可以使用哪些图像处理技术来实现检测以下图像中显示的圣诞树的应用程序?
我正在寻找可以在所有这些图像上使用的解决方案。因此,需要训练haar级联分类器或模板匹配的方法不是很有趣。
我正在寻找可以使用任何编程语言编写的东西,只要它仅使用开源技术即可。该解决方案必须使用此问题上共享的图像进行测试。有6个输入图像,答案应显示每个图像的处理结果。最后,对于每个输出图像,必须绘制红线以包围检测到的树。
您将如何以编程方式检测这些图像中的树木?
可以使用哪些图像处理技术来实现检测以下图像中显示的圣诞树的应用程序?
我正在寻找可以在所有这些图像上使用的解决方案。因此,需要训练haar级联分类器或模板匹配的方法不是很有趣。
我正在寻找可以使用任何编程语言编写的东西,只要它仅使用开源技术即可。该解决方案必须使用此问题上共享的图像进行测试。有6个输入图像,答案应显示每个图像的处理结果。最后,对于每个输出图像,必须绘制红线以包围检测到的树。
您将如何以编程方式检测这些图像中的树木?
Answers:
我有一种我认为很有趣的方法,与其他方法有所不同。与其他方法相比,我的方法的主要区别在于如何执行图像分割步骤-我使用了来自python scikit-learn 的DBSCAN聚类算法;它经过优化,可找到可能不一定具有单个清晰质心的某种无定形形状。
在最高层,我的方法很简单,可以分解为大约3个步骤。首先,我应用一个阈值(或者实际上是两个单独且不同的阈值的逻辑“或”)。与其他许多答案一样,我假设圣诞树将是场景中较亮的对象之一,因此第一个阈值只是一个简单的单色亮度测试;0-255范围(黑色为0,白色为255)上的值大于220的所有像素将保存到二进制黑白图像。第二个阈值尝试寻找红光和黄光,这在六张图像的左上角和右下角的树木中尤为突出,并且在大多数照片中普遍使用的蓝绿色背景下表现出色。我将rgb图像转换为hsv空间,并要求色相在0.0-1.0范围内小于0.2(大致对应于黄色和绿色之间的边界)或大于0.95(对应于紫色与红色之间的边界),另外我还要求明亮,饱和的颜色:饱和度和值都必须高于0.7。这两个阈值过程的结果在逻辑上“或”在一起,黑白二进制图像的结果矩阵如下所示:
您可以清楚地看到,每个图像都有一个大的像素簇,大致对应于每棵树的位置,加上一些图像还具有一些其他的小簇,它们对应于某些建筑物的窗户上的灯光,或者对应于背景场景在地平线上。下一步是使计算机识别这些是单独的群集,并使用群集成员ID号正确标记每个像素。
为此,我选择了DBSCAN。相对于其他集群算法,这里有一个很好的视觉比较,可以比较DBSCAN通常的行为。正如我之前说的,它非常适合非晶形形状。此处显示了DBSCAN的输出,其中每个集群以不同的颜色绘制:
查看此结果时,需要注意一些事项。首先,DBSCAN要求用户设置一个“接近”参数以调节其行为,该参数有效地控制了一对点必须分开的程度,以便算法声明新的单独簇,而不是将测试点聚结到已经存在的集群。我将此值设置为每个图像对角线大小的0.04倍。由于图像的大小从大约VGA到大约HD 1080不等,因此这种比例相关的定义至关重要。
另一个值得注意的点是,在scikit-learn中实现的DBSCAN算法具有内存限制,对于此示例中的某些较大图像而言,这是相当大的挑战。因此,对于一些较大的图像,我实际上必须每个群集“抽取”(即,仅保留每个第3或第4像素并丢弃其他像素),以保持在此范围内。作为这种剔除处理的结果,在某些较大的图像上很难看到其余的单个稀疏像素。因此,仅出于显示目的,上述图像中的颜色编码像素已被有效地稍微“扩张”了一点,以使其更加突出。出于叙述目的,这纯粹是一种修饰操作;尽管在我的代码中有评论提到此膨胀,
识别并标记了聚类后,第三步也是最后一步很容易:我只是在每个图像中选取最大的聚类(在这种情况下,我选择根据成员像素的总数来衡量“大小”,尽管可以却很容易地使用某种类型的度量标准来衡量物理范围)并计算该集群的凸包。凸包然后成为树的边界。通过此方法计算的六个凸包在下面以红色显示:
源代码是为Python 2.7.6编写的,它取决于numpy,scipy,matplotlib和scikit-learn。我将其分为两部分。第一部分负责实际的图像处理:
from PIL import Image
import numpy as np
import scipy as sp
import matplotlib.colors as colors
from sklearn.cluster import DBSCAN
from math import ceil, sqrt
"""
Inputs:
rgbimg: [M,N,3] numpy array containing (uint, 0-255) color image
hueleftthr: Scalar constant to select maximum allowed hue in the
yellow-green region
huerightthr: Scalar constant to select minimum allowed hue in the
blue-purple region
satthr: Scalar constant to select minimum allowed saturation
valthr: Scalar constant to select minimum allowed value
monothr: Scalar constant to select minimum allowed monochrome
brightness
maxpoints: Scalar constant maximum number of pixels to forward to
the DBSCAN clustering algorithm
proxthresh: Proximity threshold to use for DBSCAN, as a fraction of
the diagonal size of the image
Outputs:
borderseg: [K,2,2] Nested list containing K pairs of x- and y- pixel
values for drawing the tree border
X: [P,2] List of pixels that passed the threshold step
labels: [Q,2] List of cluster labels for points in Xslice (see
below)
Xslice: [Q,2] Reduced list of pixels to be passed to DBSCAN
"""
def findtree(rgbimg, hueleftthr=0.2, huerightthr=0.95, satthr=0.7,
valthr=0.7, monothr=220, maxpoints=5000, proxthresh=0.04):
# Convert rgb image to monochrome for
gryimg = np.asarray(Image.fromarray(rgbimg).convert('L'))
# Convert rgb image (uint, 0-255) to hsv (float, 0.0-1.0)
hsvimg = colors.rgb_to_hsv(rgbimg.astype(float)/255)
# Initialize binary thresholded image
binimg = np.zeros((rgbimg.shape[0], rgbimg.shape[1]))
# Find pixels with hue<0.2 or hue>0.95 (red or yellow) and saturation/value
# both greater than 0.7 (saturated and bright)--tends to coincide with
# ornamental lights on trees in some of the images
boolidx = np.logical_and(
np.logical_and(
np.logical_or((hsvimg[:,:,0] < hueleftthr),
(hsvimg[:,:,0] > huerightthr)),
(hsvimg[:,:,1] > satthr)),
(hsvimg[:,:,2] > valthr))
# Find pixels that meet hsv criterion
binimg[np.where(boolidx)] = 255
# Add pixels that meet grayscale brightness criterion
binimg[np.where(gryimg > monothr)] = 255
# Prepare thresholded points for DBSCAN clustering algorithm
X = np.transpose(np.where(binimg == 255))
Xslice = X
nsample = len(Xslice)
if nsample > maxpoints:
# Make sure number of points does not exceed DBSCAN maximum capacity
Xslice = X[range(0,nsample,int(ceil(float(nsample)/maxpoints)))]
# Translate DBSCAN proximity threshold to units of pixels and run DBSCAN
pixproxthr = proxthresh * sqrt(binimg.shape[0]**2 + binimg.shape[1]**2)
db = DBSCAN(eps=pixproxthr, min_samples=10).fit(Xslice)
labels = db.labels_.astype(int)
# Find the largest cluster (i.e., with most points) and obtain convex hull
unique_labels = set(labels)
maxclustpt = 0
for k in unique_labels:
class_members = [index[0] for index in np.argwhere(labels == k)]
if len(class_members) > maxclustpt:
points = Xslice[class_members]
hull = sp.spatial.ConvexHull(points)
maxclustpt = len(class_members)
borderseg = [[points[simplex,0], points[simplex,1]] for simplex
in hull.simplices]
return borderseg, X, labels, Xslice
第二部分是用户级脚本,该脚本调用第一个文件并生成上面的所有图:
#!/usr/bin/env python
from PIL import Image
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm
from findtree import findtree
# Image files to process
fname = ['nmzwj.png', 'aVZhC.png', '2K9EF.png',
'YowlH.png', '2y4o5.png', 'FWhSP.png']
# Initialize figures
fgsz = (16,7)
figthresh = plt.figure(figsize=fgsz, facecolor='w')
figclust = plt.figure(figsize=fgsz, facecolor='w')
figcltwo = plt.figure(figsize=fgsz, facecolor='w')
figborder = plt.figure(figsize=fgsz, facecolor='w')
figthresh.canvas.set_window_title('Thresholded HSV and Monochrome Brightness')
figclust.canvas.set_window_title('DBSCAN Clusters (Raw Pixel Output)')
figcltwo.canvas.set_window_title('DBSCAN Clusters (Slightly Dilated for Display)')
figborder.canvas.set_window_title('Trees with Borders')
for ii, name in zip(range(len(fname)), fname):
