A => README.txt +58 -0
@@ 0,0 1,58 @@
+perceptualdiff - a program that compares two images using
+a perceptually based image metric.
+Copyright (C) 2006 Yangli Hector Yee
+ yeehector@users.sourceforge.net
+ http://pdiff.sourceforge.net/
+Go version Copyright (C) 2012 Sean Russell
+
+This program is free software; you can redistribute it and/or modify it
+under the terms of version 2 of the GNU General Public License as published by
+the Free Software Foundation.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details in the
+file gpl.txt.
+
+Build Instructions
+1. Download cross platform make from http://www.cmake.org
+2. Download freeimage from https://sourceforge.net/projects/freeimage
+3. Edit CMakeLists.txt to tell it where to find your free image build
+4. Type cmake .
+5. Type make . (or on Windows systems cmake makes a Visual Studio
+Project file)
+6. To specify the install directory, use make install DESTDIR="/home/me/mydist"
+
+Usage
+
+perceptualdiff image1.(tif | png) image2.(tif | png) [options]
+-verbose : Turns on verbose mode
+-fov deg: field of view, deg, in degrees. Usually between 10.0 to 85.0.
+This controls how much of the screen the oberserver is seeing. Front row of
+a theatre has a field of view of around 25 degrees. Back row has a field of
+ view of around 60 degrees.
+-threshold p : Sets the number of pixels, p, to reject. For example if p is
+ 100, then the test fails if 100 or more pixels are perceptably different.
+-gamma g : The gamma to use to convert to RGB linear space. Default is 2.2
+-luminance l: The luminance of the display the observer is seeing. Default
+ is 100 candela per meter squared
+-colorfactor : How much of color to use, 0.0 to 1.0, 0.0 = ignore color.
+-downsample : How many powers of two to down sample the image.
+-output foo.ppm : Saves the difference image to foo.ppm
+
+Credits
+
+Hector Yee, project administrator and originator - hectorgon.blogspot.com
+Scott Corley, for png file IO code
+Tobias Sauerwein, for make install, package_source Cmake configuration
+Cairo Team for bugfixes
+Jim Tilander, Rewrote the IO to use FreeImage.
+
+Version History
+
+1.0 - Initial distribution
+1.0.1 - Fixed off by one convolution error and libpng interface to 1.2.8
+1.0.2 - [jt] Converted the loading and saving routines to use FreeImage
+1.1 - Added colorfactor and downsample options. Also always output
+difference file if requested. Always print out differing pixels even if the test passes.
+1.1.1 - Turn off color test in low lighting conditions.
A => compareargs.go +74 -0
@@ 0,0 1,74 @@
+package perceptualdiff
+
+import (
+ "flag"
+ "fmt"
+)
+
+/*
+Comapre Args
+Copyright (C) 2012 Sean Russell
+Based entirely off the C++ code by Yangli Hector Yee
+
+This program is free softwareyou can redistribute it and/or modify it under
+the terms of version 2 of the GNU General Public License as published by the
+Free Software Foundation.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTYwithout even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this programif not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+const copyright = `PerceptualDiff version 1.1.1, Copyright (C) 2006 Yangli Hector Yee
+PerceptualDiff comes with ABSOLUTELY NO WARRANTY
+This is free software, and you are welcome
+to redistribute it under certain conditions
+See the GPL page for details: http://www.gnu.org/copyleft/gpl.html
+
+`
+
+// Args to pass into the comparison function
+type CompareArgs struct {
+ ImgA *RGBAImage // Image A
+ ImgB *RGBAImage // Image B
+ ImgDiff *RGBAImage // Diff image
+ Verbose bool // Print lots of text or not
+ LuminanceOnly bool // Only consider luminanceignore chroma channels in the comparison.
+ FieldOfView float64 // Field of view in degrees
+ Gamma float64 // The gamma to convert to linear color space
+ Luminance float64 // the display's luminance
+ ThresholdPixels uint // How many pixels different to ignore
+ // How much color to use in the metric.
