我正在尝试根据体积 CT 数据制作实时模拟超声图像。诀窍是用户控制探头的位置，它定义了他们所看到的平面。
到目前为止，我所做的是将所有 dicom 图像中的像素数据读取到单个 3D 像素阵列中，现在我需要做的是以不同角度重新切片该 3D 阵列。抱歉，如果下面的描述有点草率，但想象一个 3D 矩形框（比如 100 像素宽和深 [x,z] 和 500 像素长 [y]）和 2D“观察平面”（比如 50 x 50 像素）。假设观察平面的起始位置（原点定义为平面闭合边缘的中点 - [0,25]）与原点 [50,250,0] （顶面的死点，向下看） ，从左到右并垂直向下刺穿矩形。因此，观察平面具有三个可以更改的参数 - 原点的位置，围绕垂直方向的旋转（从原点到平面相对边缘上对应点的线）和“倾斜”（平面围绕与框相交的线的旋转）。因此用户可以更改这三个参数，输出是由观察平面“触摸”的像素构建的图像。
再次，如果描述草率，我深表歉意，但我是一名没有强大数学背景的医学生。任何帮助将不胜感激。
听起来像是一个有趣的问题，我开始考虑它，但很快遇到了一些问题。它并不像您最初想象的那么简单或直接！作为开始，我将其简化为通过 2D 数组获取 1D 切片的情况。很快就很清楚，对于某些切片，对于所有像素来说，哪些像素将构成切片的一部分并不明显。我制作了一个pdf来说明我的意思。这是 pdf 文档Issues 2D的链接。在想出一个可能的解决方案之前，我或其他人需要更多的思考。抱歉，我目前无法提供更多帮助。
我会为一条线写一个二维方程，求解 x 的每个值，然后将结果 y 变量四舍五入到最接近的整数——昨天 Edje09
暂时坚持使用 2D 案例，您建议的方法有两个主要问题
此 pdf显示了 2D 案例的问题和可能的解决方案，然后可以为 3D 案例构建。
编辑经过进一步思考，我可能已经为 3D 案例制作了一个书面的 pdf 大纲解决方案，可以将其转换为算法并因此转换为代码。据我所知，我没有做任何检查，也不能保证它的正确性，但希望能让你更进一步。
添加了编辑代码以下Javascript代码似乎可以满足您的要求。它很慢，因此您需要在单击 SET 后等待。此外，视图之间的“窗格”也不清楚，因此在重新填充“窗格”之前，您无法判断正在发生任何事情。我只测试了使用 2 个图像来表示 z 方向上的 100 个像素。函数 getPixels 中的第一行代码处理了这个限制，删除了 z 方向上的完整图像集。我进行的测试相当肤浅，但似乎通过了。最好有全套图像。
我将 3D 阵列想象为一系列 D 图像 image(0) 在后面运行 z 方向到前面的 image(D-1)。每个图像在 x 方向上具有宽度 W，在 y 方向上具有高度 H。感谢我喜欢它的挑战。
所用图像的压缩文件夹的链接位于代码末尾。
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<!--
Copyright (c) 2013 John King
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-->
<title>3D Slicer</title>
<style type="text/css">
div, canvas, img {
position: absolute;
}
img {
top:0px;
left:0px;
visibility:hidden;
}
input {
text-align: right;
}
.seen {
visibility: visible;
}
#canvas3D {
left:10px;
top:10px;
visibility:hidden;
}
#canvas2D {
left:10px;
top:50px;
border:1px solid black;
}
#frame {
left:650px;
top:10px;
border:1px solid black;
background-color: #DDDDDD;
width:600px;
height:600px;
}
#framehead {
left:0px;
top:0px;
height:25px;
width:100%;
border-bottom: 1px solid black;
background-color: #999999;
}
#userdata {
top:10px;
left:10px;
}
#originins {
top:10px;
left:10px;
width:260px;
}
#origintext {
top:200px;
left:10px;
width:260px;
}
#origininput {
top:225px;
left:10px;
width:260px;
}
#originlimits {
top:250px;
left:10px;
width:260px;
}
#thetaimg {
top:10px;
left:225px;
}
#thetatext {
top:200px;
left:225px;
width:260px;
}
#thetainput {
top:225px;
left:225px;
width:260px;
}
#thetalimits {
top:250px;
left:225px;
width:260px;
}
#psiimg {
top:10px;
left:440px;
}
#psitext {
top:200px;
left:440px;
width:260px;
}
#psiinput {
top:220px;
left:440px;
width:260px;
}
#psilimits {
top:250px;
left:440px;
width:260px;
}
#setButton {
top:310px;
left:10px;
width:260px;
}
#axes {
top:350px;
left:10px;
}
</style>
<script type="text/javascript">
//add a trim function to string if not present - strips white space from start and end of string
if(typeof String.prototype.trim !== 'function') {
String.prototype.trim = function() {
return this.replace(/^\s+|\s+$/g, '');
}
}
// abbreviation function for getElementById
function $(id) {
return document.getElementById(id);
}
//parameters for 3D array of pixels set in code
var W=100; //width of array in x direction, must be even
var D=100; //depth of array in z direction, must be even
var H=500; //height of array in y direction
//parameters for the rectangular plane PQRS that will select the pixels for a 2D array by slicing through the 3D array
//PQRS moves in such a way that PQ remains parallel to xz plane and PS remains parallel to yz plane
//these parameters set in code
var L=50; //length of rectangle PQ
var B=50; //breadth of rectangle PS
//Initialisation of parameters that can be changed by the user.
