JP2000046651A - Wire appearance inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source adjustment means capable of obtaining a stable image signal via a means for uniformly lighting the surface of a three- dimensional inspection object and under the maintenance of an initially set gate level. SOLUTION: This device has a light source 3 controlled by lightness preliminarily stored in an arithmetic operation device 4 and a plurality of wires 102 as inspection objects on an inspection stage 1. In addition, the device has light guide 5 for guiding the light source 3 to a position above the inspection objects as downward lighting 3a, and a hollow cylindrical frosted glass 6. In this case, the color image signals of the wires 102 photographed with a camera 2 positioned above the hollow light guide 5 are compared with signals obtainable from conversion into hue, chroma and lightness in the arithmetic operation device 4 for the every preliminarily stored color of the wires 102, and picture elements within a preset threshold value are extracted for making judgement about the sequence of covering color and foreign matter in a cover removal part, and measuring the array distance of the cover removal part from a reference point, thereby making judgement about acceptance and non-acceptance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention carries out an appearance inspection of a wire harness in which color-coated wires used for internal wiring of a personal computer or the like as power lines or signal lines are bundled using an image processing technique.

[0002]

2. Description of the Related Art Various means have been proposed for inspecting the appearance of a product using an image processing technique depending on the inspection object. In particular, Japanese Patent Application Laid-Open No. 10-2725 proposes means for converting a color image signal into lightness, hue, and saturation to determine not only the shape but also the color of the inspection object.

The object to be inspected in the prior art is a film carrier on which a semiconductor element is mounted. The inspection target is
Examples include shape defects of semiconductor elements and attachment of foreign substances, circuit defects of lead wires, and confirmation of areas of identification characters on the surface of semiconductor elements.

The apparatus includes a color image processing apparatus that receives a color image signal captured by a camera, extracts a predetermined color distribution of an object to be inspected, and binarizes the color distribution, and a color image processing apparatus. A chip size verification section for detecting a semiconductor chip from a binarized image and verifying its size, an internal foreign substance verification section for detecting a foreign substance or a scratch inside the semiconductor chip and detecting the size, and a semiconductor. A boundary verification section for detecting the outline of the chip and verifying its linearity; a character verification section for detecting the area of the character stamped on the semiconductor chip and inspecting the character quality; It is composed of a recognition processing section comprising a judgment section for making a judgment.

In this device, the quality is determined based on the linearity of the boundary of the semiconductor chip, so that data for recognizing the position of the semiconductor chip becomes unnecessary. Further, chipping of the semiconductor chip and adhesion of foreign matter are determined based on the area of the white portion which has been inverted between black and white, a read detection area is automatically formed around the semiconductor chip, and data for generating the read detection area is unnecessary. This eliminates the need for positioning correction calculation. Further, it is described that by detecting the character area in advance, there is an effect that it is possible to avoid erroneously recognizing a character portion as a flaw or a foreign substance.

[0006]

However, the wire is a three-dimensional object to be inspected. In planar illumination, even if the surface of the curved surface has the same color, shading occurs, so that a real image cannot be recognized even if an image signal is processed at a gate level having a specific brightness as a threshold. Even if a means for recognizing a real image is established, it is necessary to adjust the gate level if the brightness of the environment in which the inspection device is installed or the intensity of the light source of the inspection device itself fluctuates. The present invention proposes a means for uniformly illuminating the surface of a three-dimensional object to be inspected, and a means for adjusting a light source capable of obtaining a stable image signal without changing an initially set gate level.

[0007]

A light source controlled to have brightness stored in an arithmetic unit in advance and a plurality of wires as an object to be inspected are laid on an inspection stage, and the light source is illuminated by incident light above the object to be inspected. A light guide and a hollow cylindrical frosted glass for guiding, and a color image signal of the wire imaged by a camera viewed from above the hollow light guide, for each wire color stored in advance, an arithmetic unit The pixels are converted to hue, saturation, and lightness, and the pixels within a predetermined threshold value are extracted to determine the order of the coating color of the wire, foreign matter in the coating removal portion, and the coating removal portion from the reference point. Is measured by measuring the size of the array position.

