Abstract:
A method for generating an animated morph between a first image and a second image is provided. The method may include: (i) reading a first set of cephalometric landmark points associated with the first image; (ii) reading a second set of cephalometric landmark points associated with the second image; (iii) defining a first set of line segments by defining a line segment between each of the first set of cephalometric landmarks; (iv)defining a second set of line segments by defining a line segment between each of the second set of cephalometric landmarks such that each line segment of the second set of line segments corresponds to a corresponding line segment of the first set of line segments; and (v) generating an animation progressively warping the first image to the second image based at least on the first set of line segments and the second set of line segments.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of copending International Application No. PCT/ES2011/070133 filed Mar. 1, 2011 which designates the United States. This application also claims priority to copending Spanish application number 201130273 filed Mar. 1, 2011. The contents of these applications are hereby incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates in general to dentofacial imaging, and more particularly to systems and methods for surgical planning using dentofacial imaging. 
       BACKGROUND 
       [0003]    Dentofacial surgery, also referred to as oral and maxillofacial surgery, is often employed to correct a wide spectrum of diseases, injuries and defects in the head, neck, face, jaws and the hard and soft tissues of the oral and maxillofacial region of humans or other non-human patients. As capabilities of computers and software improve, practitioners of dentofacial surgery increasingly use computer-aided dentofacial imaging tools in order to model dentofacial features of patients, diagnose diseases, injuries, and defects, plan dentofacial surgical procedures and other treatments, and educate patients regarding diagnoses and treatments. 
         [0004]    For example, to educate a patient regarding a potential change in physical appearance resulting from dentofacial treatment, a practitioner may desire to present the patient with a “before” image of the patient prior to treatment, an “after” image depicting the patient following treatment, and an animation or “morph” between the before and after images. Traditionally, morphing is accomplished by manually marking key features on a first image, such as the contour of the nose or location of an eye, and manually mark where these same points existed on the second image, creating multiple pairs of line segments. Software would then create an animation whereby the first image would slowly distort to have the features of the second image at the same time that it cross-faded between the two images. However, such manual marking of features may be time-consuming and thus, undesirable. 
         [0005]    As another example, to plan and simulate a dentofacial surgery, a practitioner may, with the aid of a computer-aided tool, virtually modify various bones or bone segments of the patient via a user interface of a computer. Such computer-aided planning and simulation may allow a practitioner to simulate effect of various surgical adjustments on a patient, including effects on a patient&#39;s aesthetic appearance. 
       SUMMARY 
       [0006]    In accordance with the teachings of the present disclosure, disadvantages and problems associated with traditional approaches to surgical planning using dentofacial imaging may be substantially reduced or eliminated. 
         [0007]    In accordance with embodiments of the present disclosure, a method for generating an animated morph between a first image and a second image is provided. The method may include: (i) reading a first set of cephalometric landmark points associated with the first image; (ii) reading a second set of cephalometric landmark points associated with the second image; (iii) defining a first set of line segments by defining a line segment between each of the first set of cephalometric landmarks; (iv)defining a second set of line segments by defining a line segment between each of the second set of cephalometric landmarks such that each line segment of the second set of line segments corresponds to a corresponding line segment of the first set of line segments; and (v) generating an animation progressively warping the first image to the second image based at least on the first set of line segments and the second set of line segments. 
         [0008]    In accordance with additional embodiments of the present disclosure, an article of manufacture may include a non-transitory computer-readable medium; and computer-executable instructions carried on the computer-readable medium. The instructions may be executable by one or more processors and may be configured to cause the one or more processors to: (i) read a first set of cephalometric landmark points associated with the first image; (ii) read a second set of cephalometric landmark points associated with the second image; (iii) define a first set of line segments by defining a line segment between each of the first set of cephalometric landmarks; (iv) define a second set of line segments by defining a line segment between each of the second set of cephalometric landmarks such that each line segment of the second set of line segments corresponds to a corresponding line segment of the first set of line segments; and (v) generate an animation progressively warping the first image to the second image based at least on the first set of line segments and the second set of line segments. 
         [0009]    In accordance with further embodiments of the present disclosure, a computing system may comprise a processor and a memory communicatively coupled to the processor. The memory may have stored thereon a program of instructions configured to, when executed by the processor: (i) read a first set of cephalometric landmark points associated with the first image; (ii) read a second set of cephalometric landmark points associated with the second image; (iii) define a first set of line segments by defining a line segment between each of the first set of cephalometric landmarks; (iv) define a second set of line segments by defining a line segment between each of the second set of cephalometric landmarks such that each line segment of the second set of line segments corresponds to a corresponding line segment of the first set of line segments; and (v) generate an animation progressively warping the first image to the second image based at least on the first set of line segments and the second set of line segments. 
         [0010]    Other technical advantages will be apparent to those of ordinary skill in the art in view of the following specification, claims, and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    A more complete understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
           [0012]      FIG. 1  illustrates an example cephalometric tracing of soft tissue and bone features of a profile view of an individual, in accordance with embodiments of the present disclosure; 
           [0013]      FIG. 2  illustrates an example user interface screen  200  of a computer-aided surgical planning tool, in accordance with embodiments of the present disclosure; 
           [0014]      FIGS. 3A and 3B  illustrate another example user interface screen of a computer-aided surgical planning tool, in accordance with embodiments of the present disclosure; and 
           [0015]      FIG. 4  depicts a block diagram of an example computing system, in accordance with embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]      FIG. 1  illustrates an example cephalometric tracing  100  of soft tissue and bone features of a profile view of an individual, in accordance with embodiments of the present disclosure. A cephalometric tracing may be drawn based on a radiograph or other image of the tissues of an individual&#39;s head or otherwise extracted from such radiograph or other image, and may be used to study relationships between bony and soft tissue landmarks to diagnose facial growth abnormalities prior to treatment, in the middle of treatment to evaluate progress, or at the conclusion of treatment to ascertain that the goals of treatment have been met. As shown in  FIG. 1 , such landmarks may include, without limitation:
       soft tissue glabella  102 —surface of the soft tissue covering the most anterior point of the frontal bone (e.g., between an individual&#39;s eyebrows);   soft tissue nasion  104 —the soft tissue profile&#39;s most concave point at the bridge of the nose;   bridge of nose  106 —mid-point of soft tissue nasion  104  to pronasale  108  (e.g., the first contour encountered along the length of the profile of the nose);   pronasale  108 —most anterior point of curve of nose (e.g., tip of nose);   subnasale  110 —point at which the nose connects to the center of upper lip;   soft tissue A-point  112 —most concave point between subnasale  110  and upper lip  114 ;   upper lip  114 —most anterior point on the curve of the upper lip;   stomion superius  116 —most inferior point on the curve of the upper lip;   stomion inferius  118 —most superior point on the curve of the lower lip;   lower lip  120 —most anterior point on the curve of the lower lip;   soft tissue B-point  122 —most concave point between lower lip  120  and soft tissue pogonion  124 ;   soft tissue pogonion  124 —most anterior point on the anterior curve of the soft tissue chin;   soft tissue gnathion  126 —midpoint between the soft tissue pogonion  124  and the soft tissue mention  128 ;   soft tissue menton  128 —the most inferior point of the soft tissue chin; and   throat point  130 —intersection of lines tangent to the neck and the throat.       
 
         [0032]    In some embodiments, cephalometric tracing  100  may be created by or with the assistance of a computer-aided surgical planning tool executing on a computer. For example, the computer-aided surgical planning tool may read a radiograph or other image and based on the content of such image, generate one or more portions of a cephalometric tracing and/or identify one or more cephalometric landmarks. Alternatively or in addition, the computer-aided surgical planning tool may display a radiograph or other image and a practitioner may, via a user interface of the surgical planning tool, use the image as a guide to construct the cephalometric tracing of the bony and soft tissue features and/or identify one or more cephalometric landmarks. The computer-aided surgical planning tool may store (e.g., to a computer-readable medium) the cephalometric tracing, the cephalometric landmarks, and/or their associated coordinates. 