var O=new Point(W/2,0,D/2); //O is middle of PQ
var theta=0; //angle PQ is rotated after plane is rotated about a vertical axis through O, must be between -PI/2 and PI/2
var psi=0; //angle PS is rotated after plane is rotated about PQ as an axis, must be between -PI/2 and PI/2
//variable for canvases
var c3D, c2D;
/*getPixel gets an individual pixel from the 3D array of pixels formed by a stack of D (for depth) 2D images
* numbered from 0 to D-1, with 0 being the image at the back.
* Each image having width W and height H pixels.
* 0<= x <W, 0<= y <H, 0<= z <D
* each image is on the canvas canvas3D
*
* for this test img0.jpg will be used for img0.jpg to img49.jpg and img50.jpg will be used for img50 to img99
*/
function getPixel(x,y,z) {
// line below only required because just two images img0.jpg and img50.jpg are used for testing
z=Math.floor(z/50)*50;
//Remove above line if full series of images used in z direction
this.ctx.drawImage($("i"+z),0,0);
var imdata=this.ctx.getImageData(0,0,this.width,this.height);
var col=4*(y*this.width+x);
var pix=new Pixel();
pix.red=imdata.data[col++];
pix.green=imdata.data[col++];
pix.blue=imdata.data[col++];
pix.alpha=imdata.data[col];
return pix;
}
//Pixel Object
function Pixel() {
this.red;
this.green;
this.blue;
this.alpha;
}
//Point Object
function Point(x,y,z) {
this.x=x;
this.y=y;
this.z=z;
}
function Point2D(a,d) {
this.a=a;
this.d=d;
}
function setValues() {
c2D.ctx.clearRect(0,0,c2D.width,c2D.height);
var Oobj=Ochecked($("Oin").value);
if(!Oobj.OK) {
$("Oin").style.backgroundColor="#F1B7B7";
return
}
$("Oin").style.backgroundColor="#FFFFFF";
O=Oobj.point;
var th=parseInt($("thetain").value.trim());
if(isNaN(th)) {
$("thetain").style.backgroundColor="#F1B7B7";
return
}
if(th<=-90 || th>90) {
$("thetain").style.backgroundColor="#F1B7B7";
return
}
$("thetain").style.backgroundColor="#FFFFFF";
theta=th*Math.PI/180;
var si=parseInt($("psiin").value.trim());
if(isNaN(si)) {
$("psiin").style.backgroundColor="#F1B7B7";
return
}
if(si<=-90 || si>90) {
$("psiin").style.backgroundColor="#F1B7B7";
return
}
$("psiin").style.backgroundColor="#FFFFFF";
psi=si*Math.PI/180;
printPane();
}
function Ochecked(Ovalue) {
Ovalue=Ovalue.trim();
var V=Ovalue.split(",");
if(V.length!=3) {return {OK:false}};
var x=parseInt(V[0].trim());
var y=parseInt(V[1].trim());
var z=parseInt(V[2].trim());
if(isNaN(x) || isNaN(y) || isNaN(z)) {return {OK:false}};
if(x<0 || x>=W) {return {OK:false}};
if(y<0 || y>=H) {return {OK:false}};
if(z<0 || z>=D) {return {OK:false}};
p=new Point(x,y,z);
return {OK:true,point:p};
}
function printPane(){
var p = new Point(O.x-Math.round((L/2)*Math.cos(theta)),O.y,O.z - Math.round((L/2)*Math.sin(theta)));
var q = new Point(O.x+Math.round((L/2)*Math.cos(theta)),O.y,O.z + Math.round((L/2)*Math.sin(theta)));
var s = new Point(p.x,p.y+Math.round((B)*Math.cos(psi)),p.z + Math.round((B)*Math.sin(psi)));
var n = new Point2D(q.x-p.x,q.z-p.z);
var PQincVec=getIncVec(n.a,n.d);
n = new Point2D(s.y-p.y,s.z-p.z);
var PSincVec=getIncVec(n.a,n.d);
var pixel,col;
var PSpoint =new Point(p.x,p.y,p.z); // points along PS initialised to start at P
