Patent Publication Number: US-2023156249-A1

Title: On-line video filtering

Description:
RELATED APPLICATION/S 
     This application is a continuation in part of U.S. patent application Ser. No. 16/666,440 filed 29 Oct. 2019 which is a continuation in part of PCT/IL2019/051142 filed 23 Oct. 2019 which claims priority benefit from U.S. Provisional Application No. 62/758,589, filed Nov. 11, 2018. 
     This application claims the benefit of priority of U.S. patent application Ser. No. 16/666,440 filed 29 Oct. 2019 and of International Patent Application no. PCT/IL2019/051142 filed 23 Oct. 2019 
     This application claims the benefit of priority under 35 USC § 119(e) of U.S. Provisional Patent Application No. 62/758,589, filed Nov. 11, 2018, the contents of all of the above are incorporated herein by reference in their entirety. 
    
    
     FIELD AND BACKGROUND OF THE INVENTION 
     The present invention, in some embodiments thereof, relates to a screening videos and, more particularly, but not exclusively, to a fast method of detecting a content in a video. 
     U.S. Pat. No. 8,798,402 apparently discloses “A system and method for analyzing video include segmenting video stored in computer readable storage media into keyframes. Near-duplicate keyframes are represented as a sequence of indices. The near-duplicate keyframes are rendered in a graphical representation to determine relationships between video content.” 
     U.S. Pat. No. 9,805,280 appears to the present inventor disclose, “A system including: (a) a network hub or port adapted to detect image files in transit according to their file designations; (b) an object detector configured to identify one or more regions of interest (ROI) in each image file as potentially containing an object of interest (OOI); (c) a feature analyzer adapted to express one or more General Classification Features (GCF) of each ROI as a vector; and (d) a decision module adapted accept or reject each ROI as containing said OOI based upon the one or more GCF vectors.” 
     Additional background art includes US published patent application no. 20040170321, U.S. Pat. Nos. 8,798,400, 8,311,344, US published patent application no. US published patent application no. 20120148149, US published patent application no. 20160358628, US published patent application no. 20160092561, US published patent application no. 20110301447, U.S. Pat. Nos. 6,751,354, 6,404,925, and 5,740,270. 
     SUMMARY OF THE INVENTION 
     According to an aspect of some embodiments of the invention, there is provided a method to determine a presence of a sought content in video including: summarizing the video to form a summary; preserving the content of the video in the summary; and analyzing the summary for the presence of the sought content. 
     According to some embodiments of the invention, the summarizing includes: determining a representative element volume (REV) of the sought content and reducing a level of precision to an order of the REV. 
     According to some embodiments of the invention, reducing is to a level of precision that is inherent in the video. 
     According to some embodiments of the invention, the summarizing includes selecting a collection of key frames and the summary includes the collection of key frames. 
     According to some embodiments of the invention, the summarizing includes removing low information data. 
     According to some embodiments of the invention, removing low information data includes computing an entropy of a portion of the video and removing the portion of the video when the entropy is low. 
     According to some embodiments of the invention, removing low information data includes computing an entropy of a key frame and removing the key frame in response to the computed entropy being low. 
     According to some embodiments of the invention, the summarizing includes removing redundant data. 
     According to some embodiments of the invention, removing redundant data includes computing a General Classification Features (GCF) value of at least two frames and comparing the GCF between the at least two frames and removing at least one of the at least two frames when the GCF of the at least two frames is similar. 
     According to some embodiments of the invention, the computing a GCF includes computing an Edge Histogram value for each of the at least two frames. 
     According to some embodiments of the invention, the comparing is of all frames in a group without accounting for sequencing within the group. 
     According to some embodiments of the invention, the method further includes determining an uncertainty of a determination of the presence of the content in the video. 
     According to some embodiments of the invention, the determining an uncertainty of a presence of the content in the video includes computing an uncertainty of determination the presence in a sample. 
     According to some embodiments of the invention, the determining an uncertainty of the presence of the content in the video includes computing an uncertainty of the presence of the content between two samples. 
