Questions tagged [object-recognition]

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16
votes
5answers
16k views

Scale and Rotation invariant feature descriptors

Can you list some scale and rotational invariant feature descriptors for use in feature detection. The application is for the detection of cars and humans in video captured by a UAV, using a multi-...
12
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2answers
4k views

Pedestrian counting algorithm

Currently I am developing a pedestrian counter project (using OpenCV+QT on Linux). My idea about the approach is: Capture Frames Do Background Subtraction clear noises (erode, dilate) find blobs (...
11
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2answers
21k views

Apply a Gabor filter to an input image

I tried to apply a Gabor filter with a specific scale (according to my values of lambda and sigma, so it is (7x7) and for 4 orientations (0, $\frac{\pi}{4}$, $\frac{\pi}{2}$ and $\frac{3\pi}{4}$) to a ...
10
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3answers
2k views

Detecting a filled glass object

I've been sent here from this question in stackoverflow, please excuse me if the question comes too specific and it's not in the manners in here:) The task is to find a glass with specific liquid in ...
9
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1answer
2k views

Good features / algorithms for recognizing car-models in images

I have a question concerning object recognition, especially recognizing car-models! I am at the beginning of a work about identifying the same car-model in different images. At the moment I think one ...
9
votes
1answer
346 views

Vehicle segmentation and tracking

I've been working on a project for some time, to detect and track vehicles in video captured from UAV's, currently I am using an SVM trained on bag-of-feature representations of local features ...
9
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1answer
805 views

Removing Noise from Dental Radiography

I'm working on a project of applying Active Shape Model to locate tooth in dental radiograph. For those familiar with the technique, I'm currently trying to sample along normal vectors for each ...
8
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3answers
17k views

Object detection versus object recognition

I have a slight confusion differentiating between object recognition and object detection. Some people say object detection is a sub-topic of object recognition? Can someone clarify the the difference ...
8
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3answers
7k views

OpenCV detectin skin colour invariant with illumination changes

I have to capture skin colour independent of illumination. I used the following criteria(using hsv and rgb) but it ain't working: ...
8
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3answers
382 views

Gesture recognition using only simple techniques

I'm following a computer vision course and I have this exercise: write a program that, given an hand image, it can recognize if the hand is open, closed, in a punch, or holding an "ok" posture, using ...
4
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1answer
1k views

How are Object Recognition and Content-based Image Retrieval interlinked?

I need help on understanding the linkage between Object Recognition and Content-based Image Retrieval. Does OR use CBIR to find similar objects with the help of algorithms like SIFT etc or does CBIR ...
4
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2answers
4k views

Why optical flow ? why not tracking

I have a question that might be stupide ! Supposing that I try to detect object moving in a video or human action. Many works are based on optical flow computation. My question is why using OF is ...
4
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1answer
74 views

How to calculate performance of your object recognition algorithm and compare results with others?

I am working on a novel object recognition algorithm with BoF implementation for my MSc project and it performs fairly well. I am using it on Caltech101 dataset. I want to compare the results with ...
4
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1answer
1k views

Detecting peaks in a noisy 2D correlation plot

I'm doing pattern matching by means of normalized grey-scale correlation. My input image is noisy and so the peaks in the correlation plot cannot be found just by thresholding. The original ...
4
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1answer
2k views

What is a good distance measure for matching SIFT descriptors depending on the distribution of their noise?

I have read some papers about distance measures like Euclidean, Manhattan or Chi-Square for matching gradient based image descriptors like those computed from the SIFT Algorithm (128-D vectors). Most ...
4
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0answers
479 views

How to construct descriptors for irregularly shaped image patches

As hinted in this answer, Perceptual hashing is a way to ascribe comparable measures (hashes) to images (rectangular patches). The images do not need to be the same size, and can be slightly distorted,...
3
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2answers
108 views

object level sensor fusion for multiobject tracking

I want to fuse objects coming from several sensors, with different (sometimes overlapping!) fields of view. Having object lists, how can I determine whether some objects observed by different sensors ...
3
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1answer
847 views

Multi-scale in Object detection?

