Preparation of Digital Images for Presentation and Publication
Eric J. Stern1 and
Michael L. Richardson2
1 Department of Radiology, University of Washington School of Medicine,
Harborview Medical Center, 325 Ninth Ave., Box 359728, Seattle, WA
98104-2499.
2 Department of Radiology, University of Washington School of Medicine,
University of Washington Roosevelt Radiology, 4245 Roosevelt Way N.E., Box
354755, Seattle, WA 98105.
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Fig. 1A. —Sample radiograph of finger. Screen shot shows Adobe
Photoshop (Adobe Systems, San Jose, CA) "Levels" control
window.
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Fig. 1B. —Sample radiograph of finger. Radiographs show effects of
performing "Auto Adjust Levels" feature to improve image quality
(step 3).
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Fig. 1C. —Sample radiograph of finger. Radiographs show effects of
performing "Auto Adjust Levels" feature to improve image quality
(step 3).
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Fig. 2A. —20-year-old man with primary tuberculosis. Chest radiographs
show effect on physical size of rescaling image (step 4), in this case from a
5-inch-tall (12.7-cm) image to 3-inch-tall (7.62-cm) image.
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Fig. 2B. —20-year-old man with primary tuberculosis. Chest radiographs
show effect on physical size of rescaling image (step 4), in this case from a
5-inch-tall (12.7-cm) image to 3-inch-tall (7.62-cm) image.
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Fig. 2C. —20-year-old man with primary tuberculosis. Screen shot shows
Adobe Photoshop (Adobe Systems, San Jose, CA) window for controlling image
size and performing rescaling function.
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Fig. 3A. —20-year-old man with primary tuberculosis. Series of
otherwise identical (600 dpi [dots per inch], 3.7 MB [megabytes] [A];
300 dpi, 968 KB [kilobytes] [B]; 150 dpi, 252 KB [C]; 72 dpi, 68
KB [D]; 30 dpi, 24 KB [E]) single chest radiographs show effect
of differing levels of resolution on appearance of printed digital image with
identical physical size and on size of image file. All images were saved as
uncompressed TIFF (tagged image file format) files and sampled from original
image obtained from our PACS (picture archiving and communication system)
workstation. Apparent quality is influenced by monitor on which images are
displayed or by printer output.
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Fig. 3B. —20-year-old man with primary tuberculosis. Series of
otherwise identical (600 dpi [dots per inch], 3.7 MB [megabytes] [A];
300 dpi, 968 KB [kilobytes] [B]; 150 dpi, 252 KB [C]; 72 dpi, 68
KB [D]; 30 dpi, 24 KB [E]) single chest radiographs show effect
of differing levels of resolution on appearance of printed digital image with
identical physical size and on size of image file. All images were saved as
uncompressed TIFF (tagged image file format) files and sampled from original
image obtained from our PACS (picture archiving and communication system)
workstation. Apparent quality is influenced by monitor on which images are
displayed or by printer output.
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Fig. 3C. —20-year-old man with primary tuberculosis. Series of
otherwise identical (600 dpi [dots per inch], 3.7 MB [megabytes] [A];
300 dpi, 968 KB [kilobytes] [B]; 150 dpi, 252 KB [C]; 72 dpi, 68
KB [D]; 30 dpi, 24 KB [E]) single chest radiographs show effect
of differing levels of resolution on appearance of printed digital image with
identical physical size and on size of image file. All images were saved as
uncompressed TIFF (tagged image file format) files and sampled from original
image obtained from our PACS (picture archiving and communication system)
workstation. Apparent quality is influenced by monitor on which images are
displayed or by printer output.
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Fig. 3D. —20-year-old man with primary tuberculosis. Series of
otherwise identical (600 dpi [dots per inch], 3.7 MB [megabytes] [A];
300 dpi, 968 KB [kilobytes] [B]; 150 dpi, 252 KB [C]; 72 dpi, 68
KB [D]; 30 dpi, 24 KB [E]) single chest radiographs show effect
of differing levels of resolution on appearance of printed digital image with
identical physical size and on size of image file. All images were saved as
uncompressed TIFF (tagged image file format) files and sampled from original
image obtained from our PACS (picture archiving and communication system)
workstation. Apparent quality is influenced by monitor on which images are
displayed or by printer output.
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Fig. 3E. —20-year-old man with primary tuberculosis. Series of
otherwise identical (600 dpi [dots per inch], 3.7 MB [megabytes] [A];
300 dpi, 968 KB [kilobytes] [B]; 150 dpi, 252 KB [C]; 72 dpi, 68
KB [D]; 30 dpi, 24 KB [E]) single chest radiographs show effect
of differing levels of resolution on appearance of printed digital image with
identical physical size and on size of image file. All images were saved as
uncompressed TIFF (tagged image file format) files and sampled from original
image obtained from our PACS (picture archiving and communication system)
workstation. Apparent quality is influenced by monitor on which images are
displayed or by printer output.
