewed, the image contains dark and white dots, hence the term salt and pepper noise. Morphological Closing Closing is the counterpart to opening, consisting of dilation followed by erosion. Feb 16, 2017 · In the column on the right the background is filled with noise How to detect the areas with noise? I only want to apply some kind of filter on the parts with noise because I need to do OCR on it and any kind of filter will reduce the overall recognition And what kind of filter is the best to remove the background noise in the image? 2 days ago · 5. Especially since small movements of the object get stabled by our eyes, but since we process pixels, we actually have a different contour. However, in some cases Feb 20, 2019 · I currently have an image with white horizontal lines. Images that require median filtering have small white or black dots in them. but the problem is I cant eliminate the small objects in the image output. Artifact Removal in C# with OpenCV Recently I solved a computer-vision problem that came up in a project which I found interesting and wanted to share. Feb 27, 2021 · In this article, I will show you how to implement noise reduction in three simple steps. Theory In earlier chapters, we have seen many image smoothing techniques like Gaussian Blurring, Median Blurring etc and they were good to some extent in removing small quantities of Sep 18, 2017 · Detect and remove horizontal lines. Example: Denoising a Noisy Image This example shows how to denoise a color image using OpenCV’s fastNlMeansDenoisingColored () function. Jul 23, 2025 · Image denoising techniques in computer vision are essential for enhancing the quality of images corrupted by noise, thereby improving the accuracy of subsequent image processing tasks. Click here to know more about how to remove noise from image opencv python. This processing strategy is usually performed on binary images. Therefore, mastering OpenCV Image Thresholding, specifically adaptive thresholding, becomes essential for robust object identification. I want to make image processing with chest X-rays in order to obtain a lung pattern. 1. How to remove periodic noise Oct 3, 2024 · Title: Image Processing Photo Noise Removal from Image Using OpenCV Python Mathplotlib Denoise | CamboTutorial Denoising is done to remove unwanted noise from image to analyze it in better form. 4 days ago · Goal In this chapter, You will learn about Non-local Means Denoising algorithm to remove noise in the image. contourArea(cnt) if area > threshold May 8, 2017 · According to what I've studied, noise (specifically salt/pepper noise) that produce in faulty scanner can be removed by k-Fill algorithm, but i can't understand that theory. Gaussian noise: "Each pixel in the image will be changed from its original value by a (usually) small amount. We perform “erosion” in OpenCV using erode a function on a binary image. After that, I want to extract the cancerous area from the segmented image, so I have to remove all noise and other objects outside the region of interest (the cancerous nodule). I'm trying to find an efficient solution to eliminate most small blobs in this image, leaving the big blobs absolutely intact. erosions) operations or drawContours to solve this problem. But on others, while dilating the image, I have a lot of unwanted small white blobs which get dilated along with the other pixels and In those techniques, we took a small neighbourhood around a pixel and did some operations like gaussian weighted average, median of the values etc to replace the central element. Such approach is used in fastNlMeansDenoisingColored by converting image to CIELAB colorspace and then separately denoise L and AB components with different h parameter. Jul 23, 2025 · With the right techniques and tools such as OpenCV we can effectively analyze and reduce noise ensuring our computer vision models remain robust and accurate. But i'm not able to remove the colour noise completely as it is done in Neat Image. jpg') image Mar 16, 2018 · Whenever your output image has more noise than the input image, you know you're doing something wrong. Have you ever thought of restoring it back? Learn how to remove lines and noise in OpenCV using various techniques and code examples for effective image processing. Jun 16, 2024 · Salt and pepper noise is an impulse type of noise in images. In this article, we’ll explore image filtering using convolution — understanding the mathematics behind it, and seeing how it’s practically implemented in OpenCV. So like shown in image below, I want to extract the cancerous nodule like this: How can I achieve this in android using OpenCV? Apr 7, 2024 · Median filter in image processing in Python is a noise reduction technique using OpenCV and its cv2. Image fusion: OpenCV provides the addWeighted () function for combining two images using a weighted sum. Jul 31, 2019 · 7 i have a binary image and I want to remove small white dots from the image using opencv python. More specifically it boiled down to a problem of artifact removal and it goes like this: The Problem Given the following image which is a cutout of a scan of a sheet of paper: There are one or more lines of text that are interested in and we