+ // 0.0 is the same as LuminanceOnly = true,
+ // 1.0 means full strength.
+ ColorFactor float64
+ // How much to down sample image before comparing, in powers of 2.
+ DownSample int
+}
+
+
+func NewCompareArgs() *CompareArgs {
+ c := new(CompareArgs)
+
+ c.ImgA = nil
+ c.ImgB = nil
+ c.ImgDiff = nil
+ c.FieldOfView = 45.0
+ c.ThresholdPixels = 100
+ c.Gamma = 2.2
+ c.Luminance = 100.0
+ c.ColorFactor = 1.0
+
+ return c
+}
+
+func (c *CompareArgs) Print_Args() {
+ fmt.Printf("Field of view is %f degrees\n", c.FieldOfView)
+ fmt.Printf("Threshold pixels is %d pixels\n", c.ThresholdPixels)
+ fmt.Printf("The Gamma is %f\n", c.Gamma)
+ fmt.Printf("The Display's luminance is %f candela per meter squared\n", c.Luminance)
+}
A => gpl.txt +340 -0
@@ 0,0 1,340 @@
+ GNU GENERAL PUBLIC LICENSE
+ Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The licenses for most software are designed to take away your
+freedom to share and change it. By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users. This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it. (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.) You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
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+ GNU GENERAL PUBLIC LICENSE
+ TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
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+ This program is free software; you can redistribute it and/or modify
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+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
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+ Gnomovision version 69, Copyright (C) year name of author
+ Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, the commands you use may
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+mouse-clicks or menu items--whatever suits your program.
+
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+
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+ `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+ <signature of Ty Coon>, 1 April 1989
+ Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs. If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.
A => lpyramid.go +86 -0
@@ 0,0 1,86 @@
+package perceptualdiff
+
+/*
+Laplacian Pyramid
+Copyright (C) 2012 Sean Russell
+Based heavily on C++ code by Yangli Hector Yee
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of version 2 of the GNU General Public License as published by the
+Free Software Foundation.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+const MAX_PYR_LEVELS = 8
+
+//////////////////////////////////////////////////////////////////////
+// Construction/Destruction
+//////////////////////////////////////////////////////////////////////
+
+type LPyramid struct {
+ Levels [][]float64
+ Width, Height int
+}
+
+var Kernel []float64
+
+func init() {
+ Kernel = []float64{0.05, 0.25, 0.4, 0.25, 0.05}
+}
+
+func NewLPyramid(image []float64, width, height int) *LPyramid {
+ rv := new(LPyramid)