     According to some embodiments of the invention, the uncertainty of the presence of the content between two samples takes into account a spatial autocovariance. 
     According to some embodiments of the invention, the method further includes performing further processing when the uncertainty is high. 
     According to an aspect of some embodiments of the invention, there is provided a system for in-line content filtering of video including: a connection to a public network a server receiving video content from a public network over the connection; the server including a video summary module configured to output a summary of the video content, the summary being smaller than the video content and preserving a sought content, a detection module configured to detect a sought content in the summary, a decision module configured for facilitating sending the video content a user device in response to the detection module not detecting the sought content and to inhibit the sending when the detection module detects the sought content in the summary a connection between the server and a user device configured for sending the video content to the user device in accordance with a decision from the decision module. 
     According to some embodiments of the invention, the server further includes a video disassembly module configured to separate key frames from the video and supply them to the video summary module and wherein the summary includes a subset of the key frames. 
     According to some embodiments of the invention, the video summary module is configured for: determining a representative element volume (REV) of the sought content and reducing a level of precision the summary to an order of the REV. 
     According to some embodiments of the invention, the video summary module is configured for selecting a collection of key frames and the summary includes the collection of key frames. 
     According to some embodiments of the invention, the video summary module is configured for removing low information data. 
     According to some embodiments of the invention, the video summary module is configured for computing an entropy of a portion of the video and removing the portion of the video when the entropy is low. 
     According to some embodiments of the invention, the video summary module is configured for computing an entropy of a key frame and removing the key frame from the summary in response to the computed entropy being low. 
     According to some embodiments of the invention, the video summary module is configured for removing redundant data. 
     According to some embodiments of the invention, the video summary module is configured for computing a General Classification Features (GCF) value of at least two frames and comparing the GCF between the at least two frames and removing at least one of the at least two frames when the GCF of the at least two frames is similar. 
     According to some embodiments of the invention, the video summary module is configured for computing an Edge Histogram value for each of the at least two frames and wherein a value of the GCF depends on the Edge Histogram. 
     According to some embodiments of the invention, the video summary module is configured for comparing all frames in a group without accounting for sequencing within the group. 
     According to some embodiments of the invention, the server is further configured for determining an uncertainty of a determination of a presence of the content in the video. 
     According to some embodiments of the invention, the video summary module is configured for computing an uncertainty of determination the presence in a sample. 
     According to some embodiments of the invention, the video summary module is configured for computing an uncertainty of the presence of the content between two samples. 
     According to some embodiments of the invention, the video summary module is configured for computing a spatial autocovariance between frames. 
     According to some embodiments of the invention, the video summary module is configured for performing further processing when the uncertainty is high. 
     Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting. 
     As will be appreciated by one skilled in the art, some embodiments of the present invention may be embodied as a system, method or computer program product. Accordingly, some embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, some embodiments of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. Implementation of the method and/or system of some embodiments of the invention can involve performing and/or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of some embodiments of the method and/or system of the invention, several selected tasks could be implemented by hardware, by software or by firmware and/or by a combination thereof, e.g., using an operating system. 
     For example, hardware for performing selected tasks according to some embodiments of the invention could be implemented as a chip or a circuit. As software, selected tasks according to some embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks according to some exemplary embodiments of method and/or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or removable media, for storing instructions and/or data. Optionally, a network connection is provided as well. A display and/or a user input device such as a keyboard or mouse are optionally provided as well. 
     Any combination of one or more computer readable medium(s) may be utilized for some embodiments of the invention. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
     A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. 
     Program code embodied on a computer readable medium and/or data used thereby may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. 
     Computer program code for carrying out operations for some embodiments of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
     Some embodiments of the present invention may be described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     Some of the methods described herein are generally designed only for use by a computer, and may not be feasible or practical for performing purely manually, by a human expert. A human expert who wanted to manually perform similar tasks might be expected to use completely different methods, e.g., making use of expert knowledge and/or the pattern recognition capabilities of the human brain, which would be vastly more efficient than manually going through the steps of the methods described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced. 
