Using imagemagick to identify all files in multiple subfolders - Super User
Large scale test of sensor fingerprint camera identification. Lens Correction -- IM v6 Examples. misjon.info, .. in which the image plane is recursively partitioned into quadrants. . Gait recognition systems often suffer from the challenges when query gaits are under the. in ImageMagick without restriction, including without limitation the rights to use, copy, modify, merge, ick utilities (animate, composite, convert, display, identify, import, mogrify and montage). depth Limit the plasma recursion depth. the relationship between QuantumDepth, the type of Quantum, and the overall. I have a stash of *.tif files that need to be converted to *.pdf's, but they're unfortunately in a complex tree of directories and subdirectories (some.
One varient of floating point numbers is used by " -sparse-color ", allowing you to substitute colors for some floating point values. Internally these are still converted to floating point values when the resulting array is passed into the core library function.
Freeform Strings Other options just take a string as an argument. Either for generating labels, annotating text, or saving as image meta-data. These will typically include Percent Escapes in the string which are replaced substituted at some point before the string is used. It may be an immediate substitution, or the substitution may be performed later, just before the arguemnt is actually used.
See Delayed Percent Escapes below. Arguments with Percent Escapes Because of their nature, either of last two types of arguments are often pre-processed so as to expand Image Properity Percent Escape within the string.
That means that specific sequences of characters will be expanded string replaced or substituted into some other string, or value that is looked up or calculated from the image s being processed. This typically is done just before the argument is actually are applied by the operator to a specific image, so that settings specific to that image can be used. If percent escapes are allowed in an argument, you can instead prefix the argument with a ' ' so that the whole argument is instead read from the given external file or standard input.
For example ' filename' will be replaced with the contents of the file 'filename'. If this happens, no percent or other special escapes is applied. That is string read from the file will be taken as literal, and used without modification. As such web users should pre-check input strings for this special case, or better still feed that string to IM using the ' filename' clause, as a security measure.
See Image Properity Percent Escapes for the complete list of replacements. The use of Percent Escapes in arguments, means that for growing list of operators that allow the use of such escapes, such as " -set "," -sparse-color ", " -distort ", or " -morphology ", you can generate arguments based in various image attributes and meta-data.
Not only that but you can even calculate different arguments depending in the content or index of the image! You can even pre-calculate some complex settings using per-image or predefined global settings. Typically they would only return unhelpful values of either '0' or '1', and not the actual index and number of images in the current image list.
Delayed Percent Escapes Note that for some setting options Percent Escapes are not be expanded immediately they are seen, but simply stored AS given. It is only later when the text is actually used, that any Percent Escapes found in the string should be expanded, when the image they will be used with are finally known. That is these arguments must delay the substitution of Percent Escapes until the argument is actually used. These options include the Input Settings such as: This means you can specify a " -label " containing image specific Percent Escapes long before the image it is to be applied to is actually read in.
Only when the label is actually attached to the image just after it is read in is the Percent Escapes expanded, so that it can make use of the attributes of the image to which it is being applied. The major limitation to the more wide spread use of Percent Escapes is that it is currently only applied to a limited set of option arguments.
For example we currently can not use them with Geometry Argumentswhich also use 'percent' characters, but for a different purpose. This problem is one of the major problems that IMv7 that will be fixing.
ImageMagick Commands While the bulk of these ImageMagick example pages use the "convert" command to process images, there are a number of other ImageMagick commands, which I'll briefly introduce here. Some of these commands however can not be demonstrated properly on a web page.
However I will try to give you hints and tips involving those commands here, even if I can't actually show their output directly, here. Convert -- Convert and Modify Images The "convert" command is the main workhorse of ImageMagick, and as such just about every set of examples in these pages uses this command. As such I will not cover the use of this command much here, but look at a little history instead. The command original commands purpose when IM was first created was for the conversion of images in one image format into another.
In fact it is still used for this purpose, and why it is called "convert". Because of this the command may not even read an image into memory, but may use secondary Delegate programs outside IM proper to do the conversion directly. This completely external aspect however has fallen into disuse over time, and lack of need, except as a means of reading in and writing out complex images file formats.
Over a long period of time some extra image processing features was added to make minor changes to images as they were transferred between formats, or even the same format.
These were generally simple options, but as of IM version 5 the use of these processing features had become extensive, and a far more important aspect to the "convert" command than just image conversion. As options multiplied, multiple options started to be used, the order of the options started producing weird and uncontrollable results. To users IM became known as unstable and uncontrollable when multiple image processing options was used, and it started to fall into disfavor.
IM version 6 saw the switch from a simple 'options' style, to a 'do it as you see it' style for image processing, and as a result, image processing abilities become stable, predictable and IM's command line abilities became many orders of magnitude more useful.
