Search Results

Search found 1555 results on 63 pages for 'filtering'.

Page 2/63 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

  • Filtering constant noise out of a sound stream

    - by tur1ng
    After watching the first game of the FIFA worldcup I was very annoyed by the sound of the Vuvuzelas. A theoretical question came up about filtering that noise out of the sound stream. What algorithms are needed to remove such a "constant" noise and is it possible to keep the quality of other background sounds?

    Read the article

  • Data Structure Behind Amazon S3s Keys (Filtering Data Structure)

    - by dimo414
    I'd like to implement a data structure similar to the lookup functionality of Amazon S3. For those of you who don't know what I'm taking about, Amazon S3 stores all files at the root, but allows you to look up groups of files by common prefixes in their names, therefore replicating the power of a directory tree without the complexity of it. The catch is, both lookup and filter operations are O(1) (or close enough that even on very large buckets - S3's disk equivalents - both operations might as well be O(1))). So in short, I'm looking for a data structure that functions like a hash map, with the added benefit of efficient (at the very least not O(n)) filtering. The best I can come up with is extending HashMap so that it also contains a (sorted) list of contents, and doing a binary search for the range that matches the prefix, and returning that set. This seems slow to me, but I can't think of any other way to do it. Does anyone know either how Amazon does it, or a better way to implement this data structure?

    Read the article

  • Collaborative Filtering Program: What to do for a Pearson Score When There Isn't Enough Data

    - by Mike
    I'm building a recommendation engine using collaborative filtering. For similarity scores, I use a Pearson correlation. This is great most of the time, but sometimes I have users that only share a 1 or 2 fields. For example: User 1{ a: 4 b: 2 } User 2{ a: 4 b: 3 } Since this is only 2 data points, a Pearson correlation would always be 1 (a straight line or perfect correlation). This obviously isn't what I want, so what value should I use instead? I could just throw away all instances like this (give a correlation of 0), but my data is really sparse right now and I don't want to lose anything. Is there any similarity score I could use that would fit in with the rest of my similarity scores (all Pearson)?

    Read the article

  • Best similarity metric for collaborative filtering?

    - by allclaws
    I'm trying to decide on the best similarity metric for a product recommendation system using item-based collaborative filtering. This is a shopping basket scenario where ratings are binary valued - the user has either purchased an item or not - there is no explicit rating system (eg, 5-stars). Step 1 is to compute item-to-item similarity, though I want to look at incorporating more features later on. Is the Tanimoto coefficient the best way to go for binary values? Or are there other metrics that are appropriate here? Thanks.

    Read the article

  • need suggestions about content filtering project

    - by serdar
    i'm thinking of designing and implementing a content filtering software as my graduation project. i want it to be a user contributed software. i mean, users can also add/categorize websites. it should be also a web project and extensions for browsers like chrome, firefox, ie.. my question is which programming language do you suggest for this project? i know that firefox extensions are javascript based maybe you can say use .net framework 3.5 because it's better in communication with extensions. sorry for my bad english.. btw any other suggessions about project will be good.. thx a lot.

    Read the article

  • ng-grid checkbox with filtering

    - by WilliamLou
    If I have a huge table with ng-grid, and I enabled a checkbox to select all. Is there a way for me to combine this selectAll feature with the filtering box. I mean when I filter out the rows, I want to click the checkbox so that the rows filtered will be all selected; once I clean out filter, those selectedRows are still left so that I can add more rows into it with other filters. I created a Plunker code template here. copy code here as well: // main.js var app = angular.module('myApp', ['ngGrid']); app.controller('MyCtrl', function($scope) { $scope.mySelections = []; $scope.myData = [{name: "Moroni", age: 50}, {name: "Tiancum", age: 43}, {name: "Jacob", age: 27}, {name: "Nephi", age: 29}, {name: "Enos", age: 34}, {name: "Moroni", age: 50}, {name: "Tiancum", age: 43}, {name: "Jacob", age: 27}, {name: "Nephi", age: 29}, {name: "Enos", age: 34}, {name: "Moroni", age: 50}, {name: "Tiancum", age: 43}, {name: "Jacob", age: 27}, {name: "Nephi", age: 29}, {name: "Enos", age: 34}, {name: "Moroni", age: 50}, {name: "Tiancum", age: 43}, {name: "Jacob", age: 27}, {name: "Nephi", age: 29}, {name: "Enos", age: 34},]; $scope.filterOptions = { filterText: '' }; $scope.gridOptions = { data: 'myData', checkboxHeaderTemplate: '<input class="ngSelectionHeader" type="checkbox" ng-model="allSelected" ng-change="toggleSelectAll(allSelected)"/>', showSelectionCheckbox: true, selectWithCheckboxOnly: false, selectedItems: $scope.mySelections, multiSelect: true, filterOptions: $scope.filterOptions }; });