       In the drawings: 
         FIG.  1    is a flow chart illustration of on line filtering of a video in accordance with an embodiment of the current invention; 
         FIG.  2 A  is a schematic illustration of a raw video in accordance with an embodiment of the current invention in a schematic illustration of data reduction of a video of  FIGS.  2 A- 2 E  in accordance with an embodiment of the current invention; 
         FIG.  2 B  is a schematic illustration of a set of video frames in accordance with an embodiment of the current invention; 
         FIG.  2 C  is a schematic illustration of a set of video frames after removal of null frames in accordance with an embodiment of the current invention; 
         FIG.  2 D  is a schematic illustration of a set of video frames after removal of redundant frames in accordance with an embodiment of the current invention; 
         FIG.  2 E  is a schematic illustration of a set of video frames after removal of non-candidate frames in accordance with an embodiment of the current invention; 
         FIG.  3    is a block diagram illustration of a system of on-line video filtering in accordance with an embodiment of the current invention; and 
         FIG.  4    is a flow chart illustration of determining a content of a video in accordance with an embodiment of the current invention. 
     
    
    
     DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION 
     The present invention, in some embodiments thereof, relates to an on-line filtering of videos and, more particularly, but not exclusively, to a fast method of detecting a content in a video. 
     Overview 
     In some embodiments, there may be a desire to reduce the time and/or increase accuracy for analyzing a video for a content. For example, for on-line content filtering there is a desire to analyze content (supplying permissible content and/or removing undesired content) and/or supply the content to a user with a small delay time, for example of between a fraction of second to a second to a few seconds. Such fast analysis may be difficult, especially when dealing with large data objects, for example video content and/or fine distinctions between permissible and impermissible content (for example the different between permissible sports videos and undesired pornography and/or violence). In some embodiments, the speed of analysis will be improved by making relatively fast data transformations before analyzing for content. In some embodiments, the purpose of the data transformation may be to reduce the total computational burden. For example, a fast transformation may be used to a reduce data before a more expensive transformation. In some embodiments, removal of redundant and/or unclear data when forming the summary may reduce identification errors that may result from analyzing noisy data and/or from random errors that come up while analyzing the large data set and/or from bias of repeated frames. 
     An aspect of some embodiments of the current invention relates to a system and method to increase the speed of a computer determination whether a video contains a particular content. In some embodiments, the quantity of data in the video is first reduced while preserving the searched-for content. The reduction is configured both for efficiency (e.g. high-speed execution) and to avoid losing the searched-for content. Optionally, first, the size of the data is reduced quickly, by reducing the resolution, for example resolution may be reduced without searching and/or processing the full data set. Additionally or alternatively, low quality and/or empty data is removed from the dataset. Additionally or alternatively, redundant data may be searched out and/or removed. Optionally, after data reduction, the reduced dataset is analyzed to determine if it contains the searched-for content. Optionally, part of video may be reduced to a collection of images. Images may optionally may be analyzed using image analysis tools, an example of such tools is disclosed in U.S. Pat. No. 9,805,280 of the present inventor. Optionally, based on the results of the analysis of the reduced dataset and/or knowledge about the removed data, an estimate is made of the probability of the full dataset containing the searched-for content. 
     In some embodiments resolution of a video is reduced. For example, with respect to the searched-for content, a representative elementary volume (REV) is defined. The REV may be in time and/or area. For example, when scanning a film for pornographic images it may be decided that significant pornographic scenes are unlikely to last less than 5 seconds. Then a REV (Representative elementary volume) may be defined as 5 seconds. Then the time resolution of the dataset may safely be reduced to something of the order of the REV, for example between 1 to 2 REV&#39;s and/or between ½ to 1 REV and/or between ¼ to ½ REV and/or less than ¼ REV. Optionally, the resolution reduction will be to a level that is easy to reach. For example, for a digital video it may be easy to reduce to the time resolution of the video by keeping only key frames and ignoring transition data. For example, if the frame interval is less than the REV then a reduced video may include only a portion of the key frames. 