As a result of this, "convert", is no longer so much about 'converting' images from one format to another, but as a command line API for accessing image processing functions, to create, and modify images in very complex ways, without needing a degree in image processing, or programming in a computer language such as Perl, PHP, or C.
Of course some shell scripting knowledge is helpful, though not strictly required. By default it outputs a simple compact summery, detailing the images name, file format, image size, virtual canvas size and offset, color depth, internal format type, and if known the original size of the image on disk in human terms. Also note that the image 'virtual canvas' is the same size as the actual image with a zero offset, meaning it is currently not being used.
Fred's ImageMagick Scripts: TEXTEFFECT
Adding a -verboseOperational Controlwill produce as much information about the image that IM knows about or can easily calculate.
This includes color statistics, color counts, profile information, internal image save type of the image, etc. However be warned that the output really is For example you can just extract a count of the number of colors within an image. This is no longer done, so you may need to add your own appropriate EOL characters to the " -format " string. Identify, to Ping or not to Ping IM " identify " by default only reads minimal basic information about an image, using a technique know as " -ping ".
This means identify only reads enough of the image file to determine simple image information, such as size, without trying to read the whole image into memory. See Ping, Operational Control below. This is a big advantage of " identify " has over " convert ". However, most image meta-data will not be available.
For example, image labels from a PNG image file. For example, here I create a image with a 'label', and attempt to use a simple format setting to print out that label. Any " -format " that has more complex escapes will automatically disable the use of a minimal 'ping' read. Unless you are dealing with very large images such as photos.
As we are only needing basic information we used the Ping control to prevent identify from reading in the whole image. It has no effect on the outcome in this case, but can speed up the command enormously. Extra Cavats about Identify Specific Format Details Normally IM reads in the image into memory which is essentially into own internal data formatusing various image library APIs and delegate programs, before outputting the results it sees using identify. It does not analyze how the specific file format stores or handles the image data.
This is important as there can be very specific aspects of specific file formats that "identify" will not report on. For example while it lists the contents of a GIF image color table for each image present multiple images are possibleit will not tell you if all the images in the file share the same color table or not.
If you need specific info about specific image file format, it may be better to use a tool designed specifically for that format.
Color Histogram Output Note that if image has more that colors, no histogram or color tables will be included in the verbose output. To force the generation of this information you can use the special ' histogram: Exit Status The identify program returns a non-zero exit status if a corrupted image is encountered and you add a Regard Warnings Control.
You can use a Write Operator to write to " info: You can also have it write that output to a specific file or file stream. A simplier method would be to use an " -identify " option to write to the normal 'standard output'.
This can be also combined with another option, " -print " to output other information. The main difference between " -identify " and " -print ", is that first will be run once for every image in memory, while the later will only run once. That means we can generate just about any text file we want about the images in memory, completely from within a single ImageMagick command.
One final word about these options. All of them by default will print to the 'standard output' of the "convert" command. You can not specifically output to some other 'pipeline' or to a specific file, unless you previously re-directed 'standard output'. Writing the output using " info: You can also direct the output to a previously prepared file descriptor, using the special " fd: Of course that writes once per image, so some juggling of images may be needed to arrange for it to output once only.
Mogrify -- in-place batch processing The "mogrify" command is in many ways like "convert" except it is designed to modify images in place.
That is it's primary purpose is to read images or animationsone file at a time, and modify them, before save the image back into the exact same filename the image was read from. Mogrify is dangerous, as it can easily destroy the original image!
As such, before you do anything final, test "mogrify" with a separate copy of your images. Do not do use it on an original image that has no backup. Now while "mogrify" normally saves a modified image into the same filename, it has two special options which allows it to save images into a different file. The "mogrify" specific setting " -format ", defines a different format and suffix to use when saving files. As such a command like However be warned that if there is an existing file with the same name, it will be over-written.
So let me re-iterate Think and check before you Mogrify or you may find you just overwrote something you wanted to keep. As of IM v6. This makes it safer, however it will still overwrite any images of the same name that may already be in that directory. Also any old images that was left in that directory will not be removed.
As such you can have IM save the results say image thumbnails into a existing sub-directory, using something like this From that version you can change formats and output directory location. Due to the multi-image processing capability the "mogrify" command can not use any of the Multi-Image List Operators or Image Stack Operators.
As some setting options are needed to be set before the first image is read in for example for example " -size ", " -label " and " -density "these options are processed and set before the first image is read in. After this each image is read in and the operators applied to them in command line order before the image is saved and the next image read in.
It is important to keep this in mind as if you change one of these settings later in the sequence you can make IM forget a previous setting. On the other hand the operational setting " -font " is set correctly for each of the individul " -annotate " operations. This added complexity means that it is probably a good idea to Do not attempt to do very long and complex "convert"-like operations in a batch operation using "mogrify", it will probably have 'setting' issues.
