JPH0423743B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inspection device for determining the quality of the appearance of a three-dimensional product.

INDUSTRIAL APPLICABILITY The present invention can be used to detect defects in three-dimensional products such as automobile spark plugs, such as surface scratches and chips.

[Prior art]

Conventional appearance defect inspection equipment inspects planar products and parts such as ICs. Furthermore, even when detecting defects in three-dimensional products or parts, only a portion of the external shape is judged to be good or bad.

Therefore, conventional equipment inspects the external shape only from one direction, and cannot detect scratches on the surface or defects on the back surface, making it impossible to perform a comprehensive inspection for external defects. Nakatsuta.

Image sensors or line sensors are generally considered to be used for visual defect inspection equipment for products with three-dimensional shapes, but both sensors have problems with the configuration to obtain stable images, lighting methods, and processing speed. It was hot.

[Purpose of the invention]

The present invention has been made in order to improve the conventional drawbacks, and its object is to quickly and accurately correct the appearance defects of products having three-dimensional shapes.

[Structure of the invention]

The present invention provides: a fixed base that holds and rotates an object to be measured; an image sensor that photographs the object to be measured and obtains contour information of the object from a two-dimensional planar image; and the object to be measured. a line sensor that obtains surface information of the object based on a one-dimensional image signal of the object; a first video signal processing circuit that drives the image sensor and outputs a video signal; a second video signal processing circuit that outputs a video signal and outputs a rotation signal to the fixed base; a storage device that stores output signals from the first video signal processing circuit and the second video signal circuit; and a control device that outputs control signals to the first video signal processing circuit and the second video signal processing circuit and performs data processing based on data from the storage device.

〔Example〕

The present invention will be described below based on specific examples.

FIG. 1 is a block diagram of an apparatus for inspecting appearance defects particularly for rotating bodies. In this example, an area camera was used as an image sensor, and a line camera was used as a line sensor. Column-shaped object to be measured 3
is arranged on the rotation stage 2. A light source 1 illuminates an object 3 to be measured. The rotation stage 2 has a pulse motor and rotates by a predetermined amount based on periodic pulses from the video signal processing circuit 6. The area camera 4 is arranged at a position opposite to the light source 1 with respect to the object 3 to be measured, and captures the outline of the object 3 to be measured. line camera 5
was placed at an angle within 90° with respect to the light source and the object to be measured 3. The field of view is parallel to the rotation axis 30 of the object to be measured 3 as shown in FIG. 2, and by detecting the light scattered by the convex parts of the object to be measured as shown in FIG. Characters are now detected at the same time.

A second video signal processing circuit 6 is connected to the line camera 5, and the output of the circuit 6 is input to a storage device 9. The storage device 9 has a storage area A
It has two areas, 1 and 2, and receives signals alternately. Further, the output of the area camera 4 is input to a first video signal processing circuit 7, and the output of the circuit 7 is similarly input to a storage device 9. A control signal from a CPU 8, which is a control device, is input to the video signal processing circuits 6 and 7.

In FIG. 1, the line camera 5 is placed closer to the light source than the central axis 30 of the object to be measured 3 because the central axis 30 of the object to be measured is aligned with the line due to the shake that occurs when the object to be measured 3 is rotated. This is to prevent the camera 5 from moving closer to the light source than the field of view, making it impossible to input images. Center axis 30 of line camera 5 and object to be measured 3
The amount of deviation from the measured object 3 is determined by the amount of deflection of the rotating shaft and the shape of the object 3 to be measured. Also, the angle between the line camera 5 and the light source 1 varies depending on the type of scratch or character. For example, when reading printed characters, the angle between the line camera 5 and the light source 1 should be set shallow to detect the reflected light from the object 3. Bye.

In detecting defects in the external shape due to chips, deformations, etc., it is suitable to process images from the area camera 4, but images from only one direction cannot detect defects on the back side and are insufficient. . Further, it is very difficult to read the characters on the object to be measured 3 using the area camera 4 because the image is distorted. In the present invention, the object to be measured 3 is placed on the rotating stage 2 and rotated in synchronization with the line camera 5 to detect surface defects and characters on the object to be measured 3. Also line camera 5
By stopping the input, the object to be measured 3 can be made to stand still at an arbitrary angle, and the area camera 4 can input an image of the object to be measured 3 at rest. After inputting the image by the area camera 4, the object to be measured 3 is rotated again in synchronization with the line camera 5,
Perform video input. After rotating the object to be measured 3 to an arbitrary angle in this manner, input by the line camera 5 is stopped, the object to be measured 3 is kept stationary, and input by the area camera 4 is performed. In this way, the three objects to be measured rotate once in succession, and the image input is completed. While the object to be measured 3 rotates once, the line camera 5
A developed view of the object to be measured 3 can be obtained, and scratches and characters on the surface can be detected. Furthermore, since the contour of the object to be measured 3 is inputted by the area camera 4 at any angle, it is possible to comprehensively inspect the appearance of objects having a three-dimensional shape.

The line camera 5 requires a long time to input a video signal, and if processing is started after inputting an image of a developed view, the inspection time becomes extremely long. The present invention takes this point into account and simultaneously inputs and processes images,
Inspection time is reduced to the time required for image input.

