matlab-cvst

问题 I want to extract an elliptical region from an image (a portion of a face portion from an image) preferably in MATLAB: For example, in this image, I want to extract the region within red boundary. Can anyone help me with this ? 回答1: Cropping is easy, all you have to do is apply a proper mask. The trick is to create such a mask. Assuming A is your image, try this: %# Create an ellipse shaped mask c = fix(size(A) / 2); %# Ellipse center point (y, x) r_sq = [76, 100] .^ 2; %# Ellipse radii

问题 I'm implementing Bag Of Words in opencv by using SIFT features in order to make a classification for a specific dataset. So far, I have been apple to cluster the descriptors and generate the vocabulary. As I know, I have to train SVM ... but i have some questions which i'm really confused about them. The major problem is the concept behind the implementations, these are my questions: 1- When I extract the features and then create the vocabulary, shall I extract the features for all the

问题 I have a question about preparing the dataset of positive samples for a cascaded classifier that will be used for object detection. As positive samples, I have been given 3 sets of images: a set of colored images in full size (about 1200x600) with a white background and with the object displayed at a different angles in each image another set with the same images in grayscale and with a white background, scaled down to the detection window size (60x60) another set with the same images in

问题 I'm implementing an algorithm in OpenCV that I've designed in MATLAB. I'm writing a unit test for the SURF feature extractor in OpenCV, and I want to compare the output of MATLAB's extracted SURF features to OpenCV. This issue is, using the same parameters for both MATLAB and OpenCV extractors I'm getting different numbers of features. How is this possible? Are there different ways to implement SURF? For MATLAB (http://www.mathworks.com/help/vision/ref/detectsurffeatures.html) I'm using:

问题 I am working on video surveillance application for detecting people. Currently I am implementing HOG descriptor as the detector. However, I have a problem regarding the sliding window technique. My code is only able to detect single person. I am using also Group Rectangles from MexOpen CV to creat multiple bounding boxes. Anybody has idea how to write sliding window technique to detect multiple object? Thank you. % Reading the image im = strcat ('C:\Users\Documents\MATLAB\HOG\HOG\images\16

问题 stereoParameters takes two extrinsic parameters: RotationOfCamera2 and TranslationOfCamera2 . The problem is that the documentation is a not very detailed about what RotationOfCamera2 really means, it only says: Rotation of camera 2 relative to camera 1, specified as a 3-by-3 matrix. What is the coordinate system in this case ? A rotation matrix can be specified in any coordinate system. What does it exactly mean "the coordinate system of Camera 1" ? What are its x,y,z axes ? In other words,

问题 I was looking into Kanade Lucas Tomasi Tracker in the following link. However, I was wondering how the KLT recognizes the new people have entered scene. I know that there is replenishing of bounding boxes every 10 frames, but in case a person say entered in the 5th frame. Does it mean the for his first 5th consecutive frames the person is not captured? If I understand that this threshold can be varied, however there will still be cases when this will happen whats so ever. Can someone explain

问题 I have a sliding window on my image. If the average intensity within that window is > 210 then GLCM features are calculated on that window. If the GLCM features meet the conditions in the if statements then a rectangle should be drawn around this sliding window. I have tried this using the following code however the rectangle is not in the correct position on the image. I am unsure if I have put the code which draws the rectangle in the wrong place or if I have passed in the wrong coordinates

问题 Can I input the SURF feature obtained by the MATLAB command (detectSURFFeature) as input to the neural network to train network in order to classify/detect the object in the image?.if yes how can I cop with the multidimensional data obtained by the descriptor? I am using image set of same resolution and almost similar orientation. I am using only MATLAB. 回答1: One way to do this is to use the bag of features approach. You discretize the space of the SURF descriptors, and then you compute a

问题 I am trying to use the edge(I,'sobel') method inside a Matlab function block in Simulink(MATLAB 2013a). When I try to compile, I get the error "The function 'edge' is not supported for standalone code generation". I know there is an edge detector block , but I want to call the function with in the Matlab function block. How to get around this. 回答1: If you have Computer Vision System toolbox you can use vision.EdgeDetector System object. If you have edge detector block then you already have