     In some embodiments, a video content scheme may remove low information data from a data set before analyzing the for content. For example, a low-cost algorithm may be used to detect low quality and/or low information content sections. 
     For example, a scalar and/or vector value may be assigned to each frame in a frame set. For example, key frames may be sorted according to their entropy levels. Low entropy frames may have little information and/or may be discarded. Optionally an easily computed and/or compared quantity may be used to indicate the information level. 
     In some embodiments, redundant data may be removed before analysis. Optionally, the redundant data will be found using an inexpensive quick routine without requiring high degree of quality in the identification. For example, a scalar and/or vector quantity may be used to characterize each key frame. For example, using a General Classification Function (GCF) for example an Edge Histogram Distribution (EHD). 
     In some embodiments, temporal data and/or sequencing of images may be ignored. For example, when removing redundant frames and/or detecting content temporal information may be ignored. Alternatively or additionally, frames be grouped in sets of a short time span but precise sequencing may be ignored. Alternatively or additionally, routines may consider sequencing and/or movement. 
     An aspect of some embodiments of the current invention relates to evaluating an uncertainty in a determination of a content of a video based on a quick analysis of an abbreviated version of the video. In some embodiments, after analyzing a video for a sought content a processor will estimate a probability that the content was missed and/or miss-identified. For example, the estimated probability will take into account the size of the sampling interval and the size of the REV and/or the uncertainty in analysis of each sample and/or the association with content found in the sample with the sought content and/or rate of change. Optionally, sample may be sent for further testing based on the effect of improving analysis of that sample on level of uncertainty in the entire video. 
     Specific Embodiments 
     Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. 
       FIG.  1    is a flow chart illustration of on-line filtering of a video in accordance with an embodiment of the current invention. In some embodiments, content delivered to a user is monitored  102  for undesired video content. For example, a filtering server may intercept  104  video data and summarize  106  the video. The resulting summary is optionally analyzed  108  for example to determine if it includes an undesired content. For example, a search algorithm seeks the content in the summary. In some embodiments, the server will determine  110  a probably of the undesired content searched for in the summary is present in the rest of the video that were not included in the search and/or including the probability that content present in the summary was not detected. Optionally, the server may compare the reduction in uncertainty of presence of undesired content in the video from reducing uncertainty in each of at least two samples and/or a select  112  a frame. For example, it may be determined which frame to send for further processing  114  to best reduce uncertainty. For example, the further processing  114  may include manual analysis of a set of one or more frames. For example, for videos, when the probability of infection with undesired content and/or the quantity and/or the quality of the undesired content is not beyond an acceptable limit, the server may allow delivery  118  of the content to a user. For example, for videos, when the probability of infection with undesired content and/or the quantity and/or the quality of the undesired content is beyond an acceptable limit, the server may block  120  delivery of the content to a user. 
     In some embodiments, the summarizing  106 of the data is arranged to facilitate fast of forming the summary and/or fast analyses of the summary for the content. Alternatively or additionally, the summarizing  106  of the data is arranged to avoiding removing significant data and/or reduce errors in the analysis  108  for content. 
       FIGS.  2 A- 2 E  are a schematic illustrations of data reduction of a video in accordance with an embodiment of the current invention.  FIG.  2 A  illustrates a raw video with a set of frames  230   a - 230   d  and transition data  232 . Optionally redundant data will be removed leaving enough data to determine the presence of the searched-for content with reduced excess data that might slow down analysis of content. 
