EP0939381A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Locating and aligning embedded images
Assignee: Adobe Inc
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Filing: 1999-02-24
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Granted: —
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Expires: 2019-02-24
Abstract
Abstract Apparatus and methods useful to automate the task of locating a photograph or other image that is embedded within a larger image. An edge curve is found that approximates the perimeter of the embedded image and from the edge curve the rectangle of the embedded image, or a rectangle covering the embedded image. is calculated by processing density profiles of the edge curve taken along two axes. Both location and orientation of an embedded image can be calculated. The location of the four comers of a rectangular embedded image can be calculated, which enables automatic cropping and rotation of the embedded image, even if fewer than all four comers are visible. A rectangle covering the image can be calculated, including a rectangle aligned with the axes of a larger embedding image such as is created when scanning a small photograph on a flatbed scanner. The invention operates well on rectangular images, as well as on images having polygonal and other border shapes, such as circles and ellipses, including images with irregular shapes.
Inventors
- 👤 Gregg D. Wilensky
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 11:26
CPC Classifications
G; G06; G06T; G06T3/00; G06T3/40; G06T3/403; G06T7/00; G06T7/70; G06T7/73; H; H04; H04N; H04N1/00; H04N1/387; H04N1/3872; H04N1/3877; H04N1/3878
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
71 words
Apparatus for finding an image embedded in a larger image, comprising: means for finding an edge curve of the embedded image in the larger image; means for calculating a rotation angle of the embedded image from the edge
curve; and means for calculating from the edge curve a location and orientation of one or
more line segments of a side of a rectangle bounding the embedded image in the
larger image.
Claim 2
Dependent Claim
40 words
The apparatus of claim 1, wherein the embedded image is an image of a
rectangular photograph, the apparatus further comprising: means for locating edge segments in the edge curve corresponding to sides of
the embedded image in the larger image.
Claim 3
Dependent Claim
14 words
The apparatus of claim 1, wherein the embedded image has an irregular border
shape.
Claim 4
Dependent Claim
19 words
The apparatus of claim 1, further comprising: means for locating corners of a covering rectangle of the embedded image.
Claim 5
Dependent Claim
22 words
The apparatus of claim 4, further comprising: means for cropping the embedded image in a frame of reference of the larger
image.
Claim 6
Dependent Claim
19 words
The apparatus of claim 4, further comprising: means for calculating density profiles on two axes of the larger image.
Claim 7
Dependent Claim
12 words
The apparatus of claim 4, further comprising: means for detecting edge points.
Claim 8
Dependent Claim
16 words
The apparatus of claim 7, further comprising: means for removing pixel noise from the larger image.
Claim 9
Independent Claim
68 words
A method of processing a digital raster image embedded in a larger digital raster
image, comprising: finding an edge curve of the embedded image in the larger image; calculating a rotation angle of the embedded image from the edge curve; and calculating from the edge curve a location and orientation of a line segment of
a side of a rectangle bounding the embedded image in the larger image.
Claim 10
Dependent Claim
21 words
The method of claim 9, wherein: the larger image is a digital raster image generated by scanning an analog
input image.
Claim 11
Dependent Claim
74 words
The method of claim 9, further comprising: performing a scan at a first resolution of a first area to obtain the larger digital
raster image; and using the edge curve to define a second area smaller than, and within, the first
area, and performing a scan of the second area at a second resolution higher than the
first resolution to obtain a raster image including the embedded digital raster image at
the second resolution.
Claim 12
Dependent Claim
107 words
The method of claim 9, further comprising: finding the edge curve by: calculating the positions of edge points in the larger image, and scanning from the perimeter into the larger image from starting points
on all sides of the larger image and selecting as a point in the
edge curve the first edge point encounter from each starting
point; calculating a rotation angle by calculating an average angle of the edge curve
points over a windowed set of neighboring edge curve points: rotating the edge curve by the complement of the calculated rotation angle;
and calculating the location of corners of a rectangle covering the embedded
image.
Claim 13
Dependent Claim
27 words
The method of claim 12, wherein: the two axes are perpendicular; and calculating the positions of edge points comprises applying a Sobel filter to
the larger image.
Claim 14
Dependent Claim
27 words
The method of claim 12, wherein: the two axes are perpendicular; and calculating the positions of edge points comprises applying a Hough transform
to the larger image.
Claim 15
Dependent Claim
15 words
The method of claim 12, further comprising: cropping the embedded image according the covering rectangle.
Claim 16
Dependent Claim
74 words
The method of claim 12, further comprising: performing a scan at a first resolution of a first area to obtain the larger digital
raster image; and using the bounding rectangle to define a second area smaller than, and within,
the first area, and performing a scan of the second area at a second resolution higher
than the first resolution to obtain a raster image including the embedded digital raster
image at the second resolution.
Claim 17
Dependent Claim
140 words
The method of claim 9, further comprising: removing pixel noise from the larger image before performing the step of
finding an edge curve; finding the edge curve by calculating density profiles of the larger image on two axes; calculating the positions of edge points in the larger image; and scanning from the perimeter into the larger image from starting points
on all sides of the larger image and selecting as a point in the
edge curve the first edge point encounter from each starting
point; calculating a rotation angle by calculating an average angle of the edge curve
points over a windowed set of neighboring edge curve points; rotating the edge curve by the complement of the calculated rotation angle; removing noise points from the edge curve; and calculating the location of corners of a rectangle covering the embedded
image.
Claim 18
Dependent Claim
74 words
The method of claim 17, further comprising: performing a scan at a first resolution of a first area to obtain the larger digital
raster image; and using the bounding rectangle to define a second area smaller than, and within,
the first area, and performing a scan of the second area at a second resolution higher
than the first resolution to obtain a raster image including the embedded digital raster
image at the second resolution.
Claim 19
Dependent Claim
18 words
The method of claim 18, wherein the scan of the second area is limited to the
second area.
References Cited (Backward Citations)
No citation records indexed.
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