+ rv.Levels = make([][]float64, MAX_PYR_LEVELS)
+ rv.Width, rv.Height = width, height
+ // Make the Laplacian pyramid by successively
+ // copying the earlier levels and blurring them
+ for i:=0; i<MAX_PYR_LEVELS; i++ {
+ if i == 0 {
+ rv.Levels[i] = make([]float64, width, height)
+ copy(rv.Levels[i], image)
+ } else {
+ rv.Levels[i] = make([]float64, width * height)
+ rv.convolve(rv.Levels[i], rv.Levels[i - 1])
+ }
+ }
+ return rv
+}
+
+func (l *LPyramid) convolve(a, b []float64) {
+ // convolves image b with the filter kernel and stores it in a
+ var y,x,i,j,nx,ny int
+
+ for y=0; y<l.Height; y++ {
+ for x=0; x<l.Width; x++ {
+ index := y * l.Width + x
+ a[index] = 0.0
+ for i=-2; i<=2; i++ {
+ for j=-2; j<=2; j++ {
+ nx=x+i
+ ny=y+j
+ if nx<0 { nx=-nx }
+ if ny<0 { ny=-ny }
+ if nx>=l.Width { nx=2*l.Width-nx-1 }
+ if ny>=l.Height { ny=2*l.Height-ny-1 }
+ a[index] += Kernel[i+2] * Kernel[j+2] * b[ny * l.Width + nx]
+ }
+ }
+ }
+ }
+}
+
+func (p *LPyramid) Get_Value(x, y int, level uint) float64 {
+ index := x + y * p.Width
+ l := level
+ if l > MAX_PYR_LEVELS {
+ l = MAX_PYR_LEVELS
+ }
+ return p.Levels[level][index]
+}
A => metric.go +325 -0
@@ 0,0 1,325 @@
+package perceptualdiff
+
+/*
+Metric
+Copyright (C) 2012 Sean Russell
+Based heavily on C++ code by Yangli Hector Yee
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of version 2 of the GNU General Public License as published by the
+Free Software Foundation.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY
+without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+import (
+ . "math"
+ "fmt"
+ "image/color"
+)
+
+/*
+* Given the adaptation luminance, this function returns the
+* threshold of visibility in cd per m^2
+* TVI means Threshold vs Intensity function
+* This version comes from Ward Larson Siggraph 1997
+*/
+func tvi(adaption_luminance float64) float64 {
+ // returns the threshold luminance given the adaptation luminance
+ // units are candelas per meter squared
+
+ var r float64
+ log_a := Log10(adaption_luminance)
+
+ if log_a < -3.94 {
+ r = -2.86
+ } else if log_a < -1.44 {
+ r = Pow(0.405 * log_a + 1.6 , 2.18) - 2.86
+ } else if log_a < -0.0184 {
+ r = log_a - 0.395
+ } else if log_a < 1.9 {
+ r = Pow(0.249 * log_a + 0.65, 2.7) - 0.72
+ } else {
+ r = log_a - 1.255
+ }
+
+ return Pow(10.0 , r)
+}
+
+
+// computes the contrast sensitivity function (Barten SPIE 1989)
+// given the cycles per degree (cpd) and luminance (lum)
+func csf(cpd, lum float64) (result float64) {
+ a := 440.0 * Pow((1.0 + 0.7 / lum), -0.2)
+ b := 0.3 * Pow((1.0 + 100.0 / lum), 0.15)
+
+ result = a * cpd * Exp(-b * cpd) * Sqrt(1.0 + 0.06 * Exp(b * cpd))
+
+ return result
+}
+
+/*
+* Visual Masking Function
+* from Daly 1993
+*/
+func mask(contrast float64) (result float64) {
+ a := Pow(392.498 * contrast, 0.7)
+ b := Pow(0.0153 * a, 4.0)
+ result = Pow(1.0 + b, 0.25)
+
+ return result
+}
+
+// convert Adobe RGB (1998) with reference white D65 to XYZ
+func AdobeRGBToXYZ(r, g, b float64) (x, y, z float64) {