    Read the article

  • Filtering a select list via input box & jquery

    - by zSysop
    Hi all, I was wondering if i could get some help with filtering a select list using an input box via jquery. Here's what my js looks like, but it doesnt seem to work. I'm guessing this is because options within a select list are not hide-able. <script type="text/javascript"> $(document).ready(function() { $("#inputFilter").change(function() { var filter = $(this).val(); $("#selectList option").each(function() { var match = $(this).text().search(new RegExp(filter, "i")); if (match > 0) { $(this).show(); // Does not work } else $(this).hide(); }); }); }); </script> and here's my html <input id="inputFilter" /> <select id="selectList"> <option value="1111" text="1111 - London" /> <option value="1112" text="1111 - Paris" /> </select>

    Read the article

  • User submitted content filtering

    - by Jim
    Hey all, Does anyone have any ideas on what could be used as a way to filter untrustworthy user submitted content? Take Yelp for instance, they would need to prevent competitors writing business reviews on their competitors. They would need to prevent business owners favourably reviewing their own business, or forcing friends/family to do so. They would need to prevent poor quality reviews from affecting a businesses rating and so on. I can't think what they might use to do this: Prevent multiple users from the same IP reviewing certain things Prevent business owners reviewing their own business (maybe even other businesses in the same categories as their own?) Somehow determine what a review is about and what the actual intentions behind it are Other than the first and second points, I can't think of any clever/easy way to filter potentially harmful reviews from being made available, other than a human doing it. Obviously for a site the size of Yelp this wouldn't be feasible, so what parameters could they take into consideration? Even with human intervention, how would anyone know it was the owners best buddy writing a fake review without knowing the people? I'm using this as an example in a larger study on the subject of filtering user content automatically. Does anyone have any ideas how these systems may work and what they take into consideration? Thanks!

    Read the article

  • automatic manipulation of email messages

    - by Toc
    Does it exist any web service that "filters" any email message allowing to change the subject or the content on a regexp basis and then forward it to my webmail address? For example: I want to append automatically the string "IMPORTANT! " to the subject of every message I receive with the subject containing "expiry", or I want to change any occurrence of "h2" in the body to "h1".

    Read the article

  • DDD and filtering

    - by tikhop
    I am developing an app in ddd maner. So I have a complex domain model. Suppose I have a Fare object and Airline. Each Airline should contain several or much more Fares. My UI should represent Model (only small part of complex model) as a list of Airline, when the user select the Airline, I must show the list of Fares. User can filtering the Fares (by travel time, cost, etc.). What is the appropriate place for filtering Fares and Airlines? I am assuming that I should do it in ViewModel. Like: My domain model has wrapped with Service Layer - UI works with ViewModel - ViewModel obtain data from Service Layer filtering it and create DTO objects for UI. Or I'm wrong?

    Read the article

  • ASP.NET Combo Box - Incremental Filtering Using 'Contains' v2010 vol 1

    The ASPxComboBox editor now supports searching for items using the new contains filter mode when using the incremental filtering feature. Find As You Type Filtering Based on the text thats typed into the editor's input box, the ASPxComboBox will incrementally filter on the client side. The following filter modes are available for you: None - Filtering is not applied to list items. StartsWith - The editor is filtered for list items that begin with the search string. Contains -...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

    Read the article

  • Collaborative Filtering Techniques

    - by user95261
    Good Day! I am in need of help about collaborative filtering techniques implementation in predicting psychopathy of twitter users. I have two data set, training set and test set. Training set users have already scores in psychopathy, I need any collaborative filtering techniques to predict scores of test set users. Collaborative Filtering such as Item/User-Based CF, Bayesian Belief Nets, Clustering, Latent Semantic, etc. Please help me. :( I am very confused on how to implement any of these. Thank you!

