Pixel Error Matlab
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How To Get Pixel Value In Matlab
A New Message Advanced Search Help MATLAB Central Community Home MATLAB Answers how to get pixel coordinates in matlab File Exchange Cody Blogs Newsreader Link Exchange ThingSpeak Anniversary Home Post A New Message Advanced Search Help Trial software how to calculate the pixel value of an image Pixel counts on matlab image analysis Subject: Pixel counts on matlab image analysis From: JordanPainter Painter JordanPainter Painter (view profile) 1 post Date: 13 Apr, 2010 13:18:05 Message: 1 of 20
Impixelinfo Matlab
Reply to this message Add author to My Watch List View original format Flag as spam Hiya, I'm trying to set a threshold to reduce my values to 1's and 0's then get a total of these 0's and 1's so i can work out a ratio of black to white? My image is a a large jpeg file. I've tried this
Matlab Image Pixel Coordinates
so far: im = 'image.jpg'; im = uint8(im); level = graythresh(im); BW = im2bw(im,level); x = imread(BW); blackcount = sum(BW(1,:)) whitecount = sum(BW(:,1)) I used the sum code at the bottom for just the standard image but it only pulled up the completely white and completely black pixels i think. So i added the threshold but i can't get it to work. Any help is welcome, thanks a lot! Subject: Pixel counts on matlab image analysis From: ImageAnalyst Date: 13 Apr, 2010 16:14:19 Message: 2 of 20 Reply to this message Add author to My Watch List View original format Flag as spam blackCount = sum(sum(BW == 0)); whiteCount = sum(sum(BW)); That x=imread(BW) line is unneeded and wrong, as well as your indices in your count lines. Also, make sure im is 2D monochrome, not 3D RGB image. Subject: Pixel counts on matlab image analysis From: JordanPainter Painter JordanPainter Painter (view profile) 1 post Date: 13 Apr, 2010 16:44:22 Message: 3 of 20 Reply to this message Add author to My Watch List View original format Flag as spam ImageAnalyst Support Answers MathWorks Search MathWorks.com MathWorks Answers Support MATLAB Answers™ MATLAB Central Community Home MATLAB Answers File Exchange Cody Blogs Newsreader Link how to get rgb value from image in matlab Exchange ThingSpeak Anniversary Home Ask Answer Browse More Contributors Recent Activity Flagged Content Flagged as Spam Help MATLAB Central Community Home MATLAB Answers File Exchange Cody Blogs Newsreader Link matlab impixel Exchange ThingSpeak Anniversary Home Ask Answer Browse More Contributors Recent Activity Flagged Content Flagged as Spam Help Trial software Mithra (view profile) 6 questions 0 answers 0 accepted answers https://www.mathworks.com/matlabcentral/newsreader/view_thread/279293 Reputation: 1 Vote1 changing values of pixels in an image pixel by pixel ( Thresholding ) Asked by Mithra Mithra (view profile) 6 questions 0 answers 0 accepted answers Reputation: 1 on 5 Sep 2013 Latest activity Edited by Parth Batra Parth Batra (view profile) 0 questions 0 answers 0 accepted answers Reputation: 0 on 21 Apr https://www.mathworks.com/matlabcentral/answers/86410-changing-values-of-pixels-in-an-image-pixel-by-pixel-thresholding 2014 Accepted Answer by Geert Geert (view profile) 5 questions 18 answers 7 accepted answers Reputation: 38 1,997 views (last 30 days) 1,997 views (last 30 days) Hi everyone, I'm trying to put a threshold on a grayscale image, and I'm doing it this way: that a "for" loop reads the image pixel by pixel, and if the value of the pixel is less than "0.5" sets its' value to "0", and if it is more than "3", sets it to "256". Here it is my code:my_image =imread('picture.tif'); for R=1:num of Rows for C=1:num of Columns pixel=my_image(R,C); if pixel<0.50000000 , pixel=0.000000000;, end if pixel>3.00000000 , pixel=256;, end thresh(R,C)=pixel; end end im_thresh=mat2gray(thresh); figure,imshow(im_thresh); title('thresholding'); But it doesn't work properly. Sometimes it misses some values that ought to be changed, and sometimes changes the ones that shouldn't be changed, to arbitrary values…for example changes the value "0.8182" to "0.0032". It also doesn't have enough accuracy, for example instead of changing