Abstract:
In order to detect abnormal objects with a low-cost arrangement at high speeds while avoiding unwanted influence of variations of a light source and/or regularly vibrating objects in the environment concerned, there is provided a block data calculation unit  4200  inputted from a camera into blocks, an object candidate extraction unit  4700  which compares image data of a frame to be processed and the immediately preceding frame in units of blocks to thereby extract an abnormal object candidate in accordance with the presence or absence of edges and a longitude-to-lateral edge ratio change rate, and an object judging unit  4800  for determining or “judging” whether the abnormal object candidate is a true abnormal object, wherein it is an abnormal object where movement of the abnormal object candidate is traceable for a prespecified length of time period.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates in general to technologies for monitoring scenes to be monitored as captured or photographed by cameras in the events of surveillance in road transportation monitoring fields and private surveillance within buildings plus outdoor surveillance or the like. More particularly, but not exclusively, this invention relates to a method and apparatus for monitoring of images to detect abnormalities through image processing of image data of scenes being monitored. The invention also relates to storage media for storing therein computer programs used to realize the image monitoring methodology. 
   As prior known image monitoring or surveillance apparatus, there is a method for performing abnormality detection through the steps of coding an image as captured or “photographed” by a camera into compressed data involving with-time differential image components and then directly utilizing such with-time differential images in this compressed data with no extra modifications added thereto to thereby determine or “judge” whether a change occurs in the to-be-monitored image (Japanese Patent Application Laid-open No. 2000-20857). 
   Unfortunately this method is encountered with a problem that under the circumstances with luminance variations with time such as brightness changes due to flickering of fluorescent lamps and/or turn-on/off of illumination devices and daylight variation of sunlight and clouds or the like, these can be detected as abnormalities incorrectly. In addition, due to the fact that tree swing with regular vibration in a direction of movement or alternatively curtain movements or else causes the luminance to change with time, the use of this method would result in incorrect detection of them as abnormalities in some cases. 
   Another abnormality detection method has been proposed until today, which includes the steps of subdividing an image as photographed by a camera into a plurality of blocks, applying discrete cosine transformation and compression processing to a respective of such blocks for forward transmission, expanding only high-frequency components containing therein edge information of the compressed image thus transferred, and using a difference between it and a prestored background scene image to perform the intended abnormality detection (JP-A-8-50649). 
   This method, however, suffers from problems which follow: The need for extension or “decompression” of such once-compressed image results in an unwanted increase in image information when compared to the case of compression; the resultant costs can increase undesirably due to an increase in length of time required for execution of the intended processing and also the necessity to employ an extra expansion device. A further problem faced with the prior art method is that detection accuracy stays lower. This can be said because the method tends to incorrectly detect the inherently non-abnormal objects—such as tree swing with regular vibration in movement direction, curtain movement, or else—as abnormal objects due to the fact that these exhibit changes in comparison with the background scene image thereof. 
   SUMMARY OF THE INVENTION 
   It is therefore a primary object of the present invention to provide an image monitoring apparatus capable of accurately detecting any available “true” abnormal objects with a low-cost arrangement at high speeds while avoiding a need to add any modifications and alterations to compressed images even in the environment in which tree swing with regular vibrations in movement or curtain movements are present in addition to environments with a luminance variation with time such as brightness changes due to fluorescent lamp flickers or repeated turn-on/off of luminance devices and also daylight changes of the sunlight and clouds or else. 
   To attain the foregoing object, the present invention provides an image monitoring method which comprises the steps of subdividing an image as input from an image capturing device into blocks, comparing image data of a frame to be processed with image data of its immediately preceding frame in units of the blocks to thereby extract more than one abnormal object candidate in accordance with edge presence/absence and longitudinal/lateral edge ratio change rates, and determining whether the abnormal object candidate is an abnormal object, wherein the step of determining includes a sub-step of judging the abnormal object candidate as an abnormal object in case this candidate is kept traceable for a prespecified length of time period. In addition, with the present invention, there is also provided a computer-readable storage medium which is characterized by holding therein a computer program for realization of the image monitoring method of this invention. 
   Furthermore, the instant invention provides an image monitoring apparatus which employs the image monitoring method of the invention. More specifically, with the present invention, an image monitoring apparatus is provided which comprises means for subdividing an image as input from an image capturing device into blocks, an object candidate extraction unit operable to compare image data of a frame to be processed with image data of its immediately preceding frame in units of the blocks to thereby extract more than one abnormal object candidate in accordance with edge presence/absence and longitudinal-to-lateral edge ratio change rates, and an object judging unit for determination of whether the abnormal object candidate is truly an abnormal object or not, wherein the object judging unit is operable to determine the abnormal object candidate as an abnormal object in case this candidate is kept traceable for a prespecified length of time period. 
   It should be noted that the object candidate extraction unit is capable of extracting the above-noted abnormal object candidate on the basis of a change with time of more than one frequency component that has been acquired through execution of orthogonal conversion or transformation of block data. Note here that the orthogonal transformation may include discrete cosine transform and/or orthogonal wavelet transform. 
   It must also be noted that the image monitoring apparatus of the present invention is desirably arranged so that it further has a tracking data calculation unit for tracking of an abnormal object as detected by the object judging unit, and an image capture device controller for generating and outputting based on the tracking data an image capture device-use control signal for changing an angle of an optical axis of the image capturing device. With such an arrangement, it is possible to automatically capture or “photograph” a scene in which the detected abnormal object is being tracked. 
   Additionally it is preferable that the tracking data at least include the movement amount of any detected abnormal object in at least either one of the horizontal direction and vertical direction. It is also desirable that the control signal adaptable for use with the image capture/photographing device include a control signal in accordance with the change amount of an optical axis angle of the image capture device as has been converted through computation from the movement amount of this abnormal object. 
   Further note that the image monitoring apparatus of this invention is preferably arranged to have an additive data creation unit for creation of display-use information as to the abnormal object thus detected. With such an arrangement, letting additive data along with the detected abnormal object makes it possible for a surveillance or “watchdog” person to readily recognize the information as to such abnormal object. 
   Also preferably the image monitoring apparatus of the invention further comprises an input device, a communication device, and a communication control unit operatively responsive to receipt of an instruction as input through the input device for performing communication with respect to at least one of predefined communication destinations via the communication device. With such an arrangement, it is possible for the surveillance person or watchman who has recognized the presence of any abnormal object to promptly contact appropriate “in-situ” associates or workers who are expected to cope with accidents and problems at the location or site whereat the abnormality presently occurs. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     [FIG.  1 ] A functional block diagram showing an image monitoring apparatus in accordance with an embodiment 1. 
     [FIG.  2 ] A function block diagram showing an image monitoring apparatus of an embodiment 2. 
     [FIG.  3 ] A function block diagram showing another example of the image monitoring apparatus of the embodiment 1. 
     [FIG.  4 ] A function block diagram showing an image coding device of the embodiment 1. 
     [FIG.  5 ] A function block diagram showing an object detection device of the embodiment 1. 
     [FIG.  6 ] A function block diagram showing a block data calculation unit of the embodiment 1. 
     [FIG.  7 ] A function block diagram showing another example of the block data calculator unit of the embodiment 1. 
     [FIG.  8 ] A function block diagram showing an image conversion or transformation device of the embodiment 2. 
     [FIG.  9 ] A function block diagram showing an object detector device of the embodiment 2. 
     [FIG.  10 ] A function block diagram showing a DCT data calculation unit of the embodiment 2. 
