histogram

i am working on an android project using opencv , i am creating a histogram for a black and white image (1-0 values on image file) . i am following some tutorials i found on internet on how to create the histogram . i am doing something like this ArrayList<Mat> list = new ArrayList<Mat>(); list.add(mRgba); MatOfInt channels = new MatOfInt(0); Mat hist= new Mat(); MatOfInt histSize = new MatOfInt(25); MatOfFloat ranges = new MatOfFloat(0f, 1f); Imgproc.calcHist(list, channels, new Mat(), hist, histSize, ranges); Then i want to view the data on hist Mat, if i try something like this... for(int i

I'm working on a little program in python to estimate the direction of pointing gestures with 2D picture from a monocular camera and I'm using OpenCV 2.3. I know it's a bit tricky but I'm motivated! :) My approach is fisrt to use the face detection to detect an area into which I'm sure there is a lot of skin: img = cv2.imread("/home/max/recordings/cameras/imageTEST.jpg",1) img_hsv = cv2.cvtColor(img,cv2.COLOR_BGR2HSV) hc1 = cv2.CascadeClassifier("/home/max/haarcascade_frontalface_alt.xml") faces1 = hc1.detectMultiScale(img) for (x,y,w,h) in faces1: cv2.rectangle(img, (x,y), (x+w,y+h), 255)

I have a multidimensional histogram H=histogramdd((x,y,z),bins=(nbins,nbins,nbins),range=((0,1),(0,1),(0,1))) I need to print in an array the values of H which are different from zero and I also need to know the coordinate/the bins where this happens. I am not familiar with tuples. Can you help me? use where to find the index of nozeros in H, and use the index to get the coordinate: import numpy as np x = np.random.random(1000) y = np.random.random(1000) z = np.random.random(1000) nbins = 10 H, [bx, by, bz]=np.histogramdd((x,y,z),bins=(nbins,nbins,nbins),range=((0,1),(0,1),(0,1))) ix, iy, iz =

I'm attempting to make a histogram using primarily time and date data, provided in a json file (along with other info) in this format: 2014-03-01 00:18:00. I've looked at http://bl.ocks.org/mbostock/3048450 as an example, but I haven't managed to crack it. The key part seems to be this: var data = d3.layout.histogram() .bins(x.ticks(20)) (dataset.timestamp); When I view my code in the browser it gives "TypeError: data is undefined", and refers to d3.v3.js line 5878. Assuming I fix that error, the next place it may stumble is the axis formatting: var formatDate = d3.time.format("%y-%m-%d %h:%m:

I'm trying to create a plot similar to the ones here : Basically I want a histogram, where each bin shows how long was spent in that range of cadence (e.g 1 hour in 0-20rpm, 3 hours in 21-40rpm, etc) library("rjson") # 3rd party library, so: install.packages("rjson") # Load data from Strava API. # Ride used for example is http://app.strava.com/rides/13542320 url <- "http://app.strava.com/api/v1/streams/13542320?streams[]=cadence,time" d <- fromJSON(paste(readLines(url))) Each value in d$cadence (rpm) is paired with the same index in d$time (the number of seconds from the start). The values are

I'm interested in building a Huffman Coding prototype. To that end, I want to begin by producing a histogram of the characters that make up an input Java String . I've seen many solutions on SO and elsewhere (e.g: here that depend on using the collect() methods for Stream s as well as static imports of Function.identity() and Collectors.counting() in a very specific and intuitive way. However, when using a piece of code eerily similar to the one I linked to above: private List<HuffmanTrieNode> getCharsAndFreqs(String s){ Map<Character, Long> freqs = s.chars().collect(Collectors.groupingBy

I know how to create an histogram in Python, but I would like that it is the probability density distribution. Let's start with my example. I have an array d , with a size of 500000 elements. With the following code I am building a simple histogram telling me how many elements of my array d are between every bin. max_val=log10(max(d)) min_val=log10(min(d)) logspace = np.logspace(min_val, max_val, 50) H=hist(select,bins=logspace,histtype='step') The problem is that this plot is not what I want. I would like to have the probability distribution function of my array d . Instead of having the