Questions tagged [template-matching]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0 votes
1 answer
25 views

Distance Transform & Chamfer Matching -- find actual edges

I have had good success using the Distance Transform and Chamfer Matching to locate a template in an edge image. Is there a recommended technique to then find the actual edges that match the template? ...
Andrew's user avatar
  • 101
0 votes
0 answers
36 views

Template Matching non-rectangular template in non-linear order

Question Is there an existing algorithm that does cross correlation with two images, including a weight image? In template matching, when should I prefer the sum of absolute errors vs cross ...
Jinyoung Choi's user avatar
5 votes
1 answer
284 views

Algorithm to detect tapping-events in an XYZ-signal of an accelerometer

How do I find signal-sections with a re-appearing particular shape in a noisy signal? I want to detect tap-events (user tapped a device) using the 100Hz 3-axis accelerometer data provided by the ...
ralfiii's user avatar
  • 151
1 vote
1 answer
118 views

Identify and remove repeated audio chunks

I have some audio produced by a buggy recorder, at some point it may start two recording streams, each stream captures chunks of audio and write to a file. The buffer queue is processed asynchronously,...
Bob's user avatar
  • 2,373
5 votes
6 answers
3k views

Algorithm for Scale Invariant Template Matching

I am using opencv for finding template images in a video stream. The elements I am trying to find are UI elements of android apps. Classic template matching is working quite well. But only as long as ...
stoefln's user avatar
  • 103
1 vote
3 answers
204 views

How to detect a signal while ignoring another signal which is a phase shifted version?

I have a signal coming from a sensor as shown below. This signal has high frequency noise (as can be seen from small fast wiggles) and four regions of interest where distinct spikes can be seen. The ...
user3761169's user avatar
0 votes
1 answer
859 views

Detect when signal starts oscillating

I have a signal which consists of oscillations riding on square waves as shown in the image below. I wish to detect the time at which oscillatory events occur (as shown by the red star). Each square ...
James Rowland's user avatar
0 votes
0 answers
82 views

Finding events in a signal given its number

I have a signal with14 events of 2 types: type 1: the 4th and the 10th peak type 2: the rest of the peaks I would like a function in which the input is the number of events of each type and the ...
danilinares's user avatar
2 votes
1 answer
3k 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 ...
random_dsp_guy's user avatar
2 votes
2 answers
987 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 ...
random_dsp_guy's user avatar
1 vote
1 answer
2k 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. ...
hasdrubal's user avatar
  • 111
1 vote
1 answer
39 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.
Ananya Panda's user avatar
1 vote
0 answers
197 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 $...
Frusciante89's user avatar
1 vote
1 answer
641 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 ...
tuuttuut's user avatar
  • 113
2 votes
1 answer
1k 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 ...
Peter Moran's user avatar
1 vote
0 answers
87 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 ...
Finn Poppinga's user avatar
0 votes
1 answer
182 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 ...
Beanow's user avatar
  • 11
1 vote
2 answers
829 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 ...
Mike de Klerk's user avatar
2 votes
1 answer
182 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 ...
Libor's user avatar
  • 4,255
1 vote
1 answer
196 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 ...
user2173836's user avatar
1 vote
1 answer
534 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/...
Libor's user avatar
  • 4,255
2 votes
2 answers
3k 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 ...
Vladimir's user avatar
  • 171
1 vote
0 answers
1k 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....
Muhammet Ali Asan's user avatar
1 vote
1 answer
2k 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 ...
Naveen's user avatar
  • 418
0 votes
0 answers
2k 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 ...
Muhammet Ali Asan's user avatar
0 votes
1 answer
132 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 ...
Libor's user avatar
  • 4,255
2 votes
2 answers
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. ...
Asha's user avatar
  • 121
1 vote
2 answers
3k 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 ...
ChuNan's user avatar
  • 190
6 votes
1 answer
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 ...
Dawid D's user avatar
  • 163
7 votes
2 answers
4k 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 ...
user5907's user avatar
3 votes
1 answer
1k 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 ...
avocado's user avatar
  • 877
2 votes
1 answer
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 ...
Chad Moklav's user avatar
8 votes
1 answer
262 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 ...
bill_e's user avatar
  • 195
2 votes
0 answers
1k 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 ...
user1929880's user avatar
14 votes
4 answers
24k 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 ...
Arndt Bieberstein's user avatar
10 votes
1 answer
314 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 ...
Federico's user avatar
  • 337
13 votes
2 answers
2k 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 ...
Tae-Sung Shin's user avatar