       FIG.  2 A  illustrates reducing video is from the raw video  204  by extracting  234  frames  230   a - 230   d  to give a set  222  of frames  230   a - 230   d  (e.g. as illustrated in  FIG.  2 B ). For example, the raw video may include a sequence of key frames  230   a - 230   d  and/or transition information  232  between the frames  230   a - 230   d.  The summary may be based on reducing temporal resolution, for example by extracting  234  and/or using only the key frames  230   a - 230   d  (removing the transition information  232  and/or avoiding decoding the transition data  232 ). Alternatively or additionally, for example where the temporal REV of the searched-for content is greater than an interval between key frames  230   a - 230   d,  some of the key frames  230   a - 230   d  may be removed during extraction  234  of frames, further reducing the temporal resolution. For example, a frame may occur every two seconds while a REV is 5 seconds. Accordingly, every other key frame may be removed and/or one key frame may be retained in every 4 second period. Alternatively or additionally, the level of spatial resolution in the key frames may be reduced. For example, key frames  230   a - 230   d  may be compressed using known picture compression means and/or the resolution may be reduced by combining pixels. 
     In some embodiments, the frame set  222  may be further summarized to a reduced frame set  224  (e.g. as illustrated in  FIG.  2 C ). For example, null frames containing little valuable information may be removed  236 . For example, a frame  230   b  having low entropy may be removed  236 . Alternatively, null frames  230  may be removed from the full frame set  222  and then excess frames may be removed to reduce temporal resolution. In some embodiments, removal of transition data  232  and/or poorly defined frames may also reduce errors in the analysis of content. For example, analyzing blurry and/or poorly defined inter-frame data and/or low entropy blurry frames may add to the likelihood of erroneous conclusions without significantly improving the analysis for real content. Thus, removing this data may increase the accuracy of the analysis. For example, the removal of interframe data  232  and/or low entropy data (e.g. null frame  230   b ) may serve a function like the human mind&#39;s filtering of extraneous background. 
     In some embodiments, the reduced frame set  224  may be further summarized by removing  238  redundant frames (e.g. frame  230   d ) resulting in a unique frame set (e.g. set  226  of  FIG.  2 D ). Optionally, a content dependent routine may further reduce the unique from set  226  by eliminating  240  those frames that can easily be determined as unlikely to contain the searched-for content. A summary may result in a small sample preserved data set  228  which will be searched for the searched-for content. In some embodiments, removal of transition data  232  and/or poorly defined frames  230   b  and/or redundant frames  230   d  may also reduce errors in the analysis of content. For example, analyzing the same frame multiple times may increase the chance of incorrectly identifying a content without significantly adding to the accuracy of the analysis. Furthermore, the presence of a lot of repeated slides may bias the data. Thus, in some embodiments removing  238  redundant data  230   d  may increase the accuracy of the analysis. 
     In some embodiments, the order of the operations of summarizing the dataset is from the simple to the more difficult. For example, the full video data set  204  may be reduced by extracting  234  key frames  230   a - 230   d.  Extracting  234  key frames  230   a - 230   d  optionally requires no decision making and/or analyzing of the data, the key frames  230   a - 230   d  are essentially separate from the transition data  232  in the video file. For example, a further step may include removing  236  low information frames  230   b.  To recognize a low information frame  230   b  may include computing a simple function on individual frames (e.g. entropy) without finding relations between of different frames. Decisions may optionally be made by comparing a simple value (for example a scalar entropy value) to a constant threshold value. Optionally, as the data set becomes smaller more complex operations are used for further reduction. For example, on the reduced frame set  224 , redundant frames may be removed  238  including comparing slides among the entire set  224  (e.g. frame  230   a,    230   c  and  230   d ) and/or comparing slides among subsets and/or in accordance with a sequence of the frames, for example to find and/or remove  238  redundant similar frames (e.g. removing  238  frame  230   d  which is similar to frame  230   a  which is kept) resulting in a further reduced unique frame set  226 . For example, the unique frame set  226  may be further processed using more complex content recognition routines (for example GCF functions, flesh recognition routines and the like) to get a sample preserved set  228  for full analysis. Comparing frames may include computing a distance between scalar and/or vector quantities the measure one or more aspects of different frames. 
     In some embodiments, a GCF function (for example EHD) may be used for one of both analyzing the content of a “frame” (e.g. deciding in the frame contains significant information and/or if the frame includes a particular content) and/or for identifying a frame signature (for example to compare frames and/or remove redundant frames). The identifying of a signature is optionally flexible enough to recognize redundant frames even when there are slight changes within the frames. Identifying a signature is optionally very fast. In some embodiments, when identifying a signature, the GCF output may be converted from a vector to a scalar (for example, by connecting all the parameters), for example to more easily and/or more quickly identify similar “frames.” 