[0008] Epi-illumination guided by a hollow light guide illuminates from above a plurality of wires to be inspected while diffusing through a hollow cylindrical frosted glass.
The shading on the curved wire surface is eliminated, and a uniform color image signal is obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric wire which is an object to be inspected according to the present invention is:
For example, as shown in the plan view of FIG. 7, provisional wiring is performed on a tray 101 made of a thin disposable polyethylene resin having a thickness of several μm. A wire harness 103, which is a bundle of ultra-fine wires 102 coated with urethane resin colored for identification, is temporarily fixed to a tunnel-shaped clip 101a, and has a predetermined pin hole in the inspection windows A and B. 104
And the coating removal portions 102a are arranged at predetermined positions.

After the appearance inspection of the wire harness 103 is completed, the reference pin holes 104 are placed on the guides in a sequence laid out in advance in a personal computer or the like, and the cover-removed portions 102a are electrically connected by soldering or the like. Assembled as Thereafter, the tray 101 is appropriately cut off with scissors or the like.

Conventionally, wires 102 in inspection windows A and B
Was visually inspected for the order of the coating color, the foreign matter adhering to the coating removal portion 102a, and the dimension of the arrangement position of the coating removal portion from the reference point. There was a problem with the reliability of the results. Further, it is difficult to secure skilled inspectors.

Therefore, the present invention automatically performs inspection using a wire appearance inspection apparatus shown in FIG. In FIG. 1, the inspection window A or B in the tray 101 as the inspection object in FIG. 7 is laid on the inspection stage 1 and a white score (see FIG. The light from the light source 3 is guided to the hollow cylindrical frosted glass 6 via the hollow light guide 5 and diffused, while the wire 102 is diffused as epi-illumination. Illuminate the area above. Even if the brightness of the environment in which the inspection device is installed or the deterioration or voltage of the light source of the inspection device itself and the intensity of the epi-illumination fluctuate, the brightness of the white score stored in the arithmetic unit is automatically adjusted. Therefore, the gate level for binarizing the image need not be changed.

On the other hand, the camera 2 captures a color image from above the wire 102 through the light guide 5 and the hollow portion of the frosted glass 6. This image is RGB (R;
The signals are input to the image capturing device 7 as signals of three primary colors of red, G; green, B; blue), converted into HSI (H; hue, S; saturation, I; lightness) signals, and stored in advance. Each wire 1
After comparing with the signal of No. 02, pixels within a predetermined threshold value are extracted and displayed as a two-dimensional image on the monitor 8 for each measurement item, and pass / fail is quantitatively determined.

FIG. 2 shows that a light source passing through the light guide 5 illuminates the wire 102 as epi-illumination diffused by the frosted glass 6, thereby eliminating the shadow on the surface of the wire 102 which is a three-dimensional object to be inspected. It is explanatory drawing which showed typically. That is, the light source 3a passing through the light guide 5 is diffused by the frosted glass 6 and
1. Illuminate the surface of the overlying wire 102 and eliminate any shading on at least the upper half surface. Accordingly, the upper half surface is input to the image capturing device 7 as a color image signal having the same brightness.

[0015] By the epi-illumination by the frosted glass 6,
Since the upper half of the wire 102 does not have exactly the same brightness, if the RGB signal is converted to the HSI signal, H, S
By extracting a color only by itself, a color can be correctly extracted even if there is a difference in brightness. The reason is that if the brightness is different even for the same color, the value of the RGB signal changes. However, in the HSI signal, the brightness I is separated as an independent parameter. This is because it does not change.

Then, the data is compared with HSI data registered in advance in the arithmetic unit 4, and pixels within a predetermined threshold for each wire 102 are extracted and displayed on the monitor 8 as a secondary image. First, the order of the coating colors of the wire 102 is confirmed by assuming that the coating colors shown in FIG. 3 are green for green, blue for blue, red for ha,
If d is black, pass / fail is displayed based on whether or not the order matches the HSI pattern stored in the arithmetic unit 4 in advance. This step is an important inspection to prevent erroneous wiring, since wires for signals and power are mixed in the plurality of wires 102.

