I'm trying to write an app that recognize a logo saved in app bundle and readed as UIImage. I have did a search before make this question, the only free solution seems to be OpenCv. I have tried it in a demo i had download from toptal_logo_detector . The demo works and i can find my logo everywhere i place it. Anyway the camera is very slow, too slow to use it in a real app. Maybe there's a way to optimize it, but my question is another.
I have to recognize a vector logo (always the same logo) centered in a white background ,something like this wifi logo:
My only solution is the complex OpenCV? There's a free and simpler way to achive the result: YES here there's your logo/No there isn't ?
I found this tutorial (with project download) that does what you want using OpenCV
Related
I need to detect something like a barcode but colored on live video (I don't necessarily need tracking, it is optional).I could use OpenCV but I thought it is worth a try asking here. The problem with openCV is that I am not very familiar with the whole concept of image processing. The other problem is that I use swift in most of the time, and however I could write an Obj-C wrapper with the help of google, the fact that OpenCV is written in C++ does not help at all, so maybe it would take too much time to use OpenCV.
Do you know any SDK-s that could help me in that? (It is not a problem if it is not free)
EDIT:
To be clear. By "something like a barcode" I mean that it is colored and instead of the width of the bars the colors are what metter.
I am currently working on Appcelerator (Titanium) and now I want colorize image in APP. Like I have an image and I can able to change its color through Hue or saturation just like in Photoshop. I have searched too many things but still nothing found in working condition.
Any help would be highly appreciable
Probably the best architecture is to create a webview in which you have a canvas tag, then you are able to use any canvas image manipulation library you wish. There are a number of them, but here are a few.
My basic task is to capture a part of an image and then use it. To give you an overview, I am creating an app based on OCR, I allow to user to take a picture using camera. However, rather than processing the entire image, I only want some part of it to be selected and send for processing (Preferably a rectangle). So, to sum it up, I want an overlay to be provided, and I want the image inside that overlay to be further used rather than the entire clicked image.
Now, by my understanding, I realize that AVFoundation is the tool to capture the image, however in my app I have used UIImagePicker. I am totally confused since I am a newbie and not sure hot to proceed ahead. Appreciate all for the help. Thanks again
There is fine open source library for OCR in iOS :
https://github.com/nolanbrown/Tesseract-iPhone-Demo
This will work best if the image resolution is 150 * 150 . For more in formation of other libraries you can also refer the SO question:OCR Lib
I have got one image like this
to only black and white colored image.
And I come across this ImageMagick resource
Does this can be used to generate black and white image from the above given image?
Does it is good to use this one?
If it is good one then does there is any documentation or tutorial on "How to use?".
UPDATE
SO GOT THE BEST SOLUTION FROM #ale0xB's SUGGESTION.
No third party api is required for doing this as apple's COREIMAGE.FRAMEWORK is the best for doing what I want to do. It's filters are working like charm :)
Thanks for the suggestion :)
I use this image filter. And it is great in speed and provides great output :)
Why would you want to use imageMagick instead of the standard Core Image to produce black and White images? I haven't used it before, but I doubt it's gonna give a much better performance than the native framework when it's just about creating a filter.
Since iOS 6 you have it really easy, have a look: Core Image filters, specially to CIColorMonochrome, which is the one you may be interested in.
If you're playing with images in your app, this is definitely worth checking: Core Image Programming Guide
I would like to extract out all the slides from a video lecture, using OpenCV. Here is an example of a lecture: http://www.youtube.com/watch?v=-hxOpz9c0bY.
What approaches would you recommend? So far, I've tried:
Comparing the change in grayscale intensity from frame to frame. This can have problems when an object in the foreground moves around. For example, in this lecture, there's a hand that moves around: http://www.youtube.com/watch?v=mNzu42FrlHo#t=07m00s.
Using SURF features and doing comparisons frame by frame. This approach seems kind of slow.
Does anyone have other ideas?
Most of this work is most likely already done by video encoder. You just need to extract key-frames and check how well compressed are frames between them.
It should be also fairly easy to distinguish still images. You can save lot of time by examining just the key-frames. Slides are likely to have high contrast, solid shapes, solid background. Lecture hall has blurry shapes and low contrast.
What you need is a scene change detection. After that, you'll have to classify scenes as "lecture hall" or "presentation". As for the problem with hands - you could use background subtraction with an adaptive background (just make sure you mask the foreground... you don't want the foreground to become a part of the background).
You could try an edge detection and look for a rectangular object - the slides (above a certain area threshold). You could further reduce FPs by looking for some text within the rectangle.
There are several reasons to extract slides/frames from a video presentation, especially in the case of education or conference related videos. It allows you to access the study notes without watching the whole video.
I have faced this issue several times, so I decided to create a solution for it myself using python. I have made the code open-source, you can easily set up this tool and run it in few simple steps.
Refer to this for a youtube video tutorial. Steps on how to use this tool.
Clone this project video2pdfslides
Set up your environment by running "pip install -r requirements.txt"
Copy your video path
Run "python video2pdfslides.py <video_path>"
Boom! the pdf slides will be available in the output folder Make notes and enjoy!