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Questions tagged [template-matching]

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1answer
64 views

GPS Coarse Acquisition PRN Codes

Are the actual 1023 bit sequences for each of the 32 GPS satellites available to consumers? I found the IS GPS 200 but it doesn't list the entire sequences. Are verified sequences available for ...
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2answers
110 views

GPS CA Signal Acquisition

The coarse acquisition C/A GPS signal has a symbol rate or chip rate of 1.023 Mcps with code period of 1 ms. The code bandwidth is +/-1.023MHz (to 1st sinc nulls). I'd like to record this signal using ...
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1answer
449 views

Scale invariant template matching

For my application I am looking for a free, fast and scale-invariant template matching algorithm. The templates can only be scaled within the scene (no skew or rotation) and the scale is unknown. ...
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0answers
83 views

Resolving periodic components from time-series data

From the FFT, I know that my time-series data contains a component with some periodicity at 5 Hz. Harmonics are also present because the component is both nonsinusoidal and has variable timing (i.e., ...
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0answers
27 views

Issue in template matching code

code is supposed to take the input image, extract the objects, then overlap circle masks of decreasing radius (r=64,.....1) on each object. A histogram of the no. of white pixels that coincide with ...
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0answers
57 views

Approach for determining which cells of a pill box are empty using opencv+python

I am trying to use opencv and python to determine which cells of a pillbox has pills in it (see picture 1). My original approach was: Detect edges using canny Draw lines using hough transform find ...
1
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1answer
30 views

How to extract white objects in an image(attached)? The program should then display each N as a separate figure. [closed]

The program should take the given image as input and the end result should be each white object in a separate figure window.
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0answers
117 views

Pattern recognition

I am new to the world of computer vision, so please excuse my basic questions. I have two patterns: one consisting of a single circle of radius $r$, and one made of several circles, still of radius $...
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0answers
112 views

Any other method similar to template matching?

I am trying to identify the basketball courts in my area, I've tried multiple methods/tutorials from the OpenCV website. E.g. Feature Matching + Homograph, Brute-Force Matching, FLANN Based Matcher, ...
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1answer
197 views

Affine Transformation for matching 2D point sets

I have two sets of 18 corresponding 2D points. These coordinates represent the main joint points of a human body, describing the "human pose". I want to decide if these two poses are similar/have the ...
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0answers
83 views

Approach to identify someone knocking on a door - preferably not using a neural network

Say I wanted to identify someone knocking at my door using a microphone. I have (or at least I can make) some pretty good examples of what the signal looks like, but of course it will vary from person ...
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0answers
61 views

Template matching based on orientation

I'm trying to quantify how similar is a template to each part of an image solely based on their orientation to use it as a feature for another model. The template is just a cropped portion of the ...
1
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1answer
307 views

Difference between Generalized Hough Transform and Cross-correlation Feature Matching

I've been taking the Udacity Computer Vision Course, and one thing that has confused me so far is how the Generalized Hough Transform is any different from feature matching on an edge image using ...
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0answers
38 views

Suggestions for inhomogeneous particle segmentation

I need to detect multiple particles of different colors in an image (see example image). In case of very homogeneous particle coating distributions, i.e. all particles look very similar, I can achieve ...
0
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1answer
126 views

Matching guitar signal with tablature, near real-time algorithms?

I'm looking for candidate algorithms that might work for a use-case comparable to Rocksmith's analysis system. To compare a clean electric guitar signal with a tablature reference. A higher latency ...
1
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2answers
458 views

Detecting which digital number an image represents

I photograph the dashboard of my car every day to register the mileage for work. I use OpenCv to detect the region of the digital displayed mileage, crop to the numbers and match them. The method I ...
2
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1answer
105 views

Feature matching of images without corners

I am trying to stitch aerial images using feature-based registration. Most image pairs are matched well, such as this: Others are not matched due to lack of common features: As you can see, the ...
1
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1answer
150 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
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1answer
329 views

Are there any template matching / optical flow algorithms for large image displacement?

I had some success with feature-based methods for image registration, but these methods are sometimes unsuitable (e.g. images containing repetitive patterns, very low contrast, low texture, no edges/...
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2answers
1k views

Find reappearing pattern in the signal

I am working with a signal that describes energy consumption in some house as a function of time and I am trying to find time intervals that correspond to some particular type of dish washer. What do ...
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0answers
861 views

Why correlation coefficient template matching perfoms better than cross-correlation and square-differences method

I am using this template in OpenCv's match template function by converting all images to grayscale. Here are my result using sum of square differences,cross correlation and correlation coefficient....
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1answer
1k views

Baseline correlation for template matching

In normal cross-correlation or convolution between a signal and a template(say a small portion of the signal) the template is moved along length of the signal without changing the amplitude offset of ...
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0answers
1k views

Why Normalized Cross Correlation Score of different templates is high?

I am using OpenCv's built in template matching function to search for an object in image. I am using Normalized Cross Correlation Method.The function is returning a value which I think indication of ...
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1answer
69 views

Avoid saturated pixels in cross-correlation computation

I am doing template maching using Normalized Cross-Correlation for measuring similarity between template and image. However, some images from my dataset contain saturated pixels (overshoot) which ...
2
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2answers
2k 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. ...
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2answers
2k views

fast 2D cross correlation algorithm

I want to match a small template to a larger image, that the distance between the template and the subimage with the same size of the template is minimized. It can be solved directly or by applying 2D ...
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1answer
1k views

Ambiguous results of phase correlation in pattern recognition

We are using phase correlation to find pattern on image and what we get is 15% of results is spurious. Ours pattern has 32x32 pixels and image for research has 32x512 pixels. So we put Pattern to ...
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2answers
3k views

Using DTW on the MFCC's to match a spoken word to a template

I am trying to code a simple algorithm in MATLAB that would be used to detect a single word. The goal would be to have a user record the word one time to act as a template, then make the user repeat ...
2
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1answer
697 views

how could correlation-based image patches matching works?

In general, correlation-based image matching can be referred to as $$c(I_1,I_2) = \sum_{x \in patch} f(I_1(x), I_2(x))$$ , I do think normalized cross-correlation like $$ncc(I_1, I_2) = \sum_{x \in ...
2
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1answer
2k views

Questions about log polar transform

I read various papers about the log polar transform and its application on template matching with images and have some questions: In "Image Registration Using Log Polar Transform and Phase ...
6
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1answer
204 views

How to Tell How Likely a Signal Is Present in Another One (Variance Unknown)?

I know this is probably a simple question, but I haven't been able to find a satisfactory answer anywhere... Say you have a time series signal of finite length N. Call it $y[n]$. It looks like a ...
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0answers
930 views

How to recognize a zebra crossing from top view using OpenCV?

How to recognize a zebra crossing from top view using OpenCV? It is not a straight zebra crossing - it has some twists and turns. I have some ideas: parallel line detection, but the available ...
9
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4answers
15k views

Scale and Rotation invariant Template Matching

I'm looking for a method for scale and rotation invariant Template matching. I already tried some, but they didn't work so good for my examples or took for ever to execute . SIFT and SURF Feature ...
10
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1answer
268 views

Advise on detecting anatomical landmarks in a CT reconstructed volume

I'm trying to automatically detect some medical defined anatomical landmarks in a CT reconstructed volume. Medical doctors use these landmarks to measure some patient specific parameters. I have ...
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2answers
998 views

Necessary image processing operations before template matching

Well, this may show I didn't take image processing class. I have this template to match an object in images. But real object in images, for example, does not look like that but the second image. What ...