I'm coding a software to dewarp an image.
Example : when you take a photo of a page of a book with a camera , the page is not well shaped like that:
there
So the first part of my program change the shape so the final shape is a rectangle (that almost works fine):
there
But my problem as you can see, is that at the edge of my photo the texte is smaller in the width that the texte at the middle of the image, so how what algorithm can I apply to correct that??
Thanks
From the way the text lines are morphed it seems that you are using a 2d mapping when in fact you should use 3d mapping.
See the additional reading part in http://www.vision.caltech.edu/savarese/main.htm especially the first one.
Related
I have to change pictures in a Construct 2 coloring game and i don't know how get it.
There are a some .png file that contain the old pictures:
This pictures are loaded and generated i don't know how by the data.js file that cut and put in each hole
Anybody could help me ? I'm very lost with this.
There is a solution to this problem.
https://www.construct.net/en/forum/construct-2/how-do-i-18/create-coloring-game-134338
And if you're too lazy to look at it, here it is.
*One way would be to prepare all the colorizable elements of your illustration -- the regions within the black lines -- as separate white sprites (PNGs), with the ReplaceColor effect applied. Then when the user clicks in a "color palette" sprite, store the clicked color value as a global value, and assign this to the ReplaceColor effect of any clicked illustration sprite.
Depending on the complexity of your illustration, it could be a fair amount of work to position all the illustration sprites in the appropriate positions in the layout, but it should work.
There may be other options that treat the problem more like paint fills, but I'm not aware of how to do this.* -netdzynr
I have a set of pages that look like this:
I have the content in grids with * Heights and Widths so the grid correctly scales when the entire window resizes. I would like the text to resize with the grid. Basically I would like the user to resize from this:
To this:
(preserving white space)
One way to do this would be to wrap the TextBlock in a ViewBox with margins on the right and bottom (for Grid.Row="3") to account for white space. But because I have several pages with different lengths and line counts I would have to set the margin specifically for each page otherwise the text sizes would differ on each page. Is there a better way to do this??
I don't think there is a better way to do this. There are different ways. But, I think it isn't just a matter of opinion that they would not be better.
Ways I can think of.
Render your text offscreen, rendertargetbitmap that so you've got a picture. Change your textblocks on screen to images and stretch them.
Or
Work out the size your text wants to be. Then do some calculation comes up with a different fontsize which is "better". This is a lot easier to write a description of than do.
In my opinion.
A viewbox is easier to implement. Way less error prone than calculations. Will give at least as good results as rendering to a picture.
I just want to add one more solution to the ones suggested by Andy, which is more of a scientific approach and takes a bit of practice to master.
Suppose you have to find a function F, which maps one or more variables to a desired single value. In your case that would be a function F, which takes aspect ratio of the window as input and outputs an appropriate font size.
How can you find such a function?
Well... you don't need to do any math yourself!
First, you need some data to begin with:
1. Resize the window randomly
2. Calculate aspect ration (X)
3. Pick an appropriate font size that looks good enough (Y)
4. Repeat the measurement 7 to 10 times (sorry data scientists)
5. Enter the data in Excel - one column for X and another one for Y
6. Insert a scatter chart
7. Choose the best trendline for your data, but avoid the polynomial one
8. Display the trendline equation and use the expression in your code
Now I should mention the pros and cons of this regression technique.
Pros:
1. It can solve a wide range of tricky problems:
"I use this 3rd party control, but when the text is too long it overlaps the title bar. How to trim it so it doesn't go beyond the top border?. Deadline is coming!"
2. Even if it doesn't solve the problem perfectly, the results are often acceptable
3. It takes minutes to try out unlike spending a day refreshing your math skills
Cons:
1. The biggest problem is that to keep it simple, you often lower the number of
variables by assuming some of them to be constant. In this post I've assumed that
the font family won't change for example, neither the font weight.
2. If any of the assumptions does not hold the final result could be even worse
This technique is fragile, but powerful. Use it as your last weapon and never leave magic expression like
fontSize = (int)(0.76 + 1.2 * aspectRation) without documenting how it came to be.
i was working on a program that will, depending on the input draw, shapes of different colors onto a bitmap file, it works fine if i just have to draw one shape, but if i for example take two or more shapes it just draws over the old picture and the old one gets lost but i need them to overlay to create more complex pictures. Is there a way when i am writing to a bitmap file to skip over parts i dont want to write over ? I also tryed making an array in which i would save all the pixel data, but that doesnt work if i take a bitmap of a size larger than 800x800, depending on the size of the type of the elements of the array. I am open for any suggestion and comment. Thank you in advance.
You need to draw the second shape using a transparent background, how you would do that is entirely up to you as you don't provide any information about what technology you are using.
I am trying to create a bounding box around each character in an image. I have converted the image to binary and thresholded it but I don't understand how to create a bounding box despite reading the manual.
There are a few options for the bounding box technique, but I think you'll get a great result combining these two:
First, use the technique demonstrated here to detect a large portion of text and put a bounding rectangle around it so you crop the image to this area;
Second, experiment with the technique recently presented by OpenCV, also demonstrated here. It could be used to locate/extract individual characters on the resulting image of the first step.
I suppose you are trying to implement the OCR mechanism yourself instead of relying on great APIs such as Tesseract.
If you are looking for more information on how to do digit/text recognition, check this answer.
As said before "rudely", I encourage you to rewrite your question with more detail on what you already did. We didn't understand what you would like to do. If character recognition is what you want, have a look at this.
In a 3D scene we often need to apply labels (little textelements or icons) next to 3D object that is moving around (rotation, translation) in the scene. These labels should always face the camera but still move with the object. This technique I believe is called billboard.
An additional cool feature would be if the label would stay always at the same size - no matter how far away the associated object is. So the label seems to live in 2D screenspace and not in the 3D scenegraph.
Does anyone figures out a clever way how to do this in WPF?
For billboarding you need to make sure that the face normal is pointing towards the camera. The algorithm is that the dot product between the face normal and the view direction should be -1 (minus one).
I have some old C code that does this, but it's probably not particularly useful.
For keeping the object the same size you'd need to work out the screen size and then apply a transform to keep it the constant size you desired.
However, if you want the object to appear as though it's in 2D space, why not draw it in a 2D overlay? This will solve both the billboarding and scaling problem at the same time. You work out the screen location of your label and then use the 2D drawing functions.