     [FIG.  11 ] A function block diagram showing another example of the DCT data calculator unit of the embodiment 2. 
     [FIG.  12 ] An explanation diagram showing an arrangement of coded data in the embodiment 1. 
     [FIG.  13 ] A flow diagram showing a processing procedure of an AC component longitude-to-lateral edge ratio calculation unit of the embodiment 1. 
     [FIG.  14 ] A flow diagram showing a processing procedure of an object candidate extraction unit of the embodiment 1. 
     [FIG.  15 ] An explanation diagram showing blocks as extracted with the presence of step changes in the embodiment 1. 
     [FIG.  16 ] A flow diagram showing processing procedures of the AC component longitudinal/lateral edge ratio calculation unit and DC component calculation unit in the event that a DC component value or values are used in the embodiment 1. 
     [FIG.  17 ] A flow diagram showing a processing procedure at the object candidate extraction unit in case a DC component value(s) is/are used in the embodiment 1. 
     [FIG.  18 ] A flow diagram showing a processing procedure of an object judging unit of the embodiment 1. 
     [FIG.  19 ] An explanation diagram showing tracking processing of a candidate object in the embodiment 1. 
     [FIG.  20 ] A function block diagram showing an image decoding/playback device of the embodiment 1. 
     [FIG.  21 ] A function block diagram showing an image playback device of the embodiment 2. 
     [FIG.  22 ] A function block diagram showing an image monitoring apparatus of an embodiment 3. 
     [FIG.  23 ] A function block diagram showing an object tracking function-added object detection device of the embodiment 3. 
     [FIG.  24 ] A function block diagram showing a tracking function-added object detection unit of the embodiment 3. 
     [FIG.  25 ] A flow diagram showing a processing procedure of a tracking data calculation unit in the embodiment 3. 
     [FIG.  26 ] A function block diagram showing an image monitoring apparatus of an embodiment 4. 
     [FIG.  27 ] A function block diagram showing an additive data playback device of the embodiment 4. 
     [FIG.  28 ] An explanation diagram showing a display screen example of a display device in the embodiment 4. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In the image monitoring/surveillance apparatus which incorporates the principles of the invention as disclosed and claimed herein, the block data calculation means is operable to calculate through computation the required block data for use as a minimal unit of compression and coding processing of the image coding device which is for compressing and coding an image being input from a camera, by way of example. The block data may be a frequency component with orthogonal transformation applied thereto, wherein with regard to this frequency component, the object candidate extraction means calculates a longitude-to-lateral edge ratio by use of luminance information of such frequency component to thereby extract any available change with time in longitudinal/lateral edge ratio through comparison and judgment processes. 
   The object determining or “judging” means is operable to perform correlation processing of present-time data and its previous time data between the same blocks corresponding to coded data of said image coding device and/or between image signals as reproduced or played back by said image decoding/playback device with respect to certain blocks as extracted by said object extraction means and/or the blocks also containing peripheries to thereby make a decision as an abnormal object in the case of being less than or equal to a threshold value. 
   Optionally the image monitoring apparatus of this invention is modifiable in a way such that an image conversion or transformation device is used to subdivide an image being input from a camera into a plurality of blocks whereas, with respect to more than one frequency component as has been acquired through execution of orthogonal transformation of each block data, the object candidate extraction means uses the frequency component&#39;s luminance information to calculate a longitudinal/lateral edge ratio for extraction of a change in longitudinal/lateral edge ratio due to time elapse through comparison and judgment processes. 
   In this case the object judging means performs correlation processing of a present time data and its previous time data between the same blocks with respect to a block(s) as extracted at said object candidate extraction means and/or the block(s) also including peripheries and relative to the resultant orthogonal transformation-applied frequency component in units of camera input images and/or blocks and then makes a decision as an abnormal object in the case of being less than or equal to the threshold value. 
   Alternatively the image monitoring apparatus of this invention may be arranged to employ as the image capture device a device which has a camera and its associated mount base equipment, also known as the camera platform, which is capable of changing the optical axis angle of such camera. In this case, it is the block data calculation means that successively calculates block data of the compression/coding minimum unit of the image coding device which executes compression and coding processing, with respect to video images being sequentially input from the camera of this image capture device. The block data may be a frequency component with orthogonal transformation applied thereto, wherein with regard to this frequency component, the object candidate extraction means calculates a longitude-to-lateral edge ratio by use of luminance information of such frequency component to thereby extract any available change with time in longitudinal/lateral edge ratio through comparison and judgment processes. 
   The object judging means is characterized in that with respect to certain blocks as extracted by said object candidate extraction means and/or the blocks also including peripheries, it performs correlation processing of present time data and its previous time data between the same blocks corresponding to the coded data of said image coding device and/or between the image signals as reproduced by said image decode/playback device and then makes a decision as an abnormal object in the case of being less than or equal to the threshold value while comprising tracking data calculation means for calculating, upon detection of such abnormal object at the object judging means, a horizontal direction movement amount and/or vertical direction movement amount of the abnormal object for the purpose of tracking the abnormal object and also comprising camera control means for converting the horizontal direction movement amount as calculated by the tracking data calculation means into a horizontal direction movement amount of the camera while converting the vertical direction movement amount into a vertical direction movement amount of the camera to thereby send forth camera movement control information toward the camera with its mount base or “platform” added thereto. 
   Additionally the image monitoring apparatus of this invention may be designed to have additive data creation means. In this case also, with respect to any image being input from the camera, the block data calculation means calculates or computes block data of the compression/coding minimum unit of the image coding device which is for execution of compression and coding processing. The block data may be a frequency component with orthogonal transformation applied thereto, wherein with regard to this frequency component, the object candidate extraction means calculates a longitude-to-lateral edge ratio by use of luminance information of such frequency component to thereby extract any available change with time in longitudinal/lateral edge ratio through comparison and judgment processes. The object judging means is characterized in that with respect to certain blocks as extracted by said object candidate extraction means and/or the blocks also including peripheries, it performs correlation processing of present time data and its previous time data between the same blocks corresponding to the coded data of said image coding device and/or between the image signals as reproduced by said image decode/playback device and then makes a decision as an abnormal object in the case of being less than or equal to the threshold value, wherein in the event that any abnormal object is detected by the object judging means, the additive data creation means creates and prepares additive information corresponding to the abnormal object while permitting an additive information storage means to store therein the resultant data as has been created at the additive information creation means. In the case of playback of coded data of the image coding device, it comprises display data selection means for performing selection for visual display of data being presently stored in the additive information storage means in a way corresponding to a specified video image. 
   Also note that the image monitoring apparatus of the invention may also comprise an interface capable of transmitting the abnormality toward a troubleshooting person who is responsible to deal with system troubles and accidents. In this case also, with respect to any image being input from the camera, the block data calculation means calculates or computes block data of the compression/coding minimum unit of the image coding device which is for execution of compression and coding processing. The block data may be a frequency component with orthogonal transformation applied thereto, wherein with regard to this frequency component, the object candidate extraction means calculates a longitude-to-lateral edge ratio by use of luminance information of such frequency component to thereby extract any available change with time in longitudinal/lateral edge ratio through comparison and judgment processes. The object judging means is characterized in that with respect to certain blocks as extracted by said object candidate extraction means and/or the blocks also including peripheries, it performs correlation processing of present time data and its previous time data between the same blocks corresponding to the coded data of said image coding device and/or between the image signals as reproduced by said image decode/playback device and then makes a decision as an abnormal object in the case of being less than or equal to the threshold value. In the event that any abnormal object is detected by the object judging means, the image decode/playback means reproduces coded data of said image coding device while comprising an interface which visually displays at a display device the image as reproduced by the image decode/playback means and, when the watch person has decided the object to be an abnormality, transmits the abnormality by issuance of an instruction of a specified location or position on the display device screen toward an appropriate troubleshooter who has jurisdiction over the area under surveillance. 
