This tag covers signal processing where input is an image, such as a photograph or video frame and the output could be an improved or altered image, parameters related to the image or information about features within the image.
0
votes
1answer
34 views
Image processing functions for quality control
I have to use image processing for quality control of a cookie manufacturer (as a part of my project). The program must be able to detect oversized, undersized, distorted cookies, cookies having ...
-3
votes
0answers
30 views
Want to Get Pixel Values from Mouse Pointer Location from the Mouse Click Event [closed]
I am trying to display dicom image over the picture box it works fine,
but Now When I click the mouse on the dicom image from that mouse pointer click event is fire,
I got x and y coordinate of that ...
2
votes
0answers
59 views
Determine line rate and frame rate of a system
I have as a homework to determine the line rate and frame rate for a system described above:
...
0
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0answers
10 views
Draw CAD SR Marker over Dicom Image
I refer various site for CADSR Marker to draw marker notation over MG Modality. on some sites i found the bunch of marker means more than one marker are draw at a point(Graphics Type Tag)
...
0
votes
0answers
18 views
how to display these polyline co-ordinate over dicom image
I get an Polyline co-ordinate from CADSR file(from Graphics Type Tag) I want to draw marker w.r.to that polyline co-ordinate on dicom file.
Polyline co-ordinate as ...
1
vote
3answers
54 views
How to tell the effect of kernel of an image filter (matrix) on an image?
I am going through an old exam paper and trying to understand this question where they ask us to tell them what effect the following image filter would have if its convolved with an image:
...
-3
votes
0answers
46 views
code is supposed to draw epipolar line on graph: but not drawing any line, only showing points [closed]
i am trying to draw epipolar lines for certain point, from left image to right image plane. my code is supposed to draw epipolar lines based on fundamental matrix. but it is not drawing any line, i ...
5
votes
1answer
80 views
Phase Correlation - Poor Performance on Noisy/Blurred Images?
I have successfully tested 1D phase correlation algorithm to determine vertical shift between two synthetic images.
When I moved to real images, however, it is not able to detect translation at all ...
1
vote
0answers
42 views
Digital Image Processing
I am trying to extract only urban aeas from satellite imagery Using Matlab. I have applied some edge detectors like canny and also used morphological functions and I am able to extract all the ...
1
vote
0answers
32 views
Automatic MRI Segmenation of Heart over Dicom Image [duplicate]
I have a bunch of short axis MRI images of the heart(Left Ventricle), in dicom format.
I want to do a Automatic segmentation of various structures in these images.
Does anyone know of a program I ...
1
vote
1answer
36 views
How can detect the Left Ventricle (LV) Cavity into the MR dicom file?
This is MR Modality Link
MR Modality
In this file where i find the LV Cavity in above link file. Also how to draw Tumor Marker from over it
3
votes
3answers
75 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 ...
0
votes
0answers
42 views
How to implement Hilbert-Huang transform in finding image splicing?
I have some programming experiences but am really new to these kind of algorithms. I can find a few source code about implementing HHT, and most of them are written with matlab. What I am trying to ...
-1
votes
1answer
29 views
Multithresholding- OTSU method
I'm trying to segment a specific part in a gray-scale image and I want to achieve this by applying the OSTU algorithm, but after using this function:
...
0
votes
1answer
65 views
Computation time 1) fft, 2) 2-d convolution, 3) two 1-d convolution
Consider filtering square n*n images by square,separable m*m filters. What are the general computation time for the following approaches 1) FFT 2) by 2-D convolution 3) by two 1-D convolutions. ...
1
vote
2answers
76 views
Decompose video frames into slices
I am working on a video motion feature implementation. I am implementing a work in a research paper. What I want to implement is this:
The frames contained in a video clip can be thought of as a ...
1
vote
2answers
83 views
Radon Transform reducing the number of parallel beams (MATLAB)
I am trying to understand different filters' and other things' effects on Radon Transform by using MATLAB. First I upload an image, then take its Radon transform with radon function and then ...
