I'm currently looking into creating an app that takes a picture using the phone's camera. The app will be used for clients that are pre-op for breast augmentation. The user will be able to take a picture of themselves then place two shperes over the picture, then with a slidebar manipulate the size of the spheres. This will give the user an idea which cup size they would like. I understand that there is something in photoshop that has the desired effect and this is what i'm trying to replicate but on the bitmap image.
Are there any suitable libraries out there that i can use. I'm looking into OpenGL as that is for 3D graphics.
Any ideas and input would be appreciated.
thanks Mat.
Java does have it's own 2D and 3D APIs. Hopefully you can these to achieve your goal?
Related
I am developing an android camera app. The camera pictures are later processed by OCR, so the picture must be as sharp as possible.
If you shake the camera, it looks as if the digital camera overlays multiple images, to create the effect of motion blur:
Example 1: http://i.stack.imgur.com/nqrmd.jpg
Example 2: http://i.stack.imgur.com/ZBx6F.jpg
If you examine the pictures closely, the motion blur looks to consist of 2 or 3 images taken in quick succession and blended together to simulate light exposure. I understand that this amounts to the way digital cameras work.
But I'd prefer having a single crisp image rather than a properly exposed one. The app can use histogram corrections to make the text readable again for OCR. The image does not have to appeal to the human eye.
Is there a way to better control the camera to get these sort of raw image snapshots?
I had some limited success using the "Action" scene mode on the camera. Not much, but it's as far as you can get.
I am looking for some kind of auto trim/crop functionality in android.
Which detects a object in captured image and creates a square box around object for
cropping. I have found face detection apis in android, but my problem is captured images are documents/pages not human faces so how can I detected documents or any other object from captured picture.
I am thinking of any algorithms for object detection or some color detection. Is there any apis or libraries available for it.
I have tried following link but not found any desired output.
Find and Crop relevant image area automatically (Java / Android)
https://github.com/biokys/cropimage
Any small hint would also help me alot. Please help. Thanks in advance
That depends on what you intend to capture and crop, but there are many ways to achieve this. Like littleimp suggested, you should use OpenCv for the effect.
I suggest you use edge-detection algorithms, such as Sobel, and perform image transformation on it with, for example, a Threshold function that will turn the image into a binary one (only black and white). Afterwards, you can search the image for the geometric shape you want, using what's suggested here. Filter the object you want by calculating the detected geometric figure's area and ratio.
It would help a lot to know what you're trying to detect in an image. Those methods I described were the ones I used for my specific case, which was developing an algorithm to detect and crop the license plate from a given vehicle image. It works close to perfect and it was all done by using OpenCV.
If you have anything else you'd like to know, don't hesitate to ask. I'm watching this post :)
Use OpenCV for android.
You can use the Watershed (Imgproc.watershed) function to segment the image into foreground and background. Then you can crop around the foreground (which will be the document).
The watershed algorithm needs some markers pre-defining the regions. You can for example assume the document to be in the middle of the image, so create a marked region in the middle of the image to get the watershed algorithm started.
I'd like to create a chroma key effect using the android camera. I don't need a step by step, but I'd like to know the best way to hijack the android camera and apply the filters. I've checked out the API and haven't found anything super definitive on how to manipulate data coming from the camera. At first I looked into using a surface texture, but I'm not fully aware how that helps or how to even use it. Then I checked out using a GLSurfaceView, which may be the right direction, but not really sure.
Also, to add to my question, how would I handle both preview and saving of the image? Would I process the image at minimum, twice? Once while previewing and once while saving? I think that's probably the best solution.
Lastly, would it make sense to create a C/++ wrapper to handle the processing to optimize speed?
Any help at all would be greatly appreciated. A link to some examples would also be greatly appreciated.
Thanks.
The only real chance is to use openGL ES and fragment shader (it will require at least openGL ES 2.0) and do the chroma key effect on GPU. The shader itself will be quite easy (google).
But to do that, you need to display camera preview with callback. You will have to implement Camera.PreviewCallback, create a buffer for image data and use setPreviewCallbackWithBuffer method. You can get the basic idea from my answer to a similar question. Note that there is a significant problem with performance of this custom camera preview, but it might work on hardware that supports ES 2.0.
To display the preview with openGL, you will need to extend GLSurfaceView and also implement GLSurfaceView.Renderer. Then you will bind the camera preview frame as a texture with glTexImage2D to some simple rectangle and the rest will be handled by shaders. See how to use shaders in ES here or if you have no experience with shaders, this tutorial might be a good start.
To the other question: you could save the current image from the preview, but the preview has lower resolution than a taken picture, so you will probably want to take a picture and then process it separately (you could use the same shader for it).
As for the C++, it's a lot of additional effort with questionable output. But it can improve performance if done right. Try to check this article, it's on a similar topic, it describes how to use NDK to process camera preview and display it in openGL. But if you were thinking about doing the chroma key effect in C++, it would be significantly slower than shaders.
You can check this library: https://github.com/cyberagent/android-gpuimage.
It provides a framework to do image processing on device's GPU using GL shaders.
There is also a sample showing how to use the library with a camera.
There is a Chroma-Key-Project on Google-Code: http://code.google.com/p/chroma-key-project/ It includes a way to upload pictures that are token using chroma-key:
After an exhaustive search online, I have failed to find any open source projects working >with Chroma-keying for Android devices. The aim of this project is to provide a useful >Chroma-key library, that will make it easy to implement applications and games that can take >pictures in front of a Green or Blue screen, and apply the pictures on a chosen background. >Furthermore, the application will also allow the user to upload the picture using Intent.
When taking a picture of an object (for example, a Window). Is it possible to capture the outline of a window and display the contents on the canvas.
For example,
and convert this picture of the window and displays it on the Android display
Any help or pointers to tutorials would be greatly appreciated,
an edge detection algorithm is what you want. As Renard said, this can be simple providing your input is simple like the window. Complex imagery is much harder to find edges on.
You might cruise through the Open Computer Vision library (OpenCV) to see if there's something there you can use algorithmically
I want to create a simple game for android which is supposed to use a camera. The thing is that I don't really care about the resolution of the picture, what meters to me is speed. I need the picture to be taken the moment a key is pressed. Ideal solution would be to use a frame from camera preview. I need this picture as a table of data for analysis, I don't need a file.
Is this possible to get a single frame form camera/video camera preview?
Or maybe it's easier to get a low resolution picture?
Can you tell me which function would be useful here, and maybe give a short example?
How can I get access to picture data using such a function?
Thanks in advance!
Bye
You may find the ZXing barcode scanner's source code helpful.