    Read the article

  • Windows Filtering Platform not turning off until admin logon. Win2008R2sp1

    - by rjt
    Just installed Windows Server 2008R2 SP1 to see if it would fix this problem, but it didn't. Until an administrator logs onto the domain controller, there are many events that WFP blocked a connection from Server60 to Server60 or Server60 to Server70. Both server60 and server70 are the domain controllers. One the admin logs on, the WFP events stop. The firewall is off by default GPO. Yes, i know that the WFP kicks in during the boot up sequence until the firewall takes over or in my case does not take over (since Vista), but i clearly should not have to autologon to a domain controller and call autolock or something. Example event LEVEL = Information Source = Microsoft Windows Security Auditing EventID = 5152 "Filtering Platform Packet Drop" and its evil twin id = 5157 "Filtering Platform Connection" "The Windows Filtering platform has blocked a connection." Direction %%14593 SourceAddress 192.168.10.60 SourcePort 49677 DestAddress 192.168.10.60 DestPort 389 Protocol 6 FilterRTID 65667 LayerName %%14611 LayerRTID 48 RemoteUserID S-1-0-0 RemoteMachineID S-1-0-0 windows-server-2008-r2 WFP BFE WindowsFilteringPlatform BaseFilteringEngine

    Read the article

  • Knockout.js - Filtering, Sorting, and Paging

    - by jtimperley
    Originally posted on: http://geekswithblogs.net/jtimperley/archive/2013/07/28/knockout.js---filtering-sorting-and-paging.aspxKnockout.js is fantastic! Maybe I missed it but it appears to be missing flexible filtering, sorting, and pagination of its grids. This is a summary of my attempt at creating this functionality which has been working out amazingly well for my purposes. Before you continue, this post is not intended to teach you the basics of Knockout. They have already created a fantastic tutorial for this purpose. You'd be wise to review this before you continue. http://learn.knockoutjs.com/ Please view the full source code and functional example on jsFiddle. Below you will find a brief explanation of some of the components. http://jsfiddle.net/JTimperley/pyCTN/13/ First we need to create a model to represent our records. This model is a simple container with defined and guaranteed members. function CustomerModel(data) { if (!data) { data = {}; } var self = this; self.id = data.id; self.name = data.name; self.status = data.status; } Next we need a model to represent the page as a whole with an array of the previously defined records. I have intentionally overlooked the filtering and sorting options for now. Note how the filtering, sorting, and pagination are chained together to accomplish all three goals. This strategy allows each of these pieces to be used selectively based on the page's needs. If you only need sorting, just sort, etc. function CustomerPageModel(data) { if (!data) { data = {}; } var self = this; self.customers = ExtractModels(self, data.customers, CustomerModel); var filters = […]; var sortOptions = […]; self.filter = new FilterModel(filters, self.customers); self.sorter = new SorterModel(sortOptions, self.filter.filteredRecords); self.pager = new PagerModel(self.sorter.orderedRecords); } The code currently supports text box and drop down filters. Text box filters require defining the current 'Value' and the 'RecordValue' function to retrieve the filterable value from the provided record. Drop downs allow defining all possible values, the current option, and the 'RecordValue' as before. Once defining these filters, they are automatically added to the screen and any changes to their values will automatically update the results, causing their sort and pagination to be re-evaluated. var filters = [ { Type: "text", Name: "Name", Value: ko.observable(""), RecordValue: function(record) { return record.name; } }, { Type: "select", Name: "Status", Options: [ GetOption("All", "All", null), GetOption("New", "New", true), GetOption("Recently Modified", "Recently Modified", false) ], CurrentOption: ko.observable(), RecordValue: function(record) { return record.status; } } ]; Sort options are more simplistic and are also automatically added to the screen. Simply provide each option's name and value for the sort drop down as well as function to allow defining how the records are compared. This mechanism can easily be adapted for using table headers as the sort triggers. That strategy hasn't crossed my functionality needs at this point. var sortOptions = [ { Name: "Name", Value: "Name", Sort: function(left, right) { return CompareCaseInsensitive(left.name, right.name); } } ]; Paging options are completely contained by the pager model. Because we will be chaining arrays between our filtering, sorting, and pagination models, the following utility method is used to prevent errors when handing an observable array to another observable array. function GetObservableArray(array) { if (typeof(array) == 'function') { return array; }   return ko.observableArray(array); }

