JPH0225704A - Detecting device for rotational position and direction of object - Google Patents

Abstract

PURPOSE:To stably detect a rotational position and a direction of an object by deriving the center of an image from projection data of the image and deriving the center of gravity of the image in a limited area in which said center of the image is an origin. CONSTITUTION:An image of an object which has been brought to image pickup by a television camera 1 is converted to a binary image corresponding to a gradation level by an A/D converting part 2 and stored in an image memory 4. X and Y projection detectors 3, 3A detect projection values in the horizontal X and the vertical Y directions from the binary image and store them. A microprocessor 9 derives tip coordinates XS, YS and terminal coordinates XE, YE of the object from X and Y projection data, and calculates the center coordinate C of the object. Subsequently, with regard to a pattern P in an internal area A shown by an area generator 5, primary moments XM, YM are derived by X and Y primary moment detecting parts 6, 6A, and an area value S is derived by an area detecting part 7, and by the processor 9, the center of gravity G of P is operated from XM and YM. Next, a straight line for connecting G and C is extracted, and from its inclination theta, a rotational position or a direction of the object is detected.

Description

[Detailed Description of the Invention] [Industrial Applications] This invention captures an image of an object using an imaging device such as a television camera, and processes the resulting binarized image by binarizing each pixel. The present invention relates to a detection device that detects its position and direction.

[Conventional technology]

BACKGROUND ART Conventionally, as a method for capturing an image of an object and determining its rotational position and direction, for example, a method is known in which the center of gravity of the image is determined and the principal axis of inertia passing through this center of gravity is determined.

[Problem to be solved by the invention]

However, in the above method, the principal axis of inertia is the X (horizontal) axis,
Since the calculation is performed from the second-order moment value regarding the Y (vertical) axis, if the image of the object changes locally, the principal axis direction will be significantly deviated, making it difficult to stably detect the direction.

In addition, there are problems such as the calculation processing of the principal axis of inertia becoming complicated.

Therefore, it is an object of the present invention to detect the position and direction of an object quickly and stably using simple calculations.

[Means to solve the problem]

a projection detection unit that detects the horizontal and vertical projection values of an image signal obtained by imaging an object and binarizing each pixel; and an area setting unit that sets a predetermined image observation area for the image signal. , a moment/area detector l1thlW6 that detects the first-order moment value and area value regarding the horizontal and vertical axes of the image of interest within the set area, and the center position 11t of the object based on the output from the projection detector.
and an arithmetic processing unit that calculates the position of the center of gravity of the image of interest based on the output from the moment/area detection unit,
The rotational position and direction of the object are detected from the inclination of the straight line connecting the center of gravity and the center position.

[Effect]

By determining the image center from the image projection data and determining the WJ's center of gravity within a limited area with this as the origin, local fluctuations in the internal pattern can be avoided as long as the external shape of the object is stable. Even if there is a rotational position and direction, it is possible to avoid that part and stably detect the rotational position and direction. Furthermore, since the calculation of the second moment is not necessary, the calculation process becomes simpler and faster.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the invention, and FIG. 2 is an explanatory diagram specifically explaining the operation of FIG. 1.

In FIG. 1, 1 is an imaging device such as a television camera, 2 is an analog/digital (A/D) converter, and 3 is an image pickup device such as a television camera.
, 3A is an X, Y projection detection unit, 4 is an image memory, 5 is an area generation unit, 6°6A is an X, Y-th moment detection unit, 7
8 is an input/output (ILO) interface section; 9 is an arithmetic processing fIA section such as a microprocessor; 1
゜ is the afternoon board.

The following description will be made with reference to FIG. 1 and FIG. 2.

The person/D converter 2 converts the image of the object imaged by the television camera 1 into binary II! according to its gray level. Convert to 1gN. The binary image is stored in the image memory 4. X,
Y projection detection unit 3.3 detects and stores projection values in the horizontal (X) and vertical (Y) directions from the binary value -I. Second
In the figure, X, Y projection data for the pattern shown is shown as PX m PY. The microprocessor 9 calculates the X, Y tip coordinates X8°Y8j5 and the X, Y end coordinates X of the object from this X, Y projection data. , Y, and then calculate the center coordinates of the object C (Xo e Yo
) is calculated.

xo --(Xs+ However, the keyboard lO and i10 interface 7 eighth part 8
Since it is preset in the area generation section 5 via t-,
In the example shown in FIG. 2, the area generation section 5 outputs area information as indicated by the code number. Regarding the internal pattern P in the internal area A, the X-order moment detection section 6 detects a first-order moment XMt about the X-axis, and the six Y-order moment detection sections similarly detect Y first-order moments about the Y-axis. Furthermore, the area calculation W17 detects the area value (8) of the internal pattern P. The microprocessor 9 calculates the first moments about the X and Y axes, YM, and the area value S.
The center of gravity G (to e YG ) f of the internal pattern as shown in the following formula
Calculate t.

Ryo - To detect. Note that although the internal pattern P has a complex shape as an example in the above example, it goes without saying that it may also have a simple shape.

〔Effect of the invention〕

According to this invention, the center of the object is determined from the external shape data of the object, the corresponding internal area t is set, the center of gravity of the internal pattern is determined, and the inclination (angle θ) of the straight stitch connecting the two is determined.
Since the rotational position and direction are determined from the rotational position and direction, the rotational position and direction ft can be detected stably and accurately without being affected much by image fluctuations. Also, the calculation processing is also X.

Up to the first moment about the Y axis, the second moment about the X and Y axes required by the principal axis moment method.

Complex processing such as XY moments is no longer required, resulting in faster processing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is an explanatory diagram specifically explaining its operation. Explanation of symbols■...Television camera, 2...A/D converter, 3. 3A...Projection detection section, 4...Picture memory, 5...Area generation FM, 6, 6A...
...
...Microprocessor, 10...Keyboard

Claims (1)

[Scope of Claims] A projection detection unit that detects the horizontal and vertical projection values of an image signal obtained by imaging an object and binarizing it for each pixel; and a predetermined image observation area for the image signal. a moment/area detection unit that detects the primary moment value and area value regarding the horizontal and vertical axes of the image of interest within the setting area; and a moment/area detection unit that detects the center of the object based on the output from the projection detection unit. an arithmetic processing unit that calculates the position of the center of gravity of the image of interest based on the output from the moment/area detection unit; A device for detecting the rotational position and direction of an object, characterized by detecting the rotational position and direction of the object.