JP2011031370A - Surface finish determining device - Google Patents
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本発明は、金属表面の研磨加工状態の良否を画像処理により判定する装置に関する。 The present invention relates to an apparatus for determining the quality of a polished state of a metal surface by image processing.
金属表面の研磨加工状態の良否を判断する方法として、各種粗さ計による粗さ測定を判断の指針とする方法がある。粗さ計は、接触式のものと光学式のものが一般に用いられており、研磨面のある一ラインをスキャンして粗さの分布を調べることができる。しかし、研磨面の広い領域を調べることはスキャンを何度も繰り返すことになり、時間がかかり実用的ではない。このため、生産現場に適用するとなると、抜き取りにより検査対象物を選び、検査対象物の研磨面の特定複数箇所の一ラインを計測することで研磨加工状態の良否を判断することになる。すなわち、検査するとしても、全数検査ではないとともに、全箇所を検査するものとはならない。
また、研磨対象の金属材料を回転させながら研磨する工程において、例えば研磨対象がベアリングの構成部品である、ベアリングの内輪または外輪（以下、ワークと呼ぶ）におけるボールやコロの軌道面である場合、軌道面の同心軸にてワークを回転させ、ワークの回転方向に直交する方向にて砥石を接触かつ揺動する工程にて研磨を行っている（特許文献１〜７および非特許文献１参照。）。図５〜図７に、特許文献から引用したワークの研磨例を示す。このワークにおいて、前述の接触式や光学式の粗さ計により研磨状態を検査するとなると、粗さ計をワークの回転方向に直交する方向に一ラインスキャンして粗さ分布を調べることになる。なお、本発明では、ベアリングとは、ボールや内輪、外輪などの部品ではなく、軸受け構造に組み上げられた製品を指すものとする。このため、ボールを指す時は、ベアリング球または単にボールと呼び、区別する。
As a method for judging the quality of the polished state of the metal surface, there is a method using roughness measurement with various roughness meters as a guideline for judgment. As the roughness meter, a contact type and an optical type are generally used, and a roughness distribution can be examined by scanning one line with a polished surface. However, investigating a large area of the polished surface requires repeated scans and is time consuming and impractical. For this reason, when applied to the production site, the inspection object is selected by sampling, and the quality of the polishing state is determined by measuring one line at a plurality of specific locations on the polishing surface of the inspection object. That is, even if it inspects, it is not 100% inspection and it does not inspect all the places.
Further, in the process of polishing while rotating the metal material to be polished, for example, when the object to be polished is a bearing or a raceway surface of a ball or roller on an inner ring or outer ring of a bearing (hereinafter referred to as a workpiece), Polishing is performed in a process in which the workpiece is rotated about the concentric shaft of the raceway surface and the grindstone is contacted and rocked in a direction orthogonal to the rotation direction of the workpiece (see Patent Documents 1 to 7 and Non-Patent Document 1). ). FIG. 5 to FIG. 7 show examples of polishing a workpiece cited from the patent document. In this workpiece, when the polishing state is inspected by the contact type or optical roughness meter described above, the roughness distribution is examined by scanning the roughness meter one line in a direction orthogonal to the rotation direction of the workpiece. In the present invention, the bearing refers to a product assembled in a bearing structure, not a component such as a ball, an inner ring, or an outer ring. For this reason, when referring to a ball, it is called a bearing ball or simply a ball to distinguish them.
