Re: [vox-tech] count pixels

[Wade Pinkston <blata@extent0006.entomology.ohio-staMAPSte.edu>]

I made this image with gimp as a test image.  The image is 100% #ff0000 
no matter what I convert the image to I don't get a pixel count.

$ identify -verbose red1.tiff
Image: red1.tiff
  Format: TIFF (Tagged Image File Format)
  Geometry: 256x256
  Class: DirectClass
  Colorspace: RGB
  Type: Palette
  Depth: 1 bits
  Endianess: MSB
  Channel depth:
    Red: 1-bits
    Green: 1-bits
    Blue: 1-bits
  Channel statistics:
    Red:
      Min: 1
      Max: 1
      Mean: 1
      Standard deviation: 0
    Green:
      Min: 0
      Max: 0
      Mean: 0
      Standard deviation: 0
    Blue:
      Min: 0
      Max: 0
      Mean: 0
      Standard deviation: 0
  Colors: 1
  Histogram:
  Rendering-intent: Undefined
  Resolution: 72x72
  Units: PixelsPerInch
  Filesize: 192kb
  Interlace: None
  Background Color: white
  Border Color: #DFDFDF
  Matte Color: grey74
  Dispose: Undefined
  Iterations: 0
  Compression: None
  Orientation: TopLeft
  document: /home/blata/red1.tiff
  comment: Created with The GIMP
  signature: 
d764b5e26d0f9155ebf131dcbf35ecaae5b3508c4b7d240173f5fe85b406ae64
  Tainted: False
  User Time: 0.000u
  Elapsed Time: 0:01

This image is the same with three white ovals cut out of the red.  Again 
no pixel count.  If I could get a simple pixel count per color then I 
can do the math and all is good.

identify -verbose red2.tiff
Image: red2.tiff
  Format: TIFF (Tagged Image File Format)
  Geometry: 256x256
  Class: DirectClass
  Colorspace: RGB
  Type: Palette
  Depth: 8 bits
  Endianess: MSB
  Channel depth:
    Red: 1-bits
    Green: 8-bits
    Blue: 8-bits
  Channel statistics:
    Red:
      Min: 255
      Max: 255
      Mean: 255
      Standard deviation: 0
    Green:
      Min: 0
      Max: 255
      Mean: 32.4795
      Standard deviation: 84.5242
    Blue:
      Min: 0
      Max: 255
      Mean: 32.4795
      Standard deviation: 84.5242
  Colors: 105
  Histogram:
  Rendering-intent: Undefined
  Resolution: 72x72
  Units: PixelsPerInch
  Filesize: 192kb
  Interlace: None
  Background Color: white
  Border Color: #DFDFDF
  Matte Color: grey74
  Dispose: Undefined
  Iterations: 0
  Compression: None
  Orientation: TopLeft
  document: /home/blata/red2.tiff
  comment: Created with The GIMP
  signature: 
1e69860505dfe98ecbede60074549452546deb485ce49723f2feb62ab73b40c9
  Tainted: False
  User Time: 0.000u
  Elapsed Time: 0:01



Troy Arnold wrote:
> On Wed, Feb 21, 2007 at 07:27:20PM -0800, Wade Pinkston wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > Hello,  I need to process some images and count the number of pixes of a
> > given color.
> >
> > A little background.  I want to take pix of leaves against a mat
> > background.  The leaves are then subjected to damage.  I'll then take a
> > duplicate photo.  Now what I want to do is subtract out the colors of the
> > leaf leaving only a two tone image.
> >
> > I was hoping to find a way to then use ImageMagick or Gimp to count the
> > pixels of color so I can then get a percent change between the two images.
> >
> > Does anybody know how to get ether of these two programs to give this type
> > of information.  Actually any software would be help full.
> If the image is in an indexed format, you can use identify from the
> imagemagick suite:
>
> $ identify -verbose some.gif
> [...]
>        155: (238,238,238,  0)   #EEEEEE00
>        244: (245,245,242,  0)   #F5F5F200
>        264: (249,249,249,  0)   #F9F9F900
>        139: (252,252,252,  0)   grey99
>       3885: (255,255,255,  0)   white
>       3197: (235,235,217,255)   #EBEBD9FF
>
> [...]
> This shows that this image has 3,885 white pixels.
>
>
> -troy
>
>
>
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> vox-tech@lists.lugod.org
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--
Wade Pinkston

Ipsa scientia potestas est

Windows,a
32 bit graphical interface for a
16 bit patch to an
8 bit operating system internally coded for a
4 bit processor written by a
2 bit company that can't stand
1 bit of competition

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