Method for creating a composite cephalometric image

Patent metadata

Field	Value
Publication number	US-11227415-B2
Application number	US-201616305046-A
Country	US
Kind code	B2
Filing date	May 27, 2016
Priority date	May 27, 2016
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

A composite image (300) is created from a plurality of tomographic slices by creating a plurality of two-dimensional slice images by projecting the slices, dividing each slice image into tiles (302) according to a pattern (304), calculating a focus value for each tile (302) of each slice image, selecting one tile (302) for each position in the pattern having a highest focus measure value, and assembling the composite image (300) from said selected tiles (302).

First claim

The invention claimed is:

1. A method for creating a composite image from a plurality of tomographic slices oriented parallel to and at varying distances from a reference plane, comprising the steps of:
projecting each slice to create a plurality of two-dimensional slice images;
dividing each slice image into a first set of tiles according to a pre-determined first tile pattern;
calculating a focus value for each tile of each slice image;
selecting, for each position of said first tile pattern, one of said first set of tiles having the highest focus value;
assembling the composite image from said selected tiles;
generating a first depth map from depth values of the selected tiles constituting the composite image;
smoothing discontinuities on the composite image;
amending the first depth map to reflect the smoothed composite image;
applying a cubic interpolation to the amended first depth map to produce a second depth map;
extracting a second tile pattern from the second depth map;
dividing each of the plurality of slices into a second set of tiles according to said second tile pattern;
selecting, for each position in the second tile pattern, one of said second set of tiles according to the second depth map; and
assembling an enhanced composite image from said selected tiles of said second set of tiles.

2. A method for creating a composite image from a plurality of tomographic slices oriented parallel to and at varying distances from a reference plane, comprising the steps of:
projecting each slice to create a plurality of two-dimensional slice images;
dividing each slice image into a first set of tiles according to a pre-determined first tile pattern;
calculating a focus value for each tile of each slice image;
selecting, for each position of said first tile pattern, one of said first set of tiles having the highest focus value;
assembling the composite image from said selected tiles;
applying an enhancement filter to at least one slice image to enhance anatomical features in the at least one slice image, thereby producing a working image;
removing pixels from the working image having a gradient magnitude below a mean gradient magnitude of said at least one slice image;
applying a noise filter to said working image, thereby obtaining a mask;
applying a smoothing filter to smooth the edges of the mask;
multiplying the mask and the at least one slice image, thereby producing a contour image; and
adding the contour image to the composite image.

3. The method according to claim 2 , wherein each at least one slice image contains at least one of a pre-determined set of anatomical features.

4. The method according to claim 2 , wherein the contour image produced for each slice comprises only pixels not present in the contour image of any other slice.

5. The method according to claim 2 , wherein the noise filter is a morphological operation.

6. The method according to claim 2 , wherein at least one of the enhancement filter and smoothing filter is a Difference of Gaussians filter.

Assignees

• Trophy

Inventors

• Vlachomitrou Anna-Sesilia

Classifications

• G06T12/00 Primary

  Tomographic reconstruction from projections · CPC title

• G06T7/50

  Depth or shape recovery · CPC title

• G06T2207/10072

  Tomographic images · CPC title

• G06T7/0012

  Biomedical image inspection · CPC title

• G06T2207/20021

  Dividing image into blocks, subimages or windows · CPC title