File:Kcc rescale 02 im box filter.jpg
Kcc_rescale_02_im_box_filter.jpg (557 × 425 pixels, file size: 86 KB, MIME type: image/jpeg)
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Summary
| Description |
English: Part of a series of images to compare and contrast the levels of spatial aliasing that can result when an image that contains some strong spatial frequencies is digitally rescaled. An image of an 1801 engraving of King's College Chapel, Cambridge was used as a test object, and resized to 50% using different filters and different programs.
The image on this page was resized to 50% using Image Magick 6.7.5 with the "box filter" option -- i.e. straight-forward averaging over 4 old pixels to create each new one. Compared to decimation, the unwanted Moiré patterns are much reduced. They are essentially no longer visible in the road and the building and the clouds. However, although softened a bit, they do still remain in the sky. Other images in the series look at the results of using other available lowpass filters to try to further minimse or suppress such artefacts. |
| Date | |
| Source |
This file was derived from: F. Roffe after P. Nash (1801) - King's College Chapel - sanders13001.jpg an engraving first published in 1801. |
| Author | John Roffe (1769-1850), engraver, after Frederick Nash (1782–1856) |
| Other versions |
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Source code
convert kcc.jpg -filter box -resize 50% kcc_im_box_filter.jpg
Licensing
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This is a faithful photographic reproduction of a two-dimensional, public domain work of art. The work of art itself is in the public domain for the following reason:
The official position taken by the Wikimedia Foundation is that "faithful reproductions of two-dimensional public domain works of art are public domain".
This photographic reproduction is therefore also considered to be in the public domain in the United States. In other jurisdictions, re-use of this content may be restricted; see Reuse of PD-Art photographs for details. | ||||
_-_King%27s_College_Chapel_-_sanders13001.jpg){kind=link}
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 19:08, 6 March 2012 | | 557 × 425 (86 KB) | Jheald |
File usage
The following 2 pages use this file:
