Is there anyway to detect a car (object) after a sobel detction in opencv?
This is my current's work as shown as the image below:
Advanced thanks for any guidelines or solutions!
Object detection task need quite a bit of effort.
First, extract relevant features from object you want to detect: histogram of oriented gradient should be fine for car detection. So, you need to get database of car images. Second, you need to learn models using machine learning algorithm. Boosting or support vector machine should do the work. You will find the implementation in opencv.
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I am working on a hand detection project. There are many good project on web to do this, but what I need is a specific hand pose detection. It needs a totally open palm and the whole palm face to outwards, like the image below:
The first hand faces to inwards, so it will not be detected, and the right one faces to outwards, it will be detected. Now I can detect hand with OpenCV. but how to tell the hand orientation?
Problem of matching with the forehand belongs to the texture classification, it's a classic pattern recognition problem. I suggest you to try one of the following methods:
Gabor filters: it is good to detect the orientation and pixel intensities (as forehand has different features), opencv has getGaborKernel function, the very important params of this function is theta (orientation) and lambd: (frequencies). To make it simple you can apply this process on a cropped zone of palm (as you have already detected it, it would be easy to crop for example the thumb, or a rectangular zone around the gravity center..etc). Then you can convolute it with a small database of images of the same zone to get the a rate of matching, or you can use the SVM classifier, where you have to train your SVM on a set of images by constructing the training matrix needed for SVM (check this question), this paper
Local Binary Patterns (LBP): it's an important feature descriptor used for texture matching, you can apply it on whole palm image or on a cropped zone or finger of image, it's easy to use in opencv, a lot of tutorials with codes are available for this method. I recommend you to read this paper talking about Invariant Texture Classification
with Local Binary Patterns. here is a good tutorial
Haralick Texture: I've read that it works perfectly when a set of features quantifies the entire image (Global Feature Descriptors). it's not implemented in opencv but easy to be implemented, check this useful tutorial
Training Models: I've already suggested a SVM classifier, to be coupled with some descriptor, that can works perfectly.
Opencv has an interesting FaceRecognizer class for face recognition, it could be an interesting idea to use it replacing the face images by the palm ones, (do resizing and rotation to get an unique pose of palm), this class has three methods can be used, one of them is Local Binary Patterns Histograms, which is recommended for texture recognition. and why not to try the other models (Eigenfaces and Fisherfaces ) , check this tutorial
well if you go for a MacGyver way you can notice that the left hand has bones sticking out in a certain direction, while the right hand has all finger lines and a few lines in the hand palms.
These lines are always sort of the same, so you could try to detect them with opencv edge detection or hough lines. Due to the dark color of the lines, you might even be able to threshold them out of it. Then gather the information from those lines, like angles, regressions, see which features you can collect and train a simple decision tree.
That was assuming you do not have enough data, if you have then you go into deeplearning, just take a basic inceptionV3 model and retrain the last dense layer to classify between two classes with a softmax, or to predict the probablity if the hand being up/down with sigmoid. Check this link, Tensorflow got your back on the training of this one, pure already ready code to execute.
Questions? Ask away
Take a look at what leap frog has done with the oculus rift. I'm not sure what they're using internally to segment hand poses, but there is another paper that produces hand poses effectively. If you have a stereo camera setup, you can use this paper's methods: https://arxiv.org/pdf/1610.07214.pdf.
The only promising solutions I've seen for mono camera train on large datasets.
use Haar-Cascade classifier,
you can get the classifier model file then use it here.
Just search for 'Haarcascade detection of Palm in Google' or use below code.
import cv2
cam=cv2.VideoCapture(0)
ccfr2=cv2.CascadeClassifier('haar-cascade-files-master/palm.xml')
while True:
retval,image=cam.read()
grey=cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)
palm=ccfr2.detectMultiScale(grey,scaleFactor=1.05,minNeighbors=3)
for x,y,w,h in palm:
image=cv2.rectangle(image,(x,y),(x+w,y+h),(256,256,256),2)
cv2.imshow("Window",image)
if cv2.waitKey(1) & 0xFF==ord('q'):
cv2.destroyAllWindows()
break
del(cam)
Best of Luck for your experience using HaarCascade.
I have a collection of face images, with 1 or sometimes 2 faces in each image. What I wanna do, is find the face in each image and then crop It.
