Explanation of Edge Detection of Digital Images

Can anyone suggest the best links for the complete explanation of doing edge detection using java.

http://en.wikipedia.org/wiki/Edge_detection
http://forum.java.sun.com/post!reply.jspa?messageID=4371954
If you have specific questions regarding implementing what you learn we will try to help you with those.
regards

Similar Messages

Edge Detection

I'm about to start working on an application that receives images from a wireless webcam (attached to a roving robot) and needs to process them to decide where the robot should travel to next. The processing needs to identify obstacles, walls, and doorways and guide the robot through a door into another room.
I know I'm going to need to use edge detection on the images, but don't know the best place to start. Any ideas? Also, if anyone has any experience with this, any idea what kind of performance I should expect? Given the limitations of the robot's movement, I will not need to process more than 10 frames per second. Assuming decent processing power, is 10 fps doable? 5?
Thanks in advance...

Edge Detection is basically a convolution operation. An image is simply a matrix of pixels. This matrix may be convoluted with another small matrix of values called a kernel.
// Loading Image
String imageName = "image.jpg";
Canvas c = new Canvas();
Image image = c.getToolkit().getImage(imageName);
MediaTracker waitForIt = new MediaTracker(c);
waitForIt.addImage(image, 1);
try { waitForIt.waitForID(1); }
catch (InterruptedException ie) { }
// Buffering Image
BufferedImage src = new BufferedImage(
    image.getWidth(c), image.getHeight(c),
    BufferedImage.TYPE_INT_RGB);
Graphics2D big = bi.createGraphics();
big.drawImage(image,0,0,c);
//Edge Detection
float[] values = {
    0f, -1f, 0f,
   -1f, 4f, -1f,
    0f, -1f, 0f
Kernel k = new Kernel(3, 3, values);
ConvolveOp cop = new ConvolveOp(kernel);
BufferedImage dest = null;
dest = cop.filter(src, dest);Play around with the values in the kernel to get a better idea of how this all works.

Is Java ME capable to edge detect images taken from phone camera??

I need help with creating a working edge detection method. At the moment as it stands I have the edge detection algorithim and have transformend it into code but I cannot see why it keeps returning a blue screen, Can Anyone tell me what I am doing wrong and how to fix it::
public Image edgeDetect(Image colourImg){
          int width = colourImg.getWidth();
         int height = colourImg.getHeight();
         int[] imageDataX = new int[width* height];
         colourImg.getRGB(imageDataX, 0, width, 0, 0, width,height);
         Image greyImg = Image.createImage(width,height);
         Graphics g = greyImg.getGraphics();
         int[] soblex = {-1, 0, 1, -2, 0, 2, -1, 0, 1};
         int dooplex = 0;
         int dooplex1 = 0;
         int dooplex2 = 0;
         int doople = 0;
         int doople1 = 0;
         int doople2 = 0;
         int count = 0;
         int[] sobley = {1, 2, 1, 0, 0, 0, -1, -2, -1};
         int doopley = 0;
         int doopley1 = 0;
         int doopley2 = 0;
         int count2 = 0;
         for(int y=1; y<height-1;y++){
             for(int x=1;x<width-1;x++){
                  if(doopley == 0 || doopley ==height-1){doople = 0;}
                  else if (dooplex == 0 || dooplex == height-1){doople = 0;}
                  for(int q = -1; q<=1; q++){
                       for(int r= -1; r<=1; r++){
                            int c = imageDataX[((q+y)*width+(x+r))];
                            int redx = (c&0x00FF0000)>>>16;
                            int d = imageDataX[((q+y)*width+(x+r))];
                            int bluex = (d&0x0000FF00)>>>8;
                            int e = imageDataX[((q+y)*width+(x+r))];
                            int greenx = e&0x000000FF;
                            dooplex += redx * soblex[count];
                            dooplex1+= bluex * soblex[count];
                            dooplex2+= greenx * soblex[count];
                            int f = imageDataX[((q+y)*width+(x+r))];
                            int redy = (f&0x00FF0000)>>>16;
                            int G = imageDataX[((q+y)*width+(x+r))];
                            int bluey = (G&0x0000FF00)>>>8;
                            int h = imageDataX[((q+y)*width+(x+r))];
                            int greeny = h&0x000000FF;
                            doopley += redy * sobley[count2];
                            doopley1+= greeny * sobley[count2];
                            doopley2+= bluey * sobley[count2];
                            count++;
                            count2++;
                  count= 0;
                  count2=0;
                  //MainMenu.append(" / " + doople);
                  //MainMenu.append(" / " + doople1);
                  //MainMenu.append(" / " + doople2 + "\n/*********/\n/********/");
                  doople = Math.abs(doopley)+ Math.abs(dooplex);
                  doople1 = Math.abs(doopley1)+ Math.abs(dooplex1);
                  doople2 =Math.abs(doopley2)+ Math.abs(dooplex2);
                  doople = (int)Math.sqrt(doople);
                  doople1= (int)Math.sqrt(doople1);
                  doople2 = (int)Math.sqrt(doople2);
                  //MainMenu.append(" / " + doople);
                  //MainMenu.append(" / " + doople1);
                  //MainMenu.append(" / " + doople2 + "\n/$$$$$$$$$/\n/$$$$$$$$/");
                  if(doople>=255)
                  {g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ff);
                  else if (doople<=0)
                  {g.setColor(0&0x00ff0000<<16, 0&0x0000ff00<<8, 0&0x0000ff);
                  else
                  {g.setColor(doople, doople1, doople2);
                  if(doople1>=255)
                  {g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ff);
                  else if (doople1<=0)
                  {g.setColor(0&0x00ff0000<<16, 0&0x0000ff00<<8, 0&0x0000ff);
                  else
                  {g.setColor(doople, doople1, doople2);
                  if(doople2>=255)
                  {g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ff);
                  else if (doople2<=0)
                  {g.setColor(0&0x00ff0000<<16, 0&0x0000ff00<<8, 0&0x0000ff);
                  else
                  {g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ff);
                  dooplex = 0;
                  dooplex1 = 0;
                  dooplex2 = 0;
                  doopley = 0;
                  doopley1 = 0;
                  doopley2 = 0;
                  doople = 0;
                  doople1 = 0;
                  doople2 = 0;
                  imageDataX[y*width+x] = g.getColor() & 0xFFFFFFFF;
         greyImg= Image.createRGBImage(imageDataX,width,height,false);
         return greyImg;
     }I think that the problem lies in the two areas where I take the RGB information from the pixel and try to put them back into an graphics that later get turned into an Image::
g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ffand
for(int q = -1; q<=1; q++){
                       for(int r= -1; r<=1; r++){
                            int c = imageDataX[((q+y)*width+(x+r))];
                            int redx = (c&0x00FF0000)>>>16;
                            int d = imageDataX[((q+y)*width+(x+r))];
                            int bluex = (d&0x0000FF00)>>>8;
                            int e = imageDataX[((q+y)*width+(x+r))];
                            int greenx = e&0x000000FF;
                            dooplex += redx * soblex[count];
                            dooplex1+= bluex * soblex[count];
                            dooplex2+= greenx * soblex[count];
                            int f = imageDataX[((q+y)*width+(x+r))];
                            int redy = (f&0x00FF0000)>>>16;
                            int G = imageDataX[((q+y)*width+(x+r))];
                            int bluey = (G&0x0000FF00)>>>8;
                            int h = imageDataX[((q+y)*width+(x+r))];
                            int greeny = h&0x000000FF;
                            doopley += redy * sobley[count2];
                            doopley1+= greeny * sobley[count2];
                            doopley2+= bluey * sobley[count2];
                            count++;
                            count2++;
                     }Thankyou in advance

...it keeps returning a blue screen...
                  if(doople>=255)
                  {g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ff);
                  else if (doople<=0)
                  {g.setColor(0&0x00ff0000<<16, 0&0x0000ff00<<8, 0&0x0000ff);
                  else
                  {g.setColor(doople, doople1, doople2);
                  if(doople1>=255)
                  {g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ff);
                  else if (doople1<=0)
                  {g.setColor(0&0x00ff0000<<16, 0&0x0000ff00<<8, 0&0x0000ff);
                  else
                  {g.setColor(doople, doople1, doople2);
                  if(doople2>=255)
                  {g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ff);
                  else if (doople2<=0)
                  {g.setColor(0&0x00ff0000<<16, 0&0x0000ff00<<8, 0&0x0000ff);
                  else
                  {g.setColor(255&0x00ff0000<<16, 255&0x0000ff00<<8, 255&0x0000ff);
as far as I understand, above code is equivalent to:
                  if(doople>=255)
                  {g.setColor(0, 0, 0xff); // blue
                  else if (doople<=0)
                  {g.setColor(0, 0, 0xff); // blue
                  else
                  {g.setColor(doople, doople1, doople2);
                  // no matter what was above, color will be defined below:
                  if(doople1>=255)
                  {g.setColor(0, 0, 0xff); // blue
                  else if (doople1<=0)
                  {g.setColor(0, 0, 0xff); // blue
                  else
                  {g.setColor(doople, doople1, doople2);
                  // no matter what was above, color will be defined below:
                  if(doople2>=255)
                  {g.setColor(0, 0, 0xff); // blue
                  else if (doople2<=0)
                  {g.setColor(0, 0, 0xff); // blue
                  else
                  {g.setColor(0, 0, 0xff); // blue
//......which in turn is equivalent to:
                        // no matter what was set above, color will be defined below...
                  if(doople2>=255)
                  {g.setColor(0, 0, 0xff); // blue
                  else if (doople2<=0)
                  {g.setColor(0, 0, 0xff); // blue
                  else
                  {g.setColor(0, 0, 0xff); // blue
//......which finally becomes g.setColor(0, 0, 0xff); // blue

Edge detection on a moving object

Hi
I have a problem on edge detection. I have a pulley of different types.
Pulleys where Dia is same, but height differs. Pulleys of different dia but the number of teeth (ridges) vary.
I need to identify one type of pulley from the other. I am trying to use the following logic:
1. Locate the base of the pulley (which is distinct) using pattern match
2. Define a co ordinate based on this pattern match.
3. Define edge detection tool using the co ordinate (this is where I am running into a wall)
I have used extracts of examples : battery inspection, gage and fuse inspection
I am not able to define the edge tool (Edge detector under vision assistant 7.1)
I am trying to use the co ordinates, since if the pulley moves a bit, then the edge detector appears away (in Vision assistant)
THE CATCH IS:
I have to do this in VB since Machine vision has to be integrated into existing vb application.
NOTE: attached image of pulley
Now can some one help me PLS
Thanks in advance
Suresh
Attachments:
pulley.png ‏13 KB

Hi Suresh -
I took your image and expanded the background region to make three versions with the pulley in different positions. Then I loaded the three images into Vision Assistant and built a script that finds the teeth of the pulley. Although Vision Assistant can't generate coordinate systems, I used edge detection algorithms to define a placeholder where the coordinate system code should be added.
I chose to use a clamp and midpoint instead of the Pattern Matching tool because of the nature of the image. Silhouetted images are difficult to pattern match, and the vertical line symmetry of the pulley makes it even more difficult to find a unique area of the object that can be recognized repeatedly. Instead, I generally find more success using algorithms that are designed around edge detection. I assumed that the "notch" at the bottom of the pulley will always be present in your images, so I performed a Clamp in the Horizontal Min Caliper to find this notch. The midpoint of this clamp section can be used as the origin of a coordinate system around which the following Edge Detection steps are performed. This allows you to find the teeth of the pulley no matter where it is in the image. (Note that the VA script was built using pulley with BG 3.png.)
The Builder File that was generated from the script gives you all the code you need except for the Caliper function and the Coordinate System functions. I added comments to these sections to show what type of code you will have to add there.
It may not be exactly the application you need to perform, but it should give you a solid starting point. I hope it helps.
David Staab, CLA
Staff Systems Engineer
National Instruments
Attachments:
Pulley Teeth.zip ‏18 KB

Edge detection using IMAQ Find Edge/IMAQ Edge Tool 3

Hi,
I have several images with useless background around a rectangular ROI (coordinates unknown!). So I tried using the two VIs mentioned above in order to detect these edges so that I can remove them. Regretfully, this does not work as planned.
IMAQ Find Edge usually finds an edge, but not where it should be. The edge detection is earlier than I want it to be.
IMAQ Edge Tool 3 sometimes does not find an edge at all, sometimes it finds the edge perfectly. Here I use the 'get best edge' option, which delivers the best results with all the images I tested it with.
All the other options are also not changed while running the VI with the images I have.
Does anyone have intimate knowledge of these VIs' algorithms, how they work, how they can be manipulated, ... ?

Hi,
Can you upload an example image?
That would clarify what you're trying to do?
Most of the time a change of mindset solves the problem.
Kind regards,
- Bjorn -
Have fun using LabVIEW... and if you like my answer, please pay me back in Kudo's
LabVIEW 5.1 - LabVIEW 2012

Edge detection or gauging?

Hi,
I am working on measuring difference in diameter of small millimeter thick tubes when they are dry and when they are wet. I wish to use image analysis of labview and use edge detection to measure the change in diameter from the original state to their moist state. Can anyone please help me out by naming useful tools I can use to do this. I know of a tool called gauging but I do not know how it works? I was thinking of using pixels to measure the difference as these tubes are 1-5 mm thick in their dry (original) state and when they are wet their diameter only increase on scale of 10-100 micrometers. I have enough optical resolution in the images but I am lost on how to use labview. Any advice would be greatly appreciated.
Thank You

Hi Ognee,
You could definitely use some functions from the Vision Development Module to find the edges of the tubes, and then use a Caliper function to determine the distance between those edges. I'd recommend taking a look at this tutorial about edge detection using the Vision Development Module. I hope this helps!
David S.

Adobe Flash security exposure in HP Solution Center Digital Imaging code

I have an HP Officejet 4500 with the HP Solution Center installed.
Windows XP.
My security software identifies "Adobe Flash Player Multiple Vulnerabilities" embedded in the HP Digital Imaging product.
The versions and locations are:
Adobe Flash 10.0 r2
C:\Program Files\HP\Digital Imaging\{7E0E61CC-1C99-429D-BEA7-C4DD5B898D2A}\setup\hwsetupwizard\setup_guide.exe
Adobe Flash 9.0 r115
C:\Program Files\HP\Digital Imaging\Help\player\FlashPla.exe
Apparently the Digital Imaging products uses these for help and setup functions. They were likely installed initially but I can't find any way to update them. I have tried all update functions available for the Solution Center.
Adobe Flash player is at version 11 as the standalone product on my machine, so this is not the issue.
The vulnerabilities are real
http://www.securelist.com/en/advisories/43267/?function=advisories&VN=43267
http://www.securelist.com/en/advisories/41917/?function=advisories&VN=41917
How do I get these Flash product versions updated? I am assuming if I delete the files the help and setup functions won't work.
Thanks

Alright, well.Ltaff, first of all, to let you know Solution Center does not need a different version of Adobe Flash Player. AFP is merely a conduit that puts together the coding for Solution Center so that it can function, and if AFP is not up to date then it can cause problems.
If you have the most recent version, then those security issues have already been resolved through subsequent releases. Now, what it sounds like is that your security software is falsely detecting issues in the program or AFP was not correctly configured.
As a starting step, why don't we uninstall both the printer and Flash Player and reinstall them.
First if you use a USB cord, make sure to remove it. Do not plug it back in until the software directs you to. Then go through the Devices and Printers, Programs and Features and Device Manager folders and insure that all copies, files, and programs related to the printer are removed. Then as directed, restart the computer.
In the START menu type "%temp%" and press ENTER. Here I want you to press Ctrl+A and hit DELETE. Some of the files will not allow you to delete them, skip those files and delete the majority that allows it.
Then follow this link to download the full feature software and drivers for the printer. You will need to search for the correct model number of the 4500 you have (either G510a/g/n or G509a/g/n):
www.hp.com/go/support
Then uninstall AFP from Programs and Features and install it from the download :
http://get.adobe.com/flashplayer/?fpchrome
Install that and let me know the result!
Have a great day!

Refine edge and edge detection serious issues, getting blurred and lots of contamination

Hi guys :)
a few months back I bought a grey background after being reccomended as being easier to do compositing, I was really pleased but now I have run into some big issues and was wondering if you could spare a few moments to help me out. so I've taken the image of my model on the grey background, the model has white blonde hair, simillar to this image here, http://ophelias-overdose.deviantart.com/gallery/?offset=192#/d393ia7.
Now what I have been doing is using the quick select tool, then refine edge, when I get to refine edge that's when the issues start for me, when I'm trying to pick up the stray hairs around the model to bring them back into the picture, I'm finding that the hair,when it does come back into the picture is quite washed out and faded, and almost like it has been re painted by Photoshop CS 5 instead of being brought back into the picture, when I paint over the areas with the edge detection tool. Also, even if I check the decontaminate colour box, it doesn't make a blind bit of difference!!
I'm on a bit of a deadline and am so alarmed I'm getting these issues with the grey background, how are these problems occurring?? can you please give me some idea, I would be really greatful. I have been you tubing, and going over tutorials and reading books to NO avail :(
I just keep getting this issue, even when I have tried editing a test picture from a google search of a model with brown hair! Still getting this issue.
this tool is supposed to be amazing, I'm not expecting amazing but I'm atleast expecting it to not look like a bad blurred paint job, with contamination.
really greatful, thanks :)
M

Hi Noel,
Thank you for the reply. I have attached some screen shots for you.
Im working with high resolution photos in NEF, I am trying to put the model into a darker background but i havent even got that far as I cant even cut her out.
Decontaminate doesnt seem to be working at all to be honest, it makes little difference when i check that box.
Im getting nothing close to the image of the Lion, thats brilliant!
This is the original image taken on a Calumet grey backdrop
And this is what I keep getting results wise, see around the hair there is still rather a lot of grey contamination and the hair literlly looks painted and smudged.

Looking for equivilent of Microsoft Digital Image Pro 10

Sorry if this is in the wrong topic, didn't know where to post....
I am a new Mac user and am loving my MacBook, but iPhoto isn't quite doing enough for me when it comes to working with and editing pictures. I've used Microsoft Digital Image Pro on my PC for the last few years, and REALLY like it, although of course they don't make it for macs. Any ideas on a program that would be the equivilent for macs? I don't want something as comlicated as Photoshop, but a little more than iPhoto. Thanks!

Here's a tip for controlling iPhoto's red-eye tool. It also works with the Retouch tool:
* Type Caps lock + Control + 9
* Undo caps lock
* Click on Retouch or the Red-Eye Removal tool.
* The tab key will toggle between cursor types, a cross or a circle for Red-Eye removal tool and between darken and lighten in the Retouch tool.
* The "[" and "]" keys decrease or increase the size accordingly.
* To get a lighter pupil with the red-eye tool, Shift-Click inside the circular curser.
NOTE: Using the "{" "}" keys will will change the value next to the circle and that represents the degree of change or intensity that the Retouch tool imparts on each pass.
Thanks to Old Toad for the above information.
I have found that in some situations where Elements absolutely refuses to correct the red-eye properly, I can get a better adjustment using iPhoto. But without the use of this secret mode, it is pretty much useless.
As far as iPhoto's capabilities, it is a really powerful image organizer with a few editing features for added convenience. What makes it better than other organizers is that it is not a file browser, it is a database application. Once you give the database some information, you can use that info to search and group your photos in almost infinite ways very quickly and easily. You can print your own cards, too. If you've had trouble with the 7 X 10 size you may benefit from Old Toad's tutorial. See his posts in this thread for an explanation and link: http://discussions.apple.com/thread.jspa?messageID=4605228
I agree with you that Elements can be complicated and overwhelming. It has so many features that it can be challenging trying to figure out which ones you need to correct your photo. When editing a group of photos I try to keep it simple: adjust the levels, lighten shadows (a must for many indoor shots), fix red-eye, crop. Plus, I do love the healing brush (band-aid tool) for removing the odd spec of anything that doesn't belong. My Elements experience was greatly improved after I bought and read a good book. You can get one that will tell you which features really work, which ones are more of a gimmick, and how to do the things you need to do most. If you can get through the learning curve, then the tools I listed really are quick and simple to use.
Good luck.