    Read the article

  • ELMAH - Filtering 404 Errors

    - by Nathan Taylor
    I am attempting to configure ELMAH to filter 404 errors and I am running into difficulties with the XML-provided filter rules in my Web.config file. I followed the tutorial here and here and added an <is-type binding="BaseException" type="System.IO.FileNotFoundException" /> declaration under my <test><or>... declaration, but that completely failed. When I tested it locally I stuck a breakpoint in protected void ErrorLog_Filtering() {} of the Global.asax found that the System.Web.HttpException that gets fired by ASP.NET for a 404 doesn't have a base type of System.IO.FileNotFound, but rather it is simply a System.Web.HttpException. Next I decided to try a <regex binding="BaseException.Message" pattern="The file '/[^']+' does not exist" /> in the hopes that any exception matching the pattern "The file '/foo.ext' does not exist" would get filtered, but that too having no effect. As a last resort I tried <is-type binding="BaseException" type="System.Exception" />, and even that is entirely disregarded. I'm inclined to think there's a configuration error with ELMAH, but I fail to see any. Am I missing something blatantly obvious? Here's the relevant stuff from my web.config: <configuration> <configSections> <sectionGroup name="elmah"> <section name="security" requirePermission="false" type="Elmah.SecuritySectionHandler, Elmah"/> <section name="errorLog" requirePermission="false" type="Elmah.ErrorLogSectionHandler, Elmah"/> <section name="errorMail" requirePermission="false" type="Elmah.ErrorMailSectionHandler, Elmah"/> <section name="errorFilter" requirePermission="false" type="Elmah.ErrorFilterSectionHandler, Elmah" /> </sectionGroup> </configSections> <elmah> <errorFilter> <test> <or> <equal binding="HttpStatusCode" value="404" type="Int32" /> <regex binding="BaseException.Message" pattern="The file '/[^']+' does not exist" /> </or> </test> </errorFilter> <errorLog type="Elmah.XmlFileErrorLog, Elmah" logPath="~/App_Data/logs/elmah" /> </elmah> <system.web> <httpModules> <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah"/> <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah"/> </httpModules> </system.web> <system.webServer> <modules> <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah"/> <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" /> </modules> </system.webServer> </configuration>

    Read the article

  • Flex/Air : Text Area with Line Number Filtering

    - by Ajay
    I need to have a Text Area With Line Numbers, & once the Text File is Imported to the Text Area.. the user must be able to select the line numbers & see the filtered output. I have implemented the same with Numeric steppers. I am in search of an enhanced component. are there better Advanced Components for Textarea ? Any Advanced Textarea component with built-in Search/Replace/Filter Capabilities ? Cheers, Ajay

    Read the article

  • Collaborative filtering in MySQL ?

    - by user281434
    Hi I'm trying to develop a site that recommends items(fx. books) to users based on their preferences. So far, I've read O'Reilly's "Collective Intelligence" and numerous other online articles. They all, however, seem to deal with single instances of recommendation, for example if you like book A then you might like book B. What I'm trying to do is to create a set of 'preference-nodes' for each user on my site. Let's say a user likes book A,B and C. Then, when they add book D, I don't want the system to recommend other books based solely other users experience with book D. I wan't the system to look up similar 'preference-nodes' and recommend books based on that. Here's an example of 4 nodes: User1: 'book A'->'book B'->'book C' User2: 'book A'->'book B'->'book C'->'book D' user3: 'book X'->'book Y'->'book C'->'book Z' user4: 'book W'->'book Q'->'book C'->'book Z' So a recommendation system, as described in the material I've read, would recommend book Z to User 1, because there are two people who recommends Z in conjuction with liking C (ie. Z weighs more than D), even though a user with a similar 'preference-node', User2, would be more qualified to recommend book D because he has a more similar interest-pattern. So does any of you have any experience with this sort of thing? Is there some things I should try to read or does there exist any open source systems for this? Thanks for your time! Small edit: I think last.fm's algorithm is doing exactly what I my system to do. Using the preference-trees of people to recommmend music more personally to people. Instead of just saying "you might like B because you liked A"