# Open the file and convert to rgb image
rgbimg = np.asarray(Image.open(name))
# Get the tree borders as well as a bunch of other intermediate values
# that will be used to illustrate how the algorithm works
borderseg, X, labels, Xslice = findtree(rgbimg)
# Display thresholded images
axthresh = figthresh.add_subplot(2,3,ii+1)
axthresh.set_xticks([])
axthresh.set_yticks([])
binimg = np.zeros((rgbimg.shape[0], rgbimg.shape[1]))
for v, h in X:
binimg[v,h] = 255
axthresh.imshow(binimg, interpolation='nearest', cmap='Greys')
# Display color-coded clusters
axclust = figclust.add_subplot(2,3,ii+1) # Raw version
axclust.set_xticks([])
axclust.set_yticks([])
axcltwo = figcltwo.add_subplot(2,3,ii+1) # Dilated slightly for display only
axcltwo.set_xticks([])
axcltwo.set_yticks([])
axcltwo.imshow(binimg, interpolation='nearest', cmap='Greys')
clustimg = np.ones(rgbimg.shape)
unique_labels = set(labels)
# Generate a unique color for each cluster
plcol = cm.rainbow_r(np.linspace(0, 1, len(unique_labels)))
for lbl, pix in zip(labels, Xslice):
for col, unqlbl in zip(plcol, unique_labels):
if lbl == unqlbl:
# Cluster label of -1 indicates no cluster membership;
# override default color with black
if lbl == -1:
col = [0.0, 0.0, 0.0, 1.0]
# Raw version
for ij in range(3):
clustimg[pix[0],pix[1],ij] = col[ij]
# Dilated just for display
axcltwo.plot(pix[1], pix[0], 'o', markerfacecolor=col,
markersize=1, markeredgecolor=col)
axclust.imshow(clustimg)
axcltwo.set_xlim(0, binimg.shape[1]-1)
axcltwo.set_ylim(binimg.shape[0], -1)
# Plot original images with read borders around the trees
axborder = figborder.add_subplot(2,3,ii+1)
axborder.set_axis_off()
axborder.imshow(rgbimg, interpolation='nearest')
for vseg, hseg in borderseg:
axborder.plot(hseg, vseg, 'r-', lw=3)
axborder.set_xlim(0, binimg.shape[1]-1)
axborder.set_ylim(binimg.shape[0], -1)
plt.show()
scipy.ndimage.filters.maximum_filter()
在使用阈值的同一位置替换对的调用。
编辑注释:我编辑了这篇文章,以(i)根据要求单独处理每棵树图像,(ii)考虑对象的亮度和形状,以提高结果的质量。
下面介绍一种考虑物体亮度和形状的方法。换句话说,它寻找具有三角形形状且具有明显亮度的物体。它使用Marvin图像处理框架以Java实现。
第一步是颜色阈值。此处的目的是将分析重点放在亮度很高的物体上。
输出图像:
源代码:
public class ChristmasTree {
private MarvinImagePlugin fill = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.fill.boundaryFill");
private MarvinImagePlugin threshold = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.color.thresholding");
private MarvinImagePlugin invert = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.color.invert");
private MarvinImagePlugin dilation = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.morphological.dilation");
public ChristmasTree(){
MarvinImage tree;
// Iterate each image
for(int i=1; i<=6; i++){
tree = MarvinImageIO.loadImage("./res/trees/tree"+i+".png");
// 1. Threshold
threshold.setAttribute("threshold", 200);
threshold.process(tree.clone(), tree);
}
}
public static void main(String[] args) {
new ChristmasTree();
}
}
在第二步中,将图像中最亮的点放大以形成形状。该过程的结果是具有明显亮度的物体的可能形状。应用洪水填充分割,可以检测到断开的形状。
输出图像:
源代码:
public class ChristmasTree {
private MarvinImagePlugin fill = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.fill.boundaryFill");
private MarvinImagePlugin threshold = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.color.thresholding");
private MarvinImagePlugin invert = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.color.invert");
private MarvinImagePlugin dilation = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.morphological.dilation");
public ChristmasTree(){
MarvinImage tree;
// Iterate each image
for(int i=1; i<=6; i++){
tree = MarvinImageIO.loadImage("./res/trees/tree"+i+".png");
// 1. Threshold
threshold.setAttribute("threshold", 200);
threshold.process(tree.clone(), tree);
// 2. Dilate
invert.process(tree.clone(), tree);
tree = MarvinColorModelConverter.rgbToBinary(tree, 127);
MarvinImageIO.saveImage(tree, "./res/trees/new/tree_"+i+"threshold.png");
dilation.setAttribute("matrix", MarvinMath.getTrueMatrix(50, 50));
dilation.process(tree.clone(), tree);
MarvinImageIO.saveImage(tree, "./res/trees/new/tree_"+1+"_dilation.png");
tree = MarvinColorModelConverter.binaryToRgb(tree);
// 3. Segment shapes
MarvinImage trees2 = tree.clone();
fill(tree, trees2);
MarvinImageIO.saveImage(trees2, "./res/trees/new/tree_"+i+"_fill.png");
}
private void fill(MarvinImage imageIn, MarvinImage imageOut){
boolean found;
int color= 0xFFFF0000;
while(true){
found=false;
Outerloop:
for(int y=0; y<imageIn.getHeight(); y++){
for(int x=0; x<imageIn.getWidth(); x++){
if(imageOut.getIntComponent0(x, y) == 0){
fill.setAttribute("x", x);
fill.setAttribute("y", y);
fill.setAttribute("color", color);
fill.setAttribute("threshold", 120);
fill.process(imageIn, imageOut);
color = newColor(color);
found = true;
break Outerloop;
}
}
}
if(!found){
break;
}
}
}
private int newColor(int color){
int red = (color & 0x00FF0000) >> 16;
int green = (color & 0x0000FF00) >> 8;
int blue = (color & 0x000000FF);
if(red <= green && red <= blue){
red+=5;
}
else if(green <= red && green <= blue){
green+=5;
}
else{
blue+=5;
}
return 0xFF000000 + (red << 16) + (green << 8) + blue;
}
public static void main(String[] args) {
new ChristmasTree();
}
}
如输出图像所示,检测到多种形状。在此问题中,图像中只有几个亮点。但是,实施此方法是为了处理更复杂的情况。
在下一步中,将分析每个形状。一种简单的算法可以检测形状类似于三角形的形状。该算法逐行分析对象形状。如果每个形状线的质心几乎相同(给定阈值),并且质量随着y的增加而增加,则对象具有三角形的形状。形状线的质量是该线中属于该形状的像素数。想象一下,您将对象水平切片并分析每个水平段。如果它们彼此居中,并且长度以线性模式从第一段到最后一段增加,则您可能有一个类似于三角形的对象。
源代码:
private int[] detectTrees(MarvinImage image){
HashSet<Integer> analysed = new HashSet<Integer>();
boolean found;
while(true){
found = false;
for(int y=0; y<image.getHeight(); y++){
for(int x=0; x<image.getWidth(); x++){
int color = image.getIntColor(x, y);
if(!analysed.contains(color)){
if(isTree(image, color)){
return getObjectRect(image, color);
}
analysed.add(color);
found=true;
}
}
}
if(!found){
break;
}
}
return null;
}
private boolean isTree(MarvinImage image, int color){
int mass[][] = new int[image.getHeight()][2];
int yStart=-1;
int xStart=-1;
for(int y=0; y<image.getHeight(); y++){
int mc = 0;
int xs=-1;
int xe=-1;
for(int x=0; x<image.getWidth(); x++){
if(image.getIntColor(x, y) == color){
mc++;
if(yStart == -1){
yStart=y;
xStart=x;
}
if(xs == -1){
xs = x;
}
if(x > xe){
xe = x;
}
}
}
mass[y][0] = xs;
mass[y][3] = xe;
mass[y][4] = mc;
}
int validLines=0;
for(int y=0; y<image.getHeight(); y++){
if
(
mass[y][5] > 0 &&
Math.abs(((mass[y][0]+mass[y][6])/2)-xStart) <= 50 &&
mass[y][7] >= (mass[yStart][8] + (y-yStart)*0.3) &&
mass[y][9] <= (mass[yStart][10] + (y-yStart)*1.5)
)
{
validLines++;
}
}
if(validLines > 100){
return true;
}
return false;
}
最后,如下图所示,原始图像中突出显示了每个形状类似于三角形且具有明显亮度的位置(在本例中为圣诞树)。
最终输出图像:
最终源代码:
public class ChristmasTree {
private MarvinImagePlugin fill = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.fill.boundaryFill");
private MarvinImagePlugin threshold = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.color.thresholding");
private MarvinImagePlugin invert = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.color.invert");
private MarvinImagePlugin dilation = MarvinPluginLoader.loadImagePlugin("org.marvinproject.image.morphological.dilation");
public ChristmasTree(){
MarvinImage tree;
// Iterate each image
for(int i=1; i<=6; i++){
tree = MarvinImageIO.loadImage("./res/trees/tree"+i+".png");
// 1. Threshold
threshold.setAttribute("threshold", 200);
threshold.process(tree.clone(), tree);
// 2. Dilate
invert.process(tree.clone(), tree);
tree = MarvinColorModelConverter.rgbToBinary(tree, 127);
MarvinImageIO.saveImage(tree, "./res/trees/new/tree_"+i+"threshold.png");
dilation.setAttribute("matrix", MarvinMath.getTrueMatrix(50, 50));
dilation.process(tree.clone(), tree);
MarvinImageIO.saveImage(tree, "./res/trees/new/tree_"+1+"_dilation.png");
tree = MarvinColorModelConverter.binaryToRgb(tree);
// 3. Segment shapes
MarvinImage trees2 = tree.clone();
fill(tree, trees2);
MarvinImageIO.saveImage(trees2, "./res/trees/new/tree_"+i+"_fill.png");
// 4. Detect tree-like shapes
int[] rect = detectTrees(trees2);
// 5. Draw the result
MarvinImage original = MarvinImageIO.loadImage("./res/trees/tree"+i+".png");
drawBoundary(trees2, original, rect);
MarvinImageIO.saveImage(original, "./res/trees/new/tree_"+i+"_out_2.jpg");
}
}
private void drawBoundary(MarvinImage shape, MarvinImage original, int[] rect){
int yLines[] = new int[6];
yLines[0] = rect[1];
yLines[1] = rect[1]+(int)((rect[3]/5));
yLines[2] = rect[1]+((rect[3]/5)*2);
yLines[3] = rect[1]+((rect[3]/5)*3);
yLines[4] = rect[1]+(int)((rect[3]/5)*4);
yLines[5] = rect[1]+rect[3];
List<Point> points = new ArrayList<Point>();
for(int i=0; i<yLines.length; i++){
boolean in=false;
Point startPoint=null;
Point endPoint=null;
for(int x=rect[0]; x<rect[0]+rect[2]; x++){
if(shape.getIntColor(x, yLines[i]) != 0xFFFFFFFF){
if(!in){
if(startPoint == null){
startPoint = new Point(x, yLines[i]);
}
}
in = true;
}
else{
if(in){
endPoint = new Point(x, yLines[i]);
}
in = false;
}
}
if(endPoint == null){
endPoint = new Point((rect[0]+rect[2])-1, yLines[i]);
}
points.add(startPoint);
points.add(endPoint);
}
drawLine(points.get(0).x, points.get(0).y, points.get(1).x, points.get(1).y, 15, original);
drawLine(points.get(1).x, points.get(1).y, points.get(3).x, points.get(3).y, 15, original);
drawLine(points.get(3).x, points.get(3).y, points.get(5).x, points.get(5).y, 15, original);
drawLine(points.get(5).x, points.get(5).y, points.get(7).x, points.get(7).y, 15, original);
drawLine(points.get(7).x, points.get(7).y, points.get(9).x, points.get(9).y, 15, original);
drawLine(points.get(9).x, points.get(9).y, points.get(11).x, points.get(11).y, 15, original);
drawLine(points.get(11).x, points.get(11).y, points.get(10).x, points.get(10).y, 15, original);
drawLine(points.get(10).x, points.get(10).y, points.get(8).x, points.get(8).y, 15, original);
drawLine(points.get(8).x, points.get(8).y, points.get(6).x, points.get(6).y, 15, original);
drawLine(points.get(6).x, points.get(6).y, points.get(4).x, points.get(4).y, 15, original);
drawLine(points.get(4).x, points.get(4).y, points.get(2).x, points.get(2).y, 15, original);
drawLine(points.get(2).x, points.get(2).y, points.get(0).x, points.get(0).y, 15, original);
}
private void drawLine(int x1, int y1, int x2, int y2, int length, MarvinImage image){
int lx1, lx2, ly1, ly2;
for(int i=0; i<length; i++){
lx1 = (x1+i >= image.getWidth() ? (image.getWidth()-1)-i: x1);
lx2 = (x2+i >= image.getWidth() ? (image.getWidth()-1)-i: x2);
ly1 = (y1+i >= image.getHeight() ? (image.getHeight()-1)-i: y1);
ly2 = (y2+i >= image.getHeight() ? (image.getHeight()-1)-i: y2);
image.drawLine(lx1+i, ly1, lx2+i, ly2, Color.red);
image.drawLine(lx1, ly1+i, lx2, ly2+i, Color.red);
}
}
private void fillRect(MarvinImage image, int[] rect, int length){
for(int i=0; i<length; i++){
image.drawRect(rect[0]+i, rect[1]+i, rect[2]-(i*2), rect[3]-(i*2), Color.red);
}
}
private void fill(MarvinImage imageIn, MarvinImage imageOut){
boolean found;
int color= 0xFFFF0000;
while(true){
found=false;
Outerloop:
for(int y=0; y<imageIn.getHeight(); y++){
for(int x=0; x<imageIn.getWidth(); x++){
if(imageOut.getIntComponent0(x, y) == 0){
fill.setAttribute("x", x);
fill.setAttribute("y", y);
fill.setAttribute("color", color);
fill.setAttribute("threshold", 120);
fill.process(imageIn, imageOut);
color = newColor(color);
found = true;
break Outerloop;
}
}
}
if(!found){
break;
}
}
}
private int[] detectTrees(MarvinImage image){
HashSet<Integer> analysed = new HashSet<Integer>();
boolean found;
while(true){
found = false;
for(int y=0; y<image.getHeight(); y++){
for(int x=0; x<image.getWidth(); x++){
int color = image.getIntColor(x, y);
if(!analysed.contains(color)){
if(isTree(image, color)){
return getObjectRect(image, color);
}
analysed.add(color);
found=true;
}
}
}
if(!found){
break;
}
}
return null;
}
private boolean isTree(MarvinImage image, int color){
int mass[][] = new int[image.getHeight()][11];
int yStart=-1;
int xStart=-1;
for(int y=0; y<image.getHeight(); y++){
int mc = 0;
int xs=-1;
int xe=-1;
for(int x=0; x<image.getWidth(); x++){
if(image.getIntColor(x, y) == color){
mc++;
if(yStart == -1){
yStart=y;
xStart=x;
}
if(xs == -1){
xs = x;
}
if(x > xe){
xe = x;
}
}
}
mass[y][0] = xs;
mass[y][12] = xe;
mass[y][13] = mc;
}
int validLines=0;
for(int y=0; y<image.getHeight(); y++){
if
(
mass[y][14] > 0 &&
Math.abs(((mass[y][0]+mass[y][15])/2)-xStart) <= 50 &&
mass[y][16] >= (mass[yStart][17] + (y-yStart)*0.3) &&
mass[y][18] <= (mass[yStart][19] + (y-yStart)*1.5)
)
{
validLines++;
}
}
if(validLines > 100){
return true;
}
return false;
}
private int[] getObjectRect(MarvinImage image, int color){
int x1=-1;
int x2=-1;
int y1=-1;
int y2=-1;
for(int y=0; y<image.getHeight(); y++){
for(int x=0; x<image.getWidth(); x++){
if(image.getIntColor(x, y) == color){
if(x1 == -1 || x < x1){
x1 = x;
}
if(x2 == -1 || x > x2){
x2 = x;
}
if(y1 == -1 || y < y1){
y1 = y;
}
if(y2 == -1 || y > y2){
y2 = y;
}
}
}
}
return new int[]{x1, y1, (x2-x1), (y2-y1)};
}
private int newColor(int color){
int red = (color & 0x00FF0000) >> 16;
int green = (color & 0x0000FF00) >> 8;
int blue = (color & 0x000000FF);
if(red <= green && red <= blue){
red+=5;
}
else if(green <= red && green <= blue){
green+=30;
}
else{
blue+=30;
}
return 0xFF000000 + (red << 16) + (green << 8) + blue;
}
public static void main(String[] args) {
new ChristmasTree();
}
}
这种方法的优点在于,由于它可以分析物体的形状,因此可能会与包含其他发光物体的图像一起使用。
圣诞节快乐!
编辑注2
讨论了此解决方案与其他解决方案的输出图像的相似性。实际上,它们非常相似。但是这种方法不仅可以分割对象。它还从某种意义上分析了对象的形状。它可以处理同一场景中的多个发光物体。实际上,圣诞树不必是最亮的圣诞树。我只是为了中止讨论而中止。样本中存在偏差,即仅寻找最亮的对象,便会找到树木。但是,我们真的要在这一点上停止讨论吗?在这一点上,计算机实际上能识别出类似于圣诞树的物体吗?让我们尝试缩小这一差距。
下面给出的结果只是为了阐明这一点:
输入图像
输出
这是我简单而又愚蠢的解决方案。它基于这样的假设,即树将是图片中最亮,最大的东西。
//g++ -Wall -pedantic -ansi -O2 -pipe -s -o christmas_tree christmas_tree.cpp `pkg-config --cflags --libs opencv`
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main(int argc,char *argv[])
{
Mat original,tmp,tmp1;
vector <vector<Point> > contours;
Moments m;
Rect boundrect;
Point2f center;
double radius, max_area=0,tmp_area=0;
unsigned int j, k;
int i;
for(i = 1; i < argc; ++i)
{
original = imread(argv[i]);
if(original.empty())
{
cerr << "Error"<<endl;
return -1;
}
GaussianBlur(original, tmp, Size(3, 3), 0, 0, BORDER_DEFAULT);
erode(tmp, tmp, Mat(), Point(-1, -1), 10);
cvtColor(tmp, tmp, CV_BGR2HSV);
inRange(tmp, Scalar(0, 0, 0), Scalar(180, 255, 200), tmp);
dilate(original, tmp1, Mat(), Point(-1, -1), 15);
cvtColor(tmp1, tmp1, CV_BGR2HLS);
inRange(tmp1, Scalar(0, 185, 0), Scalar(180, 255, 255), tmp1);
dilate(tmp1, tmp1, Mat(), Point(-1, -1), 10);
bitwise_and(tmp, tmp1, tmp1);
findContours(tmp1, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);
max_area = 0;
j = 0;
for(k = 0; k < contours.size(); k++)
{
tmp_area = contourArea(contours[k]);
if(tmp_area > max_area)
{
max_area = tmp_area;
j = k;
}
}
tmp1 = Mat::zeros(original.size(),CV_8U);
approxPolyDP(contours[j], contours[j], 30, true);
drawContours(tmp1, contours, j, Scalar(255,255,255), CV_FILLED);
m = moments(contours[j]);
boundrect = boundingRect(contours[j]);
center = Point2f(m.m10/m.m00, m.m01/m.m00);
radius = (center.y - (boundrect.tl().y))/4.0*3.0;
Rect heightrect(center.x-original.cols/5, boundrect.tl().y, original.cols/5*2, boundrect.size().height);
tmp = Mat::zeros(original.size(), CV_8U);
rectangle(tmp, heightrect, Scalar(255, 255, 255), -1);
circle(tmp, center, radius, Scalar(255, 255, 255), -1);
bitwise_and(tmp, tmp1, tmp1);
findContours(tmp1, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);
max_area = 0;
j = 0;
for(k = 0; k < contours.size(); k++)
{
tmp_area = contourArea(contours[k]);
if(tmp_area > max_area)
{
max_area = tmp_area;
j = k;
}
}
approxPolyDP(contours[j], contours[j], 30, true);
convexHull(contours[j], contours[j]);
drawContours(original, contours, j, Scalar(0, 0, 255), 3);
namedWindow(argv[i], CV_WINDOW_NORMAL|CV_WINDOW_KEEPRATIO|CV_GUI_EXPANDED);
imshow(argv[i], original);
waitKey(0);
destroyWindow(argv[i]);
}
return 0;
}
第一步是检测图片中最亮的像素,但是我们必须对树木本身和反射其光的雪进行区分。在这里,我们尝试排除对颜色代码应用非常简单的滤镜的雪:
GaussianBlur(original, tmp, Size(3, 3), 0, 0, BORDER_DEFAULT);
erode(tmp, tmp, Mat(), Point(-1, -1), 10);
cvtColor(tmp, tmp, CV_BGR2HSV);
inRange(tmp, Scalar(0, 0, 0), Scalar(180, 255, 200), tmp);
然后我们找到每个“明亮”像素:
dilate(original, tmp1, Mat(), Point(-1, -1), 15);
cvtColor(tmp1, tmp1, CV_BGR2HLS);
inRange(tmp1, Scalar(0, 185, 0), Scalar(180, 255, 255), tmp1);
dilate(tmp1, tmp1, Mat(), Point(-1, -1), 10);
最后,我们将两个结果结合起来:
bitwise_and(tmp, tmp1, tmp1);
现在我们寻找最大的明亮物体:
findContours(tmp1, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);
max_area = 0;
j = 0;
for(k = 0; k < contours.size(); k++)
{
tmp_area = contourArea(contours[k]);
if(tmp_area > max_area)
{
max_area = tmp_area;
j = k;
}
}
tmp1 = Mat::zeros(original.size(),CV_8U);
approxPolyDP(contours[j], contours[j], 30, true);
drawContours(tmp1, contours, j, Scalar(255,255,255), CV_FILLED);
现在我们差不多完成了,但是由于下雪还有些不完善。为了将它们剪掉,我们将使用一个圆形和一个矩形构建一个遮罩,以近似于树的形状来删除不需要的片段:
m = moments(contours[j]);
boundrect = boundingRect(contours[j]);
center = Point2f(m.m10/m.m00, m.m01/m.m00);
radius = (center.y - (boundrect.tl().y))/4.0*3.0;
Rect heightrect(center.x-original.cols/5, boundrect.tl().y, original.cols/5*2, boundrect.size().height);
tmp = Mat::zeros(original.size(), CV_8U);
rectangle(tmp, heightrect, Scalar(255, 255, 255), -1);
circle(tmp, center, radius, Scalar(255, 255, 255), -1);
bitwise_and(tmp, tmp1, tmp1);
最后一步是找到我们树的轮廓并将其绘制在原始图片上。
findContours(tmp1, contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);
max_area = 0;
j = 0;
for(k = 0; k < contours.size(); k++)
{
tmp_area = contourArea(contours[k]);
if(tmp_area > max_area)
{
max_area = tmp_area;
j = k;
}
}
approxPolyDP(contours[j], contours[j], 30, true);
convexHull(contours[j], contours[j]);
drawContours(original, contours, j, Scalar(0, 0, 255), 3);
抱歉,目前连接不好,因此无法上传图片。稍后再尝试。
圣诞节快乐。
编辑:
这里是最终输出的一些图片:
./christmas_tree ./*.png
。它们可以是任意数量,结果将一个接一个地显示,另一个按任意键。错了吗
<img src="http://i.stack.imgur.com/nmzwj.png" width="210" height="150">
只需更改图片的链接即可;)
我在Matlab R2007a中编写了代码。我用k均值粗略提取了圣诞树。我将只用一张图像显示中间结果,而用全部六个图像显示最终结果。
首先,我将RGB空间映射到Lab空间,这可以增强b通道中红色的对比度:
colorTransform = makecform('srgb2lab');
I = applycform(I, colorTransform);
L = double(I(:,:,1));
a = double(I(:,:,2));
b = double(I(:,:,3));
除了色彩空间中的功能外,我还使用了与邻域相关的纹理功能,而不是与每个像素本身相关。在这里,我将三个原始通道(R,G,B)的强度线性组合。我采用这种格式的原因是,图片中的圣诞树上都有红色的灯光,有时还有绿色/有时是蓝色的照明。
R=double(Irgb(:,:,1));
G=double(Irgb(:,:,2));
B=double(Irgb(:,:,3));
I0 = (3*R + max(G,B)-min(G,B))/2;
我在其上应用了3X3局部二进制模式I0
,将中心像素用作阈值,并通过计算阈值以上的平均像素强度值与阈值以下的平均值之间的差来获得对比度。
I0_copy = zeros(size(I0));
for i = 2 : size(I0,1) - 1
for j = 2 : size(I0,2) - 1
tmp = I0(i-1:i+1,j-1:j+1) >= I0(i,j);
I0_copy(i,j) = mean(mean(tmp.*I0(i-1:i+1,j-1:j+1))) - ...
mean(mean(~tmp.*I0(i-1:i+1,j-1:j+1))); % Contrast
end
end
由于我总共有4个特征,因此我将在聚类方法中选择K = 5。k-means的代码如下所示(来自Andrew Ng博士的机器学习课程。我之前参加过该课程,我自己在程序设计中编写了代码)。
[centroids, idx] = runkMeans(X, initial_centroids, max_iters);
mask=reshape(idx,img_size(1),img_size(2));
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function [centroids, idx] = runkMeans(X, initial_centroids, ...
max_iters, plot_progress)
[m n] = size(X);
K = size(initial_centroids, 1);
centroids = initial_centroids;
previous_centroids = centroids;
idx = zeros(m, 1);
for i=1:max_iters
% For each example in X, assign it to the closest centroid
idx = findClosestCentroids(X, centroids);
% Given the memberships, compute new centroids
centroids = computeCentroids(X, idx, K);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function idx = findClosestCentroids(X, centroids)
K = size(centroids, 1);
idx = zeros(size(X,1), 1);
for xi = 1:size(X,1)
x = X(xi, :);
% Find closest centroid for x.
best = Inf;
for mui = 1:K
mu = centroids(mui, :);
d = dot(x - mu, x - mu);
if d < best
best = d;
idx(xi) = mui;
end
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
function centroids = computeCentroids(X, idx, K)
[m n] = size(X);
centroids = zeros(K, n);
for mui = 1:K
centroids(mui, :) = sum(X(idx == mui, :)) / sum(idx == mui);
end
由于该程序在我的计算机上运行非常慢,因此我只运行了3次迭代。通常,停止条件是(i)迭代时间至少为10,或(ii)质心不再变化。以我的测试而言,增加迭代次数可能会更准确地区分背景(天空和树木,天空和建筑物等),但在圣诞树提取中并未显示出明显的变化。还要注意,k均值不能不受随机质心初始化的影响,因此建议多次运行该程序进行比较。
在k均值之后,I0
选择具有最大强度的标记区域。并使用边界跟踪提取边界。对我来说,最后一棵圣诞树是最难提取的圣诞树,因为该图片中的对比度不如前五棵圣诞树高。我方法中的另一个问题是,我bwboundaries
在Matlab中使用函数来跟踪边界,但是有时在第3、5、6个结果中也可以看到内部边界。圣诞树上的阴暗面不仅无法与发光面聚在一起,而且还导致了许多细微的内部边界追踪(imfill
改善不多)。总之我的算法还有很大的改进空间。
一些出版物指出,均值平移可能比k均值更健壮,并且许多 基于图割的算法在复杂的边界分割上也很有竞争力。我自己编写了均值漂移算法,似乎可以在没有足够光线的情况下更好地提取区域。但是均值移动有点过分,需要一些合并策略。它在我的计算机上的运行速度甚至比k-means慢得多,恐怕我不得不放弃它。我热切期待看到其他人将通过上述现代算法在此处提交出色的结果。
但是我始终相信特征选择是图像分割中的关键组成部分。选择适当的特征以使对象和背景之间的余量最大化,许多分割算法肯定会起作用。不同的算法可能会将结果从1提高到10,但是功能选择可能会将结果从0提高到1。
圣诞节快乐 !
这是我使用传统图像处理方法的最后一篇文章。
在这里,我以某种方式结合了其他两个建议,甚至取得了更好的结果。事实上,我看不到这些结果如何更好(尤其是当您查看该方法生成的蒙版图像时)。
该方法的核心是三个关键假设的组合:
考虑到这些假设,该方法的工作方式如下:
这是MATLAB中的代码(同样,脚本将所有jpg图像加载到当前文件夹中,同样,这并不是一段经过优化的代码):
% clear everything
clear;
pack;
close all;
close all hidden;
drawnow;
clc;
% initialization
ims=dir('./*.jpg');
imgs={};
images={};
blur_images={};
log_image={};
dilated_image={};
int_image={};
back_image={};
bin_image={};
measurements={};
box={};
num=length(ims);
thres_div = 3;
for i=1:num,
% load original image
imgs{end+1}=imread(ims(i).name);
% convert to HSV colorspace
images{end+1}=rgb2hsv(imgs{i});
% apply laplacian filtering and heuristic hard thresholding
val_thres = (max(max(images{i}(:,:,3)))/thres_div);
log_image{end+1} = imfilter( images{i}(:,:,3),fspecial('log')) > val_thres;
% get the most bright regions of the image
int_thres = 0.26*max(max( images{i}(:,:,3)));
int_image{end+1} = images{i}(:,:,3) > int_thres;
% get the most probable background regions of the image
back_image{end+1} = images{i}(:,:,1)>(150/360) & images{i}(:,:,1)<(320/360) & images{i}(:,:,3)<0.5;
% compute the final binary image by combining
% high 'activity' with high intensity
bin_image{end+1} = logical( log_image{i}) & logical( int_image{i}) & ~logical( back_image{i});
% apply morphological dilation to connect distonnected components
strel_size = round(0.01*max(size(imgs{i}))); % structuring element for morphological dilation
dilated_image{end+1} = imdilate( bin_image{i}, strel('disk',strel_size));
% do some measurements to eliminate small objects
measurements{i} = regionprops( logical( dilated_image{i}),'Area','BoundingBox');
% iterative enlargement of the structuring element for better connectivity
while length(measurements{i})>14 && strel_size<(min(size(imgs{i}(:,:,1)))/2),
strel_size = round( 1.5 * strel_size);
dilated_image{i} = imdilate( bin_image{i}, strel('disk',strel_size));
measurements{i} = regionprops( logical( dilated_image{i}),'Area','BoundingBox');
end
for m=1:length(measurements{i})
if measurements{i}(m).Area < 0.05*numel( dilated_image{i})
dilated_image{i}( round(measurements{i}(m).BoundingBox(2):measurements{i}(m).BoundingBox(4)+measurements{i}(m).BoundingBox(2)),...
