Replace image by standard image on 404 
From the jQuery documentation:
The event handler must be attached before the browser fires the error
event, which is why the example sets the src attribute after attaching the
handler. Also, the error event may not be correctly fired when the page is
served locally; error relies on HTTP status codes and will generally not be
triggered if the URL uses the file: protocol.
If I understood this, it means if you execute your .each loop in the
$(document).ready function all images has their error already fired.

Cant get standard deviation to work in C 
Your mean calculation will fail as you are doing integer division, and this
will then make the subsequent std dev calculation incorrect.
Change:
mean = sum/count;
to
mean = (float)sum/count;
so that the division is performed using floating point arithmetic. You
might also want to print the value of mean at this point to check that it
looks reasonable.

Weighted Standard Deviation in PHP code 
You can't calculate it exactly because the standard deviation formula
computes the difference between each element against the average.
But you can get a good approximation by the following formula:
std_dev_a3 = (n1  1)*pow(std_dev_a1, 2) + (n2  1)*pow(std_dev_a2, 2)
std_dev_a3 = sqrt(std_dev_a3 / (n1 + n2  2))
You mentioned that you use this approach because you have memory leak.
You can avoid a memory leak storing your data into a frequency table:
{[8] => 3, [9] => 4, ..., [14] => 2}
With this data structure, you can calculate the standard deviation:
// This should be provide by your data
$freq = array(8 => 3, 9 => 4, 11 => 1, 12 => 2, 13 => 1, 14
=> 2);
// Calculate mean
$mean = 0;
$n = 0;
foreach ($freq as $value => $count) {
$mean += $val

r conditional standard deviation on 2 matrices 
The problem with your approach is that you're trying to pass a matrix (B)
to your function foo, which is expecting two vectors (x and y).
You could try something like this instead:
sapply(1:ncol(A), function(i) sd(B[as.logical(abs(A[,i])),i]))
[1] 1.5275252 0.7071068
Which is basically just a loop...
Another approach would be if your A and B objects are dataframes, you can
use mapply:
A < as.data.frame(A)
B < as.data.frame(B)
mapply(foo, A,B)
V1 V2
1.5275252 0.7071068
Benchmarking the two approaches, the sapply route is maybe twice as fast. I
can imagine that this is because sapply is just taking a vector of integers
as arguments and processing matrices whereas the mapply approach is taking
dataframes as arguments (dataframes are slower than matrices and m

SAS: Calculate Standard Deviation onthefly in datastep 
Standard deviation does not have any meaning for a single bet; it would
only have meaning either for a player in total, or for a player over a
particular period of time. The choice of a particular definition (ie, what
time period, etc.) is well out of scope for Stack Overflow; that would be a
CrossValidated question. However, calculating the standard deviation
itself is certainly in scope:
proc means data=have;
class username;
var stake;
output out=want stddev=stake_stddev;
run;
You can add a type username; statement if you don't want the
acrossallplayers stddev. You can also ask for a mean or sum or whatever
you find useful.
If you want to do this across time periods, you either can create a dataset
that has a time period variable, repeats rows as needed so they're in every
time

How to calculate and display standard deviation? 
I'm wondering if there is a bug under the comment
//Obere STD grenze
in the middle block?
Are you calling the dt when you want to be calling stdSpec?
double.Parse(dt.Rows[i  1][0].ToString()
double.Parse(stdSpec.dtCoords.Rows[i  1][0]

standard deviation of a UIImage/CGImage 
To further expand on my comment above. I would definitely look into using
the Accelerate framework, especially depending on the size of your image.
If you image is a few hundred pixels by a few hundred. You will have a ton
of data to process and Accelerate along with vDSP will make all of that
math a lot faster since it processes everything on the GPU. I will look
into this a little more, and possibly put some code in a few minutes.
UPDATE
I will post some code to do standard deviation in a single dimension using
vDSP, but this could definitely be extended to 2D
float *imageR = [0.1,0.2,0.3,0.4,...]; // vector of values
int numValues = 100; // number of values in imageR
float mean = 0; // place holder for mean
vDSP_meanv(imageR,1,&mean,numValues); // find the mean of the vect