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Fig. 3F. —20-year-old man with primary tuberculosis. Close-up chest
radiographs of Figure 3B
(F) and Figure 3E
(G) are shown magnified for comparison and visualization of effects of
compression.
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Fig. 3G. —20-year-old man with primary tuberculosis. Close-up chest
radiographs of Figure 3B
(F) and Figure 3E
(G) are shown magnified for comparison and visualization of effects of
compression.
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Fig. 4A. —Sample radiograph of cervical spine. Lateral cervical spine
radiographs show comparison of maximal (A) and minimal (B)
quality JPEG (Joint Photographic Experts Group) images.
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Fig. 4B. —Sample radiograph of cervical spine. Lateral cervical spine
radiographs show comparison of maximal (A) and minimal (B)
quality JPEG (Joint Photographic Experts Group) images.
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Fig. 4C. —Sample radiograph of cervical spine. Subtraction images of
lateral cervical spine radiographs show what is removed from JPEG image during
compression: original image minus maximal-quality JPEG compressed image.
Little image detail is lost from original image during maximal-quality
compression (C). More detail is lost in maximal-quality JPEG compressed
images (D). Considerably more image detail of skull and cervical spine
is lost as one progresses from maximal- to minimal-quality compression.
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Fig. 4D. —Sample radiograph of cervical spine. Subtraction images of
lateral cervical spine radiographs show what is removed from JPEG image during
compression: original image minus maximal-quality JPEG compressed image.
Little image detail is lost from original image during maximal-quality
compression (C). More detail is lost in maximal-quality JPEG compressed
images (D). Considerably more image detail of skull and cervical spine
is lost as one progresses from maximal- to minimal-quality compression.
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Fig. 5A. —20-year-old man with primary tuberculosis. Chest radiographs
show effect of decreasing JPEG (Joint Photographic Experts Group) image
compression (JPEG level 1, 48 KB [kilobytes] [A]; JPEG level 7, 132 KB
[B]; JPEG level 10, 340 KB [C]) on appearance of printed digital
image and on corresponding image file size. Images are shown ranging from low
quality and high compression to high quality and low compression.
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Fig. 5B. —20-year-old man with primary tuberculosis. Chest radiographs
show effect of decreasing JPEG (Joint Photographic Experts Group) image
compression (JPEG level 1, 48 KB [kilobytes] [A]; JPEG level 7, 132 KB
[B]; JPEG level 10, 340 KB [C]) on appearance of printed digital
image and on corresponding image file size. Images are shown ranging from low
quality and high compression to high quality and low compression.
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Fig. 5C. —20-year-old man with primary tuberculosis. Chest radiographs
show effect of decreasing JPEG (Joint Photographic Experts Group) image
compression (JPEG level 1, 48 KB [kilobytes] [A]; JPEG level 7, 132 KB
[B]; JPEG level 10, 340 KB [C]) on appearance of printed digital
image and on corresponding image file size. Images are shown ranging from low
quality and high compression to high quality and low compression.
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Fig. 6A. —20-year-old man with primary tuberculosis. Chest radiographs,
both 300 dpi (dots per inch) TIFF (tagged image file format) files, show
subtle changes that occur in images without (A) and with (B)
allowances for dot gain.
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Fig. 6B. —20-year-old man with primary tuberculosis. Chest radiographs,
both 300 dpi (dots per inch) TIFF (tagged image file format) files, show
subtle changes that occur in images without (A) and with (B)
allowances for dot gain.
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Fig. 7A. —Steps necessary to account for dot gain. Screen shot shows
typical unadjusted histogram of shades of gray used to make up image (found
under "Image" pop-up menu and "Adjust Levels"
submenu). Note that entire gray scale is not used.
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Fig. 7B. —Steps necessary to account for dot gain. Screen shot shows
shaped histogram (same as in A) after "Adjust Auto Levels"
function has been applied. Note same overall shape of histogram adjusted to
take advantage of entire gray scale.
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Fig. 7C. —Steps necessary to account for dot gain. Screen shot shows
"Curves" window found under "Image" pop-up menu and
"Adjust Curves" submenu. Straight line reflects complete
gray-scale "Input" and "Output" to printer.
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Fig. 7D. —Steps necessary to account for dot gain. Screen shot shows
adjustment of "Input" and "Output" to account for dot
gain. This function essentially allows extreme whites and blacks to remain the
same after ink is put on paper.
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Fig. 7E. —Steps necessary to account for dot gain. Screen shot shows
shape of "Levels" histogram after "Curves" are
adjusted for dot gain.
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Fig. 8A. —Frontal view of right hip. Screen shot shows
"Unsharp Mask" tool dialog box in Photoshop (Adobe Systems,
San Jose, CA) with accompanying radiograph of right hip.
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Fig. 8B. —Frontal view of right hip. Radiograph reflects result of
unsharp masking.
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Copyright © 2003 by the American Roentgen Ray Society.