    Read the article

  • Converting python collaborative filtering code to use Map Reduce

    - by Neil Kodner
    Using Python, I'm computing cosine similarity across items. given event data that represents a purchase (user,item), I have a list of all items 'bought' by my users. Given this input data (user,item) X,1 X,2 Y,1 Y,2 Z,2 Z,3 I build a python dictionary {1: ['X','Y'], 2 : ['X','Y','Z'], 3 : ['Z']} From that dictionary, I generate a bought/not bought matrix, also another dictionary(bnb). {1 : [1,1,0], 2 : [1,1,1], 3 : [0,0,1]} From there, I'm computing similarity between (1,2) by calculating cosine between (1,1,0) and (1,1,1), yielding 0.816496 I'm doing this by: items=[1,2,3] for item in items: for sub in items: if sub >= item: #as to not calculate similarity on the inverse sim = coSim( bnb[item], bnb[sub] ) I think the brute force approach is killing me and it only runs slower as the data gets larger. Using my trusty laptop, this calculation runs for hours when dealing with 8500 users and 3500 items. I'm trying to compute similarity for all items in my dict and it's taking longer than I'd like it to. I think this is a good candidate for MapReduce but I'm having trouble 'thinking' in terms of key/value pairs. Alternatively, is the issue with my approach and not necessarily a candidate for Map Reduce?

    Read the article

  • SharePoint LDAP filtering of People Picker users

    - by 78lro
    Hi On my WSS server I have run the following stsadm command to filter the people picker results: stsadm.exe -o setproperty -url http://myserver -pn "peoplepicker-searchadcu stomfilter" -pv "(memberOf=CN=SharePoint,OU=AccessGroups,DC=contosio,DC=local)" My WSS sites are all used by different groups of users. Whenever I create a new site collection in WSS I want to ensure that I can filter the people picker to only show he relevant users for that group - can I automate this or would I have to manually do something like the above stsadm command? All the best

    Read the article

  • Awk filtering values between two files when regions intersect (any solutions welcome)

    - by user964689
    This is building upon an earlier question Awk conditional filter one file based on another (or other solutions) I have an awk program that outputs a column from rows in a text file 'refGene.txt if values in that row match 2 out of 3 values in another text file. I need to include an additional criteria for finding a match between the two files. The criteria is inclusion if the range of the 2 numberical values specified in each row in file 1 overlap with the range of the two values in a row in refGene.txt. An example of a line in File 1: chr1 10 20 chr2 10 20 and an example line in file 2(refGene.txt) of the matching columns ($3, $5, $ 6): chr1 5 30 Currently the awk program does not treat this as a match because although the first column matches neither the 2nd or 3rd columns do no. But I would like a way to treat this as a match because the region 10-20 in file 1 is WITHIN the range of 5-30 in refGene.txt. However the second line in file 1 should NOT match because the first column does not match, which is necessary. If there is a way to include cases when any of the range in file 1 overlaps with any of the range in refGene.txt that would be really helpful. It should also replace the below conditional statements as it would also find all the cases currently described below. Please let me know if my question is unclear. Any help is really appreciated, thanks it advance! (solutions do not have to be in awk) Rubal FILES=/files/*txt for f in $FILES ; do awk ' BEGIN { FS = "\t"; } FILENAME == ARGV[1] { pair[ $1, $2, $3 ] = 1; next; } { if ( pair[ $3, $5, $6 ] == 1 ) { print $13; } } ' $(basename $f) /files/refGene.txt > /files/results/$(basename $f) ; done