var PQpoint; //variable for points along line parallel to PQ
var imdata=c2D.ctx.getImageData(0,0,c2D.width,c2D.height);
for(var ps=0;ps<PSincVec.length;ps++) {
//increment along line PS
PSpoint.y+=PSincVec[ps].a;
PSpoint.z+=PSincVec[ps].d;
PQpoint =new Point(PSpoint.x,PSpoint.y,PSpoint.z); // points along line parallel to PQ initialised to current point on PS
for(var pq=0;pq<PQincVec.length;pq++) {
//increment along line PQ
PQpoint.x+=PQincVec[pq].a;
PQpoint.z+=PQincVec[pq].d;
//check that PQpoint is inside 3D array
if(0<=PQpoint.x && PQpoint.x<W && 0<=PQpoint.y && PQpoint.y<H && 0<=PQpoint.z && PQpoint.z<D) {
pixel=c3D.getPixel(PQpoint.x,PQpoint.y,PQpoint.z);
//write pixel from point along line parallel to PQ onto plane
col=4*(ps*c2D.width+pq);
imdata.data[col++]=pixel.red;
imdata.data[col++]=pixel.green;
imdata.data[col++]=pixel.blue;
imdata.data[col]=pixel.alpha;
}
}
}
c2D.ctx.putImageData(imdata,0,0);
}
function getIncVec(a,d) {
var r,t;
if(a>Math.abs(d)) {
var incVec=getIncs(a,Math.abs(d));
}
else {
var incVec=getIncs(Math.abs(d),a);
for(var i=0;i<incVec.length;i++) {
r=incVec[i];
t=r.a;
r.a=r.d;
r.d=t;
}
}
if(d<0) {
for(var i=0;i<incVec.length;i++) {
incVec[i].d*=-1;
}
}
return incVec;
}
function getIncs(a,d) {
var p=new Point2D(0,0);
var vec=[];
vec.push(p);
for(var i=0;i<a;i++) {
p=new Point2D(1,Math.floor((i+1)*d/a) - Math.floor(i*d/a));
vec.push(p);
}
return vec;
}
function main() {
//set limits and values for user input.
$("Oin").value=O.x+","+O.y+","+O.z;
$("thetain").value=theta;
$("psiin").value=psi;
$("originlimits").innerHTML="0<= x <"+W+"<br>0<= y <"+H+"<br>0<= z <"+D;
//set canvas3D so that pixels are readable
c3D=$("canvas3D");
c3D.width=W;
c3D.height=H;
c3D.ctx=c3D.getContext('2d');
c3D.getPixel=getPixel;
//set canvas2D so that pixels are settable
c2D=$("canvas2D");
c2D.width=L;
c2D.height=B;
c2D.ctx=c2D.getContext('2d');
c2D.initialise=initialise;
$("hide").style.width=L+"px";
$("hide").style.height=B+"px";
}
</script>
</head>
<body onload="main()">
<!-- list of images for 3D array -->
<img id="i0" src="images/img0.jpg">
<img id="i50" src="images/img50.jpg">
<!-- end of list of images for 3D array -->
<canvas id="canvas3D"></canvas>
<div id="frame">
<div id="framehead"> View of Slicing Pane</div>
<canvas id="canvas2D"></canvas>
</div>
<div id="userdata">
<div id="originins">Enter in form x,y,z </br> eg 40,27,83</div>
<div id="origintext">Position for Origin O</div>
<div id="origininput"><input id="Oin"></div>
<div id="originlimits">limits</div>
<img class="seen" id="thetaimg" src="images/theta.png">
<div id="thetatext">Theta in degrees</div>
<div id="thetainput"><input id="thetain"></div>
<div id="thetalimits">-90 < theta <=90</div>
<img class="seen" id="psiimg" src="images/psi.jpg">
<div id="psitext">Psi in degrees</div>
<div id="psiinput"><input id="psiin"></div>
<div id="psilimits">-90 < psi <=90</div>
<div id="setButton"><input type="button" value="SET" onclick="setValues()"></div>
<img class="seen" id="axes" src="images/axes.jpg">
</div>
<div id="msg"></div>
</body>
</html>