また、非特許文献１によると、ベアリングの転がり方向と仕上げ面の研磨加工方向が同じ場合（以下、転がり方向研磨と呼ぶ）と、転がり方向と仕上げ面の研磨加工方向が直角の場合（以下、直角方向研磨と呼ぶ）とで、油膜形成能力を比べた場合、直角方法研磨の方が、油膜形成能力が高いことが記されている。このため、非特許文献１では、方向性の無い超仕上げ表面に、大きさ１０ミクロン程度の無数の凹部をランダムにつけた軌道面を有するベアリンを開発している。一方、これまでのベアリングの研磨加工方法で研磨を行うと、ワークの軌道面には、転がり方向研磨と直角方向研磨の中間である”あやめ”模様が形成されることが知られている（特許文献６、７参照）。本発明では、このあやめ模様のある軌道面に転がり方向研磨のみの軌道面よりも油膜形成能力を高める可能性があると考え、あやめ模様の形態がベアリングの性能に関わると考えている。
しかし、ワークの研磨面は、転がり方向または直角方向に曲面であるとともに、面の粗さの評価基準であるＲａ値が０．２μｍ以下であることが望ましい鏡面または鏡面に近い状態であるため、研磨痕の分布状態を観測することが困難であり、例えば、ベアリングの生産ラインにおいて、ワークの研磨状態を検査および評価できる装置が普及していない。このため、ワークの研磨面の仕上がりは、完成したベアリングが音や振動や耐久性などを評価されることにより、間接的に評価されることとなる。
Further, according to Non-Patent Document 1, when the rolling direction of the bearing and the polishing direction of the finished surface are the same (hereinafter referred to as rolling direction polishing), the rolling direction and the polishing direction of the finished surface are perpendicular (hereinafter, referred to as “rolling direction polishing”). When the oil film forming ability is compared, it is described that the right angle method polishing has a higher oil film forming ability. For this reason, Non-Patent Document 1 has developed a bearin having a raceway surface in which innumerable concave portions having a size of about 10 microns are randomly provided on a superfinished surface having no directivity. On the other hand, it is known that when polishing is performed by the conventional polishing method for bearings, an “irregular” pattern, which is intermediate between rolling direction polishing and right angle direction polishing, is formed on the raceway surface of the workpiece (patent) References 6 and 7). In the present invention, it is considered that there is a possibility that the oil film forming ability may be increased on the raceway surface having the iris pattern as compared with the raceway surface only in the rolling direction polishing, and the form of the iris pattern is related to the performance of the bearing.
However, since the polished surface of the workpiece is a curved surface in the rolling direction or a perpendicular direction, and the Ra value which is an evaluation standard of the roughness of the surface is preferably a mirror surface or a state close to a mirror surface, which is desirably 0.2 μm or less. It is difficult to observe the distribution of polishing marks. For example, in a bearing production line, an apparatus that can inspect and evaluate the polishing state of a workpiece has not been widely used. For this reason, the finish of the polished surface of the workpiece is indirectly evaluated by evaluating the finished bearing for sound, vibration, durability, and the like.
ワークにおけるあやめ模様は、微細なプローブを接触させる表面粗さ測定器やレーザー照射を用いたレーザー変位計や電子顕微鏡などにより取得したデータに基づき評価することができるが、いずれも、測定に掛かる工数や時間および計測器のコストの面から製造現場で用いるには現実的でない評価手段である。
すなわち、本発明の目的は、金属表面の仕上げを評価する装置であって、製造現場における使用に適する装置を提供することにある。
The iris pattern on the workpiece can be evaluated based on data acquired by a surface roughness measuring instrument that makes contact with a fine probe, a laser displacement meter using laser irradiation, an electron microscope, etc. It is an unrealistic evaluation means for use in the manufacturing field from the viewpoint of time and cost of measuring instruments.
That is, an object of the present invention is to provide an apparatus for evaluating the finish of a metal surface, which is suitable for use at a manufacturing site.