    Read the article

  • Jquery Session & Table Filtering

    - by Bry4n
    This is my Jquery <script type="text/javascript"> $(function() { var from = $.session("from"); var to = $.session("to"); var $th = $('#theTable').find('th'); // had to add the classes here to not grab the "td" inside those tables var $td = $('#theTable').find('td.bluedata,td.yellowdata'); $th.hide(); $td.hide(); if (to == "Select" || from == "Select") { // shortcut - nothing set, show everything $th.add($td).show(); return; } var filterArray = new Array(); filterArray[0] = to; filterArray[1] = from; $.each(filterArray, function(i){ if (filterArray[i].toString() == "Select") { filterArray[i] = ""; } }); $($th).each(function(){ if ($( this,":eq(0):contains('" + filterArray[0].toString() + "')") != null && $(this,":eq(1):contains('" + filterArray[1].toString() + "')") != null) { $(this).show(); } }); $($td).each(function(){ if ($( this,":eq(0):contains('" + filterArray[0].toString() + "')") != null && $(this,":eq(1):contains('" + filterArray[1].toString() + "')") != null) { $(this).show(); } }); }); </script> This is my table <table border="1" id="theTable"> <tr class="headers"> <th class="bluedata"height="20px" valign="top">63rd St. &amp; Malvern Av. Loop<BR/></th> <th class="yellowdata"height="20px" valign="top">52nd St. &amp; Lansdowne Av.<BR/></th> <th class="bluedata"height="20px" valign="top">Lancaster &amp; Girard Avs<BR/></th> <th class="yellowdata"height="20px" valign="top">40th St. &amp; Lancaster Av.<BR/></th> <th class="bluedata"height="20px" valign="top">36th &amp; Market Sts<BR/></th> <th class="bluedata"height="20px" valign="top">6th &amp; Market Sts<BR/></th> <th class="yellowdata"height="20px" valign="top">Juniper Station<BR/></th> </tr> <tr> <td class="bluedata"height="20px" title="63rd St. &amp; Malvern Av. Loop"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="yellowdata"height="20px" title="52nd St. &amp; Lansdowne Av."> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="bluedata"height="20px" title="Lancaster &amp; Girard Avs"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="yellowdata"height="20px" title="40th St. &amp; Lancaster Av."> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="bluedata"height="20px" title="36th &amp; Market Sts"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="bluedata"height="20px" title="6th &amp; Market Sts"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="bluedata"height="20px" title="Juniper Station"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> </tr> </table> I have asked questions on here before and I have had success in converting textbox values to dropdown changes. However this is a bit different. I am using the sessions plugin (which works fine). On one page I have a set of normal drop downs, on submit you get taken to a separate page which runs the function above, however the rows/columns all show and they don't seem to filter at all.

    Read the article

  • spam and dirty words comment post filtering in python (django)

    - by sintaloo
    Hi All, My basic question is how to filter spam and dirty words in a comment post system under python (django). I have a collection of phrases (approximately 3000 phrases) to be filtered. Question (1), are there any existing open source python (or django) package/module/plugin which can handle this job? I knew there was one called Akismet. But from what I understood, it will not solve my problem. Akismet is just a web service and filter the words dictionary defined by Akismet. But I have my own collection of words. Please correct me if I am wrong. Question (2), If there is no such open source package I can use, how to create my own one? The only thing I can think of it's to use regular expression and join all the word phrases with 'or' in a regular expression. but I have 3000 phrases, I think it won't work in term of performance and filter every comment post. any suggestions where should I start from? Thank you very much for your help and time.

