DE102011113670A1 - Lighting device, inspection device and inspection method for the optical inspection of an object - Google Patents

Abstract

The invention relates to an illuminating device (10) for the optical examination of an object (18), with the following features: ● - the illuminating device comprises a plurality of illuminating elements (21, 22, 23, 24, 25, 26, 27, 28); ● - by means of an illuminating element, light is directed onto at least part of the object, and so light that is scattered or transmitted or reflected by the object can be sensed by a detector (14); ● - the function of an illuminating element is characterized by a colour and a number of radiation modes of the radiation emitted by the illuminating element; ● - the illuminating elements respectively differ from one another by the colour and at least one of the radiation modes; ● - an electronic control unit controls the illuminating device and the detector such that an image of the object or of a partial region of the object can be produced by joining together individual images under different illumination.

Description

The invention relates to a lighting device, an inspection device and an inspection method for the optical inspection of an object, as well as the use of an inspection device for sorting flat or tubular glass, steel components, fibers, silicon wafers or films that have defects ,

In the course of further automation in the production as well as high and increasing quality requirements of the produced products, a timely inspection and inspection of the objects is becoming increasingly important. On the one hand, it is often necessary to be able to reliably identify defects or defects on surfaces or in the volume of the objects. On the other hand, it is also necessary to distinguish quality-relevant defects and defects from typical, process-related and tolerable defects. For example, voids, pores or scratches can count among the quality-relevant defects, while any dirt particles lying over them often do not represent a quality-critical criterion since they occur as a result of the process and can be removed again in later cleaning processes.

Such different errors often can not be detected with one and the same inspection or inspection method. For example, it is difficult to distinguish dirt particles from blowholes by means of reflected-light illumination.

Automated inspection tasks can therefore often be carried out more reliably if several images of a test object are available which are recorded with different illumination. In this way, by means of a combination of different illuminations, for example a light or dark field illumination or a diffuse or directed illumination, significantly more and more specific features for the image evaluation can be made available. As a result, the detection and test security can be significantly increased.

Devices and methods of the type discussed here are, for example, from DE 10 2008 022 292 A1 known, which shows a shape detection of an object. In this case, a combination is used comprising light sources with a broad and narrow emission characteristic, as well as light sources which are arranged in the region of the object. The light sources are aligned such that their illumination distributions do not overlap or only slightly overlap on the object.

From the WO 2009/112204 A2 For example, diffuse illumination of a line-shaped area for imaging by a line camera is known. Here, a light source is positioned near the area to be illuminated, using a diffuser with retroreflective properties.

From the US 2007/0132759 A1 For example, there is known a method for eliminating mirroring components and separating reflection components in images. For this purpose, the images are transformed pixel by pixel into a new color space, in which two color channels are free from reflection components and a third channel comprises both reflection components and reflection components.

From the US 2006/0091825 is an optical sorting of bulk material by means of a camera unit with two or three color channels with different spectral sensitivity ranges known. The background of the bulk material has a multiplicity of individual luminous means, of which each individual luminous means emits light with a spectral distribution which is adapted in each case to a spectral sensitivity range of the camera.

From the US 2006/0091825 is an illumination system for illuminating an object having a cylindrical light-scattering body with an elongated opening, a scanning camera having a direct view of the object through an opening of the light-diffusing body, and a light source arranged between the light-diffusing body and the object. The illuminant is reconfigurable in response to an industrial process involving processing of the object.

From the US 6,392,754 B1 For example, the measurement of a profile of the surface of a transparent article is known, which reflects light at its top and bottom. For this purpose, a defined light pattern is projected onto the object, wherein the mirror images reflected from the top and bottom are evaluated by a camera.

From the AT 507 018 A1 For example, an apparatus for testing an object is known, which comprises a plurality of light sources which can be switched on and off at predetermined times for illuminating the object and a camera for detecting the object. The light sources are formed as light segments or sub-segments with a defined distance from each other.

The EP 1 477 793 A2 describes a device and a method for detecting defects in transparent material, in which a defined partial volume of the material is irradiated with a first radiation source and in which with a second Radiation source light is coupled into the material.

A disadvantage proves to the known method that they often require a high investment outlay. For another, they are often insufficient. flexible to be used for different products or different tests.