8
votes
1answer
86 views
Automatic Cropping of Arbitrary Shapes
I have an arbitrary shape defined by a binary mask (gray = shape, black = background).
I would like to find a largest possible rectangle containing only gray pixels (such rectangle is pictured in ...
1
vote
1answer
46 views
Which approach is better for decomposing a image into high frequency and low frequency component?
Which approach is better or there is mathematical justification for using Bilater filter and Fourier Transform to decompose a image into High Frequency and Low Frequency Component.
Both Bilateral ...
3
votes
1answer
47 views
Affine transformation on a pixel grid
I'm implementing affine transformations on images. Currently I'm doing rotation, but general transformation will be added later.
Basically each pixel is mapped by the rotation matrix R:
...
2
votes
1answer
85 views
Object-Recognition using SIFT: Switching the order of images creates two different results
I've developed a large test-system which can use every interest-point-detector and -descriptor. I use it for evaluation of the given algorithms with the standford-image-collection of cd-covers. This ...
0
votes
1answer
64 views
How do I find Gray Level Variance of the Image?
Tell me how do I find out gray level variance of the image? Is it any different from the normal variance of the image.
3
votes
3answers
190 views
Local Image Features Extraction for Road Signs
I'm working on a project to detect a road sign from the Image. Consider the sample image below:
I'm using a heuristic search to detect the road sign within an image. Basically, I want some weak ...
0
votes
2answers
36 views
maximum contrast using linear gery-level trasformation
this was a question i found online.
given an image with values between [0,1].
how can I get the maximum contrast using linear gray-level transformation?
something like I(x,y)=A*I(x,y)+B , where I is ...
0
votes
0answers
23 views
Image intensity
Let us consider three gray scale intensities 252(11111100),122(01111010),250(01111010).
If i want to group them in to two groups,
I have to see directly intensities(252&250 are grouped together)
...
0
votes
1answer
154 views
OFDM transmitter data rate
i am simulating OFDM transmitter in matlab....As u all know OFDM consists of different sub systems such as FEC coding, Bit interlever , Modulator , IFFT block and Adding cyclic prefix.... i have ...
0
votes
1answer
140 views
1
vote
1answer
105 views
Convolution in image processing ?
I got the concept of Convolution in signal processing from a video lecture that it is method to get the area overlapped between two signals when one signal is flipped over and traversed over another ...
3
votes
1answer
150 views
How to extract high freqency and low frequency component using Bilateral filter?
What does High frequency and low frequency component signify in an image.
How to separate out the high frequency as well as low frequency component of an image using Bilateral filter.
6
votes
3answers
94 views
Determining Toy Helicopter Orientation From Image
I am working on developing an autonomous control system for toy IR remote-controlled helicopters (like the Syma s107, for example) using a webcam and an Arduino with some IR LEDs. I am using C++ with ...
7
votes
1answer
139 views
White Road Sign Detection [duplicate]
Possible Duplicate:
How to extract traffic signs from a photograph?
I am working on a project which involves detecting north american speed signs (black/white) using a 720p HD camera. My ...
2
votes
1answer
41 views
Combining Distance Maps
I have two distance maps that describe distances from blue segment and the red segment. I need to compute a single weight map that describes transition from blue segment to the red segment. The weight ...
3
votes
0answers
82 views
Qualitative Evaluation of Interest-Point-Detectors and Descriptors in Computer Vision
I'm writing on a qualitative evaluation study of interest-point-detectors and descriptors. I've read all Mikolajczyk papers as well as most of the surves from Datta et al. etc. Now I'm implementing an ...
5
votes
2answers
159 views
Understanding the parameters for a Bilateral Filter
Allow me to show you a snip from Szeliski's Computer Vision book on bilateral filter. I don't know how to interpret these kernel definitions:
In the actual summation what values do the $k$ and $l$ ...
