Questions tagged [image-analysis]
Image Analysis is the extraction of meaningful information from images; mainly from digital images by means of digital image processing techniques.
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Converting cutoff_frequency_ratio to Cycles/Pixel in Butterworth Filtering with skimage
I am working on my thesis where I'm employing Butterworth filtering on images using the function butterworth from scikit-image's skimage.filters module. The code/formula I'm referring to is available ...
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Detect Longest Vertical Lines (Edges) in an Image
I have a task in image processing, which need to detect vertical lines from matrix. For example, there is a pair of white and black vertical lines segmenting the picture below. I need to find it. So I ...
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Segment Image of Small Elements on Neutral Background
I have a 8 bit gray level image where if the value = 122 it means no information, value = 0 means highly negative, and value = 255 means highly positive.
I want to connect as many positive information ...
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Distinguishing between intensity image plots
I have a series of intensity images generated by varying different scatterer geometries. An example of variation observed by varying the aspect ratio of these geometries is shown below in the three ...
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Interpreting results of Sobel Edge Detection
I am implementing A No-Reference Perceptual Blur Metric paper.
Somewhere in the prep steps they mention the use of vertical Sobel filter for finding vertical edges.
The algorithm is summarized in Fig....
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Slicing an Image into Tiles According to Content
Given an image that contains an NxM grid of icons with text below them, somewhat like this:
I'm wondering how to split it up into the individual icons with text. Some wrinkles:
The image won't ...
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How to find sharpness of an image?
I have a rather difficult image processing image. I would like to rank order a set of images I have by their sharpness. The issue is the images themselves are not of the exact same thing. Usual ...
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Blended use of DoH and LoG for blob detection, is there any paper I can cite for this?
tl;dr: For blob detection, I determine locally maximal DoH responses in image regions which correspond to negative LoG responses. Is there publication I can cite for such blended use?
Two of the most ...
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Detecting Intersections of a Ray with a Polygon
As a part of a math essay, I am writing a program that detects intersections of a line that is drawn with a shape that is inputted.
For example, in the shape below, The polygon is the input image of ...
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Computationally Efficient Ways of Determining If Pixels Are Clumped
I'm working on an application where I get a video frame that's already segmented into good and bad pixels (as in -- the hardware either coughs up a pixel value or a flag that says "bad"). I want to ...
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What are the advantages of wavelet transform for image multiresolution analysis? [closed]
Compared to gaussian pyramid and laplacian pyramid, what are the advantages and disadvantages of wavelet decomposition for multiresolution image analysis? Thank you.
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Gaussian pyramid: why needs the image to be downsampled
In the context of a gaussian pyramid, why is the image downsampled separately although the numbers of pixels are decreased through smoothing already?
In my understanding, the number of pixels will ...
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How Can PCA Be Used in Image Analysis [closed]
I am still a not how PCA can be used in image analysis and where is it is mostly used. For example how can PCA be used in order to differentiate between different faces? Can you please mention other ...
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Find the Mid Point of a Worm / Chain Like Object
I have a video of worm-like objects which move. They can move in a straight line, they can rotate in circles, they can move in a serpentine/winding/sinuous way. I need to track them.
I already have ...
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sharpness in DCT domain image
How can we calculate the sharpness of an image with Discrete Cosine Transform domain?
Is it worthy in image quality assessment?
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Measuring sharpness/contrast for autofocus
For the implementation of an auto-focus for the raspberry cam I need some measure of image sharpness. I used the following sample picture:
The first approach was to compute the shannon entropy of the ...
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Primitive Feature Detection to Detect a Black Circle within an Image
I am trying to check whether this black circle is exist or not on my images.
My current approach is like that;
Hough Circle detection
Crop the outer roi
Adaptive threshold
count zero pixels
if ...
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Why Is the Canny Edge Detection Used Instead of Sobel / Prewitt Edge Detection Before Hough Transformation?
I know that for the Hough Transform to work on an image, it needs to be a binary image. To convert from a grayscale image, an edge detection algorithm should be employed. I notice that people always ...
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What Does Multi Scale Image Analysis Mean?
I'm reading an article about multi-scale representation of image, and it is said that, convolving the image with a Gaussian kernel at different $\sigma$, then ...
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Finger print skeletonization without using matlab functions
I am trying to thin foreground pixels of a finger print until they are one pixel wide without using the built in bwmorph and thin operations.
Can anyone explain to me how to write them in matlab ...
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