   An explanation will now be given of several preferred embodiments of the present invention with reference to the accompanying drawings below. 
   [EMBODIMENT 1] 
   A. Apparatus Arrangement 
   (1) Overall Arrangement 
   As shown in  FIG. 1 , an image monitoring/surveillance apparatus embodying the invention includes a processing apparatus main body  10  and a decode-playback/display device  50 . Note here that although in the illustrative embodiment the processing apparatus main body  10  contains a camera  1000  therein, the image monitoring apparatus may alternatively be constituted from a processing apparatus main body  20  and camera  1000  plus decode-playback/display device  50  with the camera  1000  being excluded from the processing apparatus main body  20 . 
   The processing apparatus main body  10  of this embodiment comprises the camera  1000  for capturing or “photographing” the scene of interest under surveillance, an image coding device  2000  for compression and coding of a video image or images as input from the camera  1000 , and an object detection device  4000  for detection of any abnormal objects. The decode-playback/display device  50  includes an image display device  8000  for visually displaying images and an image decoding/playback device  6000  which is operable to decode the coded data of image coding device  2000  for display at the display device  8000 . 
   Here, the camera  1000 , image coding device  2000 , image decoding/playback device  6000  and display device  8000  may be arranged to employ currently available standard devices with known designs. Also note that although in this embodiment the camera  1000  and the image coding device  2000  are designed as separate devices, a device with these components integrated together may alternatively be employable—that is, the arrangement for image pickup/capturing and coding processing should not in particular be limited to the illustrated one as far as there is obtainable an output of data with a captured image being compressed and coded. 
   It should be noted that although in the image monitoring apparatus of this embodiment the object detection device  4000  is provided within the processing apparatus main body  10 , the object detection device  4000  may alternatively be provided in a decode-playback/display device  50   b  rather than in a processing apparatus main body  10   b  or  20   b  as shown in FIG.  3 . 
   It is also noted that a relationship in position of the camera  1000 , image coding device  2000 , object detection device  4000 , image decode/playback device  6000 , image display device  8000  and the like should not exclusively be limited to the one shown herein and may be arranged so that any one of them is at a remote location. Irrespective of whether communication lines used for data transmission among them are of wired links or wireless or “over-the-air” links, any given means is employable therefor. In cases where the camera  1000  or image display device  8000  or else is at a remote site, communication with such a distant component is achievable by use of currently established standard communication links including, but not limited to, public telephone lines, local area networks (LANs), wide area networks (WANS) and so forth, although online communication schemes based on the Internet using the World Wide Web (WWW) architectures may also be used when the need arises. 
   (2) Image Coding Device 
   As shown in  FIG. 4 , the image coding device  2000  of this embodiment is arranged including a conversion/transform unit  2100 , a subtraction unit  2200 , a DCT/quantization unit  2300 , a length-variable coding unit  2400 , an inverse-quantization/inverse-DCT unit  2500 , an adder  2600 , a frame memory  2700 , and a movement prediction unit  2800 . 
   The converter unit  2100  is operable to separate part of a video signal being input from the camera  1000  which corresponds to a single frame into a brightness or luminance signal and its associative two color difference signals (blue difference signal and red difference signal) and then perform subdivision into units of macro blocks (referred to as “MBs” hereinafter) for output toward the subtracter  2200  and movement prediction unit  2800 . A single MB consists essentially of six blocks, which are made up from luminance blocks formed of 16-pixel by 16-line luminance signals (i.e. an ensemble of four blocks each consisting of 8-pixel/8-line luminance signals), a blue color difference block formed of 8-pixel/8-line blue color difference signals, and a red color difference block formed of 8-pixel/8-line red color difference signals. Note here that the blue color difference signal and red color difference signal have been subjected to ½ sampling both in the horizontal direction and in the vertical direction. Here, assume that an “n” frame is a present frame while letting a past or future frame adjacent to the n frame be an “m” frame—this will be used as a reference frame. 
   The movement prediction unit  2800  performs, with respect to n-frame pixels “p” in units of luminance blocks, an operation for searching in units of 0.5 pixels specific pixels p* similar to the pixels p from an interpolated image which has been created by use of neighboring pixels within the m frame. Here, let a luminance block that is minimal in total sum of absolute value differences of luminance differences on a per-pixel basis be a maximal similarity block YBs while calling as reference blocks three blocks including a blue color difference block CbBs and a red color difference block CrBs which spatially correspond to YBs. 
   The subtraction unit  2200  calculates a prediction error as represented by a difference between an MB as input from the conversion unit  2100  and the MB&#39;s reference block(s) and then outputs it toward the DCT/quantization unit  2300 . This DCT/quantization unit  2300  uses information as divided in units of blocks of 8 pixels×8 lines to perform discrete cosine transformation (DCT) that is orthogonal transform of the luminance data and then performs quantization of its resultant DCT coefficient thus obtained to thereby output it to the length-variable coding unit  2400  and inverse-quantization/inverse-DCT unit  2500 . The DCT transform as used herein is shown in the following formula (Equation 1). 
             Equation   ⁢           ⁢   1                                     F   ⁡     (     u   ,   v     )       =       ⁢         2       M     ⁢     N         ·     C   ⁡     (   u   )         ⁢     (   v   )                       ⁢       ∑     j   =   0       M   -   1       ⁢           ⁢       ∑     k   =   0       N   -   1       ⁢           ⁢       f   ⁡     (     j   ,   k     )       ×   cos   ⁢     {         (       2   ⁢   j     +   1     )     ⁢   μπ       2   ⁢   M       }     ⁢   cos   ⁢     {         (       2   ⁢   k     +   1     )     ⁢   μπ       2   ⁢   N       }                   ⁢     
     ⁢     here   ,     
     ⁢             C   ⁡     (   u   )       ,       C   ⁡     (   v   )       =         1     2       ⁢           ⁢   when   ⁢           ⁢   u     =       0   ⁢           ⁢   or   ⁢           ⁢   v     =   0                     =       1   ⁢           ⁢   when   ⁢           ⁢   u     ≠     0   ⁢           ⁢   or   ⁢           ⁢   v     ≠   0                       (   1   )             
 
   The inverse-quantization/inverse-DCT unit  2500  applies both inverse quantization and inverse DCT processing to the data as quantized by the DCT/quantization unit  2300 , decodes a prediction error(s), performs addition of the decoded data and the reference blocks at the adder  2600  for reproduction or “playback” of a frame being presently subject to coding processing, and then stores a result in the frame memory  2700  on a per-block basis. Its immediately preceding frame that was played back through a similar procedure is also being stored in the frame memory  2700 . 
   Furthermore, the movement prediction unit  2800  calculates a movement vector in the present frame from the reference block YBs of the reference frame and also from more than one luminance block of the present frame. The movement vector is indicative of a spatial relationship in position between the present frame&#39;s luminance block and the reference block YBs, which may be represented by a horizontal component and a vertical component. The movement prediction unit  2800  outputs the resulting YBs, CbBs and CrBs thus calculated in the way stated above toward the subtraction unit  2200  and further outputs the movement vector to the length-variable coding unit  2400 . 