How to calculate a pooled standard deviation in R? 
What you're trying to do requires a more general formula which will make it
easier. No loops are required.
df$df < df$n1
pooledSD < sqrt( sum(df$sd^2 * df$df) / sum(df$df) )

How to calculate the standard deviation for every 100 points in a nx3 vector? 
I would do this:
M = randn(120,3); % substitute this for the actual data; 3 columns
N = 100; % number of elements in each set for which std is computed
cols = size(A,1);
for n = 1:ceil(cols/N)
row_ini = (n1)*N+1;
row_fin = min(n*N, cols); % the "min" is in case cols is not a multiple
of N
std(A(row_ini:row_fin,:))
end
The "for" loop could probably be vectorized, if speed is a concern.
Edit: If you want to store all results in a threecolumn matrix, you just
modify the "std" line and add some initialization, like this:
M = randn(120,3); % substitute this for the actual data; 3 columns
N = 100; % number of elements in each set for which std is computed
cols = size(A,1);
n_max = ceil(cols/N);
result = repmat(NaN,ceil(cols/N),3); % initialize
for n = 1:n_max
row_ini = (n1)*N+1

Standard deviation calculation not returning expected value 
Your calculation is incorrect.
Standard deviation is based on the sum of the squares of the difference to
the mean.
You are simply summing the squares of the data values.
You must first calculate the mean (ie the average), then once you know that
you can calculate the standard deviation using this value.
The correct procedure is (quoting from wikipedia):
To calculate the population standard deviation, first compute the
difference of each data point from the mean, and square the result of each:
Next, compute the average of these values, and take the square root:
Basically, you can't calculate the standard deviation "as you go".

iterating over lists finding standard deviation of each point 
positives = [b for b in A if b >= 0] doesn't do what you think it does.
b would be a list of 7 elements, how can a list of 7 elements be greater
than 0?
numpy makes this easy:
import numpy as np
import numpy.ma as ma
A = [[9999.0, 9999.0, 9999.0, 9999.0, 9999.0, 9999.0, 9999.0],
[9999.0, 9999.0, 9999.0, 9999.0, 9999.0, 9999.0, 9999.0],
[0.040896, 0.018690, 0.005620, 9999.0, 0.038722, 0.018323, 9999.0],
[0.039443, 0.017517, 0.003460, 9999.0, 0.035526, 0.011692, 9999.0],
[9999.0, 0.017963, 0.005264, 9999.0, 0.03788, 0.014316, 9999.0]]
A = np.array(A)
sigmas = []
for b in A:
bmask=ma.masked_array(b,mask=np.greater_equal(b,0))
b=b[bmask.mask]
print b
sigmas.append(np.std(b))
gives
[]
[]
[ 0.040896 0.01869 0.00562 0.038722 0.01

calculation variance and standard deviation in a single parse 
The formula is not quite right. Here you have a description of an online
algorithm which you can use.

Passing mean and standard deviation into dnorm() using Rcpp Sugar 
The sugar dnorm is only vectorized in terms of the first argument.
To simplify (it is slightly more involved, but we don't need to concern
ourselves with this yet here), the call
dnorm(xx, 0.0, 1.0)
uses the overload
NumericVector dnorm( NumericVector, double, double )
And the second call tries to use something like
NumericVector dnorm( NumericVector, NumericVector, NumericVector )
which is not implemented. We could implement it, it would have to go high
enough in our priority list.
In the meantime, it is easy enough to write a small wrapper, like (this
does not handle argument lengths, etc ...) :
NumericVector my_dnorm( NumericVector x, NumericVector means, NumericVector
sds){
int n = x.size() ;
NumericVector res(n) ;
for( int i=0; i<n; i++) res[i] = R::dnor

"AttributeError: sqrt" when calculating a simple standard deviation 
It seems that the problem is the dtype set as object. Even if numpy allows
it, it is generally a bad idea, as you lose most internal optimizations.
The exception is present only with the axis keyword :
>>> import numpy as np
>>> a = np.arange(10).reshape(5,2)
>>> b = np.arange(10, dtype=object).reshape(5,2)
>>> np.std(a)
2.8722813232690143
>>> np.std(a, axis=1)
array([ 0.5, 0.5, 0.5, 0.5, 0.5])
>>> np.std(b)
2.8722813232690143
>>> np.std(b, axis=1)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/distpackages/numpy/core/fromnumeric.py", line
2590, in std
keepdims=keepdims)
File "/usr/lib/python2.7/distpackages/numpy/core/_methods.py", line 105,
in _std

How to get the standard deviation from gaussian fitted curve in Matlab 
The output of fy says that you are fitting a model that consist of a linear
combination of two Gaussian functions. The functional form of the model is:
fy(x) = a1*exp(((xb1)/c1)^2) + a2*exp(((xb2)/c2)^2)
Remembering that a Gaussian is defined as:
f(x) = exp((xx0)^2/(2*s^2)) where: x0 is the mean, s is the std.dev.
then the standard deviation of each Gaussian in your model can be computed
as (respectively):
s1 = c1/sqrt(2)
s2 = c2/sqrt(2)
See http://en.wikipedia.org/wiki/Gaussian_function for more infomation.

finding standard deviation down a column of data in python 
If I understand your question correctly, you have a list of lists, where
each sublist contains multiple floats.
If you want to compute the standard deviation of a list of numbers:
import numpy
numpy.std(myList)
If you want to compute the standard deviation of all the numbers in the ith
"column" of a list of lists:
import numpy
numpy.std(zip(*myList)[i])
If you want to exclude negative numbers within a column:
import numpy
import itertools
numpy.std([i for i in itertools.izip(*myList)[i] if i>=0])
Hope this helps

How to transform a dataset's mean and standard deviation with different values per column in R 
You can use scale and sweep:
sample < scale(as.matrix(sample),TRUE,TRUE)
sample < sweep(sample,2,sdevs,"*")
sample < sweep(sample,2,means,"+")

improving code efficiency: standard deviation on sliding windows 
First off, there's more than one way to do this.
It's not the most efficient speedwise, but using
scipy.ndimage.generic_filter will allow you to easily apply an arbitrary
python function over a moving window.
As a quick example:
result = scipy.ndimage.generic_filter(data, np.std, size=2*radius)
Note that the boundary conditions can be controlled by mode kwarg.
Another way to do this is to use some various striding tricks to make a
view of the array that's effectively a moving window, and then apply np.std
along the last axis. (Note: this is taken from one of my previous answers
here: http://stackoverflow.com/a/4947453/325565)
def strided_sliding_std_dev(data, radius=5):
windowed = rolling_window(data, (2*radius, 2*radius))
shape = windowed.shape
windowed = windowed

Find Region On Image  Automatic Rotate Image OpenCv 
I don't know openCV, but you added the C# and C++ tags, which make me
suppose that you would accept an algorithm that can be implemented in these
languages.
To answer your first question:
If your images are all similar to the ones you provided, you could do
something like this (these are not necessarily sequential steps, they are
numbered just for ease of reference):
convert to black & white (you could do this only conceptually, if you
prefer, by comparing pixel values to a threshold, in what follows)
travel along the black outline in vertical, horizontal and diagonal
singlepixel steps
remember N pairs of coordinates while you travel, so that N is below the
expected minimum length, in pixels, of a straight line of your images (you
will have to tune N: too long gives you too little

MATLAB Image Processing  Find Edge and Area of Image 
If the end result is an area/diameter estimate, then why not try to find
maximal and minimal shapes that fit in the outline and then use the shapes'
area to estimate the total area. For instance, compute a minimal circle
around the edge set then a maximal circle inside the edges. Then you could
use these to estimate diameter and area of the actual shape.
The advantage is that your bounding shapes can be fit in a way that
minimizes error (unbounded edges) while optimizing size either up or down
for the inner and outer shape, respectively.

Obtained incorrect standard deviation and mean values with moving rectangle in VB2010 
You should calc mean like
mean = mean / (meancount * 3) (there is 3 colors added) and it is better to
calc running mean instead of summing all and divide later. I guess there
can be more math errors.

What is wrong with this code? I am trying to find the width of each items image, if the image is a certain width, apply a class to that item 
It will be
if(imageH == 506) {
$(this).addClass('d');
} else if (imageH == 250) {
$(this).addClass('a');
}
You are not comparing,you are assigning to imageH which will always return
true

JavaFX  Replace standard CheckBox with image 
For a tutorial, please, consult the official documentation. There was a lot
of new stuff that was added in 2.2. Also, the Introduction to FXML covers
pretty much everything you need to know about FXML. Finally, Hendrik Ebbers
made an extremely helpful blog post about custom UI controls.

creating standard tiles with background image from internet 
Unfortunately you'll need to download the image and save it locally. You
can then refer to the image from isolated storage
string fileName = @"SharedShellContentackgroundTileImage.jpg";
if(TrySaveImage(fileName, "http://foo.com/bar.png"))
{
Uri uri = new Uri("isostore:/" + fileName, UriKind.Absolute);
// Create the tile if we didn't find it already exists.
var tileData = new StandardTileData
{
Title = "My Tile",
BackgroundImage = uri,
};
}
...
private bool TrySaveImage(string fileName, string url)
{
using (var store =
System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForApplication())
{
try
{
var backImage = new Image();
backImage.Height = backImage.Width = 173;
backImage.Stretch = St

Storing and Retrieving Image Path From android application folder On Pre Created SQLite Database & Setting the image to Image View 
I would only save the image name in the db and then get the resource
identifier with context.getResources().getIdentifier(). Check out this
similar question.

How to get image from an Image Control Type in .net c#, I need to save this image in a file and then use it for later comparing 
Previewing Image in ASP.NET Image Control using C# help you to get image
from an Image Control Type.
You can save the image in the below way.
Image bitmap = Image.FromFile("C:\MyFile.bmp");
bitmap.Save("C:\MyFile2.bmp");
You should be able to use the Save Method from the Image Class and be just
fine as shown above. The Save Method has 5 different options or overloads.
//Saves this Image to the specified file or stream.
img.Save(filePath);
//Saves this image to the specified stream in the specified format.
img.Save(Stream, ImageFormat);
//Saves this Image to the specified file in the specified format.
img.Save(String, ImageFormat);
//Saves this image to the specified stream, with the specified encoder
and image encoder parameters.
img.Save(Stream, ImageCodecInfo, E

I am using CIFilter to get a blur image,but why is the output image always larger than input image? 
This is a super late answer to your question, but the main problem is
you're thinking of a CIImage as an image. It is not, it is a "recipe" for
an image. So, when you apply the blur filter to it, Core Image calculates
that to show every last pixel of your blur you would need a larger canvas.
That estimated size to draw the entire image is called the "extent". In
essence, every pixel is getting "fatter", which means that the final extent
will be bigger than the original canvas. It is up to you to determine which
part of the extent is useful to your drawing routine.

php image uplaod show default image when image has not been uploaded 
you could use file_exists(), like
if( !empty($row['article_image']) AND file_exists(YOUR_PATH .
$row['article_image']) ) {
//show your image from db
}
else {
//show your default image
}

How to convert image in to binary image using Image processing with Emgu CV 
You can transform image into binary by converting it to grayscale and then
apllying threshold after that:
var bwImage = colorImg.Convert<Gray, byte>().ThresholdBinary(new
Gray(yourThrehold), new Gray(255));
if you have small blobs (salt and pepper noise) you can use median filter
function Median or erode the image (function Erode and that dilating it 
funcrtion Dilate)

Find out the extension of an image, if that image doesn't have any extension 
There are java libraries like mimeutil or jmimemagic that can detect the
file type from the pure content.