第１の観点では、本発明は、回転させながら研削または研磨を行った加工対象に対して、該加工対象の加工表面の仕上がりを評価する表面仕上げ判定装置において、上記加工対象を回転させながら加工表面の画像をラインスキャンカメラにより撮影し、撮影した画像を画像処理した結果を用いて表面仕上げの良否判定を行うことを特徴とする表面仕上げ判定装置を提供する。
上記第１の観点による表面仕上げ判定装置では、例えば、図１に示す構成とすることができる。図１では、加工表面２００ａを有する加工対象２００をモータ１０５の回転軸に接続し、ラインスキャンカメラ（ラインセンサカメラとも言う）１０１にてレンズ１０２を介して撮影する。このとき、ラインスキャンカメラ１０１の走査線方向は、加工対象２００の回転軸に平行な方向とすることが望ましい。また図中には、ラインスキャンカメラ１０２による撮影視野３００を模式的に示す。このとき、照明は、例えばレンズ１０２を介して撮影視野３００と同方向に加工対象２００に向かって落射する照明とすることができる。また、撮影視野３００と加工表面２００ａのなす角を反射角とする入射角に位置した照明や、加工表面２００ａの周囲にて拡散光を発する照明とすることもできる。モータ１０５を駆動するモータドライバ１０５ａおよびラインスキャンカメラ１０１は、パーソナルコンピュータ（ＰＣ）１０３に接続され、ＰＣ１０３に設定したプログラムにより、ラインスキャンカメラ１０１およびモータ１０５の制御を行うことができる。また、ＰＣ１０３にはディスプレイ１０４が接続され、ＰＣ１０３によりモータ１０５を回転させながらラインスキャンカメラ１０１にて撮影した画像を表示することや、その撮影画像を画像処理した結果の画像表示や、画像処理した結果を用いた良否判定結果を表示することができる。なお、画像処理結果を用いた良否判定は、例えば、予め記録しておいた良品ワークの画像との類似度をテンプレートマッチングにて計測して、任意の閾値にて良否を分別することができる。すなわち、ラインスキャンカメラを用いて撮影対象の加工対象を回転させることにより、加工対象が回転方向に対して曲面の加工面であっても、加工表面の画像を取得することができ、加工表面全域に対する画像処理による判定が可能となる。
In a first aspect, the present invention provides a surface finish determination device that evaluates the finish of a processed surface of a processing target with respect to a processing target that has been ground or polished while rotating, while processing the processing target while rotating the processing target. Provided is a surface finish determination device characterized in that a surface image is taken by a line scan camera, and the quality of the surface finish is judged using the result of image processing of the taken image.
The surface finish determination device according to the first aspect can be configured, for example, as shown in FIG. In FIG. 1, a processing target 200 having a processing surface 200 a is connected to a rotating shaft of a motor 105, and a line scan camera (also referred to as a line sensor camera) 101 is photographed through a lens 102. At this time, the scanning line direction of the line scanning camera 101 is preferably a direction parallel to the rotation axis of the processing target 200. In the drawing, an imaging field of view 300 by the line scan camera 102 is schematically shown. At this time, the illumination can be, for example, illumination that is incident on the processing target 200 in the same direction as the imaging visual field 300 via the lens 102. Further, it may be illumination that is positioned at an incident angle having a reflection angle that is an angle formed by the imaging field of view 300 and the processing surface 200a, or illumination that emits diffused light around the processing surface 200a. A motor driver 105 a that drives the motor 105 and the line scan camera 101 are connected to a personal computer (PC) 103, and the line scan camera 101 and the motor 105 can be controlled by a program set in the PC 103. In addition, a display 104 is connected to the PC 103, and an image photographed by the line scan camera 101 is displayed while the motor 105 is rotated by the PC 103, an image display result of image processing of the photographed image, and an image processing are performed. The quality determination result using the result can be displayed. The quality determination using the image processing result can be performed by, for example, measuring the similarity with a pre-recorded image of a non-defective work by template matching and classifying the quality by an arbitrary threshold value. That is, by rotating a processing target to be imaged using a line scan camera, an image of the processing surface can be acquired even if the processing target is a curved processing surface with respect to the rotation direction. Can be determined by image processing.
第２の観点では、本発明は、第１の観点による表面仕上げ判定装置において、前記画像処理は、研磨加工表面の粗さの形態や方向性を解析することを特徴とする表面仕上げ判定装置を提供する。
上記第２の観点による表面仕上げ判定装置では、加工表面の画像を２次元的に取得する利点を活かし、２次元画像上において表面粗さの形態や方向性を画像処理により解析し、これまでの一ライン上の粗さ分布の計測ではなしえなかった、回転方向と表面粗さの形態、特に、表面粗さの方向性を新しい粗さの評価基準に提供できる。特に、前記加工対象がベアリングのワークにおけるボールやコロの軌道面であった場合、単純に表面粗さを計測して解析するのではなく、ワークの回転方向に対してどのような表面粗さの形態がベアリングの耐久性や静動性などに有効であるかを、方向性を踏まえて評価することができる。
In a second aspect, the present invention provides the surface finish determination apparatus according to the first aspect, wherein the image processing analyzes the roughness form and directionality of the polished surface. provide.