   The length-variable coding unit  2400  executes length-variable coding processing with respect to both the quantized data as created at the DCT/quantization unit  2300  and the movement vector as obtained from the movement prediction unit  2800  and others and then performs a data output operation. Note here that any available devices with standard or ordinary arrangements for video signal encoding are employable as the image coding device  2000 . 
   (3) Object Detection Device 
   As shown in  FIG. 5 , the object detection device  4000  of the illustrative embodiment is arranged to include a block data calculation unit  4200 , object candidate extraction unit  4700 , object judging unit  4800 , and coded data storage unit  4900 . In this embodiment the object detection device  4000  may be realized by an information processing device with a central arithmetic processor device and a main storage device plus an external storage device. Additionally the use of the external storage device may be eliminated where unnecessary, such as in cases where programs are to be read out of the outside via communication lines or links. 
   The coded data storage unit  4900  is a storage region as secured in either the main storage device or the external storage device. The block data calculation unit  4200 , object candidate extraction unit  4700  and object judging unit  4800  are realizable in a way such that the central arithmetic processor device is designed to execute a program as loaded into the main storage device from storage media (such as optical discs, magneto-optical disks, magnetic disks or the like) via the external storage device or else. Although in this embodiment a respective part of the object detection device  4000  is realized by a software, the present invention should not exclusively be limited thereto and may be modifiable in a way such that the object detection device  4000  is realized by use of a special-purpose or “dedicated” device (chip) including hard wired logic circuitry. 
   The block data calculation unit  4200  takes out or extracts block data as a result of the DCT as has been performed by the DCT/quantization unit  2300  and then calculates an edge ratio relative to the block data thus taken out. The object candidate extraction unit  4700  utilizes the edge ratio thus calculated to compare a present frame with its proceeding or previous frame to thereby extract a case of a change being greater than or equal to a prespecified level as a candidate of abnormal object. The object judging unit  4800  performs object judgment based on a change state or the like of a region that was determined as a candidate at the object candidate extraction unit  4700 ; in the case of judgment as an object, it stores coded data of this frame with compression and coding processing applied thereto into the coded data storage unit  4900 . 
   As shown in  FIG. 6 , the block data calculation unit  4200  comprises a DCT data extraction unit  4210 , AC component longitudinal-to-lateral edge ratio calculation unit  4230 , and calculated data storage memory  4250 . 
   The DCT data extraction unit  4210  takes out of the DCT coefficient—this is a result of the DCT in units of 8-pixel/8-line blocks as has been executed at the DCT/quantization unit  2300 —block data of a luminance block consisting of 8-pixel/8-line luminance signals. The AC component longitudinal/lateral edge ratio calculation unit  4230  makes use of an AC component which is a high-frequency component of the DCT coefficient as has been calculated by the DCT data extraction unit  4210  to calculate an edge value in the horizontal direction and an edge value in the vertical direction and, thereafter, calculates a longitudinal/lateral edge ratio and then stores the ratio thus calculated into the calculated data storage memory  4250 . The calculated data storage memory  4250  is a storage region for retaining therein the longitudinal/lateral edge ratio thus calculated. 
   It should be noted that a DC component calculation unit  4270  may further be provided in the block data calculation unit  4200  as shown in FIG.  7 . The block data calculation unit  4200  takes out of the DCT coefficient as has been calculated by the DCT data extraction unit  4210  a DC component that is a low-frequency component. The values that have been calculated by the DC component calculation unit  4270  and the AC component longitudinal/lateral edge ratio calculation unit  4230  are then stored in a calculated data storage memory  4260 . In the case of using such scheme, the object candidate extraction unit  4700  extracts one or more abnormal object candidates by use of the values as calculated by these AC component longitudinal/lateral edge ratio calculation unit  4230  and DC component calculation unit  4270  and then stored in the calculated data storage memory  4260 . 
   (4) Image Decoding/Playback Device 
   As shown in  FIG. 20 , the image decoding/playback device  6000  of this embodiment comprises an image decoding unit  6010 , image display unit  6020 , detected position display unit  6030 , detection information display unit  6040 , and display screen synthesis unit  6050 . 
   The image decoding unit  6010  may be designed to employ standard or ordinary configurations for enabling reproduction or playback of an image signal(s), which unit is arranged to perform data decoding processing through execution of a procedure reverse to that of the coding processing of the image coding device  2000 . The detection information display unit  6040  creates display data of additive or “appendix” information or the like of the abnormal object including but not limited to the name of a scene in which the abnormal object (object that is moving abnormally) as detected by the object detection device  4000  has been photographed and time/date or else whereas the detected position display unit  6030  prepares clearly indicative display data of an abnormal object position as has been detected at the object detection device  4000 . The image display unit  6020  visually displays an image signal as reproduced at the image decoding unit  6010 . The display screen synthesis unit  6050  performs, with respect to a reproduced image of the image display unit  6020 , pasting and/or synthesis of the display data of the detection information display unit  6040  and the detected position display unit  6030  to thereby produce display data for enabling a monitoring or “watchdog” person to visually judge and recognize any abnormal object information at a glance, and then displays it on the display screen of the display device  8000 . 
   B. Arrangement of Coded Data 
   As shown in  FIG. 12 , the coded data of the image coding device  2000  in this embodiment is arranged to have a hierarchical structure in a manner such that a layer at the uppermost level is used as a sequence layer  4101  with its associated layers as a GOP layer  4102 , picture layer  4103 , slice layer  4104 , macro block layer  4105 , and block layer  4110  in the order of sequence toward the lower level thereof. The sequence layer  4101  that is the uppermost level layer includes a sequence header (SH) and a group of pictures (GOP). A standard one is employable as the data structure of such coded data. 
   The DCT coefficient which is a result of the DCT processing in units of 8-pixel/8-line blocks as has been executed at the DCT/quantization unit  2300  is held at the block layer  4110 . An initial pixel  4120  of the DCT coefficient is a DC component whereas the remaining sixty three pixels, i.e. h 1  pixel  4121 , h 2  pixel  4122 , . . . , h i  pixel  4123 , v 1  pixel  4130 , b 1  pixel  4131 , h i+1  pixel  4132 , . . . , V 2  pixel  4140 , v j+1  pixel  4141 , b 2  pixel  4142 , . . . , v j  pixel  4150 , . . . , are AC components. A value that the DC component calculation unit  4270  uses for calculation is a “native” value of the initial pixel  4120  of the DCT coefficient with no modifications added thereto. Values the AC component longitudinal/lateral edge ratio calculation unit  4230  uses for calculation are such that a pixel group  4111  of the upper right half part of a block, i.e. h 1  pixel  4121 , h 2  pixel  4122 , . . . , h i  pixel  4123 , . . . , h i+1  pixel  4132 , . . . , is used for horizontal edge calculation whereas a pixel group  4112  of the lower left half part of the block, i.e. v 1  pixel  4130 , v 2  pixel  4140 , v j+1  pixel  4141 , . . . , v j  pixel  4150 , . . . , is used for vertical edge calculation. 
   C. Flow of Processing 
   The image monitoring apparatus of this embodiment is such that the image decoding/playback device  6000  visually displays at the image display device  8000  any object or objects that have been detected by the object detection device  4000  on the basis of the image data as coded by the image coding device  2000 . Standard techniques may be used execute the image coding and decoding processing required. In view of this, an explanation mainly about a flow of processing at the object detection device  4000  will be given here. 
