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How to find each black bar's begin and end row numbers ?

![image description](/upfiles/14825621517613014.png) ... (in vertical direction) A `cv::Mat` binarized image. Thanks I tried like following, `img` is given image in this question. bitwise_not(img,...

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OpenCV in platform indepentent Gradle project (for Android and Desktop)

I'm using Gluon Mobile plugin in Eclipse to deploy a basic imaging project to Desktop and Android. Gluon Mobile creates a Gradle-based project and uses javafxports. So the idea is write once - run...

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why my rectified image is like this

Hello, i have run the stereo calib simple and it have detected 80 pairs with an error equal to 0.5 but it give me a rectified image like this : ![image description](/upfiles/14825878774084198.png)...

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OpenCV: how to set the number of octaves in SIFT?

The number of octaves is a crucial parameter in the SIFT algorithm. However, according to [SIFT documentation](http://docs.opencv.org/trunk/d5/d3c/classcv_1_1xfeatures2d_1_1SIFT.html) in OpenCV you can...

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can i use Class FaceRecognizer in java native library ?

**i'm first opencv . i used opencv with java programming language and i used java native that opencv give me in folder build . when i need create face recognition application i can not use class about...

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detecting a photograph

Hi all, I'm trying to detect a photograph, maybe up to 3 or 4 at a time. I tried using https://github.com/opencv/opencv/blob/master/samples/cpp/squares.cpp But it works a bit too good (detecting lots...

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What is the best way to detect white blood cells among the red blood cells in...

Please suggest an AI based approach. Thanks.

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Doing an adaptive thresholding to a grayscale image

I have a png image which is in grayscale 'test.png'. I need to do an adaptive thresholding to this image. I am using opencv2. image = cv2.imread('test_big.png') im = cv2.adaptiveThreshold(image, 255,...

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Demo Failure : Cannot detect face .Why?

This is the result: ![image description](/upfiles/1482629490827289.png) You can see there is no detect rectangle. Where is wrong? Thanks! Below is my codes: import numpy as np import cv2 face_cascade...

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Remove camera lag in opencv python

i am working on Odroid and running a face detection using open cv python on it. but there is too much lag in the camera. i have tried a lot of things but couldn't remove the lag. please suggest how...

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How to construct 3D representation of the scene with more than 2 images?

From a video, I have took three images: i1, i2 and i3. The steps in getting the keypoints in each of the image are: 1. I detect keypoints from i1 and track it with optical flow up until i2. 2. From i2,...

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Using Accelerated (OpenVX) with OpenCV 3.2

I noticed in later OpenCV 3.2 changelog that "NVidia corporation has donated ARM optimizations for OpenCV, the Carotene library (https://github.com/opencv/opencv/tree/master/3rdparty/carotene)." Is it...

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CIE-Lab color value of pixel

Does CIE-Lab value of pixel changes as the object containing the pixel moved in different position in image?

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How do I convert 2d matrix in to a grayscale image in java????

double[][] x=new double[800][600]; Now I want to convert x into a grayscale image. I want functionality of matlab function mat2gray. https://in.mathworks.com/help/images/ref/mat2gray.html

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Converting 2D image to a 3D model

Hello everyone, I am an absolute beginner to the realm of Computer Vision. I realize it is a rather complex subject. However I am not new programming. I discovered this page here:...

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Canny using separate functions

Hi! I've tried to write Canny edge detector using OpenCV's functions for better understanding. As I can see, my own pipeline has wrong results after non-maximum suppression. cv::GaussianBlur(input,...

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tracking movement in a

Hello Forum. Need some help (well a lot really please). I am trying to track movement in an area. Imagine a cat walking across a lawn, it starts at one side and walks across to the other, how do I...

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Object detection rectangle doesn't cover whole object

Hello everyone, I just started to work with openCV. I decided to use this library to detect an object on image and cut it from them. I trained cascade, unfortunately it doesn't work very well. I tried...

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Default color space for frames in video

Hai, I have a video which is having yuv color space and H264 codec. I am using Opencv videocapture function to read a frame. I just want to know whether the frame's mat object is in BGR or YUV color...

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Generalized hough transform implementation in Opencv?

From [this](http://stackoverflow.com/questions/25669494/generalized-hough-transform-for-shape-detection) question on stack overflow i know there is no opencv implementation for generalized hough...

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