I want to ask about MultiScale Object Detection. For the multiscale, if we have an original image do I need to zoom-in at different scales in the image at a particular point or zoom-out at different ...
3
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2answers
1k views

Minimum size for positive samples for HOG (Histogram of Gradient) detector training

I'm going to train a HOG detector for detect objects (pedestrian head) with SVMLight library. But my question is not about implementation. I'm wondering how to collect samples. I have to use some ...
3
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2answers
184 views

Is there any fast algorithm to compute the most similar rectangular regions in two images?

I am working on a pattern recognition problem to find two most similar rectangular regions in two given images. Specifically, I have two 2D (gray) images of the same sizes $I_A$ and $I_B$. Denote an ...
3
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2answers
8k views

How to verify if two images have the same object/content?

I am truly new to computer vision field, but it is fascinating me! I have now a challenge in my hands and I am seeking for mentors/advisers to give me some follow up. My project is: From a picture of ...
3
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3answers
278 views

Detecting the Prescence of a “Tail”

I have a set of objects, which may be spherical or elongated, which may or may not have a tail like structure attached to one or two ends. The tail may be long or short. It may also have a curve to it....
3
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3answers
487 views

Low recognition rates using GMM for image classification

I want to use GMM for image classification. So, I have extracted SIFT features from each image in the corpus. Then, I apply EM algorithm to learn GMM parameters (I have coded it in matlab). I get ...
3
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1answer
2k views

Image Matching on iOS

Was recommended to migrate this question from SO. I am building an iOS app that, as a key feature, incorporates image matching. The problem is the images I need to recognize are small orienteering ...
2
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2answers
285 views

What is the ideal type of barcode for paper tickets?

I can use the following type of barcodes in my project: Code 39 Code 128 QR Code Data Matrix PDF-417 They will be printed with standard office printers and with boca printers. It should also be ...
2
votes
2answers
9k views

Rectangle detection in “real life” images

I have seen a lot of posts here and on SO and on various websites, using Matlab, OpenCV, name it, on how to detect rectangles in an image. I have done it myself too, using Matlab. My usual steps were: ...
2
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1answer
306 views

Algo Name: Detecting Elongated Shape in 2D Image by Convolution with Directed Lines

I am detecting a shape with roughly known orientation (obtained by using Hough line transform) in thresholded binary image by convolving the image with line with that orientation, and counting the ...
2
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2answers
3k views

Template matching or object recognition?

Problem: I have a photo of an object (a manufactured part like the attached photo below), using my Andoird phone camera I want to verify if the object in camera preview matches to the template or not. ...
2
votes
2answers
7k views

Head detection using HOG and SVM

I am currently trying to detect heads in a sequence of real-footage images and am using HOG feature descriptor and SVM as classifier. Currently I am using Dalal's HOG implementation code in MATLAB ...
2
votes
1answer
123 views

Pyramid Match Kernel: How to fit grid around data points?

I am planning to use Pyramid Match Kernel method for object recognition from depth images: I am going to extract a set of feature vectors $x \in \mathbb{R}^d$ for each object instance and then I want ...
2
votes
1answer
178 views

Recognition of household objects ( image processing, pattern recognition ) using wide lens?

Camera setup: We have setup some stereo cameras in a living apartment. That is, the indoor environment is monitored. With the stereo cameras, wide lens (3.5mm) are used to cover a big volume. The ...
2
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2answers
4k views

Object Recognition using bag of features using matlab [closed]

I want to write a MATLAB program for simple object recognition using bag of features. In short, I want to first extract the features from an image, create a visual library using those features, then ...
2
votes
2answers
772 views

Summed-area table vs Integral image?