   At the object detection device  4000 , the DCT data extraction unit  4210  extracts block data; the AC component longitudinal/lateral edge ratio calculation unit  4230  calculates a longitudinal/lateral edge ratio with respect to this block data; the object candidate extraction unit  4700  uses this to extract any available abnormal object candidate; the object judging unit  4800  determines or “judges” whether this candidate is truly an object or not and then stores coded data of a frame that was judged to be an object in the coded data storage unit  4900 . 
   (1) AC Component Longitudinal/Lateral Edge Ratio Calculation Unit 
   A flow of processing at the AC component longitudinal/lateral edge ratio calculation unit  4230  of this embodiment is shown in FIG.  13 . Firstly the AC component longitudinal/lateral edge ratio calculation unit  4230  calculates a horizontal direction absolute value total sum of the pixel group  4111  at the upper right half part of AC components in the block layer  4110  of a presently input image (present frame) on a per-block basis and then lets it be fj(h) (at step  4231 ). Then, the AC component longitudinal/lateral edge ratio calculation unit  4230  calculates a vertical direction absolute value total sum of the pixel group  4112  at the lower left part of AC components in the block layer  4110  of the presently input image (present image) on a per-block basis and then lets it be fj(v) (step  4232 ). 
   Here, fj(h) may alternatively be an addition of any given combinations of absolute values as selected from the pixel group  4111  of the upper right half part, rather than the above-noted horizontal direction absolute value total sum. Similarly fj(v) should not exclusively be the vertical direction absolute value total sum and may alternatively be an addition of those combinations as selected from the pixel group  4112  at the lower left half part while letting them have the same regularity as that of any given combinations of the absolute values as selected from the pixel group  4111  of the upper right half part. Note that the addition of combinations with the same regularity is to be understood to mean that if fj(h) is the one with the absolute value of h 1  pixel  4121  and the absolute value of h 2  pixel  4122  added together by way of example then fj(v) is also the one with the absolute value of v 1  pixel  4130  and the absolute value of v 2  pixel  4140  added together. 
   Subsequently the AC component longitudinal/lateral edge ratio calculation unit  4230  checks to determine whether an addition value of the fj(h) as has been calculated at the step  4231  and fj(v) calculated at step  4232  is greater than or equal to a threshold value (at step  4233 ). In the event that it is kept less than the threshold value at the judgment of step  4233 , this means that no edges are present in the block at step  4237 , that is, a block image is in a uniform state; thus, the AC component longitudinal/lateral edge ratio calculation unit  4230  sets a value equivalent to the edge absence (step  4238 ). Alternatively in case it is judged to be greater than or equal to the threshold value at step  4233 , it means that more than one edge must be present at the block of interest; thus, the AC component longitudinal/lateral edge ratio calculation unit  4230  calculates at step  4235  a value of fj(h)/fj(v) of the block as a longitudinal/lateral edge ratio (Rb j ) (step  4234 ) and then stores the calculated value in the block per se (step  4236 ). Note here that the longitudinal/lateral edge ratio (Rb j ) may be such that the ratio is kept calculable; for example, it may alternatively be fj(v)/fj(h). 
   Lastly the AC component longitudinal/lateral edge ratio calculation unit  4230  judges whether all the blocks available within the present frame are completed in or not (at step  4239 ): if not completed, then let the processing return to step  4231 . 
   It should be noted that in case the DC component calculation unit  4270  is provided in the block data calculation unit  4200  as shown in  FIG. 7 , add specific processing (step  4271 ) for calculation of the value (BDC j ) of a DC component that is a low-frequency component in units of blocks of the present frame, which processing is to be done by the DC component calculation unit  4270 . Also note that although in  FIG. 16  the processing of this step  4271  is inserted between the step  4232  to be done by the AC component longitudinal/lateral edge ratio calculation unit  4230  and the processing at step  4233 , the present invention should not be limited only thereto and may be modifiable in any way as far as this processing is performed with respect to all the blocks prior to execution of the processing at the object candidate extraction unit  4700 . 
   (2) Object Candidate Extraction Unit 
   A flow of processing of the object candidate extraction unit  4700  in this embodiment is shown in FIG.  14 . First, the object candidate extraction unit  4700  lets a memory storing therein the edge ratio per block of the present frame be R i  while letting a memory of its previous frame be R i−1  (at step  4701 ). Here, the previous frame may alternatively be an immediately preceding frame or a reference frame or the like. 
   Subsequently the object candidate extraction unit  4700  calculates a longitudinal/lateral ratio change rate (RVH i ) between a present frame block (BR i ) of the longitudinal/lateral edge ratio and a previous frame block (BR i−1 ) that corresponds thereto (at step  4702 ). For instance, let the longitudinal/lateral ratio change rate (RVH i ) be given as:
 
 RVH   i   =|BR   i−1   −BR   i |÷{( BR   i−1   +BR   i )÷2}
 
   Alternatively let it be:
 
 RVH   i   =|BR   i−1     31  BR   i |
 
   Still alternatively let it be:
 
 RVH   i   =|BR   i−1   −BR   i   |÷BR   i 
 
   Next, between a corresponding present frame block and its previous frame block, the object candidate extraction unit  4700  judges through comparison whether any edge is present or absent and also the longitudinal/lateral ratio change rate (step  4703 ). The comparison/judgment process is done by a method including the steps of i) judging as “change absence” in case both the previous frame block and the present frame block are of edge absence, ii) in the event that more than one edge is present both in the previous frame block and in the present frame block, setting “change presence” if the longitudinal/lateral ratio change rate (RVH i ) is greater than or equal to a threshold value while setting “change absence” if the longitudinal/lateral ratio change rate (RVH i ) is less than the threshold value, iii) setting “change presence” in case the previous frame block is of edge presence whereas the present frame block is of edge absence, and iv) setting “change presence” in case the previous frame block is of edge absence whereas the present frame block is of edge presence. 
   Subsequently the object candidate extraction unit  4700  extracts more than one block as judged to be of the change presence (step  4704 ) and then checks to determine whether all the blocks within the frame of interest have been finished (step  4705 ). In case incompleteness is judged at step  4705 , the object candidate extraction unit  4700  lets the processing get back to step  4701 ; alternatively, if completion is judged then execute the step  4706 . 
   At step  4706  the object candidate extraction unit  4700  checks a coupling number of the “change presence” blocks thus extracted. Here, the object candidate extraction unit  4700  operates in a way which follows: In case the coupling number is greater than or equal to a threshold value, it regards this block as a candidate region of abnormal object (step  4707 ); if the number is less than the threshold value then determine that the block is an isolated or “stand-alone” block and thus judge that it must be a noise and not the candidate region of any abnormal object (step  4708 ). 
   The blocks that have been extracted after the judgment of “change presence” at step  4704  are shown in FIG.  15 . There are an isolated block  4732  and a coupled block  4731  in the extracted blocks. In light of this, at step  4706 , the coupled block  4731  with its coupled number being greater than or equal to the threshold value (three blocks in this embodiment) is determined to be the candidate region of an abnormal region whereas regions  4732  and  4733  or the like each of which has less than three coupled blocks will be excluded as noises. 
   It must be noted that in the case of provision of the DC component calculation unit  4270  in the block data calculation unit  4200  as shown in  FIG. 7 , the value BDCj of DC component per block is being held in the calculated data storage memory  4260  as a result of the processing at the above-stated step  4271 . A flow of the processing at the object candidate extraction unit  4700  in this case is shown in FIG.  17 . 
   In this case, the object candidate extraction unit  4700  performs, between the step  4701  and step  4702 , processing for letting a DC component value per block of the present block be BDC i  while letting a DC component value of its previous frame be BDC i−1  (at step  4752 ). It this process also, the previous frame may alternatively be an immediately preceding frame or a reference frame or the like. 
   In addition, the object candidate extraction unit  4700  performs, in place of the step  4703 , processing (step  4754 ) for judgment of change presence/absence by also using the DC component value in further addition to the edge presence/absence and the longitudinal/lateral ratio change rate. 
   At this step  4754  the object candidate extraction unit  4700  compares for judgment, between a corresponding present frame block and its previous frame block, whether any edge is present or absent along with the longitudinal/lateral ratio change rate thereof. The comparison/judgment process in this case is to be done by using a method having the steps of i) judging as “change absence” in case no edges are found in both the previous frame block and the present frame block, ii) in the event that edges are found in both the previous frame block and the present frame block, setting “change presence” if the longitudinal/lateral ratio change rate (RVH i ) is greater than or equal to a threshold value while setting “change absence” if the longitudinal/lateral ratio change rate (RVH i ) is less than the threshold value, iii) in the event that the previous frame block is of edge presence whereas the present frame block is of edge absence, setting “change presence” if the absolute value of a difference of DC component (|BDC i−1 −BDC i |) is greater than or equal to a threshold value while alternatively setting “change absence” if it is less than the threshold value, iv) in case the previous frame block is of edge absence whereas the present frame block is of edge presence, setting “change presence” if the absolute value of a DC component difference (|BDC i−1 −BDC i |) is greater than or equal to the threshold value while alternatively setting “change absence” if it is less than the threshold value. 
   (3) Object Judging Unit 
   A flow of processing of the object judging unit  4800  in this embodiment is shown in FIG.  18 . First, the object judging unit  4800  checks a processing result of the object candidate extraction unit  4700  (at step  4801 ) and then permits the processing to proceed to step  4802  if a frame block being processed is a candidate of abnormal object. Here, in case it is not any abnormal object candidate, the object judging unit  4800  determines establishment of “abnormal object absence” (step  4811 ) and then terminates the processing. 
   At step  4802  the object judging unit  4800  performs, relative to image coded data&#39;s decoded reproduced signal and/or input image signal, correlation processing between identical regions of the previous frame and present frame of an abnormal object candidate region and/or a region which also includes the periphery of such abnormal object candidate region (also including the case of extension up to about plus/minus one pixel). Note that the previous frame may alternatively be either an immediately preceding frame or a reference frame. 
   The correlation processing to be executed here is numerical processing for digitalization through normalization correlation processing of Formula (Equation 2) with the presence/absence of correlation being as the degree of similarity. More specifically the object judging unit  4800  normalizes a respective one of luminance values of a pre-registered template pattern and an image being processed to thereby obtain a difference of luminance therein (3F-8 Application of Variable-Density Pattern Matching Processing in Motor Vehicle Number Recognition System, 49-th National Conference of the Information Processing Society of Japan, Second Half Period of 1994). 
               Equation   ⁢           ⁢   2     ⁢                                           r   ⁡     (     u   ,   v     )       =       ⁢     [       pq   ⁢         ∑     i   =   0       p     ⁢           ⁢       ∑     i   =   0     q     ⁢           ⁢     {       f   ⁡     (       u   +   i     ,     v   +   j       )       ×     T   (     i   ,   j         }           -                           ⁢     {         ∑     i   =   0       p     ⁢           ⁢       ∑     i   =   0     q     ⁢           ⁢       f   ⁡     (       u   +   i     ,     v   +   j       )       ⁢         ∑     i   =   0       p     ⁢           ⁢       ∑     i   =   0     q     ⁢           ⁢     T   ⁡     (     i   ,   j     )                 }     ]     2     /                   ⁢           [     pq   ⁢         ∑     i   =   0       p     ⁢           ⁢       ∑     i   =   0     q     ⁢           ⁢         f   ⁡     (       u   +   i     ,     v   +   j       )       2     ⁢       {         ∑     i   =   0       p     ⁢           ⁢       ∑     i   =   0     q     ⁢           ⁢     f   ⁡     (       u   +   i     ,     v   +   j       )           }     2             ]                       ⁢     [     pq   ⁢         ∑     i   =   0       p     ⁢           ⁢       ∑     i   =   0     q     ⁢           ⁢         T   ⁡     (     i   ,   j     )       2     ⁢       {         ∑     i   =   0       p     ⁢           ⁢       ∑     i   =   0     q     ⁢           ⁢     T   ⁡     (     i   ,   j     )           }     2             ]                   (   2   )             
 
   Note that in Formula (Equation 2) r(u,v) indicates the similarity in (u, v) coordinates, f(u+i, v+j) designates a photographic density value of an object image in close proximity to a (u, v) point, T(i,j) is a density value of a (i,j) point of the template image, and “p” and “q” denote x and y sizes of such template image, respectively. 
   Subsequently the object judging unit  4800  judges a result of the correlation processing at step  4802  (step  4803 ), thereby causing the processing to proceed to step  4806  in case any intended correlation is disabled while alternatively letting the processing go to step  4804  if the correlation is enabled. Note in the correlation processing that the correlation disability is a case where a region to be processed and correlated stays uniform in luminance with no edges present therein and is also a case where any specific characteristics are absent with less discrete values. 
   In the event that the correlation is possible, the object judging unit  4800  attempts to judge whether a correlation value is less than or equal to a correlative threshold value (step  4808 ). Here, if the correlation value is smaller than or equal to the threshold value to thereby mean that objects to be processed are not similar to each other (less in similarity), then the object judging unit  4800  regards an abnormal object candidate to be processed as an appeared object (step  4805 ) and then permits the processing to go to step  4806 . Alternatively if at step  4804  the correlation value is greater than the threshold value to thereby tell that the abnormal object candidate to be processed is not any appeared object, then the object judging unit  4800  forces the processing to directly proceed to step  4806 . Additionally the correlative threshold value used herein may be set at a value which falls within a range of from 0.0 to 1.0; for example, 0.7 is used as such threshold value in this embodiment. 
   At step  4806  the object judging unit  4800  checks to determine whether all available abnormal object candidates are completed in processing; in the case of incompleteness, let the processing return at step  4802  for execution of similar processing (steps  4802 - 4805 ) with respect to the next candidate region. 
   In the event that the processing has been completed relative to all available candidate regions at step  4806 , the object judging unit  4800  judges whether an appeared object is found or not (step  4807 ). If no appeared objects are found then the object judging unit  4800  determines establishment of “abnormal object absence” (step  4811 ) and then terminates the processing. 
   In case an appeared object is found, the object judging unit  4800  performs tracking from the appearance position of the candidate object&#39;s previous frame and/or immediately preceding frame and the appearance position of a present frame (step  4808 ) and then determines whether the tracking is made possible within a prespecified length of time period (step  4809 ). Here, for the tracking, a central point or the center of gravity of an abnormal object candidate region is employable as the appearance position, wherein the tracking is attainable by letting the nearest distance or the like correspond thereto. More specifically, the object judging unit  4800  operates in a way such that in case an abnormal object candidate  4820  appears at a time point ti and thereafter an abnormal object candidate  4821  and abnormal object candidate  4822  appear at an instant t i+1  for example as shown in  FIG. 19 , this unit performs an abnormal object candidate tracking operation by causing the candidate  4821  that is an abnormal object candidate with a smaller movement distance to correspond to the abnormal object candidate  4820  under an interpretation that the abnormal object candidate  4820  has moved to the candidate  4821 . This tracking is performed through sequentially repeated execution of judgment as to whether an abnormal object candidate is present or absent which is a result of movement of the same object within a frame while updating a newly input frame as a present frame to be processed. 