The operation of the apparatus of this embodiment will be explained based on FIG. When the object to be measured 3 is set on the rotation stage 2, the CPU 8 sets conditions for the area camera 4, such as setting the address on the storage device 9 that stores the video signal to be input, and then issues an input command. do. The first video signal processing circuit 7 inputs one field or one frame of image data to the storage device 9 after inputting the command. After the input, the first video signal processing circuit generates an interrupt to CPU8, and the
8 performs interrupt processing. Next, the CPU 8 sets conditions for the second video signal processing circuit 6, such as the number of input lines and the address of the image memory to be input, and then generates an input command. In response to this command, the line camera 5 starts inputting images and the object to be measured 3 rotates. After entering the specified number of lines,
The input from the line camera 5 is stopped and the object to be measured 3 is made stationary. This rotation control can be easily realized by applying a synchronization signal from the line camera 5 to a pulse motor attached to the rotation stage. When inputting a predetermined number of lines, the second
The video signal processing circuit 6 generates an interrupt to the CPU 8. The CPU 8 enters the interrupt processing routine by this interrupt, and the first video signal processing circuit 7
Set the conditions and generate the input command.
The above series of operations is continuously performed until the object to be measured 3 rotates once, and then the image input is completed.

On the other hand, the storage device 9 is divided into areas of two or more blocks, and for example, while image data is being input to the image memory A by the first video signal processing circuit 7 or the second video signal processing circuit 6. , the CPU 8 can process the data input to the image memory B in the previous cycle. After inputting the image data, the image memory is switched and the operation continues with B as the input memory and A as the data processing memory. If the time required to process the data is less than the time to input the image, the cycle time is reduced to the image input time.

Figure 4 is a flowchart 1 showing a series of operations.
It is. After initial settings are made and the input of the first image is completed, the image memory is switched and data processing is started. When the next product is set on the rotation stage during data processing, an interrupt occurs, the data processing is interrupted, and the area camera input program is executed. Next, the program returns to the data processing program and continues data processing. After the image input to the area camera 4 is completed, an interrupt is generated from the first video signal processing circuit 7 to the CPU 8 again. The CPU 8 receives this interrupt, interrupts data processing, and executes the line camera input program. here,
The number of input lines of the line camera 5 is set so that the line camera 5 is stopped at a predetermined angle, and a line camera input command is generated. Thereafter, the CPU 8 continues data processing. The object to be measured 3 thereby begins to rotate,
Stops after inputting a predetermined number of lines of video. After the input, the second video signal processing circuit 6 generates an interrupt to the CPU 8 and shifts to the area camera input program. The above-described operations are continued until the object to be measured 3 rotates once, and the input of the image of the developed view is completed.

In this manner, the apparatus of this embodiment makes it possible to recognize defects and product names of products having three-dimensional shapes, which was difficult to do with conventional image processing apparatuses, and further shortens the cycle time to the input time of image signals. That is, it has a storage device that has at least two areas, and for example, while an output signal is being input and stored in one area, data already stored in the other area can be processed, reducing cycle time. can.

In FIG. 1, the case of a product in the shape of a rotating body is particularly explained, but even if the invention is applied to a product of other shapes, the control unit may be exactly the same, and the control unit can be handled by simply arranging the camera and the light source. FIG. 5 is a layout diagram when measuring polygonal manufactured parts. Light sources 1a, 1b, and 1c are arranged as shown. The outline of the image is input using the area camera 4, the surface of the object to be measured 3 is stopped facing the line camera 5,
The light sources 1b and 1c illuminate the object to be measured 3,
The line camera 5 is moved in parallel and an image is input. After the input, the object to be measured 3 is rotated (for example, 60 degrees) and the contour image is input again using the area camera 4, and the line camera 5 is moved in parallel to input the surface image. This is repeated and the input ends when the object to be measured rotates once.

〔Effect of the invention〕

In summary, the present invention has an image sensor that obtains a two-dimensional image of a three-dimensional measured object and a line sensor that obtains a one-dimensional developed image of the three-dimensional measured object. This device uses a sensor to create a secondary developed image and at the same time captures a two-dimensional image using an image sensor to determine whether there are scratches or chips on the surface of a three-dimensional product. Therefore, according to the present invention:
Because a line sensor is used, the image is not distorted and it is possible to read scratches on the surface of the product, characters engraved on the surface, etc. with high precision. Furthermore, since an image sensor is used, it is possible to recognize three-dimensional defects in the product.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an external defect inspection apparatus according to a specific embodiment of the present invention. FIG. 2 is a perspective view showing the positional relationship between the line camera 5 and the object to be measured 3 used in the apparatus of the embodiment. FIG. 3 is a configuration diagram showing a method for detecting flaws on the surface of an object to be measured using the line camera of the device of the same embodiment. FIG. 4 is a flowchart showing the processing of the computer used in the apparatus of this embodiment. FIG. 5 is a layout diagram showing the positional relationship between the line camera, the image camera, and the object to be measured 3 in another example device.

Claims (1)

[Scope of Claims] 1. A fixed base that holds and rotates an object to be measured; an image sensor that photographs the object to be measured and obtains contour information of the object based on a two-dimensional planar image; a line sensor that scans the object to be measured in parallel and obtains surface information of the object using a one-dimensional video signal; and a first line sensor that drives the image sensor and outputs a video signal containing the contour information. a video signal processing circuit that drives the line sensor to output a video signal containing the surface information, and controls rotational movement of the fixed base to determine the parallel scanning range using the one-dimensional video signal; a second video signal processing circuit that performs the processing in synchronization with the output of the video signal processing circuit; and each output signal from the first video signal processing circuit and the second video signal processing circuit is divided into at least two storage areas and stored separately. - A readable storage device; and storage processing and data processing are performed alternately on two storage areas of the storage device, and the first and second video signal processing circuits are placed in one storage area where the storage processing is instructed. An appearance defect inspection device comprising a control device that stores signals from a circuit that is in output operation, and outputs stored data to the other storage area that has instructed data processing. 2. The control device is characterized in that it determines irregularities in the appearance based on the contour information obtained by the image sensor, and recognizes scratches or letters on the surface of the object based on the surface information obtained by the line sensor. An appearance defect inspection device according to claim 1.