Jan 8, 2013 · Image Inpainting Goal In this chapter, We will learn how to remove small noises, strokes etc in old photographs by a method called inpainting We will see inpainting functionalities in OpenCV. We’ll use morphological operations to clean it: Erosion: Shrinks white regions to remove small noise. morphologyEx () etc. I have been able to successfully do dilation and erosion, then contour detection on certain images. Theory In earlier chapters, we have seen many image smoothing techniques like Gaussian Blurring, Median Blurring etc and they were good to some extent in removing small quantities Learn effective techniques for removing noise from images using OpenCV, including methods and code examples for better image processing. Specifically poor lighting conditions or a busy backdrop can lead to very noisy backgrounds. . Hope it helps. If you use a morphological open (i. It would be better to apply morphological opening to the result to remove the noises. The top and left side is cleaned "manually". Getting a stable (no shifting in pixels) contour in a video sequence is quite hard. Mar 30, 2013 · Hello, I have a brain MRI image, that I want to segment and extract tumore area which is the area having more intensity. Jan 8, 2013 · In earlier chapters, we have seen many image smoothing techniques like Gaussian Blurring, Median Blurring etc and they were good to some extent in removing small quantities of noise. This threshold image is then used to find contours 3 days ago · Goal Concept of Canny edge detection OpenCV functions for that : cv. May 1, 2024 · I am assembling a jigsaw puzzle with opencv in python, and making good progress. In the second case, Otsu's thresholding is applied directly. We consider salt-and-pepper noise, for which a certain amount of the pixels in the image are either black or white (black or white dots). Lastly, apply closing (dilation then erosion) on the image to close all the small holes inside the words. Dilation: Expands remaining white regions to fill gaps in object contours. Jan 8, 2013 · Prev Tutorial: Anisotropic image segmentation by a gradient structure tensor Goal In this tutorial you will learn: how to remove periodic noise in the Fourier domain Theory Note The explanation is based on the book [90]. Here is the link. Learn how Gaussian Blur, Bilateral Filtering, Non-local Means Denoising, and Mean Filtering can improve your computer vision projects. dilate(dst, Mar 18, 2020 · Use "close" morphological operation to close small gaps. between those lines, there is some noise that I would like to remove. Jan 8, 2013 · 2D Convolution ( Image Filtering ) As in one-dimensional signals, images also can be filtered with various low-pass filters (LPF), high-pass filters (HPF), etc. imread('small_contour. Periodic noise produces spikes in the Fourier domain that can often be detected by visual analysis. findContours(threshold,cv2. It needs two inputs, one is our original image, second Feb 11, 2022 · Learn how to remove nearly all of the noise from your photos with just 14 lines of Pythonand it blows Adobe Lightroom out of the water. Firstly, I’m going to share which algorithm we’re going to use for noise reduction. If you look at the difference between this one and the other edge image, you can see the extra edges that are shadows that I am trying to remove (on the top and right hand side of the part) Feb 16, 2019 · I tried to use morphological thinning and the output has some noise. Nov 18, 2021 · 1 I am doing a document reader that parse all text inside it to a google spreadsheet, this script is supposed to save time in my work, the problem is that the binary image has a lot of noise (really small points around text) that confuses pytesseract. You will see different functions like cv. Clean Up the Foreground Mask The raw foreground mask may have small white "noise" blobs (e. I'm using OpenCV in C++ , and Codeblocks IDE. Dec 11, 2019 · #!/usr/bin/python37 #OpenCV 4. This article will guide you through the process of using morphological operations in OpenCV to effectively detect and remove small holes and noise from your images, leading to cleaner data and more reliable results. We effectively remove the noise by filling in the contour with cv2. Noise in images can arise from various sources such as sensor limitations, transmission errors, or environmental factors. The Noised image and Denoised image after applying the reduction are: Denoising of an image refers to the process of reconstruction of a signal from noisy images. Why Use Morphological Transformations? They are commonly used in: Noise removal Object detection and segmentation Edge and contour enhancement Bridging gaps in object Sep 19, 2023 · It is particularly useful when we want to remove noise or small objects from binary images while preserving the shape and size of larger objects. The cv2. We would like to show you a description here but the site won’t allow us. In this blog, we’ll explore how to achieve this using **OpenCV** (a powerful computer vision library) and **Python**, with step-by-step explanations, code examples, and practical tips. fastNlMeansDenoising (), cv2. However, poor thresholding— the process that converts Feb 5, 2021 · The