#!/bin/bash # # Developed by Fred Weinhaus 1/27/2017 .......... revised 10/11/2017 # # ------------------------------------------------------------------------------ # # Licensing: # # Copyright © Fred Weinhaus # # My scripts are available free of charge for non-commercial use, ONLY. # # For use of my scripts in commercial (for-profit) environments or # non-free applications, please contact me (Fred Weinhaus) for # licensing arrangements. My email address is fmw at alink dot net. # # If you: 1) redistribute, 2) incorporate any of these scripts into other # free applications or 3) reprogram them in another scripting language, # then you must contact me for permission, especially if the result might # be used in a commercial or for-profit environment. # # My scripts are also subject, in a subordinate manner, to the ImageMagick # license, which can be found at: http://www.imagemagick.org/script/license.php # # ------------------------------------------------------------------------------ # #### # # USAGE: corners [-m method] [-t threshold] [-s smooth] [-r region] [-c color] # [-d dilate] [-p print] infile outfile1 [outfile2] # # USAGE: corners [-h|-help] # # OPTIONS: # # -m method method of corner detection; choices are: morphology (m), # harris (h) or shi-tomasi (s); default=morphology # -t threshold threshold level (in percent) for choosing the strongest # corners; 0<=float<=100; default=50 # -s smooth smoothing to apply noise suppression; 0<=integer<=5; # number of applications of -enhance; default=0 # -r region region is either the morphology structure element size # for morphology method or the sigma for the gaussian # weighting of the neighborhood derivatives in the # harris and shi-tomasi methods; float>=0; default=1 # -c color color of color points to be drawn on the first output # image; any valid opaque IM color is allowed; default=red # -d dilate dilation amount for enlarging the corner point drawn # on the output image(s); integer>=0; default=1 # -p print print a list of the corner points to the terminal; # yes or no; default=no # # The first output image will show the corner points overlaid on the input # image. The second output will show the corner points as white on a black # background. # ### # # NAME: CORNERS # # PURPOSE: To detect corner structures in an image. # # DESCRIPTION: CORNERS detects corner structures in an image. Any of three # methods may be used. The first is a morphology-based corner detector. The # second is the Harris corner detector. The third is the Shi-Tomasi corner # detector. The latter two require Imagemagick compiled in HDRI mode. The # morphology corner detector uses two sets of morphology close operations using # asymmetric structuring elements. The Harris and Shi-Tomasi corner detectors # use a Gaussian weighted average of the squares and cross products of the # X and Y Sobel directional derivatives. Note that the image is first converted # to grayscale for the corner detection process. # # OPTIONS: # # -m method ... METHOD of corner detection. The choices are: morphology (m), # harris (h) or shi-tomasi (s). The default=morphology. The harris and # shi-tomasi methods require Imagemagick compile in HDRI mode. # # -t threshold ... THRESHOLD level (in percent) for choosing the strongest # corners. Values are 0<=float<=100. The default=50. Different values # are needed for each method. The optimal threshold will also depend upon # and smoothing applied and upon the region size. More smoothing or larger # regions permit lower thresholds. # # -s smooth ... SMOOTH is the amount of smoothing to apply to the image # as a preprocessing step to suppress noise. Values are 0<=integers<=5. The # value represents the number of applications of -enhance to apply. The # default=0. # # -r region ... REGION is either the morphology structure element size for # the morphology method or the sigma value for the gaussian weighting of the # neighborhood of derivatives in the harris and shi-tomasi methods. Values # are floats>=0. The default=1. Values for method=morphology are typically # integers. # # -c color ... COLOR of the corner points to be drawn on the first output # image. Any valid opaque IM color is allowed. The default=red. # # -d dilate ... DILATE is the amount of dilation for enlarging the corner # points drawn on the output image(s). Values are integer>=0. The default=1. # # -p print ... PRINT a list of the x,y corner points to the terminal. The # choices are: yes (y) or no (n). The default=no. # # REQUIREMENTS: The Harris and the Shi-Tomasi methods require that Imagemagick # be compile in HDRI mode. All methods require IM 6.8.9.10 or higher due to # the use of -connected-components. # # REFERENCES Morphology: # http://www.site.uottawa.ca/~laganier/publications/coin.pdf # # REFERENCES Harris: # http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_feature2d/py_features_harris/py_features_harris.html # http://www.math.harvard.edu/archive/21b_fall_04/exhibits/2dmatrices/ # # REFERENCES Shi-Tomasi: # http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_feature2d/py_shi_tomasi/py_shi_tomasi.html # http://www.math.harvard.edu/archive/21b_fall_04/exhibits/2dmatrices/ # # CAVEAT: No guarantee that this script will work on all platforms, # nor that trapping of inconsistent parameters is complete and # foolproof. Use At Your Own Risk. # ###### # # set default values method="morphology" # morphology, harris, shi-tomasi threshold="50" # threshold corner image (95 for checkerboard; 45 for bookends; 25/15 for desktop) smooth=0 # smoothing using repeated -enhance region=1 # morphology structuring element size (morphology) or sigma gaussian weighting (harris and shi-tomasi) color="red" # color for drawing the corner points dilate="1" # integer>=0, but 0.5 will be added for disk print="no" # print locations to terminal # set directory for temporary files tmpdir="." # suggestions are tmpdir="." or tmpdir="/tmp" # set up functions to report Usage and Usage with Description PROGNAME=`type $0 | awk '{print $3}'` # search for executable on path PROGDIR=`dirname $PROGNAME` # extract directory of program PROGNAME=`basename $PROGNAME` # base name of program usage1() { echo >&2 "" echo >&2 "$PROGNAME:" "$@" sed >&2 -e '1,/^####/d; /^###/g; /^#/!q; s/^#//; s/^ //; 4,$p' "$PROGDIR/$PROGNAME" } usage2() { echo >&2 "" echo >&2 "$PROGNAME:" "$@" sed >&2 -e '1,/^####/d; /^######/g; /^#/!q; s/^#*//; s/^ //; 4,$p' "$PROGDIR/$PROGNAME" } # function to report error messages errMsg() { echo "" echo $1 echo "" usage1 exit 1 } # function to test for minus at start of value of second part of option 1 or 2 checkMinus() { test=`echo "$1" | grep -c '^-.*$'` # returns 1 if match; 0 otherwise [ $test -eq 1 ] && errMsg "$errorMsg" } # test for correct number of arguments and get values if [ $# -eq 0 ] then # help information echo "" usage2 exit 0 elif [ $# -gt 17 ] then errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---" else while [ $# -gt 0 ] do # get parameter values case "$1" in -h|-help) # help information echo "" usage2 exit 0 ;; -m) # get method shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID METHOD SPECIFICATION ---" #checkMinus "$1" method=`echo "$1" | tr '[A-Z]' '[a-z]'` case "$method" in morphology|m) method="morphology";; harris|h) method="harris";; shi-tomasi|s) method="shi-tomasi";; *) errMsg "--- METHOD=$method IS AN INVALID VALUE ---" esac ;; -t) # get threshold shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID THRESHOLD SPECIFICATION ---" checkMinus "$1" threshold=`expr "$1" : '\([.0-9]*\)'` [ "$threshold" = "" ] && errMsg "--- THRESHOLD=$threshold MUST BE A FLOAT ---" testA=`echo "$threshold < 0" | bc` testB=`echo "$threshold > 100" | bc` [ $testA -eq 1 -o $testB -eq 1 ] && errMsg "--- THRESHOLD=$threshold MUST BE A FLOAT BETWEEN 0 AND 100 ---" ;; -r) # get region shift # to get the next parameter - radius,sigma # test if parameter starts with minus sign errorMsg="--- INVALID REGION SPECIFICATION ---" checkMinus "$1" region=`expr "$1" : '\([.0-9]*\)'` [ "$region" = "" ] && errMsg "--- REGION=$region MUST BE A NON-NEGATIVE FLOAT ---" ;; -s) # get smooth shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID SMOOTH SPECIFICATION ---" checkMinus "$1" smooth=`expr "$1" : '\([0-5]\)'` [ "$smooth" = "" ] && errMsg "--- SMOOTH=$smooth MUST BE AN INTEGER BETWEEN 0 AND 5 ---" ;; -c) # get color shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID COLOR SPECIFICATION ---" checkMinus "$1" color="$1" ;; -d) # get dilate shift # to get the next parameter - radius,sigma # test if parameter starts with minus sign