I'm building a web cam application as my C++ project in my college. I am integrating QT (for GUI) and OpenCV (for image processing). My application will be a simple web cam app that will access the web cam, show/record videos, capture images and other stuffs.
Well, I also want to put in a feature to add cliparts to captured images, or the streaming video. While on my research, I found out that there is no way we can overlay two images using OpenCV. The best alternative I was able to find was to reconfigure the whole image to add the clipart into the original image making it a single image. You see, that's not going to work for me as I have to be able to move the clipart and resize or rotate the clipart in my canvas.
So, I was wondering if anybody could tell me how to achieve the effect I want most efficiently.
I would really appreciate your help. The deadline for the project submission is closing in and its a huge bump on the road to completion. PLEEEASE... RELP!!
If you just want to stick a logo onto the openCV image then you simply define a region of interest (roi) on the destination video image and copy the source image to this (the details vary with each version of opencv)
If you want the logo to be semi transparent - like a TV channel ID - then you can copy the image but loop over the pixels writing a destination that is source_pixel/2 + dest_pixel/2;
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I am trying to organize my trading card collection digitally and am working on building a scanner using ocr to detect the names of my collection.
I need to use a webcam to snap a single image of each card in question. Snapping the image doesn't seem to be to difficult, but I need help determining how to get OpenCV to capture only a specific part of that image for OCR to work with. I'm trying to capture just the text portion of the image so that the artwork on the cards doesn't interfere with the OCR.
If my card will be placed in the same physical location each time, is there a way to get OpenCV to take an image and focus on just the area of the image that I'm interested in.
Thank You
Sour Jack
I am not sure I understand the problem. Do you want to use your OCR algorithm always on the same portion of the snapshot? If so, you can try something like:
roi = img[y:y+height, x:x+width]
There is more information here: http://answers.opencv.org/question/29260/how-to-save-a-rectangular-roi/
I am developing a sample camera and I am able to control image sensor directly. The sensors gives out Bayer image and I need to do show images as live view.
I looked at debayering codes and also white balancing. Is there any library in C/C++ that can help me in this process?
Since I need to have live view, I need to do these things very fast and hence I need algorithms that are very fast.
For example, I can change the RGB gains on sensor and hence I need an algorithm that act at that level, instead of acting on generated image.
Is there any library that help to save images in raw format?
simplecv has a function for white balance control:
simplecv project web site
I am working on a project with gesture recognition. Now I want to prepare a presentation in which I can only show images. I have a series of images defining a gesture, and I want to show them in a single image just like motion history images are shown in literature.
My question is simple, which functions in opencv can I use to make a motion history image using lets say 10 or more images defining the motion of hand.
As an example I have the following image, and I want to show hand's location (opacity directly dependent on time reference).
I tried using GIMP to merge layers with different opacity to do the same thing, however the output is not good.
You could use cv::updateMotionHistory
Actually OpenCV also demonstrates the usage in samples/c/motempl.c
I am making a simple game for fun and learning using SFML for 2D stuff. The game is rather simple.. I loath to say it is a HoG (hidden object game) but I guess that would be a way to get my point across quickly. Basically I am using SFML to load and display 2D still art and capture mouse events.
Anyway... I would like to add video clips to my project. All the art is rendered and for example.. if my image is of a park with a fountain, I would like to have a looping video of the water running so the image has some life even though it is just a still.
All I need is the ability to play videos in the window, preferably compatible with sfml but I am in the planning projects I can swap to something else if needed. The project will have a set resolution (not scalable) and I just want to load the video and play them at a certain pixel location in x,y. So if I have a 1200x720 image I play a 100x100 pixel video on loop at a certain location to make the water of the fountain move.
Now then I am thinking I can just load 2D sprites onto of the video matching the background image to do simple masking. There are some formats like quicktime that can embed an alpha channel directly into the video and if that is supported awesome.. but some planning in the set design should mean that is not really needed. Though if that was supported more options open in set design.
I am pretty good with video as I am a 3D animator by profession, new to programming as a learning hobby. So the format and container of the video is not really an issue though I have been working with OGV a lot recently.
What I see as it needing is
Load multiple videos at once
Play with out any boarders or anything
Play at specific locations in a window.
loop seamlessly
Allow zdepth so I can place sprites onto of it
Dose anyone know were I would go to start looking into this? It seams like something that could possibly be a library I could use? Preferably an open source one as this is just a for fun project nothing commercial.
Thanks in advance for any ideas you may have.
Right now, what I'm trying to do is to make a new GUI, essentially a software using directX (more exact, direct3D), that display streaming images from Axis IP cameras.
For the time being I figured that the flow for the entire program would be like this:
1. Get the Axis program to get streaming images
2. Pass the images to the Direct3D program.
3. Display the program, on the screen.
Currently I have made a somewhat basic Direct3D app that loads and display video frames from avi videos(for testing). I dunno how to load images directly from videos using DirectX, so I used OpenCV to save frames from the video and have DX upload them up. Very slow.
Right now I have some unclear things:
1. How to Get an Axis program that works in C++ (gonna look up examples later, prolly no big deal)
2. How to upload images directly from the Axis IP camera program.
So guys, do you have any recommendations or suggestions on how to make my program work more efficiently? Anything just let me know.
Well you may find it faster to use directshow and add a custom renderer at the far end that, directly, copies the decompressed video data directly to a Direct3D texture.
Its well worth double buffering that texture. ie have texture 0 displaying and texture 1 being uploaded too and then swap the 2 over when a new frame is available (ie display texture 1 while uploading to texture 0).
This way you can de-couple the video frame rate from the rendering frame rate which makes dropped frames a little easier to handle.
I use in-place update of Direct3D textures (using IDirect3DTexture9::LockRect) and it works very fast. What part of your program works slow?
For capture images from Axis cams you may use iPSi c++ library: http://sourceforge.net/projects/ipsi/
It can be used for capturing images and control camera zoom and rotation (if available).