I have an read image got with the imread function.
Now, I need to create a random number of images with noise, appling the noise function.
The main problem is: The amount of images will be random. so I tried to create a cell array and store the images in each position (array(1)=img1, array(2)=img2, and so on). But using it, the array(1) and so on doesn't let me work with my image.
So how can I really put all of them in a array and use them normaly?
Tank you!
MATLAB and Octave have pretty much the same language.
Please try the following:
for i=1:length(images)
array_of_images{i}=images(i);
end
I think it should work something similar or exactly this
I'm trying to find an algorithm for the game master mind with 4 numbers, where each number can be between 0 to 5, giving 1296 possibilities. With the first guess being 1,1,0,0
there are less options left.
I would like to know how to remove the options which are not suitable according to the first guess.
How to use an array(solutions) and array(current solutions)? Should I use parameterization for that?
Is there an algorithm in C to do that?
Thanks a lot for the help!
The simplest to implement is to simply loop trough all your elements and make the once that no longer work false. This might be the best idea here as looping trough 1300 elements is still quite fast however be aware that there is a faster solution in just finding which type of solutions are no longer available.
For mastermind there are multiple algorithms, see wikipedia, however for your first implementation I think they are too difficult.
You could start by using either
Thijser's idea (slightly better than brute-forcing all possibilities),
or try to emulate a human player: using that a white key-peg means correct color in wrong position and a black key-peg meaning correct color in correct position. You can write an easy recursion to take that info into account:
white-peg -> move the colors around ;
black-peg remove colors to find out which of the colors was the one that was correct-in-correct-pos.
For this I think to properly solve it I need to show that sigma(logn) is its lower bound. I know all of the comparisons in my book run in O(nlogn), but im not sure how to form this into a concrete answer.
I think you've misread the problem: The array you are given is sorted. You are not sorting it. You are accessing it. Let's play a game. I pick a US state and you try to guess it. Every guess I will tell you if my chosen state is alphabetically before or after your guessed state. How many guesses do you need? The problem gives you a great clue with binary search.
Add this to your general algorithm toolbox: To show a lower bound is valid (but not necessarily tight), assume there exists an upper bound that is smaller, and do a proof by contradiction. For your problem, this should be doable.
I have to make an application that recognizes inside an black and white image a piece of tetris given by the user. I read the image to analyze into an array.
How can I do something like this using C?
Assuming that you already loaded the images into arrays, what about using regular expressions?
You don't need exact shape matching but approximately, so why not give it a try!
Edit: I downloaded your doc file. You must identify a random pattern among random figures on a 2D array so regex isn't suitable for this problem, lets say that's the bad news. The good news is that your homework is not exactly image processing, and it's much easier.
It's your homework so I won't create the code for you but I can give you directions.
You need a routine that can create a new piece from the original pattern/piece rotated. (note: with piece I mean the 4x4 square - all the cells of it)
You need a routine that checks if a piece matches an area from the 2D image at position x,y - the matching area would have corners (x-2, y-2, x+1, y+1).
You search by checking every image position (x,y) for a match.
Since you must use parallelism you can create 4 threads and assign to each thread a different rotation to search.
You might not want to implement that from scratch (unless required, of course) ... I'd recommend looking for a suitable library. I've heard that OpenCV is good, but never done any work with machine vision myself so I haven't tested it.
Search for connected components (i.e. using depth-first search; you might want to avoid recursion if efficiency is an issue; use your own stack instead). The largest connected component should be your tetris piece. You can then further analyze it (using the shape, the size or some kind of border description)
Looking at the shapes given for tetris pieces in Wikipedia, called "I,J,L,O,S,T,Z", it seems that the ratios of the sides of the bounding box (easy to find given a binary image and C) reveal whether you have I (4:1) or O (1:1); the other shapes are 2:3.
To detect which of the remaining shapes you have (J,L,S,T, or Z), it looks like you could collect the length and position of the shape's edges that fall on the bounding box's edges. Thus, T would show 3 and 1 along the 3-sides, and 1 and 1 along the 2 sides. Keeping track of the positions helps distinguish J from L, S from Z.
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How have you explained nested arrays to a programmer. I'm thinking someone that has an entry level understanding of programming, but is trying to do more complicated coding.