errorMsg="--- INVALID DILATE SPECIFICATION ---" checkMinus "$1" dilate=`expr "$1" : '\([0-9]*\)'` [ "$dilate" = "" ] && errMsg "--- DILATE=$dilate MUST BE A NON-NEGATIVE INTEGER ---" ;; -p) # get print shift # to get the next parameter # test if parameter starts with minus sign errorMsg="--- INVALID PRINT SPECIFICATION ---" checkMinus "$1" print=`echo "$1" | tr '[A-Z]' '[a-z]'` case "$print" in yes|y) print="yes";; no|n) print="no";; *) errMsg "--- PRINT=$print IS AN INVALID VALUE ---" esac ;; -) # STDIN and end of arguments break ;; -*) # any other - argument errMsg "--- UNKNOWN OPTION ---" ;; *) # end of arguments break ;; esac shift # next option done # # get infile, outfile1 and outfile2 numfiles=$# if [ $numfiles -eq 3 ]; then infile="$1" outfile1="$2" outfile2="$3" elif [ $numfiles -eq 2 ]; then infile="$1" outfile1="$2" else errMsg "--- WRONG NUMBER OF OUTPUT FILES SPECIFIED ---" fi fi # test that infile provided [ "$infile" = "" ] && errMsg "NO INPUT FILE SPECIFIED" # test that outfile provided [ "$outfile1" = "" ] && errMsg "NO OUTPUT FILE 1 SPECIFIED" if [ $numfiles -eq 3 ]; then # test that outfile provided [ "$outfile2" = "" ] && errMsg "NO OUTPUT FILE 2 SPECIFIED" fi dir="$tmpdir/CORNERS.$$" mkdir "$dir" || errMsg "--- FAILED TO CREATE TEMPORARY FILE DIRECTORY ---" trap "rm -rf $dir; exit 0" 0 trap "rm -rf $dir; exit 1" 1 2 3 15 # test for hdri enabled hdri_on=`convert -list configure | grep "enable-hdri"` [ "$method" != "morphology" -a "$hdri_on" != "" ] && echo "--- REQUIRES HDRI ENABLED IN IM COMPILE ---" # set up smoothing if [ "$smooth" = "5" ]; then smoothing="-enhance -enhance -enhance -enhance -enhance" elif [ "$smooth" = "4" ]; then smoothing="-enhance -enhance -enhance -enhance" elif [ "$smooth" = "3" ]; then smoothing="-enhance -enhance -enhance" elif [ "$smooth" = "2" ]; then smoothing="-enhance -enhance" elif [ "$smooth" = "1" ]; then smoothing="-enhance" else smoothing="" fi # read the input image into the temporary cached image and test if valid convert -quiet -regard-warnings "$infile" +write $dir/tmpI.mpc -alpha off -colorspace gray $smoothing +repage $dir/tmpG.mpc || echo "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE ---" # Morphology: # asymmetric closing using 2 different structure element # corner metric = abs( I(dilate(plus)-erode(diamond)) - I(dilate(ex)-erode(square)) ) # Harris and Shi-Tomasi: # consider eigen values of 2x2 matrix M of derivatives for each of the 4 elements averaged over 3x3 image region # M = |Dx*Dx Dx*Dy| = |a b| # |Dx*Dy Dy*Dy| |c d| # the harris corner value metric = det(M) - k*trace(M)*trace(M) # where D = det(M) = L1*L2 = a*d-b*c # where T = trace(M) = L1 + L2 = a+d # where L1 and L2 are eigenvalues # where k=0.04 # L1 = T/2 + sqrt(T*T/4-D) # L2 = T/2 - sqrt(T*T/4-D) # For Harris, we just need use the corner metric = D - k*T*T # For Shi-Tomasi, we just use the corner metric = min(L1,L2) # set up thresholding if [ "$threshold" != "" ]; then thresholding="-threshold $threshold%" else thresholding="" fi # setup dilate if [ "$dilate" != "0" ]; then dilate=`convert xc: -format "%[fx:$dilate + 0.5]" info:` dilating="-morphology dilate disk:$dilate" else dilating="" fi if [ "$method" = "morphology" ]; then # compute morphology corner metric # compute the first type asymmetric closing # compute the second type asymmetric closing # get abs difference convert \ \( $dir/tmpG.mpc -morphology dilate plus:$region -morphology erode diamond:$region \) \ \( $dir/tmpG.mpc -morphology dilate cross:$region -morphology erode square:$region \) \ -compose difference -composite -auto-level $thresholding $dilating \ $dir/tmpC.miff elif [ "$method" = "harris" ]; then #line 2 - create X derivative #line 3 - create Y derivative #line 4 - create square of X derivative and apply gaussian average as term a #line 5 - create square of Y derivative and apply gaussian average as term d #line 6 - create product of X and Y derivatives and apply gaussian average as term b=c #line 7 - remove original derivatives #line 8 - compute product ad (XX*YY) #line 9 - compute product bc (XY*XY) #line 10 - compute product D (ad-bc) #line 11,12,13 - compute T*T (a+d)*(a+d) and add -0.04 = k (note need +duplicate rather than +clone) #line 14 - remove temps #line 15 - compute corner metric = D - k*T*T and