OpenCV

Fit Quadrilateral (Tetragon) to a blob

由 笑着哭i 提交于 2020-12-01 11:48:58
问题 After applying different filtering and segmentation techniques, I end up with an image like this: I have access to some contours detection functions that return a list of points on the edge of that object, or returns a fitted polygon (with many edges though, much more than 4). I want a way to fit a quadrilateral to that shape as I know it is a front face of a shoebox that is supposed to be a quadrilateral. Due to the perspective view, the parallelity is not conserved so I have no constraints

How to extract the largest connected component using OpenCV and Python?

由 一个人想着一个人 提交于 2020-12-01 11:47:42
问题 I am using OpenCV in Python to be able to identify only the Leaf presented on the image. I already be able to segment my image, and now I am currently stuck at "how to crop the largest component after I have detected all of them. Below is the codes, please have a look. Using scipy.ndimage, I was unable to advance after find the components: def undesired_objects ( image ): components, n = ndimage.label( image ) components = skimage.morphology.remove_small_objects( components, min_size = 50 )

How to extract the largest connected component using OpenCV and Python?

由 戏子无情 提交于 2020-12-01 11:47:27
问题 I am using OpenCV in Python to be able to identify only the Leaf presented on the image. I already be able to segment my image, and now I am currently stuck at "how to crop the largest component after I have detected all of them. Below is the codes, please have a look. Using scipy.ndimage, I was unable to advance after find the components: def undesired_objects ( image ): components, n = ndimage.label( image ) components = skimage.morphology.remove_small_objects( components, min_size = 50 )

2020-11-30 03_空域图像处理 笔记

由 筅森魡賤 提交于 2020-12-01 10:28:27
目录 Filters Edge detection边缘检测 车牌识别 SVM Filters 图片噪声的处理 很多图片会有噪声 滑动平均 计算下一步时不要用10 opencv中滑动平均的实现方式，两种 blur是归一化的， boxFilter可以不用归一化 看opencv文档 卷积 核是对称是两者相同 核不同则数值 不同，但意义相似 低通滤波，高通阻断 非线性滤波器 中值滤波 中间值 值的权值会不一样，上面的情况都权值采用1. 双边滤波 滤过噪点保边滤波 很慢 线下可以用 http://docs.opencv.org/2.4/doc/tutorials/imgproc/histograms/template_matching/template_matching.html 步长很近，很多像素相同 运算量增大 可以优化 采用不同的方法 2，1---2，3受到力是向下的位移 物体的形变 遍历很耗时 可以优化 减少计算量 很多常用的方法也可以用来工程问题 Edge detection边缘检测 仅有轮廓 简单的线条 可以知道其重要的形状信息和语义信息和东西 比全部像素表达的紧凑 几何视觉 找图像的水平线 为什么会有连续 1 一种是深度不连续 一种不同物体对光的反射率不同 和 阴影等 图像中如何产生边缘 真实中更多的是渐变 一维数据 求导 在极值的位置 如何用代码实现 前后像素的差平均

Pixel-wise median of sequence of cv::Mat's

由 亡梦爱人 提交于 2020-12-01 10:06:33
问题 Note: I am NOT asking about Median Filter. I have a sequence of images let us say: std::array<cv::Mat,N> sequence; I want to blend all those images in one. This one image should satisfies: Each pixel of the new image is the median of its corresponding pixels from the sequence. In other words: Result(i,j)=median(sequence[0](i,j), sequence[1](i,j), ..., sequence[N](i,j)); Is there built-in function for doing that? What would be the fastest way? What I tried till now: To iterate over each pixel

Pixel-wise median of sequence of cv::Mat's

由 血红的双手。 提交于 2020-12-01 10:05:23
问题 Note: I am NOT asking about Median Filter. I have a sequence of images let us say: std::array<cv::Mat,N> sequence; I want to blend all those images in one. This one image should satisfies: Each pixel of the new image is the median of its corresponding pixels from the sequence. In other words: Result(i,j)=median(sequence[0](i,j), sequence[1](i,j), ..., sequence[N](i,j)); Is there built-in function for doing that? What would be the fastest way? What I tried till now: To iterate over each pixel

Scene Text Image Super-Resolution for OCR

由 孤者浪人 提交于 2020-12-01 10:04:39
问题 I am working on an OCR system. A challenge that I'm facing for recognizing the text within ROI is due to the shakiness or motion effect shot or text that is not focus due to angle positions . Please consider the following demo sample If you notice the texts (for ex. the mark as a red), in such cases the OCR system couldn't properly recognize the text. However, this scenario can also come on with no angle shot where the image is too blurry that the OCR system can't recognize or partially

Deblur image with text to be recognized by OCR

由 |▌冷眼眸甩不掉的悲伤 提交于 2020-11-30 04:42:41
问题 I have an image which is blurred: This is a part of the business card and it is one of the frames taken by the camera and without proper focus. The clear image looks like this I'm looking for the method which could give me an image of better quality, so that image could be recognized by OCR, but also should be quite fast. Image is not blurred too much (I think so) but isn't good for OCR. I tried: different kinds of HPF, Laplacian, Canny detector, combinations of morphological operations

Deblur image with text to be recognized by OCR

由 て烟熏妆下的殇ゞ 提交于 2020-11-30 04:39:30
问题 I have an image which is blurred: This is a part of the business card and it is one of the frames taken by the camera and without proper focus. The clear image looks like this I'm looking for the method which could give me an image of better quality, so that image could be recognized by OCR, but also should be quite fast. Image is not blurred too much (I think so) but isn't good for OCR. I tried: different kinds of HPF, Laplacian, Canny detector, combinations of morphological operations

Permission denied while trying to install opencv4nodejs in Ubuntu

由 跟風遠走 提交于 2020-11-29 23:54:41
问题 I was trying to install opencv4nodejs in Ubuntu-20.04 using the following command and my node version is v12.19.0 sudo npm i -g opencv4nodejs But getting those errors info install installing opencv version 3.4.6 into directory: /usr/lib/node_modules/opencv4nodejs/node_modules/opencv-build/opencv ERR! Error: Command failed: mkdir -p opencv mkdir: cannot create directory ‘opencv’: Permission denied npm ERR! code ELIFECYCLE npm ERR! errno 1 npm ERR! opencv-build@0.1.9 install: `node ./install.js
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