Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Given an JPEG image as seen abovewhat's the best way to read it in, parse it into some data structure and solve the maze?
My first instinct is to read the image in pixel by pixel and store it in a list array of boolean values: True for a white pixel, and False for a non-white pixel the colours can be discarded. The issue with this method, is that the image may not be "pixel perfect". By that I simply mean that if there is a white pixel somewhere on a wall it may create an unintended path. Another method which came to me after a bit of thought is to convert the image to an SVG file - which is a list of paths drawn on a canvas.
This way, the paths could be read into the same sort of list boolean values where True indicates a path or wall, False indicating a travel-able space. Also an issue with converting to SVG is that the lines are not "perfectly" straight. This results in the paths being cubic bezier curves. With a list array of boolean values indexed by integers, the curves would not transfer easily, and all the points that line on the curve would have to be calculated, but won't exactly match to list indices.
I assume that while one of these methods may work though probably not that they are woefully inefficient given such a large image, and that there exists a better way. Is there even a best way? Then comes the solving of the maze. If I use either of the first two methods, I will essentially end up with a matrix.
How would one create a tree from the image? Any ideas? TL;DR Best way to parse? Into what data structure?
I feel that the algorithm is correct, but it's not working as hoped. Code below. It is really very simple and standard, there should not be difficulties on implementing this in Python or whatever. Note: Marks a white visited pixel grey. This removes the need for a visited list, but this requires a second load of the image file from disk before drawing a path if you don't want a composite image of the final path and ALL paths taken.
I tried myself implementing A-Star search for this problem. Followed closely the implementation by Joseph Kern for the framework and the algorithm pseudocode given here :. As A-Star is a heuristic search algorithm you need to come up with a function that estimates the remaining cost here: distance until the goal is reached.
Unless you're comfortable with a suboptimal solution it should not overestimate the cost. A conservative choice would here be the manhattan or taxicab distance as this represents the straight-line distance between two points on the grid for the used Von Neumann neighborhood.
Which, in this case, wouldn't ever overestimate the cost. This would however significantly underestimate the actual cost for the given maze at hand. Therefore I've added two other distance metrics squared euclidean distance and the manhattan distance multiplied by four for comparison. These however might overestimate the actual cost, and might therefore yield suboptimal results. Here are some images for a visualization of the results inspired by the one posted by Joseph Kern.
The animations show a new frame each after iterations of the main while-loop. The results show that the explored regions of the maze differ considerably for the heuristics being used. As such, squared euclidean distance even produces a different suboptimal path as the other metrics. Concerning the performance of the A-Star algorithm in terms of the runtime until termination, note that a lot of evaluation of distance and cost functions add up compared to the Breadth-First Search BFS which only needs to evaluate the "goaliness" of each candidate position.Also, our conditional is a little different.
Learn with Get Started. LCD Display. Maze Solving Teach Sparki how to get through mazes. Lessons You Should Know. Introduction Solving a maze is fun and will help you build your roboticist skills up- thinking about every instruction that Sparki needs to not just wander around the maze, but actually complete it.
A maze. Forget about the robot for a while, and suppose that you are a person inside a maze. Take a look to the following animation, where the red point represents the person: Do you see the trick? What do we have on our Sparki to imitate this behavior in a printed maze?
Maze Solver (shortest path finder)
There are some shape and size constraints that we should think of when leaving a poor robot alone in a maze. Some are easier to spot, like the size of the robot to the maze. Suppose that your robot is too big or too small for the maze: The robot will not even be able to see some of the turns because they are underneath it!
Sparki might sense some walls, but they might be a corridor or two over to the right or left since Sparki is so huge in comparison to the maze. But other constraints are not that obvious, and we may need to figure them out when we are programming the maze solver algorithm on a specific robot.
Things like the number of sensors, the distances between them, and the distances from the sensors to the wheels centers may become really important in the maze solving activity. Here are the most important rules to follow if you are creating your own printed maze for this Sparki activity: 1.
In a real maze there would be walls, then you would need to use a different set of sensors to sense the walls, right? Which sensors would you use for that? This is necessary to help Sparki find dead ends and branches. It also makes writing your first maze solving code a little bit easier. Once you feel comfortable with this activity feel free to draw more complicated mazes with different angle turns, it would be a great way to test your new found maze solving skills!
Now we have a good idea of which kind of maze is Sparki going to solve, and which sensors Sparki will use. Please remember to check that the batteries are properly connected and charged! But it is not always that simple for a real robot. Read on to begin your maze solving adventures! So we will use that knowledge here, but adapt it to our specific problem. About Us. Contact Us.