+ // matrix is from http://www.brucelindbloom.com/
+ x = r * 0.576700 + g * 0.185556 + b * 0.188212
+ y = r * 0.297361 + g * 0.627355 + b * 0.0752847
+ z = r * 0.0270328 + g * 0.0706879 + b * 0.991248
+ return
+}
+
+type XYZ struct {
+ x, y, z float64
+}
+func NewXYZ() XYZ {
+ return XYZ{-1,0,0}
+}
+const epsilon = 216.0 / 24389.0
+const kappa = 24389.0 / 27.0
+
+func (xyz *XYZ) XYZToLAB(x, y, z float64) (L, A, B float64) {
+ // reference white
+ if xyz.x < 0 {
+ xyz.x, xyz.y, xyz.z = AdobeRGBToXYZ(1, 1, 1)
+ }
+ f := make([]float64, 3)
+ r := make([]float64, 3)
+ r[0] = x / xyz.x
+ r[1] = y / xyz.y
+ r[2] = z / xyz.z
+ for i := 0; i < 3; i++ {
+ if r[i] > epsilon {
+ f[i] = Pow(r[i], 1.0 / 3.0)
+ } else {
+ f[i] = (kappa * r[i] + 16.0) / 116.0
+ }
+ }
+ L = 116.0 * f[1] - 16.0
+ A = 500.0 * (f[0] - f[1])
+ B = 200.0 * (f[1] - f[2])
+ return
+}
+
+func Yee_Compare(args *CompareArgs) bool {
+ for i := 0; i < args.DownSample; i++ {
+ if args.Verbose {
+ fmt.Printf("Downsampling by %d\n", 1 << uint(i+1))
+ }
+ tmp, err := args.ImgA.DownSample()
+ if err == nil {
+ args.ImgA = tmp
+ }
+ tmp, err = args.ImgB.DownSample()
+ if err == nil {
+ args.ImgB = tmp
+ }
+ }
+
+ bounds := args.ImgA.Bounds()
+ w, h := bounds.Dx(), bounds.Dy()
+ if ((w != args.ImgB.Bounds().Dx()) || (h != args.ImgB.Bounds().Dy())) {
+ fmt.Printf("Image dimensions do not match\n")
+ return false
+ }
+
+ dim := w * h
+ identical := true
+ for ix := 0; ix < w; ix++ {
+ for iy := 0; iy < h; iy++ {
+ ca := args.ImgA.At(ix, iy).(color.RGBA)
+ cb := args.ImgB.At(ix, iy).(color.RGBA)
+ if ca.R != cb.R && ca.G != cb.G && ca.B != cb.B && ca.A != cb.A {
+ identical = false
+ break
+ }
+ }
+ }
+ if identical {
+ fmt.Printf("Images are binary identical\n")
+ return true
+ }
+
+ // assuming colorspaces are in Adobe RGB (1998) convert to XYZ
+ aX := make([]float64, dim)
+ aY := make([]float64, dim)
+ aZ := make([]float64, dim)
+ bX := make([]float64, dim)
+ bY := make([]float64, dim)
+ bZ := make([]float64, dim)
+ aLum := make([]float64, dim)
+ bLum := make([]float64, dim)
+
+ aA := make([]float64, dim)
+ bA := make([]float64, dim)
+ aB := make([]float64, dim)
+ bB := make([]float64, dim)
+
+ if args.Verbose {
+ fmt.Printf("Converting RGB to XYZ\n")
+ }
+
+ var x, y int
+ xyz := NewXYZ()
+ for y = 0; y < h; y++ {
+ for x = 0; x < w; x++ {
+ ra, ga, ba, _ := args.ImgA.At(x, y).RGBA()
+ // l is never actually used, AFAICT. Bug in original algo?
+ var r, g, b float64
+ i := x + y * w
+ r = Pow(float64(ra) / 255.0, args.Gamma)
+ g = Pow(float64(ga) / 255.0, args.Gamma)
+ b = Pow(float64(ba) / 255.0, args.Gamma)
+ aX[i], aY[i], aZ[i] = AdobeRGBToXYZ(r,g,b)
+ _, aA[i], aB[i] = xyz.XYZToLAB(aX[i], aY[i], aZ[i])
+ rb, gb, bb, _ := args.ImgA.At(x, y).RGBA()
+ r = Pow(float64(rb) / 255.0, args.Gamma)
+ g = Pow(float64(gb) / 255.0, args.Gamma)
+ b = Pow(float64(bb) / 255.0, args.Gamma)
+ bX[i],bY[i],bZ[i] = AdobeRGBToXYZ(r,g,b)
+ _, bA[i], bB[i] = xyz.XYZToLAB(bX[i], bY[i], bZ[i])
+ aLum[i] = aY[i] * args.Luminance
+ bLum[i] = bY[i] * args.Luminance