The surface finish determination device according to the second aspect makes use of the advantage of acquiring a processed surface image two-dimensionally and analyzes the shape and direction of the surface roughness on the two-dimensional image by image processing. It is possible to provide a new roughness evaluation standard with the form of rotation direction and surface roughness, especially the directionality of surface roughness, which cannot be achieved by measuring the roughness distribution on one line. In particular, when the object to be processed is a raceway surface of a ball or a roller in a workpiece of a bearing, the surface roughness is not measured and analyzed simply, but the surface roughness of the workpiece in relation to the rotation direction of the workpiece. Whether the form is effective for the durability and staticity of the bearing can be evaluated based on the directionality.
第３の観点では、本発明は、第１または第２の観点による表面仕上げ判定装置において、前記画像処理は、撮影画像から加工表面の加工痕を強調する処理を含むことを特徴とする表面仕上げ判定装置を提供する。
上記第３の観点による表面仕上げ判定装置では、撮影した画像の画像処理段階において、加工痕の模様を視認しやすいように強調する処理を行うものであり、例えば、撮影画像の明るさの平均値を基準に正規化することや、移動平均や局所平均によるノイズ除去、エッジ検出により加工痕を強調することができる。
In a third aspect, the present invention provides the surface finish determination apparatus according to the first or second aspect, wherein the image processing includes a process of emphasizing a processing mark on a processing surface from a photographed image. A determination device is provided.
In the surface finish determination device according to the third aspect, in the image processing stage of the photographed image, processing for emphasizing the pattern of the processing mark so as to be easily recognized is performed. For example, the average value of the brightness of the photographed image The processing trace can be emphasized by normalization based on the above, noise removal by moving average or local average, and edge detection.
第４の観点では、本発明は、第１〜３のいずれかの観点による表面仕上げ判定装置において、前記画像処理は、任意の画像に２次元フーリエ変換、２次元離散的フーリエ変換または２次元高速フーリエ変換を行う処理を含み、上記２次元フーリエ変換、上記２次元離散的フーリエ変換または上記２次元高速フーリエ変換を行った結果の２次元スペクトル画像中の濃淡により生じる模様を表面仕上げの良否判定に用いること特徴とする表面仕上げ判定装置を提供する。
上記第４の観点による表面仕上げ判定装置では、撮影画像や加工痕の強調処理後の画像に対して、フーリエ変換（Ｆｏｕｒｉｅｒ Ｔｒａｎｓｆｏｒｍ）、離散的フーリエ変換（ＤＦＴ：Ｄｉｓｃｒｅｔｅ Ｆｏｕｒｉｅｒ Ｔｒａｎｓｆｏｒｍ）、または高速フーリエ変換（ＦＦＴ：Ｆａｓｔ Ｆｏｕｒｉｅｒ Ｔｒａｎｓｆｏｒｍ）を、画像の縦方向と横方向の２次元にて行い、その結果の２次元スペクトル画像を、縦軸に画像の一方の方向、横軸に画像の他方の方向を割り当てた周波数成分の２次元グラフに、各成分の濃淡にて示す。ここで、２次元スペクトル画像とは、フーリエスペクトルの実部の画像、虚部の画像、振幅スペクトルの画像、パワースペクトルの画像、位相スペクトルの画像など、フーリエ変換やＤＦＴやＦＦＴの結果得られたデータより作成された画像を指す（非特許文献２参照）。その周波数成分の２次元グラフに生じる模様を、例えば、良ワークにて生じた模様と例えばテンプレートマッチングにて比較して類似度を求め、表面仕上げの良否判定を行う。
ここで、画像におけるフーリエ変換（またはＤＦＴまたはＦＦＴ）の概念を説明するために、パワースペクトル画像の例をとり、元画像と変換結果による周波数成分の２次元グラフの模式図を図２に示す。画像においてフーリエ変換（またはＤＦＴまたはＦＦＴ）をしてスペクトル画像を求めることにより、画像における濃淡の変化が、大きな波長でゆっくり変化するものか、細かく小刻みに変化するものか、またはそれらの合成であるかを縦方向と横方向にて２次元的に把握することができる。なお、ＤＦＴは、フーリエ変換が連続信号を対象に行うものに対し、サンプル値などのデジタルデータに対するフーリエ変換を行う手法である。また、ＦＦＴはＤＦＴを高速に計算するアルゴリズムである。なお、２次元フーリエ変換（または２次元ＤＦＴまたは２次元ＦＦＴ）を行う領域は、画像の全領域にて行うのではなく、任意の大きさの領域に画像を区切って、この区切られた大きさ毎に２次元フーリエ変換（または２次元ＤＦＴまたは２次元ＦＦＴ）を行うことが好ましい。このとき、合否判定の比較対象に用いる２次元スペクトル画像については、例えば、良品のワーク画像の同じ大きさの任意領域にて２次元フーリエ変換（または２次元ＤＦＴまたは２次元ＦＦＴ）を行った結果を用いることができる。