   When the tracking was enabled for a predetermined length of time period, the object judging unit  4800  determines establishment of “abnormal object presence” (step  4810 ) and then terminates the processing. Alternatively when the tracking was not enabled for the predetermined time period, the object judging unit  4800  determines establishment of “abnormal object absence” (step  4811 ) and then finishes the processing. Note here that the predetermined length of time period as used herein may be at or near the degree of a residence time of a specified object being detected in a photographed scene or alternatively be less than it (where, it must be greater than zero) as long as there is a time for enabling the detected object to be distinguished from any moving disturbances. 
   [EMBODIMENT 2] 
   In the embodiment 1 discussed above, after once having coded image data by the image coding device  2000 , an available abnormal object is detected at the object detection device  4000  and thereafter the image data will be decoded by the image decoding/playback device  6000  and then visually displayed at the image display device  8000 . In contrast, this embodiment is arranged to offer an ability to display images using image data prior to image conversion or transformation as shown in FIG.  2 . Additionally the image monitoring apparatus of this embodiment is substantially the same as the embodiment 1 with respect to the remaining points. In this respect, an explanation will here be given of only different points from the embodiment 1 with any explanation as to common points eliminated herein for brevity purposes. 
   In this embodiment the image monitoring apparatus is arranged as shown in  FIG. 2  so that it includes a processing apparatus main body  10   a  and a decode-playback/display device  50  or alternatively a processing apparatus main body  20   a , a camera  1000 , and a decode-playback/display device  50   a.    
   The processing apparatus main body  10   a  of this embodiment comprises the camera  1000  for capturing or photographing the scene of interest, an image conversion or transformation device  3000  for subdividing an image as input from the camera  1000  into a plurality of blocks and for performing orthogonal data transformation in units of blocks, and an object detection device  5000  for detection of any available abnormal objects. The decode-playback/display device  50   a  includes an image display device  8000  for visually displaying images and an image playback device  7000  for visually displaying any video image of the camera  1000  at the display device  8000 . The camera  1000 , image playback device  7000  and image display device  8000  may be arranged to employ prior known standard devices. A chip with the camera  1000  and the image transformation device  3000  integrated together may also be used. 
   As shown in  FIG. 8 , the image transformation device  3000  of this embodiment comprises a block region generation unit  3400  and a DCT data calculation unit  3500 . The block region generation unit  3400  produces a plurality of blocks through subdivision of an image as photographed at the camera  1000  into unitary blocks of 8 pixels by 8 lines by way of example in order to perform orthogonal transformation on a per-block basis. The DCT data calculation unit  3500  performs luminance data orthogonal transformation from the information with subdivision into 8-pixel/8-line block units and then acquires frequency components. 
   It should be noted that although in this embodiment the orthogonal transformation for frequency component acquisition is the discrete cosine transformation (DCT) as indicated in Equation (1) described previously, orthogonal transformation excellent in degree of convergence to a low-frequency region may alternatively be employable, including orthogonal wavelet transform, K-L transform or the like. Additionally the subdivision to be done by the block region generation unit  3400  may alternatively be division into 16 pixels×16 lines or the like in place of 8 pixels×8 lines. 
   As shown in  FIG. 10  the DCT data calculation unit  3500  of this embodiment includes a DCT data extraction unit  3510 , AC component longitudinal-to-lateral edge ratio calculation unit  4230 , and calculated data storage memory  4250 . The DCT data extraction unit  3510  of this embodiment applies to the resultant luminance data in units of divided blocks the orthogonal transformation for frequency component acquisition—for example, discrete cosine transform (DCT) shown in Equation (1)—to thereby obtain a DCT coefficient. Using this, the AC component longitudinal/lateral edge ratio calculation unit  4230  calculates through computation a longitudinal/lateral edge ratio of an AC component and then stores the result in the calculated data storage memory  4250  in a way similar to that of the embodiment 1. 
   It must be noted that as in the case of the embodiment 1, in this embodiment also, a DC component calculation unit  4270  may further be provided in the DCT data calculation unit  3500 , wherein a DC component value which was calculated by this DC component calculation unit  4270  and then stored in the calculated data storage memory  4260  is used when the object candidate extraction unit  4700  extracts an abnormal object candidate(s). An arrangement of the DCT data calculation unit  3500  in this case is shown in FIG.  11 . 
   Subsequently, using the frequency component of an image as has been acquired by the DCT data calculation unit  3500 , the object detection device  5000  detects an abnormal object or objects. The object detection device  5000  of this embodiment also is an information processing apparatus in a similar manner to the object detection device  4000  of the embodiment 1, which comprises its object candidate extraction unit  4700  and object judging unit  4800  as shown in FIG.  9 . Arrangements and functions of these respective units  4700 ,  4800  are similar to those of the embodiment 1. 
   A detection result due to this object detection device  5000  is displayed by the display playback device  7000  at the display device  8000 . While the display playback device  7000  of this embodiment has a substantially similar arrangement to that of the image decoding/playback device  6000  of the embodiment 1, the image decoding unit  6010  is not provided therein as shown in FIG.  21 . Due to this, an image display unit  7020  of this embodiment is operable to output an image signal as input from the camera  1000  toward the display screen synthesis unit  6050 . The display screen synthesis unit performs, with respect to this image signal, pasting and/or composition of display data of the detection information display unit  6040  and the detected position display unit  6030  to thereby produce display data for enabling a watch person to visually judge and recognize any abnormal object information at a glance, and then displays the same at the display device  8000 . 
   [EMBODIMENT 3] 
   In this embodiment, an image monitoring apparatus is provided which is arranged to automatically track an abnormal object. As shown in  FIG. 22 , the image monitoring apparatus of this embodiment comprises a processing apparatus main body  30  along with a decode-playback/display device  50  similar to that of the embodiment 1. The processing apparatus main body  30  of this embodiment includes an image pickup/capturing or “photographing” device  1100 , image coding device  2000 , and object detection device  9000  with object tracking functionality. In this embodiment also, the image monitoring apparatus may be made up from a processing apparatus main body  40 , image capturing device  1100  and playback/display device  50  while letting the image capture device be excluded from the processing apparatus main body as in the other embodiments. 
   The image monitoring apparatus of this embodiment has the substantially the same arrangement as that of the image monitoring apparatus of the embodiment 1, except that the former has as an image capturing or photographing mechanism in addition to the camera  1000  a driving mechanism for changing or altering its optical axis direction and also that the object detection device  9000  has object tracking functionality. In light of this, an explanation will here be given of only different points from the embodiment 1 with any explanation as to common points eliminated herein. 
   The image pickup/capture device  1010  has a camera  1000  and a mount base  1100 , also known as “camera platform,” with the camera mounted thereon. The camera platform  1010  has an angle alteration mechanism for changing and adjusting an angle in the optical axis direction of a lens(es) of the attached camera  1000  being mounted thereon. Note that the image capture device  1100  may be a prior known camera having a drivable camera platform. 
   Additionally as shown in  FIG. 23 , the object detection device  9000  of this embodiment has a tracking function-added object detection unit  9100  and a camera control unit  9700 . The camera control unit  9700  is connected via communication links to the camera platform  1010  of the image capture device  1100  for outputting more than one control signal as used to control an operation of the driving mechanism of the platform  1010  and an operation of the camera  1000 . As shown in  FIG. 24  the tracking function-added object detection unit  9100  further has a tracking data calculation unit  9130  in addition to a similar arrangement to the object detection device  4000  of the embodiment 1, which is operable to calculate tracking-use data including but not limited to the horizontal movement amount and/or vertical movement amount of an abnormal object as detected by the object judging unit  4800  and then notify it to the camera control unit  9700 . The camera control unit  9700  which has received this operates to convert the input tracking-use data into a control signal for use with the image capture device  1100  and then output it toward the camera platform  1010 . With such an arrangement, this embodiment enables the image capture device  1100  to sense and capture or “photograph” a scene with continuous tracking of an abnormal object(s) thus detected. 
   A practically reduced processing procedure of the tracking data calculation unit  9130  will be explained with reference to FIG.  25 . Firstly, the tracking data calculation unit  9130  checks for the presence or absence of an abnormal object (at step  9131 ). In the event that the object judging unit determines an abnormal object is present, the tracking data calculation unit  9130  calculates, as the direction and size of a moving vector, a horizontal direction movement amount and/or vertical direction movement amount or the like up to a central point or a gravity center position or else of a detected object in a present frame from the center or gravity center position or else of the detected object in a previous frame (at step  9132 ), and then outputs through the camera control unit  9700  toward the camera platform  1010  certain control data such as the camera&#39;s panning and/or tilting or the like corresponding to the calculated horizontal direction movement amount and/or vertical direction movement amount  1010  (step  9133 ). On the other hand, in case judgment is made saying that any object is absent at the step  9131 , the tracking data calculation unit  9130  outputs via the camera control unit  9700  to the camera platform  1010  specific control data indicative of the lack of any control information (step  9134 ). 
   It should be noted that in the case of the presence of a plurality of objects, if multiple cameras are employed each of which is similar in arrangement to the camera  1000 , then it is possible to let a single camera correspond to a single object. Alternatively in case the camera  1000  is used singularly, a scheme may be used for determining an object to be tracked in accordance with a prespecified order of priority. 
   [EMBODIMENT 4] 
   An image monitoring apparatus of this embodiment is designed to create, upon detection of an abnormal object (moving object), additive information corresponding to such detected object and then visually display it at a display device along with an image of the abnormal object. In addition the image monitoring apparatus of this embodiment is provided with a communication function for performing communication with a troubleshooting person who is responsible for handling accidents and problems occurring in his or her territory or “job site.” 
   As shown in  FIG. 26  the image monitoring apparatus of this embodiment comprises a processing apparatus main body  60  having a camera  1000  and an image coding device  2000  plus additive data creation function-added object detection device  10000 , a playback/display device  80  which has an image decoding/playback device  6000  and image display device  8000  and further has an additive data playback device  9500  in addition thereto, an input device  11000 , and a communication device  12000 . In this embodiment also, the image monitoring apparatus may be constituted from a processing apparatus main body  70 , camera  1000 , playback/display device  80 , input device  11000  and communication device  12000  while letting the camera be excluded from the processing apparatus main body as in the other embodiments. 
   The image monitoring apparatus of this embodiment has an additive data creation unit  10010  in the object detection device  10000  for the purpose of displaying additive data concerning an abnormal object(s) thus detected, wherein the additive data playback device  9500  for visual display of additive data as created thereby is provided in the playback/display device  80 . Additionally it comprises the input device  11000  and communication device  12000  for use as the mechanism for communication with any abnormality occurrence job sites, with a communication control unit  10020  being provided in the object detection device  10000 . Except for these points, the image monitoring apparatus of this embodiment has an almost similar arrangement to that of the apparatus of the embodiment 1. In light of this, an explanation will here be given of only different points from the embodiment 1 with any explanation as to common points eliminated herein. 
   As shown in  FIG. 26  the object detection device  10000  of this embodiment has the additive data creation unit  10010  and communication control unit  10020  in addition to a similar arrangement to the object detection device  4000  of the embodiment 1. In addition, as shown in  FIG. 27 , the additive data playback device  9500  of this embodiment has a display data selection unit  9510  and additive information storage unit  9520 . Note that although in this embodiment the additive data playback device  9500  is provided in the playback/display device  80 , it may alternatively be provided in the processing apparatus main body  60  per se or still alternatively provided in the object detection device  10000 . Also note that although the communication control unit  10020  is provided in the object detection device  10000 , the same may alternatively be provided in another device such as the communication device  12000 . 
   The additive data creation unit  10010  creates and produces, with respect to any abnormal object as detected by the object judging unit  4800 , additional data items including but not limited to a nickname of the detected object, photograph scene title, abnormal object detection time point, position within the object&#39;s scene, object area, object&#39;s characteristics (such as taller-than-wide, wider-than-tall, dark object, bright object, etc.), icon and the like, and then stores them in the additive information storage unit  9520  of the additive data playback device  9500 . The display data selection unit  9510  selects, with respect to the scene of interest to be displayed at the display device  8000 , certain ones to be displayed from among the additive information items as held in the additive information storage unit  9520  and then sends forth them toward the image decoding/playback device  6000  to thereby permit visual display on the display screen of the display device  8000 . 
   A display screen example of the display device  8000  in this embodiment is shown in FIG.  28 . The image monitoring apparatus of this embodiment operates in a way such that in the event that an abnormal object (moving object) is detected, it visually displays on a display screen  8100  a vector  8002  indicative of movement of the abnormal object relative to a previous frame and additional data  8004  of the detected scene as created by the additive data playback device  9500  in addition to a scene  8001  in which the abnormal object is being captured or “photographed.” Whereby, it becomes possible for a watch person who is the user of this apparatus to readily recognize at a glance the additive information of any abnormal scenes. 
   Further with the image monitoring apparatus of this embodiment, there is provided an interface for enabling bidirectional communication with a troubleshooting person at any occurrence location. More specifically an image being displayed in this embodiment is provided with a selection region (button)  8005  for support of remedy notification. Upon selecting (clicking) of this region  8005  via the input device  11000 , the communication control unit  10020  selects from among pre-registered communication destinations an appropriate communication destination which is nearest to the abnormal object being presently displayed and then opens a communication link (such as a over-the-air communication line for portable or handheld wireless telephone handsets) with the communication destination. This in turn enables the watch person who is the user of this image monitoring apparatus to perform bidirectional communication with a troubleshooter at any abnormality occurrence location or job site. 
   In accordance with the present invention, the longitudinal/lateral edge ratio of a frequency component of “rare” image data with compression-coding processing applied thereto is utilized to perform judgment as to whether an abnormal object candidate is present or absent by use of a change rate of the edge ratio between a previous frame and a present frame. Accordingly, as comparison is done between such two frames by utilizing the longitudinal/lateral edge ratio of the frequency component, there is an effect of enabling significant reduction of a processing time and memory while at the same time offering an effect that any appreciable influence depending on luminance variation does no longer occur due to the use of the edge ratio. In addition, since the processing is done with no extra modification applied to the image&#39;s compression-coded data, there is a “double” effect which follows: it is possible to shorten an image processing time while further making it possible to shorten a time taken to perform the intended image transfer. Additionally, as the correlation processing is used for abnormal object judgment, there is an effect that the abnormality judgment much increases in precision. On the other hand, in the case of using one or more platform-attached cameras, object tracking is performed; thus, it is possible to photograph a wider range with a less number of cameras, which in turn makes it possible to establish a system arrangement at low costs.