I've tested a couple of methods, which are implemented in python using openCV, but the results weren't that good. These methods are:
1- Implementation 1
2- Implementation 2
There's one more model that I've tested, but I'm not allowed to post more than two links.
The problem is that these Haar-Feature based algorithms, are not robust to face size, and when I tried them on images which were taken close to the face, they couldn't find any faces.
Someone mentioned to try deep learning based algorithms, but I couldn't find one corresponding to what I want to do. Basically, I guess I need a pre-trained model, which can give me the coordinates of the face bounding box in the image, or better, a pre-trained model which gives out the cropped face image as output.
You don't need machine learning algorithms, Graph-Algorithms is enough. For example Snapchats face recognition algorithm works as follows:
Create a Graph with Nodes and Edges from a most common Face ("Standard Face").
Deform that Graph / Recoordinate the Nodes to the fitted pixels in the Input Image
voila you got the face recognized in the Input Image.
Easy said, but harder to code. We implemented in our university the Dijkstra Algorithm for example and I can hand you my "Graph" Class if you need it. But I wrote it in C++.
With these graph-algorithm you can crop out the faces more efficient.
I have been given an image with rgb channels. I only want to see the persons face. How would I do that? Are neural nets used for this? If so, are there existing data files from neural nets that have already done the processing?
Since your questions is tagged with OpenCV, I will assume that you are looking for a solution within this library.
The first step is to find the faces. For this, use one of the cascade object detectors that are available: either the Viola-Jones one or the LBP one.
OpenCV comes with cascades trained for face detection for each of these detectors.
Then, it depends if getting a bounding box is enough or not.
If you need something more accurate, then you can:
[coarse face] use a skin color detector inside the face bounding box to get a finer face estimate, binarize the image and finally close the face shape using morphological filtering;
[fine face contour] use something like a grabcut procedure to get a pixel-accurate contour. You can initialize the grabcut with borders of the bounding box as background and center part of the bounding box as foreground.
Not really sure what you want to do, but you can use Haar Classifier for face detection.
From then on, it should be easy to only display the face. While there are available classifiers online, you can try training your own classifier should you have the time. I have done classifiers on hand, face, eyes before and it have an impressive result.
Should you need more help on training classifier, etc, just comment here, I will try my best to assist you.
Face detection functionality is also available in the Computer Vision System Toolbox for MATLAB in the form of the vision.CascadeObjectDetector object.
Can (or maybe should) I use facial recognition software to detect non-faces? For example, let's say I'm trying to find a can of soda in a picture of a bedroom. If I use the haartraining algorithms on many pictures of cans of soda, will the facial recognition feature then find the can of soda in a picture of a bedroom?
Yes you can. Those algorithms are based on extracting features from training sets. If you pass them faces the will be good at detecting features from faces. If you pass them cans they will be good at detecting cans.
A different idea is when you specialize an algorithm on a specific object by restricting the search, but haar are not the case.
I think you are referring to face-detection not face-recognition.
In general, face detection works on discriminating appearance or textures within the face area. They also implicitly assume a mostly planar object.
You can use the same classifiers to detect other mostly-flat objects which are discriminated by appearance, for example, facial features like eyes and mouth, book covers etc.
Soda cans are cylindrical, so you may have to use multiple overlapping rotated view of each can to get it to work.
I realize this is a non-trivial task, but what's the most practical method of detecting a face, and then tracking the body associated with that face in a video with moving background?
Detecting a face is fairly simple with OpenCV's trained Haar cascade for the face. Unfortunately, OpenCV's trained Haar cascades for the human body are so inaccurate as to be effectively unusuable, so my thought was to use the face detector to determine roughly where the "person" is, and then use something like OpenTLD to dynamically "learn" what the person's body looks like and track that over frames. This should have the benefit of being able to handle a moving background, which most motion-tracking code in OpenCV currently doesn't seem to handle. The main downside is that OpenTLD is still quite new, and all the public implementations I've tested are very buggy and difficult to use.
Does this seem like a practical approach? Are there better ways?
If you are interested in human body detection/tracking rather than face detection, you should check people detection sample in the OpenCV. OpenCV contains a HoG descriptors and SVM classifier based people detector, which is actually one of the most successfull people detection algorithms available.