     In some exemplary embodiments of the invention, an initial screening to recognize and/or remove  240  non-candidates is conducted using one or more Boosted Cascade classifier algorithms selected from the group consisting of Haar, LBP, LRD, LRP, HOG textural features, and SkinBlob Detection or every other possible detection feature different from GCF used for post filtering. According to various exemplary embodiments of the invention one or more additional General Classification Features (GCF) are used to improve the accuracy of the initial screening. According to various exemplary embodiments of the invention the GCFs include one or more of color moment, Gabor function, color histogram, skin blob geometric information, color layout, intensity edge histogram, 3 colors plane edge histogram, color structure and scalable color. In some embodiments, each GCF is expressed as a vector with a natural number value of 1 or 2 representing two class discrimination system and two probability variables between 0 and 1. In some embodiments, a global probability vector is used to summarize 2, 3, 4, 5, 6, 7, 8 or more GCFs. Alternatively or additionally, in some embodiments a formula is used to summarize 2, 3, 4, 5, 6, 7, 8 or more GCFs and/or the global probability vector. In some embodiments various types of artificial intelligence to detect reduce data and/or detect content. For example, a Convolutional neural network (CNN) routine may be used (for example available routines may be used such as AlexNet, VGG, GoogLeNet or ResNet). 
     In some embodiments, data may be added back at some points along the process. For example, after the first analysis for content some frames may be sent for hand processing. For example, hand processing may not be slowed significantly by large resolution of individual frames. Optionally, in a case where a spatial resolution of a frame was reduced during processing, the original high-resolution version of the frame may be used for hand processing.  FIG.  3    is a block diagram illustration of a system of on-line video filtering in accordance with an embodiment of the current invention. In some embodiments, a user device  243  may request a video file (e.g. from an Internet server  244 ). The server  244  optionally retrieves the file from the Internet  260 . Before delivering the file to user device, the sever optionally passes the file through an automatic in-line filter  245 . The file may be sent to the user only after receiving approving from the filter. It may be desired to supply the video content such that 1) the user does not have to wait long before receiving the first block of the video and/or 2) further blocks of the video are sent to the user within a time faster then the buffer time of the previous block (e.g. the video is screened smoothly without breaks waiting for the next video block). In some embodiments, before sending approval to the server  244 , the filter  245  analyzes the video to determine if it contains an undesired content. Optionally the filter  245  includes modules to perform the analysis fast enough to deliver the video within the time limitations. 
     In some embodiments, the video may include a sequence of key frames and/or transition data, Decoding the checking the entire video may be prohibitively expensive in terms of computing time. Optionally the data and/or complexity of the video may be reduced to a collection of samples preserving the undesired content. Optionally analysis is performed on a summary of the video rather than decoding and/or checking the entire the entire video. 
     In some embodiments, a video disassembly module  247  may be supplied to extract the key frames from the video. Optionally, a collection of frames is sent from the disassembly module  247  to a video summary module  246 . For example, the video summary module  246  may remove frames that are closer in time than a critical time interval (such as a REV and/or a portion thereof). Alternatively or additionally, the summary module may search for low information frames and/or remove them. Alternatively or additionally, the summary module may remove redundant frames. For example, the summary module may use a measure of content and keep only one frame of a group of slides having a similar measure of content. For example, the measure of content may be represented by a vector and/or a scalar value. For example, an edge histogram EHD may be use as a measure of similarity. Optionally, redundant similar frames are removed regardless to their position on the video. Alternatively or additionally, redundant similar frames are only eliminated if they are close to each other in time in the video. Alternatively or additionally, eliminating similar slides accounts for the sequence of the frames. In some embodiments the summary module will contain a content specific filter. For example, a when searching for pornography, a filter may eliminate slides that do not contain a lot of skin tones and/or have full color (i.e. are not dark and/or are not dominated by one color [e.g. a picture taken under blue light may be dominated by blue and not include recognizable skin tones due to the source light]). Optionally the summary module  246  outputs summary data to a detection module  248 . 