In a fourth aspect, the present invention provides the surface finish determination apparatus according to any one of the first to third aspects, wherein the image processing is performed by converting a desired image into a two-dimensional Fourier transform, a two-dimensional discrete Fourier transform, or a two-dimensional high-speed. Including the process of performing the Fourier transform, the pattern generated by the shading in the two-dimensional spectral image as a result of the two-dimensional Fourier transform, the two-dimensional discrete Fourier transform or the two-dimensional fast Fourier transform is used to determine the quality of the surface finish. Provided is a surface finish determination device characterized by being used.
In the surface finish determination device according to the fourth aspect, a Fourier transform (Fourier Transform), a discrete Fourier transform (DFT), or a fast Fourier transform is performed on a captured image or an image after processing mark enhancement processing. (FFT: Fast Fourier Transform) is performed two-dimensionally in the vertical and horizontal directions of the image, and the resulting two-dimensional spectrum image is plotted with one direction of the image on the vertical axis and the other direction of the image on the horizontal axis. The two-dimensional graph of the allocated frequency components is shown by the shading of each component. Here, the two-dimensional spectrum image is obtained as a result of Fourier transform, DFT, or FFT, such as an image of a real part, an image of an imaginary part, an image of an amplitude spectrum, an image of a power spectrum, and an image of a phase spectrum. It refers to an image created from data (see Non-Patent Document 2). The pattern generated in the two-dimensional graph of the frequency component is compared with, for example, a pattern generated in a good workpiece by, for example, template matching, and a similarity is obtained to determine whether the surface finish is good or bad.
Here, in order to explain the concept of Fourier transform (or DFT or FFT) in an image, an example of a power spectrum image is taken, and a schematic diagram of a two-dimensional graph of frequency components based on an original image and a conversion result is shown in FIG. By performing Fourier transform (or DFT or FFT) on the image to obtain a spectral image, the change in shading in the image changes slowly at a large wavelength, changes in small increments, or a combination thereof Can be grasped two-dimensionally in the vertical and horizontal directions. Note that DFT is a technique for performing Fourier transform on digital data such as sample values, whereas Fourier transform is performed on a continuous signal. FFT is an algorithm for calculating DFT at high speed. Note that the area where the two-dimensional Fourier transform (or two-dimensional DFT or two-dimensional FFT) is performed is not performed in the entire area of the image, but is divided into areas of an arbitrary size, and this divided size. It is preferable to perform two-dimensional Fourier transform (or two-dimensional DFT or two-dimensional FFT) every time. At this time, with respect to the two-dimensional spectrum image used as the comparison target of the pass / fail determination, for example, a result of performing a two-dimensional Fourier transform (or two-dimensional DFT or two-dimensional FFT) in an arbitrary region of the same size of a non-defective work image Can be used.