    Read the article

  • DSP - Filtering in the frequency domain via FFT

    - by Trap
    I've been playing around a little with the Exocortex implementation of the FFT, but I'm having some problems. Whenever I modify the amplitudes of the frequency bins before calling the iFFT the resulting signal contains some clicks and pops, especially when low frequencies are present in the signal (like drums or basses). However, this does not happen if I attenuate all the bins by the same factor. Let me put an example of the output buffer of a 4-sample FFT: // Bin 0 (DC) FFTOut[0] = 0.0000610351563 FFTOut[1] = 0.0 // Bin 1 FFTOut[2] = 0.000331878662 FFTOut[3] = 0.000629425049 // Bin 2 FFTOut[4] = -0.0000381469727 FFTOut[5] = 0.0 // Bin 3, this is the first and only negative frequency bin. FFTOut[6] = 0.000331878662 FFTOut[7] = -0.000629425049 The output is composed of pairs of floats, each representing the real and imaginay parts of a single bin. So, bin 0 (array indexes 0, 1) would represent the real and imaginary parts of the DC frequency. As you can see, bins 1 and 3 both have the same values, (except for the sign of the Im part), so I guess bin 3 is the first negative frequency, and finally indexes (4, 5) would be the last positive frequency bin. Then to attenuate the frequency bin 1 this is what I do: // Attenuate the 'positive' bin FFTOut[2] *= 0.5; FFTOut[3] *= 0.5; // Attenuate its corresponding negative bin. FFTOut[6] *= 0.5; FFTOut[7] *= 0.5; For the actual tests I'm using a 1024-length FFT and I always provide all the samples so no 0-padding is needed. // Attenuate var halfSize = fftWindowLength / 2; float leftFreq = 0f; float rightFreq = 22050f; for( var c = 1; c < halfSize; c++ ) { var freq = c * (44100d / halfSize); // Calc. positive and negative frequency indexes. var k = c * 2; var nk = (fftWindowLength - c) * 2; // This kind of attenuation corresponds to a high-pass filter. // The attenuation at the transition band is linearly applied, could // this be the cause of the distortion of low frequencies? var attn = (freq < leftFreq) ? 0 : (freq < rightFreq) ? ((freq - leftFreq) / (rightFreq - leftFreq)) : 1; // Attenuate positive and negative bins. mFFTOut[ k ] *= (float)attn; mFFTOut[ k + 1 ] *= (float)attn; mFFTOut[ nk ] *= (float)attn; mFFTOut[ nk + 1 ] *= (float)attn; } Obviously I'm doing something wrong but can't figure out what. I don't want to use the FFT output as a means to generate a set of FIR coefficients since I'm trying to implement a very basic dynamic equalizer. What's the correct way to filter in the frequency domain? what I'm missing? Thanks in advance.

    Read the article

  • HTML Tables with jQuery Filtering

    - by Bry4n
    Let's say I have... <form action="#"> <fieldset> to:<input type="text" name="search" value="" id="to" /> from:<input type="text" name="search" value="" id="from" /> </fieldset> </form> <table border=1"> <tr class="headers"> <th class="bluedata"height="20px" valign="top">63rd St. &amp; Malvern Av. Loop<BR/></th> <th class="yellowdata"height="20px" valign="top">52nd St. &amp; Lansdowne Av.<BR/></th> <th class="bluedata"height="20px" valign="top">Lancaster &amp; Girard Avs<BR/></th> <th class="yellowdata"height="20px" valign="top">40th St. &amp; Lancaster Av.<BR/></th> <th class="bluedata"height="20px" valign="top">36th &amp; Market Sts<BR/></th> <th class="yellowdata"height="20px" valign="top">Juniper Station<BR/></th> </tr> <tr> <td class="bluedata"height="20px" title="63rd St. &amp; Malvern Av. Loop"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="yellowdata"height="20px" title="52nd St. &amp; Lansdowne Av."> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="bluedata"height="20px" title="Lancaster &amp; Girard Avs"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="yellowdata"height="20px" title="40th St. &amp; Lancaster Av."> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="bluedata"height="20px" title="36th &amp; Market Sts"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> <td class="bluedata"height="20px" title="Juniper Station"> <table width="100%"><tr><td>12:17am</td></tr><tr><td>12:17am</td></tr><tr><td>12:47am</td></tr></table> </td> </tr> </table> Now depending upon what data is typed into the textboxes, I need the table trs/tds to show or hide. So if I type in 63rd in "to" box, and juniper in the "from" box, I need only those two trs/tds showing in that order and none of the others.

    Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >