Image analysis – Applications – Target tracking or detecting
Reexamination Certificate
1999-11-26
2003-09-30
Au, Amelia M. (Department: 2723)
Image analysis
Applications
Target tracking or detecting
C382S291000, C356S620000
Reexamination Certificate
active
06628803
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a calculation of camera position (photographing position) in a photogrammetric analytical measurement system, in which a survey map is produced on the basis of a set of photographed pictures obtained at two different photographing positions.
2. Description of the Related Art
For example, photogrammetry is carried out at a traffic accident spot. The traffic accident spot is photographed by a camera in at least two different positions, and a survey map of the traffic accident spot is produced based on a set of photographed pictures obtained at the different positions.
In particular, a two-dimensional coordinate system is defined on each of the photographed pictures, and two-dimensional positions of the objects, which are recorded on each picture, are determined by the two-dimensional coordinate system. Then, a three-dimensional coordinate system is defined on the basis of the two sets of two-dimensional coordinate systems, and three-dimensional positions of the recorded objects are determined from the three-dimensional coordinate system. Accordingly, it is possible to produce a survey map of the traffic accident spot by drawing the objects on a sheet of paper in such a manner that the objects are projected on one of the three planes defined by the three-dimensional system.
Before accurately scaled distances and lengths can be reproduced on the survey map, a standard measurement scale must be recorded together with the objects in the photographed pictures. Also, a standard reference plane, on which the survey map should be drawn, must be defined in the photographed pictures.
Usually, in order to define the standard measurement scale and the reference plane, three respective cone-shaped markers, which are identical to each other, are positioned at suitable locations around a traffic accident spot. Namely, a distance between two apexes of the cone-shaped markers is measured, for example, with a measuring tape, and set as the standard measurement scale, and a plane, defined by the three apexes of the cone-shaped markers, is utilized as the reference plane. As the positioning of the cone-shaped markers and the measurement of the distance between the two apexes are performed by operators, a process of preparing for photographing is onerous and requires a lot of time.
In order to solve the above mentioned problems, photogrammetric analytic measurement, using a target which has a triangular frame instead of the three cone-shaped markers, is disclosed in Japanese Unexamined Patent Publication (Kokai) No. P10-221072. Standard point members are respectively mounted on each of three apexes of the target. A distance between the standard point members is set as the standard measurement scale, and a plane defined by the standard point members is utilized as the reference plane. A reflecting sheet, for example, is attached on the standard point members so that the standard point members can be viewed easily in photographed pictures.
The determination of the three-dimensional positions of the recorded objects from the three-dimensional coordinate system is carried out by iterating a series of approximate calculations, using a computer having a monitor on which the set of photographed pictures is displayed.
Initially, before a first series of approximate calculations is executed, the standard point members and a suitable point on one of the recorded objects in the set of photographed pictures displayed on the monitor, are selected with a cursor, by manipulating a mouse, whereby three sets of two-dimensional coordinates, corresponding to the standard point members, and a set of two-dimensional coordinates on the suitable point of the selected object are inputted to the computer. Namely, the execution of the first series of approximate calculations is based upon the inputted two-dimensional coordinates of the standard point members and the inputted two-dimensional coordinates of the suitable point on the selected object, thereby determining three-dimensional positions of the standard point members and a three-dimensional position of the suitable point of the selected object from the three-dimensional coordinate system.
Then, another suitable point on the selected object in the set of photographed pictures displayed on the monitor is indicated with the cursor, by manipulating the mouse, whereby a set of two-dimensional coordinates of the other suitable point on the selected object is inputted to the computer, and a second series of approximate calculations is executed on the basis of the inputted two-dimensional coordinates of the other suitable point on the selected object, thereby determining a three-dimensional position of the other suitable point on the selected object from the three-dimensional coordinate system. This procedure is continued until a sufficient number of points on the selected object are indicated, to thereby specify a three-dimensional profile of the selected object.
The aforementioned series of approximate calculations is executed based on positional data of the camera at which the pictures are photographed. The positional data of the camera includes a distance from the camera to the selected object, an angle of the camera against the object. The positional data of the camera is calculated based on the two-dimensional coordinates of the standard point members selected by the operator.
However, it takes a comparatively long time to select the standard point members in the set of photographed pictures displayed on the monitor, with the cursor, by manipulating the mouse. Therefore, when there are a lot of the photographed pictures, it becomes onerous for the operator to operate the above mentioned manipulation of the mouse. Further, the accuracy of the photogrammetric analytic measurement is dependent upon the skill of the operator.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a device for calculating positional data of standard points of a target of photogrammetric analytic measurement.
In accordance with an aspect of the present invention, there is provided a device, for calculating positional data of standard points of a target of photogrammetric analytic measurement, comprising an image data obtaining processor and a value of two-dimensional coordinates calculating processor.
The image data obtaining processor photographs an object of photogrammetric analytic measurement with a target that has a first standard point and a second standard point and a third standard point.
Each length of distance between the first standard point and the second standard point and the third standard point is predetermined. An angle defined by a first straight line connecting the first standard point and the second standard point, and a second straight line connecting the second standard point and the third standard point, is predetermined. A number of assistant points provided on the first straight line and a number of assistant points provided on the second straight line are different.
The value of two-dimensional coordinates calculating processor calculates each two-dimensional coordinate value of the first standard point, the second standard point and the third standard point in a photograph coordinate system that is a two-dimensional coordinate system of a photographed image, obtained by the image data obtaining processor, after determining each position of the first standard point, the second standard point and the third standard point in the photographed image, by comparing the number of the assistant points provided on the first straight line and the number of the assistant points provided on the second straight line.
The first standard point, the second standard point, the third standard point and the assistant points provided on the first straight line and provided on the second line are made of a reflecting material, such that the first standard point, the second standard point, the third standard point and the assistant points have a relatively higher brightness than
Hara Masato
Kaneko Atsumi
Kida Atsushi
Nakayama Toshihiro
Wakashiro Shigeru
Au Amelia M.
Greenblum & Bernstein P.L.C.
LaRosa Colin
PENTAX Corporation
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