第５の観点では、第４の観点による表面仕上げ判定装置において、前記２次元フーリエ変換、前記２次元離散的フーリエ変換または前記２次元高速フーリエ変換を行った結果の２次元スペクトル画像中の濃淡により生じる模様から近似直線を抽出し、該近似直線の傾き値を用いて表面仕上げの良否判定を行うことを特徴とする表面仕上げ判定装置を提供する。
上記第５の観点による表面仕上げ判定装置では、例えば、ＦＦＴを行った後の２次元グラフの模様を直線近似した結果の模式図を図３に示す。図３中、ＦＦＴ表示結果４００に、クロスする直線４００ａが生じる。直線４００ａは、元画像において斜め方向の模様成分が多かったことに起因すると考えられ、すなわち、あやめ模様の角度に関係していると考える。このため、直線４００ａの有無や傾きを評価することにより、あやめ模様の評価すなわち表面仕上げの良否判定を行うことができる。
According to a fifth aspect, in the surface finish determination device according to the fourth aspect, by the shading in the two-dimensional spectrum image as a result of performing the two-dimensional Fourier transform, the two-dimensional discrete Fourier transform, or the two-dimensional fast Fourier transform Provided is a surface finish determination device characterized in that an approximate straight line is extracted from a generated pattern, and the quality of the surface finish is determined using the slope value of the approximate line.
In the surface finish determination device according to the fifth aspect, for example, FIG. 3 shows a schematic diagram of a result obtained by linearly approximating a pattern of a two-dimensional graph after performing FFT. In FIG. 3, a crossing straight line 400 a is generated in the FFT display result 400. It is considered that the straight line 400a is caused by the fact that there are many pattern components in the oblique direction in the original image, that is, it is related to the angle of the iris pattern. Therefore, by evaluating the presence / absence and inclination of the straight line 400a, it is possible to evaluate the iris pattern, that is, determine whether the surface finish is good or bad.
第６の観点では、本発明は、第３の観点による表面仕上げ判定装置において、前記画像処理結果についての縦方向および／または横方向の分散値を、表面仕上げの良否判定に用いることを特徴とする表面仕上げ判定装置を提供する。
上記第６の観点による表面仕上げ判定装置では、元の画像を任意の領域に区切って、偏差の２乗を計算要素数で割った値である分散値を、縦方向や横方向ごとに求め、その領域において、縦方向の変化や横方向の変化の激しさを定量的に判断する。例えば、縦方向に模様が入っている場合は縦方向の分散値が低く、横方向に模様が入っている場合は横方向の分散値が低いため、良否判定評価の基準とすることができる。
In a sixth aspect, the present invention is characterized in that, in the surface finish determination device according to the third aspect, the vertical and / or horizontal dispersion values for the image processing result are used for determining the quality of the surface finish. Provided is a surface finish determination device.
In the surface finish determination device according to the sixth aspect, the original image is divided into arbitrary regions, and a dispersion value that is a value obtained by dividing the square of the deviation by the number of calculation elements is obtained for each of the vertical direction and the horizontal direction, In that region, the intensity of the change in the vertical direction or the change in the horizontal direction is quantitatively determined. For example, when a pattern is included in the vertical direction, the dispersion value in the vertical direction is low, and when the pattern is included in the horizontal direction, the dispersion value in the horizontal direction is low.
第７の観点では、本発明は、第６の観点による表面仕上げ判定装置において、前記分散処理を行った画像領域ごとに分散値に応じた色分けをした任意の画像を表示することを特徴とする表面仕上げ判定装置を提供する。
上記第７の観点による表面仕上げ判定装置では、分散処理結果を、例えばＲＧＢのグラデーション色に割り当て、撮影画像や強調処理後の画像に着色して表示することにより、分散結果を視覚的に容易に確認することができる。
In a seventh aspect, the present invention is the surface finish determination apparatus according to the sixth aspect, wherein any image that is color-coded according to a dispersion value is displayed for each image area on which the dispersion processing has been performed. A surface finish determination device is provided.