     In some embodiments, the summary data is sent from the summary module to a detection module. Optionally the detection module  248  determines whether the searched-for content (for example undesirable content) is present in the summary data. Alternatively or additionally, the detection module  248  determines a probability that the searched-for content is present in the data set and/or in a frame and/or in a group of frames. Optionally, the decision module  254  computes the probably of the presence of the content in the video and/or a level of uncertainty and/or a way to reduce the uncertainty. Optionally, for example, if the uncertainty is too great, the decision module  254  will send a portion of the video to a further processing module  252  for further processing, for example to reduce the uncertainty. 
     In some embodiments, data for further processing is further summarized. For example, further summarizing may include removing certain data to make the further processing fast. Alternatively or additionally, the further summarizing may include restoring certain data that was removed in the first summarizing set. For example, in some embodiments, further processing module  252  may include manual classification group (for example human viewers and/or viewing equipment). Optionally, one or more frames are selected from the summary data for manual classification. Optionally, the selection of frames for further processing is based on the level of uncertainty in each frame. Alternatively or additionally, selection of frames for further processing is based on the level of uncertainty that each frame can reduce in the video. For example, in some cases when resolution was reduced to speed automatic processing, higher resolution frames (for example the original frames stored in a memory) are sent for further processing. Optionally, the results of the further processing are sent to the decision module  254 . For example, the decision may be based on the results of the detection module  248  and/or the further summary module  254  (for example including an extended processing center) instruct the server  244  whether to supply the video to the user device  243 . 
     In some embodiments, a user device and/or the further processing module  252  may include a video decoding module and/or a user interface for displaying a video and/or a frame therefrom. Alternatively or additionally, the user device  243  and/or the further processing module  252  may include a user interface for communication of a human with the system. Alternatively or additionally, the user device  243  and/or the extended processing module  252  may include communication components for communicating with the server  244  and/or the decision module  254 . 
       FIG.  4    in a flow chart overview of a method of detecting content in accordance with an embodiment of the current invention. In some embodiment, an initial simple method is used to reduce content from the full video. For example, resolution may be reduced  462 . For example, steps of the reduction  462  of data may take advantage of inherent divisions in the data, for example the division between key frames and transition data. In some embodiments, a representative element is determined and resolution is reduced to a level at which and acceptable preserving of information on the scale of the REV. Optionally, significant data will not be lost while the volume of the data is significantly reduced. 
     In some embodiments, further reduction of the data set may employ progressively more complex routines. For example, the resolution reduced data set may be processed to remove  236  low information data and/or remove  238  redundant data. Optionally, simple detection routines may be used to recognize and remove  240  non-candidate data. 
     In some embodiments, the reduced data set is analyzed  408  for the searched-for content and/or an uncertainty is computed  410 . Optionally, content may be found using an image analysis system, an example of such a system is disclosed in U.S. Pat. No. 9,805,280 by the present inventor. Optionally, further processing  414  may be used for example to reduce the uncertainty. Optionally, the data is further prepared  464  for further processing  414 . For example, preparing  464  may include further reducing the data (e.g. by extracting only data that has high uncertainty and/or where reducing uncertainty will significantly reduce the uncertainty of the entire video) and/or only a portion of the summary data set is sent for further processing  414 . Optionally some of the original data is restored to the data set before further processing. 
     It is expected that during the life of a patent maturing from this application many relevant robotic technologies and/or Artificial Intelligence technologies will be developed and the scope of the terms are intended to include all such new technologies a priori. 
     As used herein the term “about” refers to ±10% 
     The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to”. 
     The term “consisting of” means “including and limited to”. 
     The term “consisting essentially of” means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure. 
     As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof. 
     Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. 
     Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween. 
     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements. 
     Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. 
     All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.