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3
votes
0answers
60 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 ...
0
votes
0answers
9 views

Computer vision - What is the difference between appearance based and feature based in object recognition?

As English is not my first language, I have a little trouble in understanding these terms. I hope someone can explain this to me (if possible, in a simple to understand way). Plus, is there any other ...
1
vote
1answer
52 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
vote
1answer
47 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 ...
0
votes
0answers
5 views

Using multiple input modalities in Computer vision

This might be a rather broad question, but I hope it will result in a couple of insights or even recipes people have used for the following problem: Suppose you have ...
0
votes
0answers
30 views

Object detection, counting the number of leaves of a plant over time

I don't have much knowledge in image processing, and I have several images of a plant from above, one image per day say, and I need to count the number of leaves at each day; certain leaves may grow, ...
-1
votes
1answer
22 views

How does the PASCAL VOC challenge evaluate the task of object detection?

I fail to understand the evaluation parameters like true positive, false positive and false negative in detection and classification tasks. can anyone help me to figure out what does each of these ...
0
votes
0answers
8 views

Training an object detector using “object present/absent” labels on image

I want to know the generic name for this technique of object detection: You're given a set of images labeled as "containing a cat" or "not containing a cat", and with this information you train a ...
0
votes
1answer
541 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 ...
0
votes
0answers
17 views

Doubt about the LFW‏ database

I post below a part of the mail I wrote to the creators of the database LFW: i am currently working on a face recognizer which has given me very good results in small tests performed, now i would ...
0
votes
1answer
66 views

Object detection using several images

how do people combine different information (e.g., RGB and depth image or RGB and thermal image) to make their object detection algorithms better? If the single modality images A and B are perfectly ...
0
votes
0answers
65 views

ImageJ Object Detection within AVI Stack

I am working on a project in which I am attempting to analyze a fish within a petri dish using ImageJ and an AVI clip of the fish under a microscope. My first hurdle is to locate the fish within the ...
0
votes
0answers
27 views

Effects of simplifying normalized cross correlation equation

The normalized cross-correlation equation for images looks like this (from here): \begin{equation} \sigma(u, v)=\frac{\sum_{x,y}(f(x, y)-\bar{f}_{u,v})(t(x-u, y-v) - \bar{t})}{\sqrt{\sum_{x,y}(f(x, ...
0
votes
0answers
45 views

Object detection algorithm

I need detect object in series of pictures. This object has something like nonsymetric relief structure with some irregularities. In this conditions. Light conditions can change from almost dark to ...
4
votes
1answer
42 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 ...
0
votes
0answers
22 views

How to use ' hard examples ' in the experiment of HOG?

I have some doubt about the use of 'hard examples'. In my experiment, I write HOG extract procedure in Matlab, and do the classification using libsvm. The train set is INRIA person dataset, involving ...
1
vote
1answer
111 views

How to use ImageNet Database in Matlab [closed]

How to use ImageNet Database in Matlab for object classification or recognition? I didn't find any tutorial which could practically tell me how to train images on ImageNet database and classify the ...
0
votes
0answers
22 views

Motion vectors and motion estimation

I want to compare 2 or more frames in video and need to extract redundant objects from that frames.I'm going to use block matching algorithm for this.But I'm not clear about what are motion ...
2
votes
1answer
155 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.
0
votes
0answers
11 views

Good features/attributes for objects of which the location is already known

Suppose the object is outlined or in a bounding box already within the image. I want to know what kind of features is good to use, invariant to illumination and rotation. Obviously I aim to describe ...
1
vote
1answer
127 views

Machine Vision Techniques for Sign Language Recognition and Interpretation(using Matlab)

I'm currently working on applying Machine Vision methods to sign language interpretation and I'm really overwhelmed with the body of knowledge out there. I've been reading up on object recognition ...
1
vote
0answers
151 views

How to implement HOG with trilinear interpolation by Matlab?