Next, the confirmation of the foreign matter at the portion where the coating of the wire 102 is removed is performed by recognizing the pattern of the foreign material or the incompletely removed portion of the coating shown in FIG. The pass / fail status is displayed on the monitor 8 for comparison. This step is necessary in order to eliminate in advance the trouble caused by the presence of foreign matter in the coating removal portion when performing the soldering robot or the flow soldering.

Then, the reference pin hole 10 of the wire 102 is
The dimension confirmation of the arrangement position of the coating removal unit 102a from No. 4
The pass / fail status is displayed on the monitor 8 by comparing with the allowable value of the dimensional accuracy stored in the arithmetic unit 4 in advance. FIG. 5 shows a dimension measurement position from the reference pin hole 104. For the wire 102, the length of the coating removal is recognized from Ia and Ib, and the arrangement position of the coating removal portion is recognized from Ic. This step is necessary in order to accurately and surely connect the wire-removed portion 102a to a predetermined terminal portion by a soldering robot.

In order to automatically inspect using the wire appearance inspection apparatus shown in FIG. 1, the steps in the flowchart of FIG. 6 may be followed. First, (1) the inspection object is manually set on the inspection stage. (2) The brightness of the white score captured by the camera is stored in the arithmetic unit as a reference value.
(3) The light source automatically adjusted by the light guide is guided to the hollow cylindrical frosted glass. (4) The inspection object is illuminated by epi-illumination diffused by frosted glass. (5) A color image is captured by the camera and input to the image capturing device.

(6) The RGB signal is converted to HS by the image capturing device.
Convert to I signal. (7) The color image is binarized by the arithmetic unit. (8) Check the order of the coating colors of the wires.
(9) Check the presence or absence of foreign matter adhesion or incomplete removal of the wire coating removal portion. (10) The arrangement position of the wire coating removal portion is confirmed from the reference pin hole. (11) The pass / fail is determined by comparing the pattern with the pattern stored in the arithmetic unit.
(12) Pass / Fail is displayed on the monitor screen. It is preferable to call attention to a rejected product by displaying it in red. Thus, a series of inspections is completed, and the inspection object may be sequentially replaced and the monitor screen may be reset.

[0021]

The present invention illuminates the epi-illumination guided from the light source to the light guide from above the object to be inspected while diffusing through the hollow cylindrical frosted glass. Even if the inspection object has a curved surface,
Shading on the surface is eliminated, and a uniform color image signal is obtained.

Further, even if the brightness of the environment in which the inspection device is installed, the deterioration of the light source of the inspection device itself, or the voltage changes, and the intensity of the epi-illumination fluctuates, the brightness of the light source is located at one corner of the field of view of the camera. Since the reference white score is captured and stored in the arithmetic unit and automatically adjusted to the brightness range of the white score, the brightness level when binarizing the image can be changed without changing the gate level. Good.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a wire appearance inspection apparatus of the present invention.

FIG. 2 is an explanatory view schematically showing that a light source for an inspection object of the present invention is diffused by ground glass.

FIG. 3 shows a state in which the coating color sequence of the wire of the present invention is captured by a camera.

FIG. 4 shows a state in which a foreign matter in a portion of the wire where the coating is removed is captured by a camera.

FIG. 5 shows a state in which the arrangement position of the wire removing portion of the present invention is captured by a camera.

FIG. 6 is a view showing a flowchart illustrating an inspection process of the present invention.

FIG. 7 is a plan view of the inspection object of the present invention as viewed from above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1; Inspection stage 2; Camera 3; Light source 4; Calculation device 5; Light guide 6; Ground glass 7; Image capture device 8;

Claims (1)

[Claims] 1. A light source controlled to a brightness stored in a computing device in advance and a plurality of wires as an object to be inspected are laid on an inspection stage, and the light source is guided above the object to be inspected as epi-illumination. A color image signal of the wire captured by a camera that is viewed from above the hollow light guide, the color image signal of the wire being stored in advance for each color of the wire. The pixels are converted to hue, saturation, and lightness, and the pixels within a predetermined threshold value are extracted to determine the order of the coating color of the wire, foreign matter in the coating removal portion, and the coating removal portion from the reference point. A wire appearance inspection device that measures the dimensions of the arrangement positions of the wires to determine pass / fail.