auto-level and threshold #line 16 - write tmpC.miff as image of white points on black background convert \ \( $dir/tmpG.mpc -define convolve:scale=\! -morphology convolve Sobel:0 \) \ \( $dir/tmpG.mpc -define convolve:scale=\! -morphology convolve Sobel:90 \) \ \( -clone 0 -clone 0 -define compose:clamp=off -compose multiply -composite -blur 0x$region \) \ \( -clone 1 -clone 1 -define compose:clamp=off -compose multiply -composite -blur 0x$region \) \ \( -clone 0 -clone 1 -define compose:clamp=off -compose multiply -composite -blur 0x$region \) \ -delete 0,1 \ \( -clone 0 -clone 1 -define compose:clamp=off -compose multiply -composite \) \ \( -clone 2 -clone 2 -define compose:clamp=off -compose multiply -composite \) \ \( -clone 3 -clone 4 -define compose:clamp=off +swap -compose minus -composite \) \ \( -clone 0 -clone 1 -define compose:clamp=off -compose plus -composite \ \( +clone \) -define compose:clamp=off -compose multiply -composite \ -evaluate multiply -0.04 \) \ -delete 0-4 \ -define compose:clamp=off -compose plus -composite -auto-level $thresholding \ $dir/tmpC.miff elif [ "$method" = "shi-tomasi" ]; then #line 2 - create X derivative #line 3 - create Y derivative #line 4 - create square of X derivative and apply gaussian average as term a #line 5 - create square of Y derivative and apply gaussian average as term d #line 6 - create product of X and Y derivatives and apply gaussian average as term b=c #line 7 - remove original derivatives #line 8 - compute product ad (XX*YY) #line 9 - compute product bc (XY*XY) #line 10 - compute product D (ad-bc) #line 11 - compute T (a+d) #line 12 - compute T*T (a+d)*(a+d) #line 13 - remove temps #line 14,15 - compute sqrt of discriminant (T*T/4-D) and clip at 0 (to remove negatives) #line 16 - compute L1 = T/2 + sqrt(T*T/4-D) #line 17 - compute L2 = T/2 - sqrt(T*T/4-D) #line 18 - remove temps #line 19 - get min of L1 and L2 and auto-level and threshold #line 20 - write tmpC.miff as image of white points on black background convert \ \( $dir/tmpG.mpc -define convolve:scale=\! -morphology convolve Sobel:0 \) \ \( $dir/tmpG.mpc -define convolve:scale=\! -morphology convolve Sobel:90 \) \ \( -clone 0 -clone 0 -define compose:clamp=off -compose multiply -composite -blur 0x$region \) \ \( -clone 1 -clone 1 -define compose:clamp=off -compose multiply -composite -blur 0x$region \) \ \( -clone 0 -clone 1 -define compose:clamp=off -compose multiply -composite -blur 0x$region \) \ -delete 0,1 \ \( -clone 0 -clone 1 -define compose:clamp=off -compose multiply -composite \) \ \( -clone 2 -clone 2 -define compose:clamp=off -compose multiply -composite \) \ \( -clone 3 -clone 4 -define compose:clamp=off +swap -compose minus -composite \) \ \( -clone 0 -clone 1 -define compose:clamp=off -compose plus -composite \) \ \( -clone 6 -clone 6 -define compose:clamp=off -compose multiply -composite \) \ -delete 0-4 \ \( -clone 2 -evaluate multiply 0.25 -clone 0 +swap \ -define compose:clamp=off -compose minus -composite -evaluate max 0 -evaluate pow 0.5 \) \ \( -clone 1 -evaluate multiply 0.5 -clone 3 -define compose:clamp=off -compose plus -composite \) \ \( -clone 1 -evaluate multiply 0.5 -clone 3 -define compose:clamp=off +swap -compose minus -composite \) \ -delete 0-3 \ -evaluate-sequence min -auto-level $thresholding \ $dir/tmpC.miff fi # do ccl to get centroids and color with underscore between them data=`convert $dir/tmpC.miff \ -define connected-components:verbose=true \ -connected-components 8 null: | tail -n +2 | \ sed -n 's/^.*[:][ ]*[^ ]*[ ]*\([^ ]*\)[ ]*[^ ]*[ ]*\([^ ]*\)[ ]*$/\1_\2/p'` # print points to terminal i=1 points="" for item in $data; do coords=`echo "$item" | cut -d_ -f1` colour=`echo "$item" | cut -d_ -f2` if [ "$colour" != "srgb(0,0,0)" -a "$colour" != "gray(0)" -a "$colour" != "black" ]; then [ "$print" = "yes" ] && echo "pt=$i coords=$coords" points="$points point $coords" i=$((i+1)) fi done if [ $numfiles -eq 3 ]; then saving="+write $outfile2" else saving="" fi # overlay new corners in $color on input image as outfile1 # if specified, write white corners on black as outfile2 convert $dir/tmpI.mpc \ \( -clone 0 -fill "$color" -colorize 100 \) \ \( -clone 0 -evaluate set 0 -fill white \ -draw "$points" -alpha off $dilating $saving \) \ -compose over -composite "$outfile1" exit 0