Edge detection not so great?

I have been using PS since v1.0. I have cs4 but have been trying out cs5. With cs4 I only occasionally used the refine edge. I just found it to be to slow. I saw some videos on the new refine edge tools and it looked promising, but when I tried it on a high res image I found it to not really work all that well. Here is a sample. I masked the car with pen tool, then applied a layer mask. Then ran refine edge, started to move the edge dection and found that it started to make my edge choppy. Now I know that you need to also use the adjust edge tools to get the full effect, but it seems like edge detection dose more harm than good? Any thoughts?
Thanks,
Steve

that's why you have an edge detection brush and an edge detection eraser.. and several other parameters and controls that interact between each other and give you a lot of control. or a lot of headaches if you don't know how to use them.. to get the best out of your tools you need to practice with them, and, as i already said, the web is full of precious information, if you search for it...
try some video tutorials, you wouldn't imagine how many small great things are under the hood in a software like PS..
Tommaso

Negative Edge Detection DI

Hello,
I want to read in several counter inputs in my USB-6008 but this has only one counter input.
The frequency of the pulses (to read) isnt high so i thought maybe i could use a digital input. When the input is high, a certain value has to be incremented. The only problem is that the high-level of the pulse takes to long and the value is incremented more than once. To solve this problem I think I need an edge detection that generates a pulse when a negative edge has occured. Can somebody help me to solve this problem?
Greetings,
Kevin Duerloo
KaHo Sint-Lieven, Belgium

Hi,
There is no change detection available on the digital lines of these USB devices. So you will not be able to trigger on a Rising edge or Falling edge by using the Digital lines. The only thing you could do is to use the digital trigger line. So, create a program that starts an acquisition on a digital trigger (PFI0) and set it to Rising or Falling. Put this task inside a loop. Everytime a Rising edge occurs, the acquisition will start and each time the dataflow arrives at the DaqmxBaseRead.vi/DaqmxRead.vi you can add some code that increases a value. Put a sequence around the Read.vi and add the code. This is just a workaround. You can test if this good enough for you.
Regards.
JV

Crued and fast edge detection.

hi, i need a way to do a fast edge detection. ive already got something using getpixel but get pixel is really really slow. does anyone have a faster method. it needs to work on a 300mhz processor and 64 megs of ram. accuraccy doesnt really concern me. thanx in advance.

Hi! I dont hav a solution for your query. I m doing a project in Image Processing and need to know the pixel values for particular pixel at a given coordinate. Can u post the code for getPixel ? I dont know how to make the getPixel work. Please post the whole code.
Thank you.

Automating Edge Detection?

I have a question about the IMAQ edge detection VI. I am designing a VI that will be counting edges in an image many times in succession. My question is that since the area in question will not change as the image changes, is it possible to just measure along the same line every time? Can I select a start and end pixel location for the edge detection? At this point I have to click and drag a line and it is very tedious for the amount of images that will be measured.
Thanks,
Mack

Hi Mack24,
Which tool are you using for edge detection? The shipping example "Edge Detection.vi" allows you to specify a ROI of a line to detect edges against.
The example can be found under Toolkits and Modules->Vision->Caliper->Edge Detection.vi
-N
National Instruments
Applications Engineer

VBAI Edge detection

Hello everyone,
can the edge detection function of the VBAI detect a curve in a picture?
Thanks in advance for your help
Max

Hi Max,
you can use the function "find circular edge" to detect a curved edge in an image.
This function is located in the locate features palette.
Stephan
Attachments:
Find_Circular_edge.png ‏146 KB

Imperfections in the canny edge detection

There are imperfections in the area just inside of the detected edge. I have seen this in multiple programs and am only now looking for solutions. Thank you greatly in advance.
Attachments:
dafsdf.png ‏3 KB
FGDFG.png ‏215 KB

Hi agator2,
To reiterate Taki1999's post, you can always threshold the image before you do an edge detection to try and get a more precise edge. Your image looks like it is fading colors from the darker color to the lighter color. The more you can threshold this image to more precise edges, the less imperfections you will have. I hope this helps!
Kim W.
Applications Engineer
National Instruments

Explanation of Edge Detection of Digital Images

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