OpenCV cvFindContours questions - objective-c

I'm following this guide: http://www.aishack.in/2010/08/sudoku-grabber-with-opencv/2/
and modifying to iOS 5.0.
I managed to find the largest contour (the sudoku "board"), however, it only locates the surrounding square, without the lines inside, as in the tutorial. can this be easily solved?
I'll try and find a way around it, but still would like to know. thanks!

I assume that you are using the camera right now. Try to load the image what is used in the tutorial and check if your implementation works on that image. Then you can continue with nice sudoku images from the web. You may also change the camera angle and distance from the sudoku when taking pictures to get a better, clearer view.

Related

Unreal Engine 5.1 Retargeted Animation From Manny to Mixamo Model Causes Single Animation Sequence To Rotate 90*

I apologize if this has been asked before. I tried searching for this first and nothing is coming up. I'm pretty new to Unreal Engine 5.1 so this might be something I'm doing as well.
I've been exploring animation retargeting in unreal and have tried following the steps we learned in class using one of the models from mixamo.com. Everything appears to work fine at the start and I can get the actual IK and IKR objects working just fine. However when I try to export the animations either from the IKR object or by right clicking the ABP object for the source mesh one and only one of the animation sequences rotates 90*. It is always the same animation (the Land animation sequence) and I'm not sure how to go about fixing it.
Also tried looking on google and turned up nothing.
I'm hoping this is some stupid newb mistake that is easy to fix or maybe there's something I'm overlooking. Any help is greatly appreciated and I will continue trying to fix the problem myself as well and will post if I fix it
Tried retargeting using the following steps
Create an IK_Object for the model you wish to project your animations on with chains for each. Mine looked like the following
IK_Remy
Repeat step 1 for the model you wish to source animations from. Mine looked like the following
IK_Manny
Create an IKR_Object Linking the two together, here's what mine looked like
IKR_Remy
Find the ABP for your source model, right click, and select "Retarget Animation Assets->Duplicate and Retarget Animation Assets". Here's what I'm selecting for that
Retarget Dialog
When I do the following most of the animation sequences for "Manny" export just fine. However the "Land" animation flips for some reason (see image below)
Exported Animation Images
Even stranger, when I preview the MM_Land animation in my IKR object it looks fine i.e. not rotated. However, if I try to export the animation from the IKR object the same thing happens i.e. it rotates 90*. I would expect this to be a case of WYSIWYG where if it's working in the preview it would export correctly. However that apparently is not the case
Also I tried modifying the animation sequence manually but it won't let me. If I try to rotate the model in the animation sequence and save it, once I close the sequence it's re-rotated and the changes do not persist.
I can export the sequence as a new sequence, modify it, and save it, and then rename it as my exported "Land" animation to hard force it and it at least looks normal. However when I actually play the game and jump, when the land animation it still flips sideways and in addition causes the character to scale and warp for a second which makes me think there's something going on here that I don't know enough to fix. Really hoping someone with more experience in Unreal Engine can help.
EDIT: Fixed Image Descriptions
I can confirm that this is an issue - I'm seeing the same behaviour. I haven't managed to fix it yet, but my suspicion is that it's due to scaling - in my instance, I have had to scale up my custom character by around 2.5 times to replicate the scale of the default mannequin. Did you scale your custom character at all?

How to achieve this image distortion effect in iOS?

I'm building an iphone photo app. I don't know how to achieve this kind of effect on an image:
When the user drags a finger across the arrow, I want the image to be distorted accordingly. How can I achieve this? Is there any framework that makes this process simple?
Thank you.
No clue about iOS, but the look reminds me of a thin-plate spline warp. It's quite easy to implement in OpenGL, a quick Google search for example code returns plenty of hits.
From the sound of it I think your looking for the CoreImage framework. Look into the various distortion effects...in particular CIBumpDistortionLinear.
I don't have any code so check out this tutorial and read up on CoreImage.