3
votes
0answers
41 views
Perceptually Corresponding Error Map
Is there any better measurement of error between two images than just taking pixel value differences?
The problem I am tackling is stitching images containing "sensitive" objects, such as moving ...
3
votes
0answers
58 views
Gradient Domain Reconstruction - Scaling Problem
I am implementing reconstruction of image from gradient domain. This requires solving the following partial differential equation (a Poisson equation) on a 2D grid:
$$\nabla^{2}I=\mathbb{div} G$$
...
0
votes
0answers
25 views
A few queries about 'Joint Image and Word Sense Discrimination For image Retrieval'
I had a query regarding the model used in the paper here. What would be the problem in going for a hierarchical clustering approach?
What they did:
We solve problem (ii) by cross-validation, trying ...
3
votes
1answer
139 views
Signal Processing using Fourier Transform
So I'm trying to understand how MRI machines work. I understand all the concepts of it, the parts, what they do, how the machine works, etc. The part I'm having trouble with is the fourier transform ...
5
votes
2answers
106 views
Commonly used test image sets
In the image analysis literature there are a variety of ways people show the usefulness of their method. For example, performance on an ideal signal corrupted by noise, an artificial signal ...
3
votes
1answer
150 views
KNN method for different values of K on a handwritten digit data set
We're supposed to use KNN (K Nearest Neighbor) method for different values of K to classify a handwritten digit data set.
The problem is, this is the first time I want to do a project like that in ...
5
votes
1answer
72 views
Increasing image resolution
I know of some oscilloscopes (DSA8300) that repeatedly sample at a few hundred kS/s to reconstruct a few GHz signal. I was wondering if this could be extended to 2D signals (photographs). Can I take a ...
4
votes
1answer
110 views
Removing parallel edges from binary image
This is a binary image. I want to remove the portion in the red region, and keep the one in the green region.
The red region has the property of double parallel edges, whereas green does not. If ...
3
votes
1answer
118 views
Relation between histogram equalization and 'Auto Levels'
I need to enhance an image using only global linear adjustment of intensity, i.e.:
$$I'=aI+b,\qquad a,b\in \mathbb{R}$$
where $I$ and $I'$ are input and output (enhanced) image.
I already know how ...
2
votes
1answer
357 views
Measuring the contrast of an image
For a project, I want to measure the contrast of a global image.
I want to compare different images to get the image with the best contrast.
I know about the Weber contrast, but I need a normalized ...
2
votes
1answer
102 views
What is the role of Freqency in Digital Images [duplicate]
Possible Duplicate:
What does frequency domain denote in case of images?
If we look deeply into Digital Images they are purely generated by the pixels distributed in rows and coloumn and ...
2
votes
1answer
62 views
Contrast Enhancement for subjects under Flash
For a machine vision application, we take short duration (50uSec) monochrome pictures with IR flash. The images we get are decent quality however the light color subjects (light blue, light green, ...
0
votes
2answers
172 views
How does Fourier Transform manipulates image technically?
I need a little bit more explanation on technical details regarding Fourier Transform in Image Processing, mainly on the frequency aspect.
I see that we can use Discrete Fourier Transform to change ...
0
votes
0answers
64 views
how to align vector and raster images?
how to align vector and raster images?
For example vector images will be static/rigid and raster image will be morphable. For example I manually do initial guess and algorithm must converge to optimal ...
4
votes
1answer
164 views
Online boosting (training on the fly) for face detection
I want to implement an on-the-fly training process for face detection. I'm not sure but it seems it's called online boosting.
Š’efore, I have used OpenCV face detection with my own cascades, but I'm ...
5
votes
2answers
158 views
Finding similar pictures in a database
I have large database of pictures, about a few million.
I need an algorithm to find pictures which are similar to those in the database, up to a scale factor or a crop and shift (I have only these ...