         [0033]      FIG. 2  illustrates an example user interface screen  200  of a computer-aided surgical planning tool, in accordance with embodiments of the present disclosure. As shown in  FIG. 2 , user interface screen  200  may include a pre-surgical profile image  202  of an individual with the pre-surgical cephalometric tracing  100  of  FIG. 1  overlaid upon image  202 , and a planned post-surgical image  204  of the same individual with a planned post-surgical cephalometric tracing  206  overlaid upon image  204 . 
         [0034]    Pre-surgical profile image  202  may be generated by taking a profile photograph of the subject individual. The computer-aided surgical planning tool may be configured to read the image (e.g., from a computer-readable medium) and, in response to user input, overlay cephalometric tracing  100  upon image  202 . In some embodiments, the surgical planning tool may be configured to detect and align corresponding features of image  202  and cephalometric tracing  100  and align image  202 . In other embodiments, the surgical planning tool may be configured to permit a user via a user interface to adjust image  202  and/or cephalometric tracing  100  in order to align features. Once image  202  and cephalometric tracing  100  are aligned as desired, various cephalometric landmarks (e.g., landmarks  102 - 130 ) may be stored as part of profile image  202  (e.g., as metadata in a digital file of profile image  202 ). 
         [0035]    Planned post-surgical cephalometric tracing  206  may be created from pre-surgical cephalometric tracing  100  by a practitioner interacting with the computer-aided surgical planning tool to modify (e.g., with a mouse or other similar user input device) cephalometric tracing  100  and/or locations of cephalometric landmarks to obtain desired post-surgical characteristics. For example, computer-aided surgical planning tool may warp cephalometric tracing  100  in response to user input, according to well-known methods. The computer-aided surgical planning tool may store (e.g., to a computer-readable medium) planned post-surgical cephalometric tracing  206  and its associated cephalometric landmarks (as modified). 
         [0036]    Planned post-surgical image  204  may be created from pre-surgical image  202  based on differences between planned post-surgical cephalometric tracing  206  and pre-surgical cephalometric tracing  100 . For example, based on differences of locations of elements of cephalometric tracings  100  and  206  and/or differences in locations of cephalometric landmarks, computer-aided surgical planning tool may warp image  202  according to well-known methods to align corresponding features of planned post-surgical image  204  and planned post-surgical cephalometric tracing  206 . After creation of planned post-surgical image, the computer-aided surgical planning tool may store (e.g., to a computer-readable medium) modified cephalometric landmarks as part of planned post-surgical image  204  (e.g., as metadata in a digital file of planned post-surgical image  204 ). 
         [0037]      FIGS. 3A and 3B  illustrate another example user interface screen  300  of a computer-aided surgical planning tool, in accordance with embodiments of the present disclosure. As shown in  FIG. 3A , user interface screen  300  may include three panes displaying pre-surgical image  202 , planned post-surgical image  204 , and animation mid-point frame image  302 . Also as shown in  FIG. 3A , the computer-aided surgical planning tool may also load and display on each of pre-surgical image  202  and planned post-surgical image  204  various cephalometric landmarks  102 - 130  and line segments  304  between adjacent cephalometric landmarks. Accordingly, each line segment  304  of image  202  has a corresponding line segment  304  in image  204  (e.g., line segment  304  between soft tissue glabella  102  and soft tissue nasion  104  of image  202  corresponds to line segment  304  between soft tissue glabella  102  and soft tissue nasion  104  of image  204 , and so on). 
         [0038]    As is known in the art, metamorphosis from one image to another (e.g., creating a “morph”) typically includes creation of an animation that gradually cross-dissolves between the first image and the second image, while at the same time warping the first image into the second image. Thus, often the middle frame of the animation is an average of the first image distorted and cross-faded halfway towards the second image and the second image distorted and cross-faded halfway towards the first image. 
         [0039]    As is known in the art, warping from one image to another may include establishing one or more line segments on the first image each associated with a particular feature, and a corresponding line segment in the second image for each line segment of the first image. Each intermediate frame of the animation may defined by creating a new set of line segments by interpolating the line segments from their positions in the first image to their positions in the second image. Both images are distorted toward the position of the line segments in each intermediate frame, and the two resulting images are cross-dissolved throughout the animation. Each pixel of the images may be distorted by a rotation, translation, and/or a scale based on its distance and relationship to each of the line segments. 
