ImageTrim

ImageTrim[image,roi]

gives the smallest subimage of image that includes the specified region of interest roi.

ImageTrim[image,roi,r]

adds a margin of size r back to the resulting image.

ImageTrim[image,{roi1,roi2,…},…]

extracts multiple subimages specified by roii from image.

ImageTrim[video,…]

extracts the subimages from video.

Details and Options

  • Image trimming, also known as image cropping, is the process of removing border pixels from an image and is typically used for extracting regions of interest.
  • ImageTrim[image,roi] returns a subimage containing the region of interest roi. The region roi can be any of the following:
  • {{x1,y1},…}or {{x1,y1,z1},…}a list of 2D or 3D image positions
    regiona 2D or 3D geometric region (Point, Rectangle, etc.)
    maskimagenonzero pixels of a 2D or 3D object
    fa region returned by a function f
  • For video inputs, the trim specification can be a fixed specification for all frames or a function of time (in seconds from the start).
  • ImageTrim assumes the standard image coordinate system.
  • For integer coordinate values the trimmed image will include all pixels touching the point . Coordinates lie at the center of pixels. »
  • ImageTrim[image,{pt1,…},{rx,ry}] specifies different horizontal and vertical margins.
  • The following options can be given:
  • DataRange Fullrange of pixel positions in image
    Padding Nonepadding scheme to use
  • By default, if fewer elements exist than are requested, ImageTrim returns the elements that are present. By setting the Padding option to anything else, pixels outside the original image can also be included. »
  • Possible settings for DataRange include:
  • Automatic{{0,1},{0,h/w}} in 2D, {{0,1},{0,d/w},{0,h/w}} in 3D
    Full{{0,w},{0,h}} in 2D, {{0,1},{0,d},{0,h}} in 3D (default)
    {{left,right},{bottom,top}}explicit coordinate ranges in 2D
    {{left,right},{front,back},{bottom,top}}explicit coordinate ranges in 3D

Examples

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Basic Examples  (1)

Trim an image:

Scope  (7)

Data  (3)

Trim a 2D image:

Trim frames of a video:

Trim a 3D image:

Region of Interest  (3)

Extract a single-pixel image:

Extract an image containing a list of positions:

Specify the region of interest using a graphics primitive:

Extract an image containing the nonzero pixels of a reference image:

Define the region of interest using a function:

Trim multiple regions of interest:

Trim frames of a video using a region that evolves with time:

Extract three slices from a 3D image:

Trim multiple regions of interest:

Margin  (1)

By default, no extra margin is added to the trimmed regions:

This is equivalent to zero margin:

Use a larger margin:

Options  (2)

DataRange  (1)

Remove pixels from each side using the standard coordinate system:

This is equivalent to DataRange->Full:

Remove 25% of pixels from each side using a scaled coordinate system:

Padding  (1)

By default, the returned subimage is not padded to include coordinates outside of an image:

Pad the subimage to include all specified coordinates:

Applications  (7)

Trim faces detected from an image:

Trim lines of detected text from an image:

Trim the detected barcode:

Trim the area around the maximum:

Trim around an object of a specific color:

Trim areas that contain no keypoints:

Add some margins around keypoints:

Trim a 3D image to a detected region of interest:

Find the region of interest:

Trim the volume around it:

Mask the image with the region of interest before trimming:

Properties & Relations  (2)

Half-integer coordinates represent the center of the pixels and return the specific pixel:

Integer coordinates yield an image including all neighboring pixels:

Show the two pixel positions on the image:

Trimming with multiple coordinates is the same as using their bounds:

Compute the coordinate bounds:

Wolfram Research (2010), ImageTrim, Wolfram Language function, https://reference.wolfram.com/language/ref/ImageTrim.html (updated 2021).

Text

Wolfram Research (2010), ImageTrim, Wolfram Language function, https://reference.wolfram.com/language/ref/ImageTrim.html (updated 2021).

CMS

Wolfram Language. 2010. "ImageTrim." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2021. https://reference.wolfram.com/language/ref/ImageTrim.html.

APA

Wolfram Language. (2010). ImageTrim. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ImageTrim.html

BibTeX

@misc{reference.wolfram_2022_imagetrim, author="Wolfram Research", title="{ImageTrim}", year="2021", howpublished="\url{https://reference.wolfram.com/language/ref/ImageTrim.html}", note=[Accessed: 27-March-2023 ]}

BibLaTeX

@online{reference.wolfram_2022_imagetrim, organization={Wolfram Research}, title={ImageTrim}, year={2021}, url={https://reference.wolfram.com/language/ref/ImageTrim.html}, note=[Accessed: 27-March-2023 ]}