The array with array works, but they can't quite get their mind around the idea.
Edit: example of a nested array:
array(
'array1' => array(
'key1' => 'val1',
'key2' => 'val2',
),
'array2' => array(
'key1' => 'val1',
'key2' => 'val2',
),
);
Of course, they are usually more complicated than this and maybe that's the problem.
Tell them to think of an array as a list- it helps to give them something less abstract, like a grocery list. Then, a nested array is simply a list of lists.
Maybe I have a todo list, a grocery list, and a wishlist at amazon.com . Now I have a list of all of my lists, and I can look at all of those elements in each list by stepping through them.
A nested array is a set within a set. So, a library has a set of books, a book has a set of chapters. A chapter has a set of paragraphs, a paragraph has a set of sentences. A sentence has a set of words.
For each book in library
For each chapter in book
For each paragraph in chapter
etc...
How have you explained it? It doesn't seem like a big jump for someone that understands one dimensional arrays to be able to grasp the concept that instead of an int or a string that each array element contains another array instead.
Perhaps an analogy comparing directories will help, a one dimensional array would be analogous to a directory that contains a bunch of files, a two-dimensional array to a directory which contains several other directories, each containing a bunch of files, etc.
Draw it.
A variable is a box
1 dimensional array is a row of boxes.
2 dimensional array is a grid of boxes.
3 dimensional array is a cube of boxes.
If they have having trouble with the general concept, don't attempt to visually explain 4 dimensions.
Use a bitmap as an example. In C, you can make a bitmap of an X like this:
int x[5][5] = {
{ 1,0,0,0,1 },
{ 0,1,0,1,0 },
{ 0,0,1,0,0 },
{ 0,1,0,1,0 },
{ 1,0,0,0,1 }
};
Then show them how to use nested for loops to display the bitmap.
Examples always help, and this also gets them to think of nested arrays as multi-dimensional arrays. Actually it's probably better to understand multi-dimensional arrays in a language like C before learning about the "nested" arrays in languages like Python where you can have different levels of nesting in the same array.
Sports can provide appropriate analogies to describe applying nested arrays. A team is an array of people, a competition is an array of teams that play against each other.
However its a case of finding the analogy that clicks with the learner. Find the right analogy and you'll get even the slowest of learners to understand. Just ensure you're analogies are water tight. Like abstractions, they are leaky.
A concrete example is the index at the back of a book. A list of words, each word associated with a list of page numbers.
apples - 1, 2, 3-4
bears - 32-35, 79, 83
cats - 14, 15
If you are looking at C type, non-ragged, arrays, comparing it to numbers, the base 10 part, and there digits might help. Another good source for this same effect would be time as it has a non uniform base 60s = 1m, 60m = 1h, 24h = 1day, 7day = 1week
2 dimensions is easy to explain. Just think of a table. 3 dimensions just think of a cube or other 3d image. 4 dimensions think of a series of images like a movie with the 4th dimension being time.
4+ dimensions is hard to visualize using that model. But think of it as a filing cabinet with another file cabinet inside helps. You open the drawer and out pops a filing cabinet. You find the drawer you want and open that drawer and out pops another filing cabinet....over and over until finally you get your paper.
Perhaps you are explaining it from the context of someone who understands an array of arrays. I would attempt to trick them into realizing that they already understand them by starting at the smallest(read inner array)...and slowly expanding out, giving them plenty of time to ask questions until they are done.
Drawing helps, but you need to give the student in this case some information and go slowly, most programmers I know tend to go to fast and to like to explain things EVEN when the listener no longer is tracking what is being said.
I am a metaphor guy, so I would probably cook something up about a series of boxes with each one numbered, each box then containing a similiar(but much smaller series) also numbered. I would take this to only two levels get understanding and then perhaps talk about 3 dimensions for confirmation. But I would avoid 4 dimensions on the grounds that they may get hung in the idea that there is no such thing as 4 dimensions, or you can't measure time, or other such metaphorical landmines/distractions...cause that's the other problem, programmers tend to be ADD and enjoy getting side tracked.
Also why aren't you using a hash of hashes, much easier to reference. :)
Bottom line, baby steps.
an array is just an object - a thing. everything should be simple to understand once they get that