round(measurements{i}(m).BoundingBox(1):measurements{i}(m).BoundingBox(3)+measurements{i}(m).BoundingBox(1))) = 0;
end
end
% make sure the dilated image is the same size with the original
dilated_image{i} = dilated_image{i}(1:size(imgs{i},1),1:size(imgs{i},2));
% compute the bounding box
[y,x] = find( dilated_image{i});
if isempty( y)
box{end+1}=[];
else
box{end+1} = [ min(x) min(y) max(x)-min(x)+1 max(y)-min(y)+1];
end
end
%%% additional code to display things
for i=1:num,
figure;
subplot(121);
colormap gray;
imshow( imgs{i});
if ~isempty(box{i})
hold on;
rr = rectangle( 'position', box{i});
set( rr, 'EdgeColor', 'r');
hold off;
end
subplot(122);
imshow( imgs{i}.*uint8(repmat(dilated_image{i},[1 1 3])));
end
高分辨率结果仍可在这里!
在这里可以找到更多带有其他图像的实验。
我的解决步骤:
获取R通道(从RGB)-我们在此通道上进行的所有操作:
创建兴趣区(ROI)
最小值为149的阈值R通道(右上图)
扩大结果区域(左中图)
在计算的投资回报率中检测矿石。树有很多边缘(右中图)
膨胀结果
半径较大的腐蚀(左下图)
选择最大的(按区域)对象-这是结果区域
ConvexHull(树是凸多边形)(右下图)
边界框(右下图-grren框)
一步步:
第一个结果-最简单但不是开源软件-“ Adaptive Vision Studio + Adaptive Vision Library”:这不是开源的,但原型制作起来确实非常快:
完整的圣诞树检测算法(11个块):
下一步。我们需要开源解决方案。将AVL滤镜更改为OpenCV滤镜:在这里,我进行了一些更改,例如,“边缘检测”使用cvCanny滤镜,以尊重roi,我确实将区域图像与边缘图像相乘,选择了我使用的最大元素findContours + outlineArea,但是想法是相同的。
https://www.youtube.com/watch?v=sfjB3MigLH0&index=1&list=UUpSRrkMHNHiLDXgylwhWNQQ
我现在无法显示具有中间步骤的图像,因为我只能放置2个链接。
好的,现在我们使用openSource过滤器,但它还不是全部开源。最后一步-移植到C ++代码。我在版本2.4.4中使用了OpenCV
最终的c ++代码的结果是:
C ++代码也很短:
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/opencv.hpp"
#include <algorithm>
using namespace cv;
int main()
{
string images[6] = {"..\\1.png","..\\2.png","..\\3.png","..\\4.png","..\\5.png","..\\6.png"};
for(int i = 0; i < 6; ++i)
{
Mat img, thresholded, tdilated, tmp, tmp1;
vector<Mat> channels(3);
img = imread(images[i]);
split(img, channels);
threshold( channels[2], thresholded, 149, 255, THRESH_BINARY); //prepare ROI - threshold
dilate( thresholded, tdilated, getStructuringElement( MORPH_RECT, Size(22,22) ) ); //prepare ROI - dilate
Canny( channels[2], tmp, 75, 125, 3, true ); //Canny edge detection
multiply( tmp, tdilated, tmp1 ); // set ROI
dilate( tmp1, tmp, getStructuringElement( MORPH_RECT, Size(20,16) ) ); // dilate
erode( tmp, tmp1, getStructuringElement( MORPH_RECT, Size(36,36) ) ); // erode
vector<vector<Point> > contours, contours1(1);
vector<Point> convex;
vector<Vec4i> hierarchy;
findContours( tmp1, contours, hierarchy, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, Point(0, 0) );
//get element of maximum area
//int bestID = std::max_element( contours.begin(), contours.end(),
// []( const vector<Point>& A, const vector<Point>& B ) { return contourArea(A) < contourArea(B); } ) - contours.begin();
int bestID = 0;
int bestArea = contourArea( contours[0] );
for( int i = 1; i < contours.size(); ++i )
{
int area = contourArea( contours[i] );
if( area > bestArea )
{
bestArea = area;
bestID = i;
}
}
convexHull( contours[bestID], contours1[0] );
drawContours( img, contours1, 0, Scalar( 100, 100, 255 ), img.rows / 100, 8, hierarchy, 0, Point() );
imshow("image", img );
waitKey(0);
}
return 0;
}
std::max_element()
通话吗?我也想感谢您的回答。我想我有gcc 4.2。
...另一种老式解决方案-完全基于HSV处理:
一个字的启发式在HSV处理:
当然,可以尝试许多其他可能性来微调这种方法。
这是实现此技巧的MATLAB代码(警告:代码远未优化!!!我使用了不推荐用于MATLAB编程的技术,只是为了能够跟踪过程中的任何内容,因此可以对其进行极大地优化):
% clear everything
clear;
pack;
close all;
close all hidden;
drawnow;
clc;
% initialization
ims=dir('./*.jpg');
num=length(ims);
imgs={};
hsvs={};
masks={};
dilated_images={};
measurements={};
boxs={};
for i=1:num,
% load original image
imgs{end+1} = imread(ims(i).name);
flt_x_size = round(size(imgs{i},2)*0.005);
flt_y_size = round(size(imgs{i},1)*0.005);
flt = fspecial( 'average', max( flt_y_size, flt_x_size));
imgs{i} = imfilter( imgs{i}, flt, 'same');
% convert to HSV colorspace
hsvs{end+1} = rgb2hsv(imgs{i});
% apply a hard thresholding and binary operation to construct the mask
masks{end+1} = medfilt2( ~(hsvs{i}(:,:,1)>(210/360) & hsvs{i}(:,:,1)<(320/360))&hsvs{i}(:,:,3)>0.4);
% apply morphological dilation to connect distonnected components
strel_size = round(0.03*max(size(imgs{i}))); % structuring element for morphological dilation
dilated_images{end+1} = imdilate( masks{i}, strel('disk',strel_size));
% do some measurements to eliminate small objects
measurements{i} = regionprops( dilated_images{i},'Perimeter','Area','BoundingBox');
for m=1:length(measurements{i})
if (measurements{i}(m).Area < 0.02*numel( dilated_images{i})) || (measurements{i}(m).BoundingBox(3)>1.2*measurements{i}(m).BoundingBox(4))
dilated_images{i}( round(measurements{i}(m).BoundingBox(2):measurements{i}(m).BoundingBox(4)+measurements{i}(m).BoundingBox(2)),...
round(measurements{i}(m).BoundingBox(1):measurements{i}(m).BoundingBox(3)+measurements{i}(m).BoundingBox(1))) = 0;
end
end
dilated_images{i} = dilated_images{i}(1:size(imgs{i},1),1:size(imgs{i},2));
% compute the bounding box
[y,x] = find( dilated_images{i});
if isempty( y)
boxs{end+1}=[];
else
boxs{end+1} = [ min(x) min(y) max(x)-min(x)+1 max(y)-min(y)+1];
end
end
%%% additional code to display things
for i=1:num,
figure;
subplot(121);
colormap gray;
imshow( imgs{i});
if ~isempty(boxs{i})
hold on;
rr = rectangle( 'position', boxs{i});
set( rr, 'EdgeColor', 'r');
hold off;
end
subplot(122);
imshow( imgs{i}.*uint8(repmat(dilated_images{i},[1 1 3])));
end
在结果中,我显示了蒙版的图像和边界框。
一些老式的图像处理方法...
这个想法是基于这样的假设,即图像在通常较暗和较平滑的背景(在某些情况下为前景)上描绘了发光的树。该点燃树面积更“有活力”,具有较高的强度。
流程如下:
您得到的是每个图像的二进制掩码和边界框。
这是使用这种幼稚技术的结果:
MATLAB上 的代码如下:该代码在包含JPG图像的文件夹上运行。加载所有图像并返回检测到的结果。
% clear everything
clear;
pack;
close all;
close all hidden;
drawnow;
clc;
% initialization
ims=dir('./*.jpg');
imgs={};
images={};
blur_images={};
log_image={};
dilated_image={};
int_image={};
bin_image={};
measurements={};
box={};
num=length(ims);
thres_div = 3;
for i=1:num,
% load original image
imgs{end+1}=imread(ims(i).name);
% convert to grayscale
images{end+1}=rgb2gray(imgs{i});
% apply laplacian filtering and heuristic hard thresholding
val_thres = (max(max(images{i}))/thres_div);
log_image{end+1} = imfilter( images{i},fspecial('log')) > val_thres;
% get the most bright regions of the image
int_thres = 0.26*max(max( images{i}));
int_image{end+1} = images{i} > int_thres;
% compute the final binary image by combining
% high 'activity' with high intensity
bin_image{end+1} = log_image{i} .* int_image{i};
% apply morphological dilation to connect distonnected components
strel_size = round(0.01*max(size(imgs{i}))); % structuring element for morphological dilation
dilated_image{end+1} = imdilate( bin_image{i}, strel('disk',strel_size));
% do some measurements to eliminate small objects
measurements{i} = regionprops( logical( dilated_image{i}),'Area','BoundingBox');
for m=1:length(measurements{i})
if measurements{i}(m).Area < 0.05*numel( dilated_image{i})
dilated_image{i}( round(measurements{i}(m).BoundingBox(2):measurements{i}(m).BoundingBox(4)+measurements{i}(m).BoundingBox(2)),...
round(measurements{i}(m).BoundingBox(1):measurements{i}(m).BoundingBox(3)+measurements{i}(m).BoundingBox(1))) = 0;
end
end
% make sure the dilated image is the same size with the original
dilated_image{i} = dilated_image{i}(1:size(imgs{i},1),1:size(imgs{i},2));
% compute the bounding box
[y,x] = find( dilated_image{i});
if isempty( y)
box{end+1}=[];
else
box{end+1} = [ min(x) min(y) max(x)-min(x)+1 max(y)-min(y)+1];
end
end
%%% additional code to display things
for i=1:num,
figure;
subplot(121);
colormap gray;
imshow( imgs{i});
if ~isempty(box{i})
hold on;
rr = rectangle( 'position', box{i});
set( rr, 'EdgeColor', 'r');
hold off;
end
subplot(122);
imshow( imgs{i}.*uint8(repmat(dilated_image{i},[1 1 3])));
end
使用与我所见不同的方法,我创建了一个 的PHP通过它们的灯光检测圣诞树的脚本。结果始终是对称的三角形,如有必要,还可以使用数字值,例如树的角度(“脂肪度”)。
显然,此算法的最大威胁是(大量)或树前(更大的问题,直到进一步优化)旁边的灯。编辑(添加):做不到的事情:找出是否有一棵圣诞树,在一幅图像中找到多棵圣诞树,正确检测拉斯维加斯中部的圣诞前夜树,检测严重弯曲的圣诞树,倒置或切碎...;)
不同的阶段是:
标记说明:
源代码:
<?php
ini_set('memory_limit', '1024M');
header("Content-type: image/png");
$chosenImage = 6;
switch($chosenImage){
case 1:
$inputImage = imagecreatefromjpeg("nmzwj.jpg");
break;
case 2:
$inputImage = imagecreatefromjpeg("2y4o5.jpg");
break;
case 3:
$inputImage = imagecreatefromjpeg("YowlH.jpg");
break;
case 4:
$inputImage = imagecreatefromjpeg("2K9Ef.jpg");
break;
case 5:
$inputImage = imagecreatefromjpeg("aVZhC.jpg");
break;
case 6:
$inputImage = imagecreatefromjpeg("FWhSP.jpg");
break;
case 7:
$inputImage = imagecreatefromjpeg("roemerberg.jpg");
break;
default:
exit();
}
// Process the loaded image
$topNspots = processImage($inputImage);
imagejpeg($inputImage);
imagedestroy($inputImage);
// Here be functions
function processImage($image) {
$orange = imagecolorallocate($image, 220, 210, 60);
$black = imagecolorallocate($image, 0, 0, 0);
$red = imagecolorallocate($image, 255, 0, 0);
$maxX = imagesx($image)-1;
$maxY = imagesy($image)-1;
// Parameters
$spread = 1; // Number of pixels to each direction that will be added up
$topPositions = 80; // Number of (brightest) lights taken into account
$minLightDistance = round(min(array($maxX, $maxY)) / 30); // Minimum number of pixels between the brigtests lights
$searchYperX = 5; // spread of the "search beam" from the median point to the top
$renderStage = 3; // 1 to 3; exits the process early
// STAGE 1
// Calculate the brightness of each pixel (R+G+B)
$maxBrightness = 0;
$stage1array = array();
for($row = 0; $row <= $maxY; $row++) {
$stage1array[$row] = array();
for($col = 0; $col <= $maxX; $col++) {
$rgb = imagecolorat($image, $col, $row);
$brightness = getBrightnessFromRgb($rgb);
$stage1array[$row][$col] = $brightness;
if($renderStage == 1){
$brightnessToGrey = round($brightness / 765 * 256);
$greyRgb = imagecolorallocate($image, $brightnessToGrey, $brightnessToGrey, $brightnessToGrey);
imagesetpixel($image, $col, $row, $greyRgb);
}
if($brightness > $maxBrightness) {
$maxBrightness = $brightness;
if($renderStage == 1){
imagesetpixel($image, $col, $row, $red);
}
}
}
}
if($renderStage == 1) {
return;
}
// STAGE 2
// Add up brightness of neighbouring pixels
$stage2array = array();
$maxStage2 = 0;
for($row = 0; $row <= $maxY; $row++) {
$stage2array[$row] = array();
for($col = 0; $col <= $maxX; $col++) {
if(!isset($stage2array[$row][$col])) $stage2array[$row][$col] = 0;
// Look around the current pixel, add brightness
for($y = $row-$spread; $y <= $row+$spread; $y++) {
for($x = $col-$spread; $x <= $col+$spread; $x++) {
// Don't read values from outside the image
if($x >= 0 && $x <= $maxX && $y >= 0 && $y <= $maxY){
$stage2array[$row][$col] += $stage1array[$y][$x]+10;
}
}
}
$stage2value = $stage2array[$row][$col];
if($stage2value > $maxStage2) {
$maxStage2 = $stage2value;
}
}
}
if($renderStage >= 2){
// Paint the accumulated light, dimmed by the maximum value from stage 2
for($row = 0; $row <= $maxY; $row++) {
for($col = 0; $col <= $maxX; $col++) {
$brightness = round($stage2array[$row][$col] / $maxStage2 * 255);
$greyRgb = imagecolorallocate($image, $brightness, $brightness, $brightness);
imagesetpixel($image, $col, $row, $greyRgb);
}
}
}
if($renderStage == 2) {
return;
}
// STAGE 3
// Create a ranking of bright spots (like "Top 20")
$topN = array();
for($row = 0; $row <= $maxY; $row++) {
for($col = 0; $col <= $maxX; $col++) {
$stage2Brightness = $stage2array[$row][$col];
$topN[$col.":".$row] = $stage2Brightness;
}
}
arsort($topN);
$topNused = array();
$topPositionCountdown = $topPositions;
if($renderStage == 3){
foreach ($topN as $key => $val) {
if($topPositionCountdown <= 0){
break;
}
$position = explode(":", $key);
foreach($topNused as $usedPosition => $usedValue) {
$usedPosition = explode(":", $usedPosition);
$distance = abs($usedPosition[0] - $position[0]) + abs($usedPosition[1] - $position[1]);
if($distance < $minLightDistance) {
continue 2;
}
}
$topNused[$key] = $val;
paintCrosshair($image, $position[0], $position[1], $red, 2);
$topPositionCountdown--;
}
}
// STAGE 4
// Median of all Top N lights
$topNxValues = array();
$topNyValues = array();
foreach ($topNused as $key => $val) {
$position = explode(":", $key);
array_push($topNxValues, $position[0]);
array_push($topNyValues, $position[1]);
}
$medianXvalue = round(calculate_median($topNxValues));
$medianYvalue = round(calculate_median($topNyValues));
paintCrosshair($image, $medianXvalue, $medianYvalue, $red, 15);
// STAGE 5
// Find treetop
$filename = 'debug.log';
$handle = fopen($filename, "w");
fwrite($handle, "\n\n STAGE 5");
$treetopX = $medianXvalue;
$treetopY = $medianYvalue;
$searchXmin = $medianXvalue;
$searchXmax = $medianXvalue;
$width = 0;
for($y = $medianYvalue; $y >= 0; $y--) {
fwrite($handle, "\nAt y = ".$y);
if(($y % $searchYperX) == 0) { // Modulo
$width++;
$searchXmin = $medianXvalue - $width;
$searchXmax = $medianXvalue + $width;
imagesetpixel($image, $searchXmin, $y, $red);
imagesetpixel($image, $searchXmax, $y, $red);
}
foreach ($topNused as $key => $val) {
$position = explode(":", $key); // "x:y"
if($position[1] != $y){
continue;
}
if($position[0] >= $searchXmin && $position[0] <= $searchXmax){
$treetopX = $position[0];
$treetopY = $y;
}
}
}
paintCrosshair($image, $treetopX, $treetopY, $red, 5);
// STAGE 6
// Find tree sides
fwrite($handle, "\n\n STAGE 6");
$treesideAngle = 60; // The extremely "fat" end of a christmas tree
$treeBottomY = $treetopY;
$topPositionsExcluded = 0;
$xymultiplier = 0;
while(($topPositionsExcluded < ($topPositions / 5)) && $treesideAngle >= 1){
fwrite($handle, "\n\nWe're at angle ".$treesideAngle);
$xymultiplier = sin(deg2rad($treesideAngle));
fwrite($handle, "\nMultiplier: ".$xymultiplier);
$topPositionsExcluded = 0;
foreach ($topNused as $key => $val) {
$position = explode(":", $key);
fwrite($handle, "\nAt position ".$key);
if($position[1] > $treeBottomY) {
$treeBottomY = $position[1];
}
// Lights above the tree are outside of it, but don't matter
if($position[1] < $treetopY){
$topPositionsExcluded++;
fwrite($handle, "\nTOO HIGH");
continue;
}
// Top light will generate division by zero
if($treetopY-$position[1] == 0) {
fwrite($handle, "\nDIVISION BY ZERO");
continue;
}
// Lights left end right of it are also not inside
fwrite($handle, "\nLight position factor: ".(abs($treetopX-$position[0]) / abs($treetopY-$position[1])));
if((abs($treetopX-$position[0]) / abs($treetopY-$position[1])) > $xymultiplier){
$topPositionsExcluded++;
fwrite($handle, "\n --- Outside tree ---");
}
}
$treesideAngle--;
}
fclose($handle);
// Paint tree's outline
$treeHeight = abs($treetopY-$treeBottomY);
$treeBottomLeft = 0;
$treeBottomRight = 0;
$previousState = false; // line has not started; assumes the tree does not "leave"^^
for($x = 0; $x <= $maxX; $x++){
if(abs($treetopX-$x) != 0 && abs($treetopX-$x) / $treeHeight > $xymultiplier){
if($previousState == true){
$treeBottomRight = $x;
$previousState = false;
}
continue;
}
imagesetpixel($image, $x, $treeBottomY, $red);
if($previousState == false){
$treeBottomLeft = $x;
$previousState = true;
}
}
imageline($image, $treeBottomLeft, $treeBottomY, $treetopX, $treetopY, $red);
imageline($image, $treeBottomRight, $treeBottomY, $treetopX, $treetopY, $red);
// Print out some parameters
$string = "Min dist: ".$minLightDistance." | Tree angle: ".$treesideAngle." deg | Tree bottom: ".$treeBottomY;
$px = (imagesx($image) - 6.5 * strlen($string)) / 2;
imagestring($image, 2, $px, 5, $string, $orange);
return $topN;
}
/**
* Returns values from 0 to 765
*/
function getBrightnessFromRgb($rgb) {
$r = ($rgb >> 16) & 0xFF;
$g = ($rgb >> 8) & 0xFF;
$b = $rgb & 0xFF;
return $r+$r+$b;
}
function paintCrosshair($image, $posX, $posY, $color, $size=5) {
for($x = $posX-$size; $x <= $posX+$size; $x++) {
if($x>=0 && $x < imagesx($image)){
imagesetpixel($image, $x, $posY, $color);
}
}
for($y = $posY-$size; $y <= $posY+$size; $y++) {
if($y>=0 && $y < imagesy($image)){
imagesetpixel($image, $posX, $y, $color);
}
}
}
// From http://www.mdj.us/web-development/php-programming/calculating-the-median-average-values-of-an-array-with-php/
function calculate_median($arr) {
sort($arr);
$count = count($arr); //total numbers in array
$middleval = floor(($count-1)/2); // find the middle value, or the lowest middle value
if($count % 2) { // odd number, middle is the median
$median = $arr[$middleval];
} else { // even number, calculate avg of 2 medians
$low = $arr[$middleval];
$high = $arr[$middleval+1];
$median = (($low+$high)/2);
}
return $median;
}
?>
图片:
奖励:来自维基百科的德国人Weihnachtsbaum,网址:http://commons.wikimedia.org/wiki/File:Weihnachtsbaum_R%C3%B6merberg.jpg
我将python与opencv一起使用。
我的算法是这样的:
编码:
import numpy as np
import cv2
import copy
def findTree(image,num):
im = cv2.imread(image)
im = cv2.resize(im, (400,250))
gray = cv2.cvtColor(im, cv2.COLOR_RGB2GRAY)
imf = copy.deepcopy(im)
b,g,r = cv2.split(im)
minR = 200
_,thresh = cv2.threshold(r,minR,255,0)
kernel = np.ones((25,5))
dst = cv2.morphologyEx(thresh, cv2.MORPH_GRADIENT, kernel)
dst = cv2.morphologyEx(dst, cv2.MORPH_CLOSE, kernel)
contours = cv2.findContours(dst,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)[0]
cv2.drawContours(im, contours,-1, (0,255,0), 1)
maxI = 0
for i in range(len(contours)):
if len(contours[maxI]) < len(contours[i]):
maxI = i
img = copy.deepcopy(r)
cv2.polylines(img,[contours[maxI]],True,(255,255,255),3)
imf[:,:,2] = img
cv2.imshow(str(num), imf)
def main():
findTree('tree.jpg',1)
findTree('tree2.jpg',2)
findTree('tree3.jpg',3)
findTree('tree4.jpg',4)
findTree('tree5.jpg',5)
findTree('tree6.jpg',6)
cv2.waitKey(0)
cv2.destroyAllWindows()
if __name__ == "__main__":
main()
如果将内核从(25,5)更改为(10,5),则除左下角以外的所有树都可获得更好的结果,
我的算法假设这棵树上有灯,在左下方的树中,顶部的灯比其他树的灯少。