Image tag  hide the image but show the background image 
Why cant you use a div/span instead of using img tag and give background to
the div/span?
I think that is the best thing to do.
<div id="image"></div>
#image {backgroundimage: url('close16.png') !important;}

get pixel color when image view ' s width is set match_parent when image view contain small image 
You need to check the dimensions of your bitmap against the bitmap itself.
if ((bmp.getHeight() < (int)event.getY()  (bmp.getWidth() <
(int)event.getX() ) {
// not within range
}

Best way to find image resolution 
For newly uploaded images, handle it in your post_save of your model using
a signal:
django.db.models.signals.post_save
To get the size, using PIL,
img = Image.open(path_to_file)
width, height = img.size
For existing images, you probably want to just script something to do this
for existing database entries.
The alternative to scripting something would be to update your application
to try to find the width, height and update them if they are not already
set.

How to find the image location 
Because the filename set in the name value is based on userprovided
filename and because you don't do any apparent sanitizing of the content or
the name, the user could upload a file that is executable by apache and
give it a name like:
../../../wickedevilnaughtyfile and get it in the host system's root
directory or similar nasty place it doesn't belong and it could be executed
from the web browser since http server (apache or whatevs) has access to it
since it created the file.
This isn't an actual answer, but as demanded in the comments, security
threats need more than 600 characters to explain sometimes
BTW, if I missed anything in this somewhat terse explanation or got
something just wrong, feel free to edit and sign your name right in the
answer.

find subimages within an image 
If you have only pixels, you'll need image processing algorithms to find
subimages.
Your solution will be specific to what the image you are processing looks
like. For example, if states are outlined in a certain color, you could
try edge detection. If states are each different colors, you could run a
flood fill like algorithm to create boundaries for each state.
This is a difficult problem. Try computer vision or object recognition for
keywords in your research.
However, I suggest instead you build up vector files which define
boundaries of subimages by hand. If you've only a few to do, this isn't a
big deal.

Image View find by Name 
The problem is that you are trying to load an ImageView with an id with the
name"id". However, the XML layout file does not have an ImageView with
android:id=@+id/id". This means that findViewById() cannot find the
ImageView you are requesting. The specified id must exactly match one from
your XML view file.
Using getResources().getIdentifier() is completely unnecessary. The typical
way to get a View object in Java code is to use the R.id class which is
generated from your XML layout files when you build your app. In this case,
you have defined in your XML layout file a ImageView resource with id
imgFirst. So you can call findViewById() like this:
ImageView img = (ImageView) findViewById(R.id.imgFirst);
This assumes that you have previously called setContentView() to load the
XML layou

Where can I find the pygame.image class? 
If related to SDL wrapper from
https://bitbucket.org/marcusva/pysdl2/downloads then see: SDL../sdl2/ext
folder has the image.py
Assuming you want the precompiled C version, see the pygame/src has a
image.c and image.doc (documentation).
Best of luck!

Cannot find any of the supported PHP image extensions 
It's probably looking for GD and/or ImageMagick extensions. Clearly you
have neither installed.
The reason they're not installed will depend on who hosts your PHP
environment. It seems likely that shared hosting providers may not have
them enabled.

How to find a checkbox in an Image and here state 
Sorry, didn't read all of your code, but it seems to me that you are not
using (much) preprocessing. I think some morphological operations might be
the first step to take. Implementing a dilation followed by a closing
should bring some good results. Those are really simple to program and tend
to deliver some very good results.
Some side notes:
play a lot with the structuring element size and shape
if you using binaries, with 0 for black, then the operators will act on the
white portion, which is rather counterintuitive (dilate makes your lines
skinnier and open closes wholes), so always try both ways.
don't fear overdoing it with the size of the structuring elements or the
number of iterations, in such a simple application like this, there's not
much that can go wrong.
here a small

Need to add a caption to a jpg, python can't find the image 
That exception, Cannot identify image file, means that it was able to open
the file, but then could not determine what type of image it is. PIL does
this by reading the first 16 bytes and seeing if they match any of the well
known magic numbers.
Could you verify that the file you're trying to read is actually a jpeg?
If so, how did you get the version of PIL? If it was compiled on a machine
without libjpeg (or whatever the windows equivalent is), it might not
support jpegs. See this other question for a possible solution to that
issue, though I don't have a windows machine to test with.
