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2019-01-30 03:10:32 -0600	asked a question	Combining two warpAffine, shift and rotate image Combining two warpAffine, shift and rotate image Hi, I currently use the following sequence of code to first shift an i
2018-06-22 01:52:09 -0600	commented question	Using OpenCV for bullet time photograpy alignment Tetragramm, you're right, aligning only on the center point indeed is not enough. Using this method the center is correc
2016-03-28 01:55:11 -0600	commented question	Using OpenCV for bullet time photograpy alignment You are correct but I don't think I need the complexity of the chessboard. I mean, it is difficult to build a pattern that all cameras will see and if I go with calibrating batch of cameras it will take too long. Another idea is to suspend two red balls in the center of the rig, one ball at the top and the order one exactly under the first one at about 20cm, so I will end up having two red balls that I know they are perpendicular to the floor plan. Then I am thinking I need to find the center of both balls than I can use those coordinates to also shift the crop X/Y and also correct the rotation ( since I have to balls I can draw a line between them that will represent the rotation ). What do you think about this method ? Are there ... (more)
2016-03-27 14:15:43 -0600	commented question	Using OpenCV for bullet time photograpy alignment Yes, you are right. I am thinking of making a round chess board pattern that I will suspend in the middle. What would be the workflow for this ? I am not very familiar with OpenCV. - Get the coordinate of the chess board - Crop the image so the chess board ends up in the same spot in each picture ? - How to take in account the rotation ? Thanks !
2016-03-27 12:41:26 -0600	asked a question	Using OpenCV for bullet time photograpy alignment Hi all, Recently I started building a bullet time photography rig consisting of 24 cameras that are placed on a 360 circle. I am facing a problem aligning the images, all cameras trigger exactly at the same moment and all pictures are saved on a computer following the scheme 1.jpg, 2.jpg, 3.jpg and so on. ( each digit represent the camera position on the rig ). All cameras are fixed very stable onto position but it is impossible to align them perfectly. I am trying to figure out a way to align and maybe interpolate some frames in order to make the final animation better. So far my idea was to first shoot a picture with ( let's say ) a red ball in the middle, figure out the position of the red ball inside each picture and build a JSON file ( or any other format ) containing the offsets of the ball inside each picture. After this process I guess I can use that information to further align other photos ( since the cameras are fixed in the same position and do not move ) without any ball in the middle ( using the JSON data from the calibration photo ). I guess that pictures must be aligned on X Y axis and also we need to align the rotation in case the cameras are not perfectly leveled. Here's my idea of making it: Before starting to do the actual shooting I need to calibrate the rig, the steps for this should be: 1. Place a ball or any other shape object suspended in the center of the circle, all cameras pointing at this ball. 2. Take a picture using all cameras 3. The photo from camera 1 will be considered the reference shot 4. Detect the position of the ball inside each picture and build a mapping, I mean: Picture 1: ball is at 320 x 360 px Picture 2: ball is at 325 x 376 px Picture 3: ball is at 321 x 350 px Since picture 1 is our reference and the ball in this picture is at 320x360px then I know that I have to crop the rest of the pictures so that the ball ends up at the same 320x360px. A better explanation would be that I need to crop and offset the area in relation with the coordinates of the ball in the first picture. After we calculate the necessary coordinates to crop and offset the pics then we can further use this information to stabilize all the pictures taken with the camera rig with the condition that nothing moves ( structure, cameras, etc... ). In order to take in account also the rotation in each picture I think I need to use a rectangular object as the reference. What do you think about this method and what is the simplest method to achieve it ?