You will learn to solve simple digital maze as well as photos of printed out maze puzzles this one is a bit more complex but I promised solving mazes in under a minute so Yesthat is it. So let's get started!
Solving Maze Using Photoshop, Gimp, Paint or Any Other Software
And don't forget to vote for me in how to play a game contest and automation contest if you like it :. Did you use this instructable in your classroom? Add a Teacher Note to share how you incorporated it into your lesson. Microsoft Paint might be useless when it comes to image processing but it has all the necessary tools for solving mazes. For small ones like the one on above pictures this is the best option. No preparations needed whatsoever - two quick steps and you are done.
The part where you follow colour gap may get harder when overall maze size and complexity increase. To avoid headaches or just support your laziness : I prepared a tutorial that does that step for you step 2 if you have Photoshop, step 3 if you prefer Gimp.
You have photoshop, you are lazy and you want to solve a maze. If this description fits you, you came to the right place! You solved another maze in well under a minute!
This method is the the best as it can be used unchanged for solving infinitely large mazes in seconds. You are lazy, you want to solve a maze and you don't have photoshop. I know I almost repeated introduction from previous step but there is a reason: there are no differences except for where functions are and how they are named!
You solved yet another maze in well under a minute! Ready for something a bit more serious? Go to next step lazy ones as well - it will be fun. It requires a bit more work sorry lazy ones, I tricked you into coming here with "fun" : but trust me, It is worth it! This process might sound difficult but it takes you less than two minutes when you get a gang of it.
The idea behind all techniques found in this Ible come from this: every maze is nothing but two walls next to each other, each with some dead allies and turns. The two walls are not connected see image above. Most common computer generated mazes follow this criteria though I may have lied when I said you will be able to solve any maze.
Be aware however, that this method does require some trial and error. In most cases cutting outside wall does the job but in some cases, you will need to experiment. If enough of you show support I might write an app for solving mazes.During these challenging times, we guarantee we will work tirelessly to support you.
We will continue to give you accurate and timely information throughout the crisis, and we will deliver on our mission — to help everyone in the world learn how to do anything — no matter what. Thank you to our community and to all of our readers who are working to aid others in this time of crisis, and to all of those who are making personal sacrifices for the good of their communities. We will get through this together. Updated: March 29, References. Otherwise you might find yourself stuck.
There are a few tricks you can use to easily get through a maze, though they do take away from the challenge of finding your way out. You can use the right-hand rule for simple mazes, which are mazes where all walls are connected. Log in Facebook Loading Google Loading Civic Loading No account yet?2016 Taiwan Halfsize micromouse First Prize Kojimouse 11, Hirokazu Kojima
Article Edit. Learn why people trust wikiHow. This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. Learn more Tips and Warnings. Related Articles. Method 1 of Trying to do this in the middle of a maze will keep you lost.
Start walking, following the right wall. Always keep your hand along the wall for guidance. Walk ahead, away from the exit, until you reach an intersection or a dead end. Keep following the right wall through intersections and around dead ends. At a dead end, following the right wall will have you loop around it until you exit the dead end. As long as you keep your hand on the right wall and walk forward, you will find the exit. Method 2 of Find an item you can use to mark each path.
For example, you can use chalk on a hard surface like wood or concrete. For other surfaces, consider using objects you can leave behind, like bread crumbs or some rocks. Pick a random path and follow it to the next junction.The article presents a simple technique to find the shortest path between two points in a 2D Maze. Similar applications use graphs in such situations but this article shows how this can be done without the headache of graphs.
It uses a technique similar to breadth-first search. The MazeSolver class stores the Maze as a 2D integer array with value '0' for open available nodes and non-zero for closed nodes walls.
If a path is to be found, a new 2D integer array is created with the path traced by PathCharacter whose default value is ''.
The class can also trace diagonal paths if it is allowed to do so. Throughout this article, we will use "node" to refer elements of the matrix 2D integer array representing a maze.
I assume that reader is familiar with graphs and its terminologies edges, nodes, etc. The general idea behind a breadth-first search algorithm is that we examine a starting node, say A. Then we examine all the neighbors of A, then we examine all the neighbors of all the neighbors of A, and so on. Naturally, we need to keep a track of all the nodes to assure that no node is processed more than once. This is accomplished by linking a field "status" with all the nodes. The outline of the algorithm is as follows:.
A minimum path between two nodes can be found using breadth-first search if we keep track of the origin of each edge i. This method is used in the class. Yes, the class uses breadth-first search technique without actual implementation of graphs. The only thing is mathematics ; the class uses certain mathematical formulae to access the adjacent nodes of an element node in the matrix maze. Lets see how it is done. First, we assign node numbers to every element of the array starting from 0 to ' RowsXCols -1' in the manner below.
The class, however, doesn't use separate methods for these transformations, they are done directly. To apply the above algorithm, the class uses two integer array; Queue and Origin. A dummy array equivalent to that of maze is used to hold the current status of the respective nodes in the maze. To examine a node's adjacent nodes, we have to examine its left, right, top, bottom and 4 diagonal nodes if diagonals are also to be searched. Lets concentrate on the above picture representing node numbers of array elements.
We'll have the following observations. To access the left node of a current node, the node number decreases by 1. If the current node is referred by iCurrentthen its left node can be accessed as:.
Also in this case, we only have to check whether the new node no. We can also access 4 diagonals nodes using similar approach. For simplicity of the article, lets only see how our upper-left diagonal is accessed:. Now lets see what is this "do something" in the above code fragments. Once we get the nodes adjacent to the current node, we have to add them to "Queue" if their status is Ready and change their status to Waiting.
Code Review Stack Exchange is a question and answer site for peer programmer code reviews. It only takes a minute to sign up. This code takes an image containing a 2-color maze as input and solves the maze and produces an image of the solution or an animated GIF.
The parameters to your MazeSolver. Just accept it as another parameter, and do the input and validation at a higher level. Just have a separate boolean to trigger automatic mode. This is somewhat fragile. You're at the mercy of the resizing algorithm not to slightly change the colours of the image, particularly if there's interpolation enabled. So first, make sure interpolation is disabled during resize I'm not sure if this is already the case.
And also, you may want to have a nearest-match algorithm that finds pixel colours close to the colours your program expects for borders, etc. In the end this might look like a conversion to a two-dimensional Python list of enum values that represent business logic instead of colours. Sign up to join this community. The best answers are voted up and rise to the top.
Home Questions Tags Users Unanswered. Maze image solver and animator in Python Ask Question. Asked 6 months ago. Active 6 months ago. Viewed times. Generation of animated GIF custom solving color and frame size seconds for default values, takes longer for custom values Algorithms implemented so far: 1.
You will be shown the maze, click twice, first to indicate the starting point and second to indicate ending point and then press any key to proceed. Active Oldest Votes.Free maze maker to make printable puzzle worksheets for kids: Tools for Educators hosts a variety of fun worksheet makers teachers can use to print unique and fun worksheets for their classrooms.
23 Free Online Mazes
The Maze Game Maker is a free, online worksheet app that allows you to create mazes with 6, 9, or 12 pictures or 6, 9, or 12 content areas for text, math problems, questions for students to answer and more.
So, not only language teachers, but math, science, social studies teachers and more can create exciting materials to add to their lesson plans. Give it a try! You can make a text only version with any category. So if you want text only, click on 6, 9, or 12 under any set and choose the text option before you hit 'make it'.
Christmas: 6 9 Easter: 6 9 Halloween: 6 9 Patrick's: 6 9 Thanksgiving: 6 9 Valentine's: 6 9 With the 6 and 9 square options you can include questions below the maze.
Students can use the content in the first square to answer the first question, and so on. With the 12 square option there is room at the bottom for students to write, but not enough room on the page for the maker to add lines. You can have students write something related to the content squares, make sentences with the words, anything.
These can handle some foreign languages as well. If you are on a mobile device and the print menu doesn't appear, you need to print the worksheet just like you would print any page off the Internet.
You will also need to use the smallest font Before printing, you'll also need to go to 'file' and select 'page properties. Reduce the top and bottom margins to 0 and then close that window. Now you are ready to print.
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Currently available sets: adjectives: 6 9 12 animals: 6 9 12 bathroom: 6 9 12 bedroom: 6 9 12 body parts: 6 9 12 buildings: 6 9 12 chores: 6 9 12 Christmas: 6 9 12 classroom: 6 9 12 clothing: 6 9 12 colors: 6 9 12 countries: 6 9 12 daily routines: 6 9 12 Easter: 6 9 12 family: 6 9 12 fantasy: 6 9 12 feelings: 6 9 12 food: 6 9 12 fruit: 6 9 Patrick's: 6 9 12 super powers: 6 9 12 Thanksgiving: 6 9 12 time: 6 9 12 tools: 6 9 12 transportation: 6 9 12 Valentine's: 6 9 12 vegetables: 6 9 12 verbs: 6 9 12 weather: 6 9 12 all vocab: 6 9