The invention has for its object to provide a lighting for the examination of an object which has defects on its surface or in the object volume, the illumination is flexible for a variety of defects usable. Furthermore, it should also be easy and flexible for different tests or for tests on different products can be used.

The invention is further based on the object of providing a method which, on the one hand, offers the advantages of object images in the case of different illuminations and, on the other hand, requires only little technical effort.

In particular, images should be able to be recorded with different illumination of objects, wherein a relative movement between the object to be measured and the device is present during the measurement process.

The objects should comprise individual objects or objects as well as continuously manufactured objects or web or band goods such as glass bands, foils or metal strips. An examination should also be possible under production conditions.

This object is achieved in a surprisingly simple manner by the subject matter of the independent claims. Advantageous embodiments and further developments are specified in the dependent claims. The features of the developments can, as far as technically feasible, be combined.

One aspect of the invention relates to a flexible illumination device for the non-contact optical examination of an object. The optical inspection may preferably be carried out to detect a defect, damage or defect in the surface or in the volume of the object.

The illumination device may include at least one or a plurality of illumination elements, a computer-aided control electronics and at least one detector.

The detector may be designed as an optical image recorder and one or more, preferably side by side, d. H. transverse to a direction of movement of the object, arranged image sensors and one or more imaging elements. In this case, the image sensor can be designed as a matrix or line scan camera based on CCD or CMOS chip technology. However, it may also be formed on the basis of hybrid chip technology comprising a photosensitive material and a silicon readout technology. In general, the detector may preferably be designed so that it can receive electromagnetic radiation in the relevant wavelength spectrum. This may include both electromagnetic radiation in the visible and in the non-visible region, for example in the infrared region. The detector can therefore also be designed, for example, as an IR camera.

The imaging element may comprise optical elements, such as transmission or reflection optics. The image sensor can be designed as a matrix sensor, it can cost-effectively be designed as a line scan camera, wherein it is particularly cost-effective as a monochrome line scan camera.

For the purposes of the invention, the illumination device can illuminate the object differently, in order to have several features of the object available for an optical examination. For capturing images of the object or portions of the object, the detector may be used.

The different illuminations can be clocked particularly advantageously sequentially and synchronized with the image recording of the detector, wherein different individual images of the object can be recorded at each different illumination. As a result, it is also possible to obtain features of the object for testing which are recognizable in each case only with a specific illumination.

For the purposes of the invention, the control electronics can trigger the recording of a sequence of individual images by means of an internal or external pulse. For example, an external pulse may include a signal from a transport device that contains information about the speed of the object relative to the lighting device. An internal impulse can be generated, for example, by programs or control parameters stored in the control electronics.

A single image comprises one or more lines which the detector receives from the object or from a subarea of the object in response to a signal from the control electronics. For each Single frame, the control electronics control the recording time and the exposure time of the detector. In addition, the control electronics for each individual frame can control the operating state of the lighting elements of the lighting device flexibly with regard to an active or a passive operating state of said lighting element.

The individual images of a sequence can subsequently be combined to form an image of the object or a subarea of the object. An image composed of the individual images of a sequence is also referred to below as a so-called superimage. From a plurality of superimages of the object or of a partial area of the object, an overall image of the object can then be generated. For a subsequent test, you can use single images of a sequence, a superimage or an overall image.

For each individual image, therefore, the illumination generated by the lighting device can be adjusted flexibly and individually by controlling the operating state of the individual lighting elements. At the same time, the start and duration of the exposure of the detector can be controlled. The control of detector and lighting device can thus be synchronized by the control electronics.

The detector can be designed as a color line camera and particularly cost-effective as a monochrome line scan camera.

An illumination element can be a spot radiator, spherical radiator, line radiator, cylindrical radiator or else a free-form surface radiator or a radiator with an irregular radiation characteristic. The lighting element can be designed as an incandescent lamp, as a gas discharge lamp, as a light-emitting diode or as an induction lamp. It may further include laser radiation. In addition, it may also comprise radiation emitted from conductive plastic or glass fibers. The radiation may be coherent or incoherent. The radiation emitted by a lighting element can also be designed such that it generates certain patterns, for example speckle patterns or grid-like patterns, on the object in order to be able to check, for example, very specific features of the object. Thus, for example, the roughness of an object surface can be checked by means of speckle patterns. The lighting elements can thus be preferably designed so that they allow the examination of the relevant features of the object.

The term "a lighting element" below refers to any lighting element or, in other words, any lighting element of the lighting device that can emit electromagnetic radiation.

For simplicity's sake, lighting or photometric quantities are frequently referred to below, and in the context of the invention the electromagnetic radiation emitted by a lighting element or the corresponding radiation-related variables should also be correspondingly included.

According to the invention, the electromagnetic radiation emitted by a lighting element is limited not only to the visible range but also to the adjacent wavelength ranges such as UV and IR. For example, it is particularly advantageous to use electromagnetic radiation in the infrared range of one or more illumination elements in order to test components made of silicon in the volume. For this purpose, the detector can be designed as an IR camera.

The detector can also be designed in such a way that it can record not only the emitted electromagnetic radiation of a lighting element but also radiation in other wavelength ranges. This can be used, for example, if the Nachklingen after a pulse or lightning-like excitation with a radiation of a particular wavelength to be checked by reading a radiation of a different wavelength.

An illumination element can emit light omnidirectionally, with a directional characteristic that is constant in all directions, or directionally, with a directional characteristic oriented in the direction of the object or a reflector or a scattering element.

The lighting device may comprise a plurality of element groups, wherein in each case one element group comprises at least one lighting element. The lighting elements can thus also be arranged in element groups, preferably next to each other.

• – einen oder mehrere punktförmige, nebeneinander entlang einer geraden Linie angeordnete Beleuchtungselemente, oder
• – einen oder mehrere lineare, hintereinander entlang einer geraden oder gekrümmten Linie angeordnete Beleuchtungselemente, oder
• – einen oder mehrere halbkreisförmige, koaxial nebeneinander angeordnete Beleuchtungselemente

umfassen.Thus, an element group may preferably

• One or more point-like lighting elements arranged side by side along a straight line, or
• One or more linear lighting elements arranged one behind the other along a straight or curved line, or
• - One or more semi-circular, coaxially juxtaposed lighting elements

include.

By means of a lighting element, light can be directed to at least a part of a surface of the object. That is, a lighting element may emit light on a part of the surface of the object, for example in the form of a light spot or spot, or on the entire surface of the object.

The object may be wholly or partially in the beam path of one or more lighting elements. In this case, the object can perform a movement relative to the detector and / or the illumination device. However, it is also possible to measure a stationary object, wherein the detector and / or the lighting device can be moved.

The radiation scattered and / or transmitted by the object and / or reflected and / or produced by luminescence can be detected by the detector. By luminescence is meant that after radiation absorption, the object itself emits radiation that can be measured by the detector.

The function of a lighting element can be characterized by one color and several radiation modes of the radiation emitted by the lighting element.

The function of each element group can be characterized by a color pattern and multiple radiation modes.

The color pattern of an element group may relate to a sequence of colors that the light of the lighting elements of the element group has. For example, a color pattern may include the sequence "red-blue-green-yellow-pink".

The radiation modes of an element group may, in accordance with the radiation modes of a lighting element, relate to an orientation, direction, emission characteristic, and / or light mode of the light emitted by the element group.

The lighting elements may each differ from each other or, in other words, one lighting element may differ from another lighting element, by the color and at least one radiation mode. A combined radiation generated by the illumination device can be scattered and / or transmitted and / or reflected by the object. It can also excite the object for luminescence.

The element groups may, in analogy to the lighting elements, each differ from each other by the color pattern and / or at least one radiation mode.

By using element groups, emitters with similar properties with regard to color and radiation modes can advantageously be positioned flexibly and with little effort in space in accordance with the desired and desired luminous effect and controlled efficiently.

For example, the object can be illuminated with red light in a bright field illumination in reflected light and with green light in a dark field illumination in transmitted light. In the present example, the respective lighting elements would differ from one another by their colors and by two modes of radiation.

The color of a lighting element can relate to a wavelength and a spectral width of the radiation emitted by the lighting element and thus to the radiation properties of the lighting element.

• – eine Orientierung,
• – eine Richtung,
• – eine Abstrahlcharakteristik,
• – eine Leuchtart

des von dem Beleuchtungselement ausgestrahlten Lichts betreffen.The radiation modes of a lighting element can

• - an orientation,
• - a direction,
• A radiation characteristic,
• - a light

of the light emitted by the lighting element.

The orientation can determine whether a luminous segment is perpendicular or parallel to the relative movement between the object and the detector. Thus, the radiation mode "orientation" may take the values "vertical," "parallel," or "tilted." If the lighting element is designed as a curved lighting segment, the orientation refers to how the plane comprising the curved lighting segment is arranged opposite the directional vector of the relative movement between the device and the object.

The direction can determine whether the object is illuminated by a lighting element in transmitted or reflected light.

The emission characteristic can determine whether a lighting element emits diffused or directed light.

The light mode can determine whether the illumination of a lighting element with respect to the object is a bright field illumination or dark field illumination.

The interaction of the radiation properties with the arrangement of the illumination element relative to the detector and / or object can thus be characterized by the illumination modes "emission characteristic", "orientation" or "light mode". The interaction of the radiation properties with the nature of the interaction of the light with the object can be characterized by the illumination mode "direction".

• – eine Polarisation,
• – einen Einfallswinkel,
• – eine Amplitude,
• – eine mittlere Amplitude, oder
• – eine mittlere Wellenlänge

umfassen.The radiation modes can also

• - a polarization,
• An angle of incidence,
• An amplitude,
• - a mean amplitude, or
• - a medium wavelength

include.

The polarization may indicate what polarization the light emitted by a lighting element has with respect to an incident plane of the emitted light.

The angle of incidence may indicate the angle that a light beam originating from the illumination element encloses with a surface normal vector of the object at the point of impact of the light beam.

The amplitude may relate to the light emitted by a monochromatic illumination element, which thus has a small spectral width. The average amplitude and average wavelength may relate to the light emitted by a lighting element having a larger spectral width.

The control electronics can control the lighting device and / or the detector. In this case, the control electronics send signals for control to the lighting device and / or element groups and / or lighting elements and / or the detector. These may be digital signals that generate a switching operation in the lighting device and / or the element group and / or the lighting element and / or the detector.

Preferably, the control electronics to send switching operations send rectangular signals. A switching operation may change the operating state of the detector and / or lighting element and / or element group, for example from an active operating state "on" to an inactive operating state "off" or vice versa.

The control electronics can further receive information about the speed of the object to be measured relative to the detector in order to be able to optimally adapt the signal frequency to the object or to the speed of the object relative to the detector. This information may be input by an operator, for example. Likewise, the control electronics also information about the speed of a transport device on which moves an object to be measured, directly obtained from this. Advantageously, an encoder can be used for this purpose.

By means of stored or programmed functions or also stored values, the control electronics can adjust the generation of the signals based on the information about the speed of the object relative to the detector. In this way, the time sequence of the signals, or their frequency or their duration, can be determined and adapted flexibly to the object or to its speed relative to the detector.

For example, if the subject is moving at a high speed relative to the detector, it is recommended that you take still images of the subject at a high recording frequency. The maximum recording frequency can be given on the one hand hardware-related, on the other hand also physically conditioned.

In a preferred embodiment for currently available hardware, the control electronics may generate signals having a frequency that may be in a range of 1 to about 500 kHz, and preferably in a range of about 1 to 120 kHz. Preferably, the frequency of the signals is selected taking into account the recording characteristics of the detector. Preferably, the signal frequency does not exceed the recording frequency of the detector.

The control electronics may particularly preferably comprise a frame grabber as a central control instrument. The frame grabber of the control electronics particularly preferably comprises modules with additional functions or specific functionalities for the time control of the detector and / or the lighting device and / or the lighting elements and / or the element group.

The frame grabber preferably comprises a so-called field programmable gate array (FPGA), which can control the dynamic parameters of the detector, for example the exposure time of the detector. The frame grabber is preferably freely programmable for different detectors.

The frame grabber can thus take over a control and monitoring function via one or more detectors, as well as other frame grabbers and associated detectors on the Synchronize sequence. Furthermore, it can also determine the size and position of a readout window for each image capture of the detector. The readout window defines the area that can be imaged by the detector. For the purposes of the invention, the frame grabber may further comprise functionalities for controlling and checking the lighting device and / or the lighting elements and / or the element groups.

By means of the frame grabber, the signals for generating the individual images of a sequence can be generated. In this case, it preferably sends frame grabbers rectangular signals which can trigger one or more switching operations on the detector and / or the lighting device and / or a lighting element. Thus, the frame grabber can control the operating state of the detector and / or the lighting device and / or a lighting element.

The detector can convert a captured frame into a digital frame signal and route it to the frame grabber. In this case, a specific area of the object or of the object surface, which may be defined by the read window, be displayed sharply. In the case of a line or linear area, this area can also be referred to as a camera line. In other words, a camera line designates that line-shaped area of the object which can be sharply imaged by the detector.

The detector can send a single image recorded at a specific time as a digital image signal or individual image signal to the frame grabber, which can be equipped with image processing functions for this purpose.

The detector can assume different operating states. The operating state ON can determine the beginning of a recording, the operating state OFF the end of the recording. In this way, the exposure time can be controlled. By a signal of the control electronics or the frame grabber so the operating conditions of the detector can be switched.

The control electronics, in particular the frame grabber, can combine the digital frame signals belonging to a sequence to form a superimage. From several super pictures an overall picture of the object can be put together by the frame grabber.

The frames, the super picture and the whole picture can be saved.

In a surprisingly simple manner, thus, an image or an overall image of the object can be generated, which corresponds to a superimposition of several images of the same object with approximately the same recording times with different illumination, when the signals of the control electronics or the frame grabber synchronously or approximately simultaneously with the control the lighting device or the lighting elements are used and the lighting elements or groups of elements differ in their illumination from one another.

In this case, the control electronics or the frame grabber send the same signals for controlling a plurality of devices or even different signals, which are sent at the same time.

Certain lighting elements, groups of elements and / or detectors can also be connected to one another such that they can each be controlled by a specific frame grabber, which in turn is controlled by the control electronics or the central frame grabber.

Another aspect of the invention relates to an inspection device for the optical inspection of an object.

• – die oben beschriebene Beleuchtungsvorrichtung, welche elektromagnetische Strahlung auf das Objekt ausstrahlt, und
• – einen Detektor, der von dem Objekt gestreute und/oder transmittierte und/oder reflektierte und/oder durch Lumineszenz erzeugte Strahlung zum Erzeugen eines Bildes erfasst, sowie
• – eine Steuerungselektronik mit einem Framegrabber

umfassen.The inspection device can

• - The above-described lighting device which emits electromagnetic radiation to the object, and
• A detector which detects radiation scattered and / or transmitted and / or reflected and / or produced by luminescence from the object for generating an image, and
• - A control electronics with a frame grabber

include.

• – einer Beleuchtungsvorrichtung mit mehreren Beleuchtungselementen, die elektromagnetische Strahlung auf das Objekt ausstrahlt, und
• – eines Detektors, auf welchen vom Objekt gestreute und/oder transmittierte und/oder reflektierte und/oder durch Lumineszenz erzeugte Strahlung gerichtet wird zum zumindest teilweise Erfassen des Objekts und zum Erzeugen eines Bildes,

wobei die Funktion eines Beleuchtungselements durch eine Farbe und mehrere Strahlungsmodi charakterisiert ist.Another aspect of the invention relates to an inspection method for optically testing an object by means of

• A lighting device with a plurality of lighting elements that emits electromagnetic radiation to the object, and
• A detector on which the object scattered and / or transmitted and / or reflected and / or generated by luminescence radiation is directed to at least partially detect the object and to generate an image,

wherein the function of a lighting element is characterized by one color and a plurality of radiation modes.

In a first step of the inspection process, the colors and radiation modes of the lighting elements can be determined. The determination can generally be made by an operator or, if appropriate, by control parameters stored in the control electronics. The determination can be made such that the lighting elements differ from each other by the color and by at least one radiation mode.

• – die Oberfläche des Objekts, das Objektvolumen oder ein Teil der Oberfläche oder des Objektvolumens durch die Beleuchtungsvorrichtung auf Basis der Steuerparameter ausgeleuchtet werden,
• – die von dem Objekt gestreute und/oder transmittierte und/oder reflektierte und/oder durch Lumineszenz erzeugte Strahlung durch den Detektor erfasst werden, und
• – ein Bild durch den Detektor erzeugt werden.

In further steps of the inspection process can

• The surface of the object, the object volume or a part of the surface or the object volume are illuminated by the illumination device on the basis of the control parameters,
• The radiation scattered and / or transmitted by the object and / or reflected and / or produced by luminescence is detected by the detector, and
• - An image can be generated by the detector.