+ }
+ }
+
+ if args.Verbose {
+ fmt.Printf("Constructing Laplacian Pyramids\n")
+ }
+
+ la := LPyramid{[][]float64{aLum}, w, h}
+ lb := LPyramid{[][]float64{bLum}, w, h}
+
+ num_one_degree_pixels := (2.0 * Tan(args.FieldOfView * 0.5 * Pi / 180.0) * 180.0 / Pi)
+ pixels_per_degree := float64(w) / num_one_degree_pixels
+
+ if (args.Verbose) {
+ fmt.Printf("Performing test\n")
+ }
+
+ num_pixels := 1.0
+ var adaptation_level uint
+ for i := uint(0); i < MAX_PYR_LEVELS; i++ {
+ adaptation_level = i
+ if num_pixels > num_one_degree_pixels {
+ break
+ }
+ num_pixels *= 2
+ }
+
+ cpd := make([]float64, MAX_PYR_LEVELS)
+ cpd[0] = 0.5 * pixels_per_degree
+ for i := 1; i < MAX_PYR_LEVELS; i++ {
+ cpd[i] = 0.5 * cpd[i - 1]
+ }
+ csf_max := csf(3.248, 100.0)
+
+ F_freq := make([]float64, MAX_PYR_LEVELS - 2)
+ for i := 0; i < MAX_PYR_LEVELS - 2; i++ {
+ F_freq[i] = csf_max / csf(cpd[i], 100.0)
+ }
+
+ var pixels_failed uint
+ for y = 0; y < h; y++ {
+ for x = 0; x < w; x++ {
+ index := x + y * w
+ contrast := make([]float64, MAX_PYR_LEVELS - 2)
+ var sum_contrast float64
+ for i := uint(0); i < MAX_PYR_LEVELS - 2; i++ {
+ n1 := Abs(la.Get_Value(x,y,i) - la.Get_Value(x,y,i + 1))
+ n2 := Abs(lb.Get_Value(x,y,i) - lb.Get_Value(x,y,i + 1))
+ var numerator float64
+ if n1 > n2 { numerator = n1 } else { numerator = n2 }
+ d1 := Abs(la.Get_Value(x,y,i+2))
+ d2 := Abs(lb.Get_Value(x,y,i+2))
+ denominator := d2
+ if d1 > d2 { denominator = d1 }
+ if denominator < 1e-5 { denominator = 1e-5 }
+ contrast[i] = numerator / denominator
+ sum_contrast += contrast[i]
+ }
+ if sum_contrast < 1e-5 { sum_contrast = 1e-5 }
+ F_mask := make([]float64, MAX_PYR_LEVELS - 2)
+ adapt := la.Get_Value(x,y,adaptation_level) + lb.Get_Value(x,y,adaptation_level)
+ adapt *= 0.5
+ if adapt < 1e-5 { adapt = 1e-5 }
+ for i := 0; i < MAX_PYR_LEVELS - 2; i++ {
+ F_mask[i] = mask(contrast[i] * csf(cpd[i], adapt))
+ }
+ var factor float64
+ for i := 0; i < MAX_PYR_LEVELS - 2; i++ {
+ factor += contrast[i] * F_freq[i] * F_mask[i] / sum_contrast
+ }
+ if factor < 1 { factor = 1 }
+ if factor > 10 { factor = 10 }
+ delta := Abs(la.Get_Value(x,y,0) - lb.Get_Value(x,y,0))
+ pass := true
+ // pure luminance test
+ if delta > factor * tvi(adapt) {
+ pass = false
+ } else if !args.LuminanceOnly {
+ // CIE delta E test with modifications
+ color_scale := args.ColorFactor
+ // ramp down the color test in scotopic regions
+ if adapt < 10.0 {
+ // Don't do color test at all.
+ color_scale = 0.0
+ }
+ da := aA[index] - bA[index]
+ db := aB[index] - bB[index]
+ da = da * da
+ db = db * db
+ delta_e := (da + db) * color_scale
+ if delta_e > factor {
+ pass = false
+ }
+ }
+ if !pass {
+ pixels_failed++
+ if args.ImgDiff != nil {
+ args.ImgDiff.Set(x, y, color.RGBA{255, 0, 0, 255})
+ }
+ } else {
+ if args.ImgDiff != nil {
+ args.ImgDiff.Set(x, y, color.RGBA{0, 0, 0, 255})
+ }
+ }
+ }
+ }
+
+ different := fmt.Sprintf("%d pixels are different\n", pixels_failed)
+
+ // Always output image difference if requested.