I have been going through few research papers around face recognition and I came across two texture extraction algorithms : Summed-area table by Crow et al. ("Summed-area tables for texture mapping",...
2
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2answers
2k views

Training custom classifiers using trainCascadeObjectDetector

Is there any good documentation about training your own classifiers(with examples included) different from this one provided by MathWorks. Thanks in Advance
2
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1answer
104 views

Methods for searching a large face database

I have a large face database, and I want to search through it. For example, if I input a new face image, the system would return the best N similarities. I know that PCA, LDA, and Procrustes analysis ...
2
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1answer
2k views

Improving Template Matching Algorithm for OpenCV

Car detection using OpenCV I am working on a small personal project where i have to know wether an image shown is a car or not. I am using the basic OpenCV python based template matching. Positive ...
2
votes
1answer
571 views

KLT tracker implementation

I'm working on a object tracker based on KLT algorithm using matlab. Can anybody guide me how I can find the features and calculate the distance in the sequence of the frames? Thanks.
1
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3answers
179 views

Can I use standard computer vision techniques for images taken in the NIR spectral range?

I'm relatively new in Computer Vision and I need some advice with respect to the general possibilities and shortcomings of images taken in the near infrared (NIR) range. I passed a great deal of time ...
1
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1answer
69 views

How to constrain the object detection problem?

How to constrain the object detection problem? It would be tempting to ask for precision such as: "It depends, does it have to be viewpoint invariant, is there going to be viewpoint changes, etc.?" ...
1
vote
3answers
215 views

Ship detection from aerial image

I have an aerial image, like this I want to detect the outline of the ship without shadow. How can I do it? I tried threshold in both graylevel, RGB and HSV. It doesn't work perfectly.
1
vote
1answer
356 views

Object Classification using pyramid match kernel

I have been reading up on the pyramid match kernel as an alternative to using the bag-of-words model for object classification using a SVM. The bag-of-words model provides a model for transforming a ...
1
vote
1answer
235 views

Red Blood Cell Color Image Segmentation

I want to segment this Red Blood Cell Image on HSI color space.I want to try the Otsu Method but from what I read that method work only on Grayscale image.Do you have any suggestion for suitable image ...
1
vote
1answer
74 views

Video processing to detect a logo in frames

I am trying to detect a TV channel logo inside a video file, so simply given an input .mp4 video, detect if it has that logo present in all (or most) of frames or not (or maybe what percentage of ...
1
vote
1answer
410 views

How to recognize an object from a small training set of images?

Given a small training set of images (say, around 6 max) of the same object, how to measure how likely is another query image to contain the given object? The training images are "clean", i.e. only ...
1
vote
1answer
162 views

Best reference for object size estimation in an image

I'm working on a project where I need to measure the size of a 2D object on a flat surface from an image. I have total freedom to create a reference with any shape and size. The camera I am using is ...
1
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1answer
164 views

How to find a noisy line in a picture

Hi I would like to find a line in a noisy image as showed bellow. I tried gabor filter and cany edge detection, but it didn't produce anything usefull. I am looking for lines of specific orientation ...
1
vote
1answer
1k views

OpenCV Haar Classifier - best type of positive images

I'm currently collating images to try and develop a HAAR classifier using the OpenCV traincascade functionality. The objects I want to detect are small and numerous (bees), and I'm curious as to ...
1
vote
1answer
248 views

3d CT segmentation

It's my first attempt at 3D analysis. I am trying to segment a 3D CT data. My case study is very simple: trying to segment circular objects in my data. Do you have any suggestions on how to achieve ...
1
vote
1answer
281 views

Alternative to support vector machine?

I have to make comparison between 155 image feature vectors. Every feature vector has got 5 features. My image are divided in 10 classes. Unfortunately for using support vector machine i need at ...
1
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0answers
22 views

Algorithm for smoothing the output of an object detector operating on a video?

Please could you point me towards an algorithm that takes a series of object detections performed on a frame by frame basis as input and outputs a filtered series of object detections in which the ...