Improve perfomance of my threejs

I have some issues about my model. Is is an easy model buy I can not make It work well...
I upload my project here: http://webgl.drapps.info
I have a car model with some pieces that change material when mouse is over them. I use threex.domevent.js library with "on" function. My model is loaded by json files.
Issue 1
when mouse is out of canvas, threejs detects that mouse is over a piece of my model, but this is not true, and that piece change its material (triggering mouseOver event).
Furthermore, I tried to get better mouseover event because even when mouse is really over a piece, that event doesn't trigger.
Issue 2
This is about TrackballControls. Is there any way to control rotation of my world? I mean: rotation only in one axis, rotation only for 180 degrees, etc... Is there any tutorial or article to learn how to rotate and translate camera?
Thanks for everything, I will so please to anybody who wants answer this... because I am a little lost
Thanks
Sorry, but you are out of luck.
Question 1. Yikes! You are using threex.js which is a third-party app that hasn't been updated in almost a year, so I can't help you with that.
You are also using an older version of three.js. Please update to the current version.
If you still have problems, post a new question with a simple demo -- not your entire project. Better yet, Google your question first.
Question 2. TrackballControls is not part of the library -- it is part of the examples -- so it is not officially supported. If you are not happy with it, you will have to hack the code yourself.
This question has come up a lot. Google it. To the best of my knowledge, there is not a good solution.
Personally, I would use OrbitControls in your case -- it keeps the scene right-side-up, and you can constrain the maximum polar angle, keeping the camera "above ground".
The best examples/tutorials are the official three.js examples, which will work with the current version of the library.
I can't help with issue 1.
Issue2:
I am also working on a project to visualize vehicles and needed to be able to rotate. I also tried Trackballcontrolls but it did not suit my needs.
What I ended up doing was creating a a master Object3d and then instead of adding objects/models to the scene, I added them to the master Object3d. That way to rotate everything in the scene, I just had to rotate the master object.
To actually do the rotation I just used the code from one of the cube examples.

Image processing - How detect array similar colors from a image on ios

I want to create a area of similar colors when user touches into a point on imageview. Who knows library or technique to resolve problems for ios.
Original image link:
http://cannshine.com/images/1.jpg
After touched by user, link:
http://cannshine.com/images/2.jpg
Please helping, thanks!
It looks to me like you want to create a magic wand tool, correct? I can't help you come up with a way to handle this and I don't know of any libraries that can select a group of like-colored pixels based on tolerance, but there is this article here I found. It covers implementing a magic wand tool using Objective-C. I found it in the answer to this similar question on SO.

iOS: compare a slice of an image to library of options

I'm basically trying to work out how to take a slice of an image, say a screenshot of an iPhone home screen, slice out the first icon and compare it to a set array of images in a library. Any help on where to start?
I'm no iPhone programmer, but I might be able to suggest a few things:
The SURF feature detection implemented in OpenCV should help you with this
There is a nice article on using OpenCV in Objective-C code.
A quick & dirty way might be to use the difference blend mode which should return the difference between the 1st image(top) and the 2nd image(bottom). If there is no difference the result will be completely black. So, the more black pixels in the difference result, potentially, the more similarities between the compared images.
I'm not an iOS developer, so I don't know if there is an image library that ships with sdk or if there's a free/opensource library for basic image processing. Still this should be trivial to implement:
e.g.
- (int)difference((int)topPixel,(int)bottomPixel)
{
return abs(topPixel-bottomPixel);
}
Note: Syntax might not be correct :)
HTH
This may not help you with taking a screenshot of the iOS home screen... But these articles show how to take snapshots from within a UIKit application:
https://developer.apple.com/library/prerelease/ios/#qa/qa1703/_index.html
https://developer.apple.com/library/prerelease/ios/#qa/qa1714/_index.html
Perhaps you would instruct the user to press home-power (buttons) to take a snapshot and store in the photo roll, then load that screenshot into an app to process the screenshot.
Hope this helps!