+ if args.ImgDiff != nil {
+ if args.ImgDiff.WriteToFile(args.ImgDiff.Name) {
+ fmt.Printf("Wrote difference image to %s\n", args.ImgDiff.Name)
+ } else {
+ fmt.Printf("Could not write difference image to %s\n", args.ImgDiff.Name)
+ }
+ }
+
+ if pixels_failed < args.ThresholdPixels {
+ fmt.Printf("Images are perceptually indistinguishable\n%s\n", different)
+ return true
+ }
+
+ fmt.Printf("Images are visibly different\n%s\n", different)
+
+ return false
+}
A => perceptualdiff/main.go +88 -0
@@ 0,0 1,88 @@
+package main
+
+/*
+PerceptualDiff - a program that compares two images using a perceptual metric
+based on the paper :
+ A perceptual metric for production testing.
+ Journal of graphics tools, 9(4):33-40, 2004, Hector Yee
+Copyright (C) 2012 Sean Russell
+Based heavily on C++ code by Yangli Hector Yee
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of version 2 of the GNU General Public License as published by the
+Free Software Foundation.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+import (
+ "perceptualdiff"
+ "os"
+)
+
+func main() {
+ args := perceptualdiff.NewCompareArgs()
+
+ if !parse_Args(args) {
+ os.Exit(-1)
+ }
+
+ passed := perceptualdiff.Yee_Compare(args)
+
+ if passed {
+ os.Exit(0)
+ } else {
+ os.Exit(1)
+ }
+}
+
+
+func parse_Args(c *CompareArgs) bool {
+ flag.BoolVar(&c.Verbose, "verbose", false, "Turns on verbose mode")
+ flag.Float64Var(&c.FieldOfView, "fov", 45.0, "Field of view in degrees (0.1 to 89.9)")
+ flag.UintVar(&c.ThresholdPixels, "threshold", 100, "#pixels p below which differences are ignored")
+ flag.Float64Var(&c.Gamma, "gamma", 2.2, "Value to convert rgb into linear space")
+ flag.Float64Var(&c.Luminance, "luminance", 100.0, "White luminance")
+ flag.BoolVar(&c.LuminanceOnly, "luminanceonly", false, "Only consider luminanceignore chroma (color) in the comparison")
+ flag.Float64Var(&c.ColorFactor, "colorfactor", 1.0, "How much of color to use, 0.0 to 1.0, 0.0 = ignore color.")
+ flag.IntVar(&c.DownSample, "downsample", 0, "How many powers of two to down sample the image.")
+ output_file_name := flag.String("output", "", "Write difference to a file")
+ flag.Usage = func() {
+ fmt.Printf(copyright)
+ fmt.Printf("PeceptualDiff <image1> <image2>\n\n")
+ fmt.Printf("Compares image1 and image2 using a perceptually based image metric\n")
+ flag.PrintDefaults()
+ fmt.Printf("Note: Input or Output files can also be in the PNG or JPG format ")
+ fmt.Printf("or any format\n")
+ fmt.Printf("that FreeImage supports.\n")
+ }
+ flag.Parse()
+
+ if flag.NArg() < 2 {
+ flag.Usage()
+ return false
+ }
+
+ var err error
+ c.ImgA, err = perceptualdiff.ReadFromFile(flag.Arg(0))
+ if err != nil {
+ fmt.Printf("FAIL: Cannot open %s\n", flag.Arg(0))
+ return false
+ }
+ c.ImgB, err = perceptualdiff.ReadFromFile(flag.Arg(1))
+ if err != nil {
+ fmt.Printf("FAIL: Cannot open %s\n", flag.Arg(1))
+ return false
+ }
+
+ if *output_file_name != "" {
+ c.ImgDiff = NewRGBAImage(c.ImgA.Bounds().Dx(), c.ImgA.Bounds().Dy(), *output_file_name)
+ }
+ return true
+}
A => rgbaimage.go +129 -0
@@ 0,0 1,129 @@
+package perceptualdiff
+
+import (
+ "fmt"
+ "image"
+ "image/color"
+ "image/draw"
+ "image/jpeg"
+ "image/png"
+ "os"
+ "path"
+ _ "image/gif"
+)
+
+/*
+rgbaimage.go
+Copyright (C) 2012 Sean E. Russell
+Based heavily on C++ code by Yangli Hector Yee, which was rewritten by Jim Tilander
+
+This program is free software; you can redistribute it and/or modify it under
+the terms of version 2 of the GNU General Public License as published by the
+Free Software Foundation.