In the surface finish determination device according to the seventh aspect, the dispersion processing result is assigned to, for example, RGB gradation colors, and the captured image or the image after the enhancement processing is colored and displayed, so that the dispersion result can be visually easily viewed. Can be confirmed.
第８の観点では、本発明は、第１〜７のいずれかの観点による表面仕上げ判定装置において、撮影系にテレセントリックレンズを用い、照明系に同軸落射照明を用いることを特徴とする表面仕上げ判定装置を提供する。
上記第８の観点による表面仕上げ判定装置では、照明系に同軸落射光源を用いることにより、装置構成を簡潔にすることができ、ワークハンドリング機構の設計自由度を上げることができる。また、撮影レンズにテレセントリックレンズを用いることで、被写界深度内では、撮影対象の撮影面に多少の凹凸や傾斜がある場合にも、遠近の影響なく撮影することができる。
In an eighth aspect, the present invention provides the surface finish determination apparatus according to any one of the first to seventh aspects, wherein a telecentric lens is used for the photographing system and coaxial epi-illumination is used for the illumination system. Providing equipment.
In the surface finish determination apparatus according to the eighth aspect, by using a coaxial incident light source for the illumination system, the apparatus configuration can be simplified and the degree of freedom in designing the work handling mechanism can be increased. In addition, by using a telecentric lens as a photographing lens, it is possible to photograph within the depth of field without the influence of perspective, even if there are some unevenness and inclination on the photographing surface to be photographed.
本発明の表面仕上げ判定装置を用いれば、接触やレーザー反射にて得る表面粗さを判定するのではなく、カメラが撮影した画像にて表面仕上げを評価するため、製造現場における使用に適する。
特に現状のベアリングの製造工程では、工程の最終段階の振動検査（非特許文献３参照）などでなければ不良が発見できず、不良対策に遅れが生じる可能性があるが、本発明を利用することにより、研磨加工直後に表面粗さの判定が可能となるため、生産性の向上が期待できる。
さらに、本発明は、１ラインをスキャンする従来の粗さ評価方法では検出が非常に困難であった金属曲面の粗さ分布を二次元画像として取得できるため、最適な粗さ状態、粗さの方向性などを解析でき、より詳細な不良原因究明が可能となり、製品の品質改善にも好適である。
If the surface finish judging device of the present invention is used, the surface finish is evaluated by an image taken by a camera, rather than judging the surface roughness obtained by contact or laser reflection, so that it is suitable for use at the manufacturing site.
In particular, in the current bearing manufacturing process, a defect cannot be found unless the vibration inspection at the final stage of the process (see Non-Patent Document 3) is used, and there is a possibility that a delay in countermeasures against the defect may occur. This makes it possible to determine the surface roughness immediately after the polishing process, so that improvement in productivity can be expected.
Furthermore, the present invention can acquire a roughness distribution of a metal curved surface as a two-dimensional image, which is very difficult to detect by a conventional roughness evaluation method that scans one line, so that an optimum roughness state and roughness can be obtained. It is possible to analyze the directionality, etc., and to investigate the cause of failure in more detail, which is also suitable for improving product quality.
発明を実施するための形態として、本発明の第８の観点による表面仕上げ判定装置を実施した例を実施例１に示す。 As a mode for carrying out the invention, an example in which a surface finish determination device according to an eighth aspect of the present invention is implemented is shown in Example 1.
図４に、実施例１として本発明の第８の観点による表面仕上げ判定装置を実施した表面仕上げ判定装置の外観写真を示す。図中の符号は図１と共通である。 FIG. 4 shows a photograph of the appearance of a surface finish determination apparatus that implements the surface finish determination apparatus according to the eighth aspect of the present invention as Example 1. FIG. The reference numerals in the figure are the same as those in FIG.