For examples of modifying lots of images using a script see Advanced ImageMagick Examples. Just remember, "mogrify" is a dangerous command, and should always be thoroughly tested on backup images, before putting into production. Actually I also recommend that scripts include a quick 'tests' on things like "mogrify" to make sure the command does not break anything due to version changes or differences in computer installations before processing a very large collection of images.
That is do a small 'test case' and abort if it fails to produce a correct, before proceeding. This is actually a good idea for any large scale image processing project, so as to protect users from unforeseen consequences.
I do this myself in IM Examples, and it has saved me a lot of trouble. Alpha Composition using "mogrify" Because "mogrify" can not use Multi-Image List Operators it can not easily overlay thing like logos, or mask images using Alpha Composition.
There is one exception to this, using " -draw " to perform image alpha composition. This allows you to specify the second image, as part of the operators arguments, outside of the current image list. This image file format does not need to be parsed by IM as it will be mapped directly from disk into memory for the same machine it was created on.
This saves a lot of processing time, especially in dealing with a large number of images. Using Convert Instead of Morgify Using a special technique to modify the output filename using Percent Escapessee Filename Percent Escapesyou can replace " mogrify " with a more versatile " convert " command. Not only that but it will provide you with a more control of the final destination name of the image.
IM will not see it when deciding on the image file format to use. Note that IM can't decide from the filename it will fall back to the original file format that was read in, so a clear suffix, or a coder prefix can be important, when using this technique.
Of course these all have the filename suffix, in the filename setting, whch IM does not use, but that should be okay as it is the same image file format. The real problem with using " convert " instead of " mogrify " is that ALL the images are read into memory first! But " convert " does not. As such you can very easily exceed memory limits if you are not careful. Though there are ways around this. See examples in Read Modifiers and Thumbnails.
Also as all the images are in memory as a single image list, you will need to be careful on how you process those images. For example you can not directly use Alpha Composition as you normally would, but may need to use the specialised Multi-Image List Composition to do the job.
Of course just as with "mogrify" this method of using "convert" can be dangerous, as it could easily overwrite and destroy the original image files. Batch Processing Alternatives If batch processing images using "mogrify" is not practical, especially if you are copying the images rather than modifying them in place, then it may be better to use some other non-IM looping solutions.
Use a simple shell loop, to process each of the images. This also provides the ability to recurse though directories by removing the -prune option, as well as doing other file checks like image type, or the disk space used by an image. I recommend the use of both "find" and "xargs" for doing recursive or even non-recursive file processing.
Read their man pages. For a quick introduction see this IM Discussion Postas well as the guide Xargs - Wikipedia which includes information on the dangers involved. If your commands start to get more complicated than this, it may be time to go to a shell script, or API program, to read in multiple images, gather information, calculate appropriate arguments, and process the images.
I also recommend a good look at the " parallel " command typically a drop in replacement for "xargs". This can not only let you run multiple commands simultaneously, but can with a little work run each command on different computers, allowing you to do network distributed processing of a very large number of tasks.
This is done to allow the use of these meta-characters on the old DOS command line shell. However this could cause a bug, repeated mogrify execution, or possibly even a 'hack' from a some evil source that provided the filename to use. Caution and complete understanding of security issues is advised. Composite -- overlaying images in special ways The "composite" command is designed specifically for simple alpha compositing overlaying of two images together in various ways.
This includes limiting the area in which images are combined together, though the use of a third masking image. Outline is text that has an outline or border around it of user specified thickness and presumably of a different color. Glow has an outline and a glow effect. Both shadows have an outline and a shadow effect darkening on the SouthEast side. Stamp is similar to hardshadow, but has the darkening on the NorthWest side in order to make a stamped or indented effect.
Bevel has brightening on the NorthWest and darkening on the SouthEast. Antibevel is the opposite with brightening on the SouthEast and darkening on the NorthWest. Bevel and antibevel allow both a line weight and smudge to soften the style.
Innerbevel and roundbevel have brightenning on the Northwest side and darkening on the SouthEast side, but inside the text rather than on the outside as in Bevel. The innerbevel amount is determined by the linewt. Plain and outline allow an undercolor. The others do not. The default is plain. Values are floats between and Values may be floats greater than 0.
Glow and shadow styles require lineweights of atleast 1. The default is 1 pixel.
Values may be floats between 0 and 1. The default is 0. Larger values produce more distortion, i. Values are floats ranging from to degrees. Padding will be background color. See below for background color. Excess-area padding is an integer greater than or equal to 0. The default is 10 pixels. Any single valid IM color or any dual hyphenated opaque-opaque or opaque-none combination may be used. If a hyphenated pair of different colors is provided, a gradient effect will be produced.
The default is skyblue. Any valid IM text color may be used. The default is black. The default is white. Use none for transparent background.