Image analysis – Applications – Target tracking or detecting
Reexamination Certificate
1998-04-02
2001-10-02
Mancuso, Joseph (Department: 2621)
Image analysis
Applications
Target tracking or detecting
C348S169000
Reexamination Certificate
active
06298143
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a moving target detecting system and a moving target detecting method.
2. Description of the Related Art
Various proposals have been put forth with respect to a moving target detecting system which is suitable for tracking other flying airplanes, etc. if loaded on a guided missile, a military airplane, etc., for example, and a moving target detecting method for use in the moving target detecting system.
As an example, in the event that the guided missile tracks other moving airplanes, such a system has been known that a image pick-up device such as CCD camera is loaded on the guided missile to pick up a spatial domain including a target airplane as a still image, and then an image pattern of the airplane can be grasped by scanning the still image as a whole in unit of pixel to thus detect the presence of the moving target and its location.
More particularly, the system has been known wherein, for example, brightness average of the resultant still image is calculated, and then the brightness in respective pixels of the still image are compared with each other to thus identify/extract the image of the target whose brightness is considerably different from a brightness average level, so that the target can be detected by removing a background such as cloud, land, etc. from the picked-up image.
However, such system needs a plenty of processing time to discriminate/extract the moving target from the overall still image since one frame of the overall still image in the picked up area is scanned in unit of pixel to thus carry out the image processing for profile pattern recognition.
Besides, another system has been proposed wherein, for example, processing gates are provided in the vicinity of the target which has been extracted once to improve a processing speed and then an input signal level to an image processor can be adjusted by calculating brightness average within the processing gates.
Meanwhile, if the image pattern of the background having the brightness which is resemble and confusing to that of the target, e.g., the images of land and cloud, in addition to the image of the target exists in the picked-up image, difference in brightness between the moving target as an object and the background other than the moving target, i.e., contrast between them has been made relatively vague because of influence of the sunlight, etc., otherwise the contrast has dispersed over the screen as a whole although the contrast is sharp. For this reason, such a problem has been arisen that it is not easy to distinguish the target from the background precisely by identifying the target only and thus to detect the target quickly. Even if the processing gates are provided, the brightness average level becomes an inadequate value, for example, when the background image pattern enters into the processing gates. Therefore, such situation has occurred similarly.
SUMMARY OF THE INVENTION
A main object of the present invention is to provide a moving target detecting system and a moving target detecting method, which are capable of identifying a moving target by distinguishing the moving target precisely from the background and thus to detect the target precisely and quickly.
In order to achieve the above object, according to a first aspect of the present invention, there is provided a moving target detecting system comprising:
image pick-up means for picking up images of an objective area including at least an identical region up to two screens or more on a time series basis;
feature value detecting means for dividing respective images, which have been picked up by the image pick-up means into plural segments to have substantially identical profiles and then detecting image feature values in connection with brightness information in respective segments from each of the plural segments; and
discriminating means for discriminating the moving target based on differences in locations between respective segments which can exhibit substantially identical image feature values, by comparing the image feature values in respective segments on one screen out of the screens, from which the image feature values are detected by the feature value detecting means, with the image feature values in respective segments on another screen on a time series basis.
In such detecting system of the present invention, more particularly, in the feature value detecting means, the picked-up images are divided into plural segments and the image feature values in the segments are detected. In the discriminating means, only the target is detected with the use of motional difference between the moving target and the background other than the moving target in the change of the images on a time series basis based on the detected image feature values in respective segments.
Like this, since the discriminating means distinguishes the moving target from the background other than the moving target according to the change of the image on a time series basis based on the image feature values in respective segments, a calculation amount in the discriminating means is in proportion to the number of segments of the image.
Therefore, since process calculation amount can be limited by selecting the number of the segment, the process calculation time required for detection of the moving target can be reduced extremely.
In addition, in such detecting system of the present invention, since there exists difference in relative locations, i.e., difference between the moving direction and the moving distance of the overall background segments and the moving direction and the moving distance of in the segments including the moving target if two screens are relatively compared on a time series basis, the moving target can be distinguished from the background to be detected.
Accordingly, even if the segments having the contrast to the same degree are scattered and therefore sufficient contrast to identify the moving target as a whole screen cannot be obtained although some contrast can be detected in the vicinity of the moving target, differences in relative location displacement occur between the particular segments wherein the moving target exists and remaining majority segments. Therefore, the moving target can be detected more precisely.
According to a second aspect of the present invention, there is provided a moving target detecting method comprising the steps of:
picking up images of an objective area including at least an identical region up to two screens or more on a time series basis;
segmenting the images picked up by the images picking-up step into plural segments each having a substantially identical profile;
calculating image feature values in connection with brightness information in respective segments which are divided by the segmenting step;
extracting differences in locations between the segments which exhibit substantially identical image feature values as respective vectors, by comparing the image feature values in respective segments, which have been calculated by the image feature values calculating step, with each other between two screens or more correspondingly on a time series basis; and
separating/detecting the moving target based on respective vectors which have been extracted by the extracting step.
In such detecting method of the present invention, the picked-up images are divided into plural segments on a time series basis in the segmenting step and the image feature values calculating step, and then only the target is detected from position displacements between the segments having the substantially identical image feature values on both screens, by distinguishing from the background based on the image feature values in respective segments.
Like this, since the moving target is separated and extracted based on the segment number of the image via location detection of the segments having the substantially identical image feature values, a calculation amount can be limited and the process calculation time required for detection of the moving
Kikuchi Minoru
Taniguchi Yasuhiro
Kabushiki Kaisha Toshiba
Mancuso Joseph
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tabatabai Abolfazl
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