Diptutor's Blog

Morphological opening in IDL

diptutor — Tue, 03 Aug 2010 07:28:42 +0000

pro Mopening
; Handle TrueColor displays:
DEVICE, DECOMPOSED=0

;Read the image
path=FILEPATH(‘pollens.jpg’,SUBDIR=['examples','demo','demodata'])
READ_JPEG, path, img

; Create window:
WINDOW, 0, XSIZE=700, YSIZE=540

;Show original image
XYOUTS, 180, 525, ‘Original Image’, ALIGNMENT=.5, /DEVICE
TV, img, 20, 280

;Apply the threshold
thresh = img GE 140B

;Load a simple color table
TEK_COLOR

;Display edges
XYOUTS, 520, 525, ‘Edges’, ALIGNMENT=.5, /DEVICE
TV, thresh, 360, 280

;Apply opening operator
open = MORPH_OPEN(thresh, REPLICATE(1,3,3))

;Show the result
XYOUTS, 180, 265, ‘Opening Operator’, ALIGNMENT=.5, /DEVICE
TV, open, 20, 20

;Show pixels that have been removed in white
XYOUTS, 520, 265, ‘Removed Pixels in White’, ALIGNMENT=.5, /DEVICE
TV, open + thresh, 360, 20
end

Filed under: IDL

Hit or Miss operation in IDL

diptutor — Tue, 03 Aug 2010 07:26:31 +0000

pro Mhotmiss
;Handle TrueColor displays:
DEVICE, DECOMPOSED=0

;Read the image
path=FILEPATH(‘pollens.jpg’,SUBDIR=['examples','demo','demodata'])
READ_JPEG, path, img

WINDOW, 0, XSIZE=700, YSIZE=540

; Display the original image
XYOUTS, 180, 525, ‘Original Image’, ALIGNMENT=.5, /DEVICE
TV, img, 20, 280

rh = 2 ;Radius of hit disc
rm = 4 ;Radius of miss disc

;Create a binary disc of given radius.
hit = SHIFT(DIST(2*rh+1), rh, rh) LE rh

;Complement of disc for miss
miss = SHIFT(DIST(2*rm+1), rm, rm) GT rm

;Load discrete color table
TEK_COLOR

;Apply the threshold
thresh = img GE 140B

; Display the thresholded image
XYOUTS, 520, 525, ‘Thresholded Image’, ALIGNMENT=.5, /DEVICE
TV, thresh, 360, 280

;Compute matches
matches = MORPH_HITORMISS(thresh, hit, miss)

;Expand matches to size of hit disc
matches = DILATE(matches, hit)

;Show matches.
XYOUTS, 180, 265, ‘Matches’, ALIGNMENT=.5, /DEVICE
TV, matches, 20, 20

;Superimpose, showing hit regions in blue.
;(Blue = color index 4 for tek_color.)
XYOUTS, 520, 265, ‘Superimposed, hit regions in blue’,$
ALIGNMENT=.5, /DEVICE
TV, thresh + 3*matches, 360, 20
end

Filed under: IDL

Image Resizing in IDL

diptutor — Tue, 03 Aug 2010 07:24:26 +0000

Pro Image_Resizing
device,decompose=0
loadct,0
READ_JPEG,’C:\ITT\IDL64\examples\data\md1107g8a.JPG’,im
sz=SIZE(im,/DIMENSIONS)
WINDOW,0,XSIZE=sz[0],YSIZE=sz[1],TITLE=’IMAGE’
TV,im
sz1=sz*1.5 ; IMAGE SIZE
PRINT,SZ1
im1 = CONGRID(im,sz1[0],sz1[1],/interp) ; RESIZE THE IMAGE
WINDOW,1,XSIZE=sz1[0],YSIZE=sz1[1],TITLE=’RESIZED_IMAGE’
TV,im1

end

Filed under: IDL

RGB to NTSC Color Conversion in IDL

diptutor — Tue, 03 Aug 2010 07:22:18 +0000

PRO rgbcolorconversion
file = FILEPATH(‘rose.jpg’,SUBDIRECTORY = ['examples', 'data'])
queryStatus = QUERY_IMAGE(file, imageInfo)
PRINT, ‘Query Status = ‘, queryStatus
HELP, imageInfo, /STRUCTURE
imageSize = imageInfo.dimensions
READ_JPEG,file,image
imageDims = SIZE(image, /DIMENSIONS)
; rgb to gray conversion
gimage=fltarr(imagedims[0],imagedims[1],imagedims[2])
CM=[[0.299, 0.587, 0.144],[0.596, -0.274, -0.322],[0.211, -0.523,0.312]]
for i=0,imagedims[1]-1 do begin
for j=0,imagedims[2]-1 do begin
V=image[*,i,j]
gimage[*,i,j]=CM * TRANSPOSE(V)
endfor
endfor

interleaving = WHERE((imageDims NE imageSize[0]) AND $
(imageDims NE imageSize[1])) + 1
PRINT, ‘Type of Interleaving = ‘, interleaving
DEVICE, DECOMPOSED = 1
WINDOW, 0, XSIZE = imageSize[0], YSIZE = imageSize[1], $
TITLE = ‘An RGB Image’
TV, image, TRUE = interleaving[0]
WINDOW, 1, XSIZE = imageSize[0], YSIZE = imageSize[1], $
TITLE = ‘An NTSC Image’
TV, gimage, TRUE = interleaving[0]
end

Filed under: IDL

Wavelet Transformation in IDL

diptutor — Tue, 03 Aug 2010 07:19:04 +0000

PRO WAVELETTRANSFORM

READ_GIF,’d:\Image\bird.gif’,f
sz=size(f,/dimensions)
DEVICE,DECOMPOSED = 0
LOADCT, 0
WINDOW,0,XSIZE=SZ[0],YSIZE=SZ[1],TITLE=’Original Image’
tvscl, congrid(f,sz[0],sz[1])
f1 = wtn(f,20)
f2=abs(f1)^2
f2 = alog10(f2)
WINDOW,1,XSIZE=SZ[0],YSIZE=SZ[1],TITLE=’Transformed Image’
tvscl, congrid(f2,sz[0],sz[1])
f3 = wtn(f1,20,/inverse)
WINDOW,2,XSIZE=SZ[0],YSIZE=SZ[1],TITLE=’inverse Transformed Image’
tvscl, congrid(f3,sz[0],sz[1])

END

Filed under: IDL

POWER SPECTRUM of IMAGES in IDL

diptutor — Tue, 03 Aug 2010 07:17:51 +0000

PRO POWER_SPECTRUM_EX
im = [64,64]
file = FILEPATH(‘abnorm.dat’,SUBDIRECTORY =['examples','data'])
f = READ_BINARY(file,DATA_DIM=im)
sz = 2*im
DEVICE, DECOMPOSED = 0
loadct, 0
f1 = FFT(f)
center = im/2 + 1
fs = SHIFT(F1,center)
ps = ABS(fs)^2
sps = ALOG10(ps)
WINDOW,0,XSIZE = SZ[0],YSIZE = SZ[1],TITLE = ‘POWER SPECTRUM’
TVSCL,CONGRID(sps,sz[0],sz[1])
END

Filed under: IDL

Creating Object boundaries in IDL

diptutor — Tue, 03 Aug 2010 07:10:53 +0000

pro OBJECTBOUNDARY_SMOOTHING

;Initializing the display
DEVICE, DECOMPOSED = 0, RETAIN = 2
LOADCT, 0

;Reading a jpeg file
file = FILEPATH(‘meteor_crater.jpg’, SUBDIRECTORY = ['examples','data'])
READ_JPEG,file, f,/GRAYSCALE
sz = SIZE(f, /DIMENSIONS)
print, sz

;creating a window
WINDOW, 0, XSIZE = (2*SZ[0]),YSIZE=(SZ[1])

TV,f,0

;writing a text object on image
XYOUTS, 50, 220, ‘Original Image’, ALIGNMENT = 0.5, /DEVICE, COLOR = 255

;Image smoothing
f1 = smooth(f,7,/edge_truncate)
tvscl, f1,1
XYOUTS, (50+SZ[0]), 220, ‘SMOOTH IMAGE’, ALIGNMENT = 0.5, /DEVICE, COLOR = 255

end

Filed under: IDL

HIGH_PASS filter in IDL

diptutor — Tue, 03 Aug 2010 07:07:32 +0000

PRO HIGH_PASS_FILTER

READ_GIF,’d:\Image\bird.gif’,im
sz=SIZE(im,/DIMENSIONS)
im1=float(im)/255;
nim=im1
KER = REPLICATE(-1.0,3,3)
KER[1,1]=8.0
kER=FLOAT(KER)
PRINT,KER

nim=CONVOL(im1,ker)
nim=byte(nim*255)
WINDOW,0,XSIZE=sz[0],YSIZE=sz[1],TITLE=’INPUT IMAGE’
TV,im
WINDOW,1,XSIZE=sz[0],YSIZE=sz[1],TITLE=’MEAN filtered’
TV,nim
PRINT,NIM[0:9,0:9]
END

Filed under: IDL

MEAN filter in IDL

diptutor — Tue, 03 Aug 2010 07:04:33 +0000

PRO MEAN_FILTER

READ_GIF,’d:\Image\bird.gif’,im
sz=SIZE(im,/DIMENSIONS)
im1=float(im)/255;
nim=im1
ker=float([[1,1,1],[1,1,1],[1,1,1]])/9
print,ker
nim=CONVOL(im1,ker)
nim=byte(nim*255)
WINDOW,0,XSIZE=sz[0],YSIZE=sz[1],TITLE=’INPUT IMAGE’
TVSCL,im
WINDOW,1,XSIZE=sz[0],YSIZE=sz[1],TITLE=’MEAN filtered’
TV,nim
END

Filed under: IDL

MEDIAN filter in IDL

diptutor — Tue, 03 Aug 2010 07:02:56 +0000

PRO MEDIAN_FILTER
READ_GIF,’d:\Image\bird.gif’,im
im1=im
sz=SIZE(im,/DIMENSIONS)
s=[0,0,0,0,0,0,0,0,0]
FOR i=1,sz[0]-2 DO BEGIN
FOR j=1,sz[1]-2 DO BEGIN
CO=0;
FOR k = i-1,i+1 DO BEGIN
FOR l = j-1,j+1 DO BEGIN
s[CO]=im[k,l]
CO=CO+1
ENDFOR
ENDFOR
im1[i,j]=MEDIAN(s)
ENDFOR
ENDFOR
WINDOW,0,XSIZE=sz[0],YSIZE=sz[0],TITLE=’ORIGINAL IMAGE’
TV,im
WINDOW,1,XSIZE=sz[0],YSIZE=sz[0],TITLE=’MEDIAN IMAGE’
TV,im1
END

Filed under: IDL

REGION GROWING in IDL

diptutor — Tue, 03 Aug 2010 07:00:00 +0000

pro REGION_GROWING

; initialize the device
DEVICE, DECOMPOSED = 0, RETAIN = 2
LOADCT, 0
;read the image

file = FILEPATH(‘md1107g8a.jpg’,SUBDIRECTORY = ['examples','data'])
READ_JPEG, file, f,/GRAYSCALE
sz = SIZE(f,/DIMENSIONS)

;RESIZE THE IMAGE
f = REBIN(BYTSCL(f),sz[0]*2,sz[1]*2)
sz=2*sz

WINDOW,0,XSIZE = SZ[0], YSIZE=SZ[1],TITLE = ‘SELECT A POINT ON THE IMAGE’
TVSCL, F

;SELECT A POINT FROM THE IMAGE
CURSOR, xi,yi, /DEVICE
x = LINDGEN(10*10) MOD 10 + xi
y = LINDGEN(10*10) / 10 + yi
roiPixels = x + y * sz[0]

WDELETE, 0
TOPCLR = !D.TABLE_SIZE – 1
TVLCT, 255,0,0, TOPCLR
regionPts = BYTSCL(F, TOP = (topClr – 1))
regionPts[roiPixels] = topClr

WINDOW, 0, XSIZE = sz[0], YSIZE = sz[1], TITLE = ‘ORIGINAL REGION’
TV, regionPts

;REGION GROWING FUNCTION

ROIPIXELS = REGION_GROW(F,roiPixels, THRESHOLD = [185,235])

F1 = BYTSCL(F, TOP = (TOPCLR-1))
F1[ROIPIXELS] = TOPCLR

WINDOW,2, XSIZE=SZ[0],YSIZE=SZ[1],TITLE = ‘THRESHOLD GROWN REGION’
TV, F1

end

Filed under: IDL

Morphology Edge Detection

diptutor — Mon, 02 Aug 2010 12:12:57 +0000

clear all; close all; clc;
a = imread(‘circles.png’);
a = imresize(a,[256,256]);
%a = imcrop(a);
[m n]=size(a);
b = zeros([m n]);
figure,imshow(a);
w = [1 1 1 1 1]; % structuring element
for i=1:m-1
for j=3:n-2
con=0;
for p=j-2:j+2
con=con+1;
s(con)= a(i,p)*w(con);
end
s1 = 1;
for r=1:con
s1 = s1*s(r);
end
if s1 > 0
b(i,j)=1;
end
end
end
figure,imshow(b);
f1 = a-b;
figure,imshow(f1);

Filed under: Matlab

Chain Coding

diptutor — Mon, 02 Aug 2010 12:10:08 +0000

clear all; close all; clc;
a = imread(‘circles.png’);
a = imresize(a,[256,256]);
[m n]=size(a);
b = zeros([m n]);
figure,imshow(a);
w = [0 1 0 1 1 1 0 1 0]; % structuring element
for i=2:m-1
for j=2:n-1
con=0;
for k=i-1:i+1
for p=j-1:j+1
con=con+1;
s(con)= a(k,p)*w(con);
end
end
if sum(s) > 0
b(i,j)=1;
end
end
end
f2 = xor(a,b);
figure,imshow(f2),title(‘Object Edge’);
Ipo = a(19,35);
co=0; Cont = 0;Cva = 0;
i=19; j=35;
while (co==0)
if a(i,j)==Ipo
if a(i,j+1) == a(i,j)
Cont=Cont+1;
CVa(Cont)=0;
i=i;j=j+1;
if (i==19) && (j == 35)
co=1;
end
elseif a(i-1,j+1) == a(i,j)
Cont=Cont+1;
CVa(Cont)=1;
i=i-1;j=j+1;
if (i==19) && (j == 35)
co=1;
end
elseif a(i-1,j) == a(i,j)
Cont=Cont+1;
CVa(Cont)=2;
i=i-1; j=j;
if (i==19) && (j == 35)
co=1;
end
elseif a(i-1,j-1) == a(i,j)
Cont=Cont+1;
CVa(Cont)=3;
i=i-1; j=j-1;
if (i==19) && (j == 35)
co=1;
end
elseif a(i-1,j) == a(i,j)
Cont=Cont+1;
CVa(Cont)=4;
i=i-1; j=j;
if (i==19) && (j == 35)
co=1;
end
elseif a(i+1,j-1) == a(i,j)
Cont=Cont+1;
CVa(Cont)=5;
i=i+1; j=j-1;
if (i==19) && (j == 35)
co=1;
end
elseif a(i+1,j) == a(i,j)
Cont=Cont+1;
CVa(Cont)=6;
i=i+1; j=j-1;
if (i==19) && (j == 35)
co=1;
end
elseif a(i+1,j+1) == a(i,j)
Cont=Cont+1;
CVa(Cont)=7;
i=i+1; j=j+1;
if (i==19) && (j == 35)
co=1;
end
else
co=1;
end
else
co=1;
end
end

Filed under: Matlab

Morphology Dilation

diptutor — Mon, 02 Aug 2010 12:07:36 +0000

clear all; close all; clc;
a = imread(‘Bimage1.bmp’);
a = imresize(a,[256,256]);
[m n]=size(a);
b = zeros([m n]);
figure,imshow(a);
w = [0 1 0 1 1 1 0 1 0]; % structuring element
for i=2:m-1
for j=2:n-1
con=0;
for k=i-1:i+1
for p=j-1:j+1
con=con+1;
s(con)= a(k,p)*w(con);
end
end

if sum(s) > 0
b(i,j)=1;
end
end
end
figure,imshow(b);

Filed under: Matlab

Morphology Erosion

diptutor — Mon, 02 Aug 2010 12:06:07 +0000

clear all; close all; clc;
a = imread(‘Bimage1.bmp’);
a = imresize(a,[256,256]);
%a = imcrop(a);
[m n]=size(a);
b = zeros([m n]);
figure,imshow(a);
w = [1 1 1 1 1]; % structuring element
for i=1:m-1
for j=3:n-2
con=0;
for p=j-2:j+2
con=con+1;
s(con)= a(i,p)*w(con);
end
s1 = 1;
for r=1:con
s1 = s1*s(r);
end
if s1 > 0
b(i,j)=1;
end
end
end
figure,imshow(b);

Filed under: Matlab

Image segmantation using Region Splitting and merging

diptutor — Mon, 02 Aug 2010 12:03:59 +0000

clear all; close all; clc;
f = imread(‘coins.png’);
g = splitmerge(f,2,@predicate);
figure,imshow(f);
figure,imshow(g);

function g = splitmerge(f, mindim, fun)
% splitmerge Segment an image using a split-and merge algorithm.
% split regions down to size 1-by-1.
q = 2^nextpow2(max(size(f)));
[m n]=size(f);
f = padarray(f, [q-m, q-n], ‘post’);
s = qtdecomp(f, @split_test, mindim, fun);
lmax = full(max(s(:)));
g=zeros(size(f));
marker = zeros(size(f));
for k = 1:lmax
[vals, r, c] = qtgetblk(f, s,k);
if ~isempty(vals)
for i= 1:length(r)
xlow = r(i);
ylow = c(i);
xhigh = xlow + k -1;
yhigh = ylow + k -1;
region = f(xlow:xhigh, ylow:yhigh);
flag = feval(fun, region);
if flag
g(xlow:xhigh, ylow:yhigh) = 1;
marker(xlow, ylow) = 1;
end
end
end
end
g = bwlabel(imreconstruct(marker,g));
g = g(1:m,1:n);

Filed under: Matlab

Image segmantation using region growing

diptutor — Mon, 02 Aug 2010 12:01:39 +0000

clear all; close all; clc;
f = imread(‘coins.png’);
t=70; % Thres Hold value
s = 60; % Seed Value
[g, nr,si,ti] = regiongrow(f,s,t);
figure,imshow(f),title(‘Input Image’);
figure,imshow(ti),title(‘After Segmentation’);

function [g,nr,si,ti]=regiongrow(f,s,t)
% regiongrow perform segmentation by region growing.
f = double(f);
if numel(s) ==1
si =f == s;
s1 = s;
else
si = bwmorph(s, ‘shrink’, Inf);
j = find(si);
s1 = f(j);
end
ti = false(size(f));
for k=1:length(s1)
seedvalue = s1(k);
s = abs(f – seedvalue) <= t;
ti = ti | s;
end
[g, nr] = bwlabel(imreconstruct(si, ti));

Filed under: Matlab

Point Detection on Image

diptutor — Mon, 02 Aug 2010 11:58:58 +0000

clear all ; close all; clc;
I = imread(‘House24.png’);
I = rgb2gray(I);
I = im2double(I);
h = [-1 -1 -1;-1 8 -1;-1 -1 -1];
f = imfilter(I,h);
figure,imshow(I),title(‘Original Image’);
figure,imshow(f),title(‘After filtering’);

Filed under: Matlab

Hough Edge detection

diptutor — Mon, 02 Aug 2010 11:57:42 +0000

clear all; close all; clc;
f = imread(‘House24.png’);
f = rgb2gray(f);
f = imcrop(f,[3 3 255 255]);
%f = im2double(f);
%f = imrotate(f,33,’crop’);
BW = edge(f,’canny’);
[H, theta, rho] = hough(BW);
imshow(theta, rho, H, [], ‘notruesize’);
axis on, axis normal
xlabel(‘\theta’), ylabel(‘\rho’);
p = houghpeaks(H,5,’threshold’,ceil(0.3*max(H(:))));
c = theta(p(:,2));
r = rho(p(:,1));
hold on
plot(c,r, ‘linestyle’, ‘none’, ‘marker’, ‘S’, ‘color’, ‘w’);
lines = houghlines(BW,theta,rho,p,’FillGap’,5,’MinLength’,7);
figure,imshow(f), hold on
for k = 1:length(lines)
xy = [lines(k).point1; lines(k).point2];
plot(xy(:,1),xy(:,2),’LineWidth’,2,’Color’,'green’);
end

Filed under: Matlab

Roberts Edge Detection

diptutor — Mon, 02 Aug 2010 11:55:45 +0000

clear all; close all; clc;
I = imread(‘lena.gif’);
%I = rgb2gray(I);
I = im2double(I);
h = [-1 0;0 1]; % 45 degree Mask
h1 = [0 -1;1 0]; % -45 degree Mask
f1 = imfilter(I,h,’replicate’);
f2 = imfilter(I,h1,’replicate’);
figure(1),imshow(I),title(‘Original Image’);
figure(2);
subplot(1,2,1),imshow(f1),title(’45 Degree Edge’);
subplot(1,2,2),imshow(f2),title(‘-45 Degree Edge’);

Filed under: Matlab