+
+This program is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE. See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+/** Class encapsulating an image containing R,G,B,A channels.
+ *
+ * Internal representation assumes data is in the ABGR format, with the RGB
+ * color channels premultiplied by the alpha value. Premultiplied alpha is
+ * often also called "associated alpha" - see the tiff 6 specification for some
+ * discussion - http://partners.adobe.com/asn/developer/PDFS/TN/TIFF6.pdf
+ *
+ */
+
+type RGBAImage struct {
+ *image.RGBA
+ Name string
+}
+
+func NewRGBAImage(w, h int, name string) *RGBAImage {
+ rv := new(RGBAImage)
+ rv.RGBA = image.NewRGBA(image.Rect(0, 0, w, h))
+ if name != "" {
+ rv.Name = name
+ }
+ return rv
+}
+
+type ImgError struct {
+ mesg string
+}
+func (i ImgError) Error() string {
+ return i.mesg
+}
+
+
+func (r *RGBAImage) DownSample() (*RGBAImage, error) {
+ b := r.Bounds()
+ if b.Dx() <= 1 || b.Dy() <= 1 {
+ return nil, ImgError{"bad boundaries"}
+ }
+ nw := b.Dx() / 2
+ nh := b.Dy() / 2
+ img := NewRGBAImage(nw, nh, r.Name)
+ for y := 0; y < nh; y++ {
+ for x := 0; x < nw; x++ {
+ d := make([]color.RGBA, 4)
+ // Sample a 2x2 patch from the parent image.
+ d[0] = r.At(2*x+0, 2*y+0).(color.RGBA)
+ d[1] = r.At(2*x+1, 2*y+0).(color.RGBA)
+ d[2] = r.At(2*x+0, 2*y+1).(color.RGBA)
+ d[3] = r.At(2*x+1, 2*y+1).(color.RGBA)
+ // Find the average color.
+ ra := (d[0].R + d[1].R + d[2].R + d[3].R) / 4
+ rg := (d[0].G + d[1].G + d[2].G + d[3].G) / 4
+ rb := (d[0].B + d[1].B + d[2].B + d[3].B) / 4
+ img.Set(x, y, color.RGBA{ra, rg, rb, 255})
+ }
+ }
+ return img, nil
+}
+
+func (r *RGBAImage) WriteToFile(filename string) bool {
+ fout, err := os.Create(filename)
+ if err != nil {
+ fmt.Print(err)
+ return false
+ }
+ defer fout.Close()
+ switch path.Ext(filename) {
+ default:
+ fmt.Printf("Can't save to unknown filetype %s\n", filename)
+ fmt.Printf("Supported extensions are png, jpg, and jpeg\n")
+ return false
+ case "png", "PNG":
+ err = png.Encode(fout, r)
+ case "jpg", "jpeg", "JPG", "JPEG":
+ err = jpeg.Encode(fout, r, &jpeg.Options{100})
+ }
+ if err != nil {
+ fmt.Print(err)
+ return false
+ }
+ return true
+}
+
+func ReadFromFile(filename string) (*RGBAImage, error) {
+ fin, err := os.Open(filename)
+ if err != nil {
+ return nil, err
+ }
+ defer fin.Close()
+
+ fimg, _, err := image.Decode(fin)
+ if err != nil {
+ return nil, err
+ }
+ b := fimg.Bounds()
+ rgba := image.NewRGBA(image.Rect(0, 0, b.Dx(), b.Dy()))
+ draw.Draw(rgba, rgba.Bounds(), fimg, b.Min, draw.Src)
+ return &RGBAImage{rgba, filename}, nil
+}