Logicool C200で撮影したJPGファイルが対象。
対象環境
- Raspberry pi 3 Model B
- Raspbian jessie 2016-09-23
前提
Exif情報
閲覧する
C200にはExif情報が付与されない？
$ identify -verbose /tmp/work/img/20180912070626_F0.jpg
Image: /tmp/work/img/20180912070626_F0.jpg
Format: JPEG (Joint Photographic Experts Group JFIF format)
Mime type: image/jpeg
Class: DirectClass
Geometry: 640x480+0+0
Resolution: 96x96
Print size: 6.66667x5
Units: PixelsPerInch
Type: TrueColor
Endianess: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
Pixels: 307200
Red:
min: 0 (0)
max: 255 (1)
mean: 19.1263 (0.0750052)
standard deviation: 9.28849 (0.0364254)
kurtosis: 167.136
skewness: 7.96758
Green:
min: 0 (0)
max: 140 (0.54902)
mean: 14.3607 (0.0563164)
standard deviation: 3.52827 (0.0138364)
kurtosis: 75.6936
skewness: 3.67261
Blue:
min: 0 (0)
max: 108 (0.423529)
mean: 5.32058 (0.020865)
standard deviation: 2.68146 (0.0105155)
kurtosis: 99.0157
skewness: 4.20816
Image statistics:
Overall:
min: 0 (0)
max: 255 (1)
mean: 12.9359 (0.0507289)
standard deviation: 5.9418 (0.0233012)
kurtosis: 389.521
skewness: 12.5804
Rendering intent: Perceptual
Gamma: 0.454545
Chromaticity:
red primary: (0.64,0.33)
green primary: (0.3,0.6)
blue primary: (0.15,0.06)
white point: (0.3127,0.329)
Background color: white
Border color: srgb(223,223,223)
Matte color: grey74
Transparent color: black
Interlace: None
Intensity: Undefined
Compose: Over
Page geometry: 640x480+0+0
Dispose: Undefined
Iterations: 0
Compression: JPEG
Quality: 100
Orientation: Undefined
Properties:
comment: CREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 255
date:create: 2018-09-12T07:06:34+09:00
date:modify: 2018-09-12T07:06:27+09:00
jpeg:colorspace: 2
jpeg:sampling-factor: 2x2,1x1,1x1
signature: c8a76884c13ea0ea29ff3914bf57b3976efc8062044aeb480030ef409fecf538
Artifacts:
filename: /tmp/work/img/20180912070626_F0.jpg
verbose: true
Tainted: False
Filesize: 15.2KB
Number pixels: 307K
Pixels per second: 10.24MB
User time: 0.040u
Elapsed time: 0:01.029
Version: ImageMagick 6.8.9-9 Q16 arm 2018-06-26 http://www.imagemagick.org
削除する
$ convert -strip /tmp/before.jpg /tmp/after.jpg
| ファイル | サイズ |
|---|---|
| /tmp/before.jpg | 14.8KB |
| /tmp/after.jpg | 13.2KB |
削除後のExif閲覧すると以下。
$ identify -verbose /tmp/work/img/20180912070626_F0_convert.jpg
Image: /tmp/work/img/20180912070626_F0_convert.jpg
Format: JPEG (Joint Photographic Experts Group JFIF format)
Mime type: image/jpeg
Class: DirectClass
Geometry: 640x480+0+0
Resolution: 96x96
Print size: 6.66667x5
Units: PixelsPerInch
Type: TrueColor
Endianess: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
Pixels: 307200
Red:
min: 0 (0)
max: 255 (1)
mean: 19.1208 (0.0749836)
standard deviation: 9.21754 (0.0361472)
kurtosis: 161.701
skewness: 7.77976
Green:
min: 0 (0)
max: 133 (0.521569)
mean: 14.3508 (0.0562778)
standard deviation: 3.51319 (0.0137772)
kurtosis: 70.038
skewness: 3.57098
Blue:
min: 0 (0)
max: 102 (0.4)
mean: 5.34156 (0.0209473)
standard deviation: 2.67788 (0.0105015)
kurtosis: 102.004
skewness: 4.3912
Image statistics:
Overall:
min: 0 (0)
max: 255 (1)
mean: 12.9377 (0.0507362)
standard deviation: 5.90132 (0.0231424)
kurtosis: 376.659
skewness: 12.3229
Rendering intent: Perceptual
Gamma: 0.454545
Chromaticity:
red primary: (0.64,0.33)
green primary: (0.3,0.6)
blue primary: (0.15,0.06)
white point: (0.3127,0.329)
Background color: white
Border color: srgb(223,223,223)
Matte color: grey74
Transparent color: black
Interlace: None
Intensity: Undefined
Compose: Over
Page geometry: 640x480+0+0
Dispose: Undefined
Iterations: 0
Compression: JPEG
Quality: 100
Orientation: Undefined
Properties:
date:create: 2018-09-12T08:19:01+09:00
date:modify: 2018-09-12T08:19:01+09:00
jpeg:colorspace: 2
jpeg:sampling-factor: 2x2,1x1,1x1
signature: e2c9f02fc547b6e2fa5f29d8937febdb34dc0a1db23cf3fd6c458651a4105276
Artifacts:
filename: /tmp/work/img/20180912070626_F0_convert.jpg
verbose: true
Tainted: False
Filesize: 13.6KB
Number pixels: 307K
Pixels per second: 7.68MB
User time: 0.040u
Elapsed time: 0:01.039
Version: ImageMagick 6.8.9-9 Q16 arm 2018-06-26 http://www.imagemagick.org
どの情報が削除されたのかわかりにくい。Web Diff ツールを使って比較すると……
削除前と比べて以下の情報が削除されていた。
comment: CREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 255