         [0040]    To facilitate creation of an animation between pre-surgical image  202  and planned post-surgical image  204 , the computer-aided surgical planning tool may, as described above, generate a plurality of line segments  304  for pre-surgical image  202  and a plurality of corresponding line segments  304  for post-surgical image  204  based on cephalometric landmarks and display such line segments  304 . In addition, the computer-aided surgical planning tool may allow a user to define and display additional pairs of line segments for other features (e.g., an ear, hairline, clothing neckline, etc.) to further enhance the quality of the animation. 
         [0041]    In addition, as described above, the computer-aided surgical planning tool may display animation mid-point frame image  302 . Mid-point frame image  302  may represent the middle frame of the animation between image  202  and image  204  using the corresponding pairs of line segments  304  generated by the computer-aided surgical planning tool and any corresponding pairs of line segments defined by a user. Such mid-point frame image  302  may provide a visual guide to the user, potentially identifying features for which a user may desire to define associated line segments in order to create a higher-quality animation. For example, mid-point frame image  302  may indicate areas of non-overlap or ghosting of the halfway-distorted pre-surgical image  202  and halfway-distorted planned post-surgical image  204  for which a user may define additional pairs of line segments. 
         [0042]    Generation of line segments  304  by the computer-aided surgical planning tool may reduce the effort required by a user to generate an animation, as it may reduce or eliminate the need for a user to define numerous line segments required for a quality metamorphosis between images. This advantage may be seen by reference to  FIG. 3B , which depicts mid-point frame image  302  in the absence of line segment  304  pairs in images  202  and  204 . As evident from  FIG. 3B , the absence of line segment  304  pairs in images  202  and  204  may lead to significant areas of non-overlap or ghosting of the halfway-distorted pre-surgical image  202  and halfway-distorted planned post-surgical image  204 , requiring a user to manually define many line segment pairs in order to create a quality animation. 
         [0043]      FIG. 4  depicts a block diagram of an example computing system  1200 , in accordance with embodiments of the present disclosure. Computing system  1200  may be used in whole or part to provide or perform various functions and operations described above with respect to  FIGS. 1-3B . As shown in  FIG. 12 , computing system  1200  may include processor  1202 , memory  1204 , and logic  1206 . 
         [0044]    Computing system  1200  may comprise any suitable combination of hardware and/or software implemented in one or more modules to provide or perform the functions and operations described above with respect to  FIGS. 1-3B . In some embodiments, computing system  1200  may comprise a mainframe computer, general-purpose personal computer (PC), a Macintosh, a workstation, a Unix-based computer, a server computer, or any suitable processing device. In some embodiments, the functions and operations described above may be performed by a pool of multiple computing systems  1200 . 
         [0045]    Memory  1200  may comprise any suitable arrangement of random access memory (RAM), read only memory (ROM), magnetic computer disk, CD-ROM, or other magnetic, optical or solid state storage media, or any other volatile or non-volatile memory devices that store one or more files, lists, tables, or other arrangements of information. Although  FIG. 4  illustrates memory  1204  as internal to computing system, it should be understood that memory  1204  may be internal or external to computing system  1200 , depending on particular implementations. Memory  1204  may be separate from or integral to other memory devices to achieve any suitable arrangement of memory devices for use in providing or performing desired operations or functionality. 
         [0046]    Memory  1204  may be further operable to store logic  1206 . Logic  1206  generally comprises rules, algorithms, code, tables, and/or other suitable instructions executable by processor  1202  to provide or perform the functions and operations described above with respect to  FIGS. 1-3B . 
         [0047]    Memory  1204  may be communicatively coupled to processor  1202 . Processor  1202  may be generally operable to execute logic to perform operations described herein. Processor  1202  may comprise any suitable combination of hardware and software implemented in one or more modules to provide the described function or operation. 
         [0048]    Although the present disclosure has been described in detail, it should be understood that various changes, substitutions, and alterations can be made hereto without departing from the spirit and the scope of the invention as defined by the appended claims.