# Spandan Tiwari

### MathWorks

Professional Interests: Image Processing, Computer Vision, Machine Learning,Signal Processing, Pattern Recognition, Partial Differential Equations

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**Content Feed**

Is medfilt2 a zero-phase filter?

medfilt2 is a median filter, which is a non-linear filter. So, no, it cannot be considered a zero-phase filter.

7 years ago | 0

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What is moments of image?

Your question is very broad to be answered fully here. There are many tutorials on Zernike moments that you can find online with...

8 years ago | 0

How to use filter

The classical homomorphic filtering might be able to help here. See the following blog post on the blog Steve on Image Processin...

8 years ago | 0

sharpening image and removing noise

Also for the image sharpening part, you can use the function IMSHARPEN in the Image Processing Toolbox. It has parameters that y...

8 years ago | 0

blood vessel segmentation help

This may not be directly relevant but since you mentioned FCLAHE I wanted to point out that the ADAPTHISTEQ function in the Imag...

8 years ago | 0

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Calculating the number of pixels inside a freehand region.

Since you are already using imfreehand, you can use the method named createMask available in the imfreehand object to rasterize ...

8 years ago | 0

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Radius precision of circles when using "imfindcircles" to find circles?

The 'Phasecode' method inherently supports radius estimation with sub-pixel accuracy, and hence the results have floating-point ...

8 years ago | 0

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Use of Bresenham line algorithm to generate 1D profiles from a DTM

If you can morph the data into a 2D matrix, say as a 2D image, you can use the function *improfile* from the Image processing To...

8 years ago | 0

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detecting rectangle in real images

If your rectangle does not change orientation, you can try using normxcorr2 (in Image Processing Toolbox) with the rectangle as ...

8 years ago | 0

finding of mse and psnr

There's a function named psnr() in Image Processing Toolbox in R2014a for computing PSNR. MSE is also computed on the way to com...

8 years ago | 0

Exactly Which otsu extension is working at back end of multithresh.m in matlab2013a.

The algorithms are from the paper: Otsu, N., "A Threshold Selection Method from Gray-Level Histograms," IEEE Transactions on ...

9 years ago | 0

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need matlab code for image texture analysis

You can look at the functions graycomatrix and graycoprops for computing the popular Gray-Level Cooccurrence Matrix (GLCM) text...

9 years ago | 0

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Help with cropping a binary image?

Use IMCOMPLEMENT to invert the polarity of the binary images so that the object (fist) is white. Then use BWBOUNDARIES to get th...

9 years ago | 0

How to remove small CLUTTER from images?

BWAREAOPEN assumes that the objects are white. In your case the objects (regions that you want to remove) are black. So first co...

9 years ago | 1

how to find Windowed Fourier Transform of an image? If possible function script is needed.

STFT computation requires computing Fourier Transform of sub-blocks of the image. You can use fft2() to get Fourier Transform. F...

9 years ago | 0

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To fill a closed curve

If you can make a binary image for the closed curve, you can use imfill in Image Processing Toolbox.

9 years ago | 0

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dashed line imrect of imline

Something like this would help you make a dashed line using *imline* . h = imline(); h1 = get(h,'Children'); set(h1(...

9 years ago | 1

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how to divide into blocks of 8x8 pixels?

The function *blockproc* in the Image Processing Toolbox maybe a natural fit if you would like to do process the image in blocks...

9 years ago | 0

colour image segmentation using k means

Another alternative could be to use multi-level Otsu's thresholding to get the segmentation. You can use the function *multithre...

9 years ago | 1

how to compare the color image to another color image in directory?

One way to compare the images quickly would be compute a structural quality metric such as SSIM between the two images. It is a ...

9 years ago | 0

directional filter for detecting edges on a circle and rectangle

Look at the function IMFINDCIRCLES in Image Processing Toolbox (R2012a onwards) for detecting circles in your image.

9 years ago | 0

segmentation

No the initial mask can be any shape although it is preferable to start with a relatively smooth shape such as a circle. You...

9 years ago | 0

Best Segmentation technique for a structurally homogenous image

Try using the new function activecontour in the Image Processing Toolbox that shipped in R2013a. It should be useful for this pr...

9 years ago | 0

Looking for an implementation of the active contours without edges method which can be/is initialized with multiple contours?

There's a new function in Image Processing Toolbox in R2013a named activecontour which can do Chan-Vese segmentation and can be ...

9 years ago | 0

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how to cut out circle from an eye image

Can you show some code that you tried.

9 years ago | 0

Detecting circles in an image.

IMFINDCIRCLES allows you to specify a radius range which can include the entire range of expected radii.

9 years ago | 0

how to speed up imfindcircles

Two ways to get IMFINDCIRCLES run faster in your code are: 1) Sending in the image at a lower resolution. 2) Use smaller r...

9 years ago | 2

How can I use imfindcircles in real time video?

Two ways to get IMFINDCIRCLES run faster in your code are: 1) Sending in the image at a lower resolution. 2) Use smaller r...

9 years ago | 0

Optimize the edge detection

imopen might be more selective in removing segments based on their size.

10 years ago | 1

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change color "bwperim"

You can change the color by filling the perimeter pixels with a color value instead of a scalar 255. One possible way to do this...

10 years ago | 1