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