I am studying HOG. I have find the code code1 and code2 about HOG. However, both of them don't implement trilinear interpolation. I have also read some websites, including web1 and web2. I still don't ...
0
votes
0answers
61 views

How do I deal with occlusion, warping, or perspective distortion for object detection

I am using SIFT features for detecting logos in clothes. SIFT is quite powerful, as it is scale invariant, but how do I deal with the problem of occlusion and warping? More specifically, the logos in ...
1
vote
1answer
112 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 ...
0
votes
1answer
414 views

Object Detection Algorithms

I'm a complete beginner to object recognition. I need to identify and count how many of a certain type of Lego, in a picture full of different pieces of Lego, using MATLAB. The pieces of Lego I need ...
3
votes
2answers
555 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 ...
1
vote
2answers
2k 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 ...
0
votes
0answers
27 views

Need good resources to study 'Speeded up Robust features'

My current project is about Speeded up Robust features(SURF). I am a beginner in Image processing and new to this concept. Even though i found a lot of information on Internet, i am not able to find ...
2
votes
1answer
39 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 ...
0
votes
1answer
579 views

AGAST vs FAST evaluation

In ~2006 the FAST corner detector was introduced. One of it characteristics is that you have to train a decision tree from some test image in order to learn the types of corners present and relevant ...
2
votes
2answers
1k 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: ...
1
vote
1answer
60 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.?" ...
0
votes
2answers
860 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. ...
0
votes
2answers
103 views

Floating point Descriptor evaluation

I have come up with a new descriptor(floating point). I want to evaluate this descriptor against SIFT, GLOH, etc etc. I am using the K. Mikolajczyk, C. Schmid, approach. The method is described in ...
0
votes
2answers
346 views

Ship/Boat Detection

I want to do boat detection in almost real time around 2-3 frames/sec and my computation power is not very high. I want to keep the computations as low as possible. Which is the best method to do it? ...
2
votes
2answers
238 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 ...
1
vote
1answer
644 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 ...
0
votes
0answers
23 views

Pedestrian Re-identification during tracking

During the multi-camera tracking, there is a situation where one person moves from one camera's coverage area to another. In that case that person has to be re-identified(as the one from previous ...
0
votes
1answer
375 views

k-NN match for object recognition

The $\frac{d_1}{d_2}<0.6$ gives a large number of false matches and it assumes the nearest neighbour is a correct match. Anybody knows any good method to reduce number of false matches or filter ...
0
votes
1answer
239 views

Which is the best method for comparing the histogram obtained after BOW?

Euclidian distance Cosine similarity Histogram Intersection Or any other? Consider the importance of the method in case of images. Eg, Cosine Similarity matches angle of two vectors... What impact ...
0
votes
0answers
136 views

Distance-metric for SIFT descriptors matching

Will using Cosine-Similarity or Histogram Intersection as distance-metric, for matching SIFT descriptors, help to get better results? Anybody tried on that ever?
0
votes
2answers
125 views

Increasing Recall rate for SIFT

Is there a better way to increase Recall Rate when using SIFT features? I am thinking a way to replace the NN1/NN2 ratio to account for slightly distorted objects. Moving towards clustering and using ...
2
votes
2answers
591 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 ...
2
votes
1answer
552 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 ...
1
vote
1answer
3k 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 ...
1
vote
0answers
94 views

Train Pulse Recognition in Medium Voltage Networks

I just started a project in the Smart Grids area. It involves the recognition and quick extinction of earth faults in a medium voltage system. The system works automatically and pretty much gets rid ...
10
votes
2answers
13k 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 ...
2
votes
1answer
123 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 ...
1
vote
1answer
130 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
votes
2answers
99 views

obtain the position of an object in an image [closed]

I would like to compare the positions of the same object in 2 different pictures and get the difference between the positions in in terms of x and y coordinates.Suppose I have a picture with a square ...