edges we actually want - (I can filter out the small noise edges). I wanted to eliminate those small objects, so i used openCV's cvFindContours() method to detect contours in Binary image. You will get a black window during first few frames. For algorithms like SURF (Speeded Up Robust Features), binary masks play a critical role in isolating regions of interest and improving keypoint detection accuracy. Noise Reduction Since edge detection is susceptible to noise in the image, first step is to remove the noise in Sep 29, 2022 · The images above are tiles taken from a scanned painting. I have the following binary image as input: The image is the result of this code: dilation = cv2. I am using open cv to do this job it is working fine but the problem is I need to set different lower threshold to Nov 17, 2020 · Also, cv2. Remove text contours. filter2D () to convolve a kernel with an image. dilate (), cv. Nov 14, 2025 · We will use Python and OpenCV, a popular computer vision library, to implement these techniques step-by-step. I was able to create a mask using OpenCV but t For images like these which are very binary, I would suggest OpenCV's morphological transformations. If so the code below allows you to set the contours of a rectangle manually by clicking mouse on the 4 corners and immediately apply transform. Learn effective techniques for removing noise from images using OpenCV, including methods and code examples for better image processing. As the color of noises is a Feb 3, 2020 · i have a problem with my python code. It removes noise while preserving details and displays original and denoised images side by side using Matplotlib. However, this won't get of the object on the right. Some pieces here: I applied some morphological operations, that helps smooth the contours, but this is far from perfect. CHAIN_APPROX_NONE) for cnt in contours: area = cv2. Here is the code: Feb 20, 2017 · I have a Canny edge detected image of a ball (see link below) which contains a lot of noisy edges. I use erode () function, dilate () function, and fastNlMeansDenoising () function to remove small pattern noises. This transformation is probably what you'd want to do to remove the noise, although it will slightly change the shape of your letters: This is called "opening" and it erodes white space (completely erasing small little flecks like your noise Aug 28, 2018 · I have process an image for OCR, I encountered a problem where the processed image has too much noise. This section focuses its attention on reducing noise from digital images and videos. You would also need to get optimum value for noisy components threshold value. Plus, the small green regions look similar. By the end, you will have a clear understanding of how to apply erosion and dilation to clean up noisy images. Why Use Morphological Transformations? They are commonly used in: Noise removal Object detection and segmentation Edge and contour enhancement Bridging gaps in object May 12, 2021 · My project requires choosing the right parameters for cv2. Thus, I proposed a method that is to detect that specific color of noises and remove the similar color of those noises. I'll let you look at the documentation but you need the second element of this tuple, which is the filled in image. How could i remove this noise? the code i am using to binarize the image is : May 28, 2020 · Then blur the image to reduce the noise in the background. Excellent to remove "salt and pepper noise" - pixels that are 0 or 255, instead of the expected value. And then, I’m going to share how many parameters it has and what each one means. It is successful but not perfect for all my sample images. Jan 6, 2022 · I'm trying to de-noise an image which looks like this: How can the white noisy pixels be removed? Initially I thought a median filter should suffice, but it doesn't look like it. HPF filters help in finding edges in images. From here we find contours on the mask and "fill in" the detected horizontal contours with white to effectively remove the lines Repair image. This operation is useful in many applications. It is here on colab. 4 days ago · OpenCV, a popular computer vision library, provides robust tools for color segmentation and contour detection. Can anyone help me or direct me on how I can resolve this? The uploaded image is a binary image. Oct 2, 2017 · 1) Apply the range on depth data. However, I am able to quite correctly detect the line in grayscale image - see the red line in image. We will see different functions like : cv. Jan 19, 2025 · The original image displays considerable amount of salt-and-pepper noise hindering fine details like puppy's fur and facial expressions. I need help to get rid of the background noise without damaging the text. Oct 20, 2021 · Learn to use Python to denoise images and get better OCR accuracy. Find contours and filter using contour area to remove small particles. RETR_TREE,cv2. Still, I am getting some noise of the floor (refer output image). Jul 28, 2019 · I am processing images for tesseract's ocr. Denoising is done to remove unwanted noise from image to analyze it in better form. oaf zqh mobfey kessh grrxj abglnnty dsd elgh ungbni muaephd kjqyhz blyx osjz wspinah nuwe