the value "0.425" to "0", changes it to "0.0002". Could you please tell Support Support Newsreader MathWorks Search MathWorks.com MathWorks Newsreader Support MATLAB Newsgroup MATLAB Central Community Home MATLAB Answers File Exchange Cody Blogs Newsreader http://www.mathworks.com/matlabcentral/newsreader/view_thread/256974 Link Exchange ThingSpeak Anniversary Home Post A New Message Advanced Search http://stackoverflow.com/questions/12687231/camera-calibration-matlab-toolbox Help MATLAB Central Community Home MATLAB Answers File Exchange Cody Blogs Newsreader Link Exchange ThingSpeak Anniversary Home Post A New Message Advanced Search Help Trial software matlab camera calibration toolbox Subject: matlab camera calibration toolbox From: Ed Ed (view profile) 7 posts Date: 26 how to Jul, 2009 14:09:01 Message: 1 of 4 Reply to this message Add author to My Watch List View original format Flag as spam We downloaded the toolbox on the following link http://www.vision.caltech.edu/bouguetj/calib_doc/ We are using the Matlab-camera calibration toolbox for our images acquired by the camera-onsite in order to calibrate and removal of distortion of the how to get oblique image. The toolbox has its instruction manual and sample images on how to run the matlab toolbox. Our concern with the toolbox is how to get small amount of pixel error and to cover almost the entire area of interest. While following the manual, we also made our own checkered box acquired by the camera on-site as our input images. Unfortunately, our result was not successful because we got a high pixel error value but small portion was reduced on our area of interest. May we seek your technical experts on what are the Matlab camera calibration toolbox main factors that will give a best result for undistorting images. (will it consider the focal length, principal point, number of pictures with different position?) Hoping for your kindness support. Subject: matlab camera calibration toolbox From: us us (view profile) 9405 posts Date: 26 Jul, 2009 15:19:02 Message: 2 of 4 Reply to this message Add author to My Watch List View original format Flag here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up camera calibration MATLAB toolbox up vote 7 down vote favorite 4 I have to perform re-projection of my 3D points (I already have data from Bundler). I am using Camera Calibration toolbox in MATLAB to get the intrinsic camera parameters. I got output like this from 27 images (chess board; images are taken from different angles). Calibration results after optimization (with uncertainties): Focal Length: fc = [ 2104.11696 2101.75357 ] ± [ 23.13283 22.92478 ] Principal point: cc = [ 969.15779 771.30555 ] ± [ 21.98972 15.25166 ] Skew: alpha_c = [ 0.00000 ] ± [ 0.00000 ] Distortion: kc = [ 0.11555 -0.55754 -0.00100 -0.00275 0.00000 ] ± [ >0.05036 0.59076 0.00307 0.00440 0.00000 ] Pixel error: err = [ 0.71656 0.63306 ] Note: The numerical errors are approximately three times the standard deviations (for reference). I am wondering about the numerical errors i.e. Focal length error +- [23.13283 22.92478] , principal point error etc. What these error numbers actually represent and what are their impact?? The pixel error is really less. So far I use the following matrix from above data for my re-projection: K=[ 2104.11696 0 969.15779; 0 2101.75357 771.30555;0 0 1] The above matrix "K" seems right to me. Correct me if I am doing something wrong... Will be waiting for your replies. matlab opencv bundler camera-calibration matlab-cvst share|improve this question edited Sep 19 '14 at 12:46 Dima 29.2k115496 asked Oct 2 '12 at 8:53 user1388142 311416 1 I guess you can modify the focal length and the principal point by the estimated errors, re-project back the points and estimate the pixel error. Then you will know the effect of these errors. –Genís Oct 2 '12 at 13:54 hi, in my opinion the main thing is the pixel error which is re-projection error of points . . . . –user1388142 Oct 2 '12 at 20:52 Are you using OpenCV or Matlab to perform your calibration ? Have a look to this toolbox (It the matlab version of the OpenCV)Matlab Show Image Pixel Value