１０１ ラインスキャンカメラ
１０２ レンズ
１０３ ＰＣ
１０４ ディスプレイ
１０５ モータ
１０５ａ モータドライバ
２００ 加工対象
２００ａ 加工表面
３００ 撮影視野
４００ ＦＦＴ表示結果
４００ａ 近似直線
101 Line scan camera 102 Lens 103 PC
104 Display 105 Motor 105a Motor driver 200 Processing object 200a Processing surface 300 Field of view 400 FFT display result 400a Approximate line
Claims (8)
上記加工対象を回転させながら加工表面の画像をラインスキャンカメラにより撮影し、
撮影した画像を画像処理した結果を用いて表面仕上げの良否判定を行うことを特徴とする表面仕上げ判定装置。 In a surface finish determination device that evaluates the finish of a processed surface of a processing target for a processing target that has been ground or polished while rotating,
Take an image of the processing surface with a line scan camera while rotating the processing target,
A surface finish determination apparatus, wherein the quality of surface finish is determined using a result of image processing of a photographed image.
前記画像処理は、研磨加工表面の粗さの形態や方向性を解析することを特徴とする表面仕上げ判定装置。 In the surface finish determination apparatus according to claim 1,
The image processing is a surface finish determination device characterized by analyzing a roughness form and directionality of a polished surface.
前記画像処理は、撮影画像から加工表面の加工痕を強調する処理を含むことを特徴とする表面仕上げ判定装置。 In the surface finish determination apparatus of Claim 1 or Claim 2,
The surface finish determination apparatus according to claim 1, wherein the image processing includes a process of enhancing a processing mark on a processing surface from a photographed image.
前記画像処理は、任意の画像に２次元フーリエ変換、２次元離散的フーリエ変換または２次元高速フーリエ変換を行う処理を含み、
上記２次元フーリエ変換、上記２次元離散的フーリエ変換または上記２次元高速フーリエ変換を行った結果の２次元スペクトル画像中の濃淡により生じる模様を表面仕上げの良否判定に用いること特徴とする表面仕上げ判定装置。 In the surface finish determination apparatus in any one of Claims 1-3,
The image processing includes a process of performing a two-dimensional Fourier transform, a two-dimensional discrete Fourier transform or a two-dimensional fast Fourier transform on an arbitrary image;
Surface finish determination characterized by using a pattern generated by shading in a two-dimensional spectrum image as a result of performing the two-dimensional Fourier transform, the two-dimensional discrete Fourier transform, or the two-dimensional fast Fourier transform for determining the quality of the surface finish. apparatus.
前記２次元フーリエ変換、前記２次元離散的フーリエ変換または前記２次元高速フーリエ変換を行った結果の２次元スペクトル画像中の濃淡により生じる模様から近似直線を抽出し、該近似直線の傾き値を用いて表面仕上げの良否判定を行うことを特徴とする表面仕上げ判定装置。 In the surface finish determination apparatus according to claim 4,
An approximate straight line is extracted from a pattern generated by shading in a two-dimensional spectrum image as a result of performing the two-dimensional Fourier transform, the two-dimensional discrete Fourier transform, or the two-dimensional fast Fourier transform, and an inclination value of the approximate line is used. The surface finish determination device is characterized by determining whether the surface finish is good or bad.
前記画像処理結果についての縦方向および／または横方向の分散値を、表面仕上げの良否判定に用いることを特徴とする表面仕上げ判定装置。 In the surface finish determination apparatus according to claim 3,
A surface finish determination apparatus, wherein the vertical and / or horizontal dispersion values of the image processing result are used for determining the quality of the surface finish.
前記分散処理を行った画像領域ごとに分散値に応じた色分けをした任意の画像を表示することを特徴とする表面仕上げ判定装置。 In the surface finish determination apparatus according to claim 6,
An apparatus for determining a surface finish that displays an arbitrary image that is color-coded according to a dispersion value for each image area that has undergone the dispersion process.
撮影系にテレセントリックレンズを用い、照明系に同軸落射照明を用いることを特徴とする表面仕上げ判定装置。 In the surface finish determination apparatus in any one of Claims 1-7,
A surface finish determination device using a telecentric lens for an imaging system and coaxial epi-illumination for an illumination system.
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