sazr's profile - activity

Calculate median/mode but ignore black colour In OpenCV Python, I have masked out parts of the image, thus they are blac

Median value doesn't exist in the input list? I have something weird going on, I am attempting to find the median colour

Identify all values that are close to zero I have a numpy array and I am minusing a constant value from the array. I wan

Can you use cv::integral on a BGR Mat? I want to calculate the integral image for each channel. Do I need to split the channels and call cv::integral for each channel or can I just use the function with a 3 channel Mat?

I am currently using this utility class that helps but I'm not sure if its made to handle multichannel Mats?

http://pi-virtualworld.blogspot.com/2...

@berak thanks, is that link to an integral image correctly handling/calculating the variance and mean for a 3 channel im

@berak, thats exactly what I am doing, reimplementing my algorithm using cv::integral instead of meanStdDev() to test if

@berak In a video frame I am sliding a window over a 3 channel image and inspecting the variance under that window. If i

@berak In a video frame I am sliding a window over a 3 channel image and inspecting the variance under that window. If i

Use cv::integral() on multi-channel image? Can you use cv::integral on a BGR Mat? I want to calculate the integral image

@berak I would prefer the radius be variable if possible.

@berak please see the updated post

Get perimeter of pixels around centre pixel I am attempting to get a circle of pixels around a centre pixel. Ie, just li

Get perimeter of pixels around centre pixel I am attempting to get a circle of pixels around a centre pixel. Ie, just li

Incorrect Mode Calculation or is this salt and pepper? I have a very simple usecase, I am gridding an image and calculat

cv2.matchTemplate using non-rectangular template? I have a specific kernel and I want to search an image/matrix and find

Using gabor kernel to extract vertical lines results in black image I understand the concept of the gabor kernel and how

Understanding the effects of Gabor kernel parameters In OpenCV you can create a Gabor kernel and specify some parameters

Most accurate visual representation of Gradient Magnitude I know of a couple of ways to visually show the gradient magni

Implementing hysteresis: keep common edges between 2 images I am attempting to implement hysteresis in OpenCV. I am almo

Implementing hysteresis: keep common edges between 2 images I am attempting to implement hysteresis in OpenCV. I am almo

Implementing Hystersis: keep common edges between 2 images I am attempting to implement hysteresis in OpenCV. I am almos

Implementing Hystersis: keep common edges between 2 images I am attempting to implement hysteresis in OpenCV. I am almos

When should you use the Gabor Filter? In my learning I've come across a filter I've never heard of - the Gabor Filter. I

Do you achieve anything different if you blur each channel independently? I saw in a tutorial (cant remember where the t

Thanks I have looked into these but will look more closely. But there must be some succinct difference that an informed

Thanks I have looked into these but will look more closely. But there must be some succinct difference that an informed

Difference between FloodFill and Watershed What is the difference between OpenCV's functions floodFill() and watershed?

How does findChessboardCorners() find its corners I am attempting to detect right-angle corners in an image. I notice th

@LBerger Thanks, I should have double checked that silly mistake.

Gradient Directions: Shouldn't they range from 0-360 around a circles edge? I have the below image and I am inspecting t

Gradient Directions: Shouldn't they range from 0-360 around a circles edge? I have the below image and I am inspection t

Gradient Directions: Shouldn't they range from 0-360 around a circles edge? I have the below image and I am inspection t

Sliding a window with cavities over an image Often I need to slide a window across an image. But the window has cells I

@berak my understanding is that the png is loaded/read in as a 4 channel Mat where the 4th channel is the alpha. So I am

Watermarking Images: preserve quality, control opacity I set myself a task to create a simple OpenCV program to watermar

Drawing Gradient Directions I have created some code to visually display the average gradient direction in a cell/kernel

Visually display gradient direction I have computed the gradient magnitude and gradient direction for an image. Whats an

Visually display gradient direction I have computed the gradient magnitude and gradient direction for an image. Whats an

Generally, this is my practical application of my learning. I have learnt the theory of SSD and now I am implementing it

@berak thanks. Is there a difference between Sum of Squared Errors, Sum of Squared Differences and Mean Squared Error?

Critique my SSD implementation: is it correct? I have implemented sum of squared differences in C++. Is my code correct,

Critique my SSD implementation: is it correct? I have implemented sum of squared differences in C++. Is my code correct,

Can an Integral Image assist in producing histograms? I am reading 'OpenCV Computer Vision Application Programming Cookb

Structuring Element or Morphological Op to extract thick lines? Is the a morphological operation I can use to preserve m

Extract blobs that intersect between 2 images In OpenCV, how would I be able to extact all the blobs in image A that col

Ways to measure homogeneity between images In computer vision, what are technique/algorithms/ways to measure the homogen

Make Descriptor Matcher more discrimatory? So I've tried out my idea of using cv::BFMatcher to find matches between my c

When I attempt to get the matches between 2 key descriptor lists I get the following error:

OpenCV Error: Assertion failed (masks.size() == imageCount) in cv::DescriptorMatcher::checkMasks, file C:\build\master_winpack-build-win64-vc14\opencv\modules\features2d\src\matchers.cpp, line 617

I'm unsure what I am doing wrong? The error occurs when I call cv::BFMatcher::match() and I am not passsing any masks into the function. Any idea what the issue could be?

My code is:

std::vector<Mat> descriptors1, descriptors2;

descriptors1.push_back(Mat({
    174.483, 19.170, 12.503, 10.454, -81.230, 0.003765
}).reshape(1));

descriptors2.push_back(Mat({
    137.942, 24.953, 31.512, 27.309, -69.655, 0.000575
    }).reshape(1));
descriptors2.push_back(Mat({
    133.888, 14.031, 18.080, 13.974, -114.655, 0.00191
    }).reshape(1));
descriptors2.push_back(Mat({
    165.547, 36.802, 19.982, 34.661, 28.909, 0.000625
    }).reshape(1));
descriptors2.push_back(Mat({
    188.496, 19.021, 10.202, 8.445, -78.267, 0.005702
    }).reshape(1));
descriptors2.push_back(Mat({
    192.788, 23.360, 14.752, 20.407, 89.840, 0.001577
    }).reshape(1));
descriptors2.push_back(Mat({
    182.088, 29.258, 17.928, 28.822, 74.453, 0.000868
    }).reshape(1));
descriptors2.push_back(Mat(std::vector<double>{
    161.119, 34.396, 19.787, 22.862, 91.313, 0.001094
    }).reshape(1));
descriptors2.push_back(Mat({
    159.954, 17.733, 14.422, 11.519, -83.997, 0.002935
}).reshape(1));

cv::BFMatcher matcher(NORM_L2);
std::vector<cv::DMatch> matches;
matcher.match(descriptors1, descriptors2, matches);