According to one embodiment, the illumination elements may differ from each other by the color and / or by two, three or four radiation modes. The higher degree of difference in the light components emitted by the illumination device may allow additional highlighting of the defects to be examined in the surface of the object.

A lighting element may advantageously have a switching state indicating whether the lighting element is active or inactive. In other words, the switching state indicates whether the lighting element is switched on or off.

An illumination element can be switched individually, that is to say independently of other illumination elements, in order to activate or deactivate the illumination element.

The circuit can be preferably carried out by means of the frame grabber.

An illumination element may be formed as a preferably straight or possibly curved light segment. The luminous segment may be linear or planar, wherein a planar-like luminous segment has a radiation surface.

The light emitted by a lighting element may strike the object in a light spot comprising a part of the object or the entire object. The light spots of every two illumination elements may overlap, or overlap, or be disjoint.

An element group may have a switching pattern indicating a sequence of ON-OFF switching states in which the lighting elements of the element group are at a certain time. When an element group is switched on, the individual lighting elements can thus be switched on if the corresponding value in the switching pattern is ON or remain off if the corresponding value in the switching pattern is OFF. When switching off the element group, all lighting elements can be switched off or remain off.

An element group can be switched individually, ie separately from other element groups, to activate or deactivate the element group. The switching-on can preferably be carried out according to the switching pattern of the element group.

The illumination device may further comprise a reflector and / or a scattering body, on which the light of the illumination elements is emitted, so that it is diffused or directed by the reflector on the object. Diffuse radiation can be generated for example by a flat or curved shell with a rough surface. Directed radiation can be generated for example by a section of a parabolic cylinder or a rotary paraboloid, in the focus of which a lighting element or a group of elements is arranged.

The lighting device may include a lighting support structure having slots, each providing a supply voltage and to which each lighting elements and / or element groups can be mounted by means of plug-and-socket connections for creating the lighting device. The assignment of the lighting elements to the element groups can be realized by a corresponding electrical wiring or by a circuit logic. The arrangement of the lighting elements can be changed very flexibly in this way.

The lighting support structure may comprise pivotable and / or flexible arms on which the connectors are arranged. In a particular embodiment, the lighting support structure may have a matrix of attachment points for receiving the illumination elements in order to be able to fasten, for example, glass fibers, glass fiber bundles, fiber cross-section transducers, individual LEDs, LED line lights, LED surface lights or lasers.

Such a modular system can be very advantageous in terms of a simple, inexpensive and flexible construction of the lighting device depending on the respective technical objective and the needs of a user.

The lighting structure may further comprise the detector. In this way, a highly flexible and mobile lighting device for optical inspection can be formed, which can be used for example for inspecting tubular objects or containers. By means of suitable movement devices, therefore, the illumination support system comprising the detector can be moved, whereas the object to be tested can stand firmly.

The illumination elements can be arranged in a luminous matrix which spans a flat or curved luminous surface. The luminous surface may form a partial surface of a rotary body, in particular a ball or a cylinder.

One lighting element or one element group can be switched individually for activating or deactivating the lighting element or the element group.

The lighting elements and / or element groups can each be switched individually or in groups, simultaneously or consecutively, periodically recurring in a predetermined cycle.

The inspection device may advantageously comprise a control electronics coupled to the illumination device and the detector and a frame grabber.

The control electronics can be designed to determine the optical properties of the object. For this purpose, when emitting light with a predetermined spectral characteristic, preferably of white light, by the illumination device on the object, a calibration image can be generated by the detector. The optical properties of the object can be determined by means of a processing of the calibration image by the control electronics.

The optical properties of the object can be used to produce optimal illumination of the object by the illumination device. The illumination can be optimized to maximize the hit rate in detecting defects in the surface of the object.

The control electronics can be designed to determine or set the signals for controlling the lighting device by means of the optical properties of the object. A definition of the control parameters can be carried out, for example, by an operator by means of a keyboard input. Optionally, an automatic determination of the control parameters may be performed by a pattern recognition system based on the optical properties of the object.

The control electronics can be designed to control the lighting device by means of the signals or the control parameters in order to effect a corresponding illumination of the object by the lighting device.

The control electronics can also be designed to evaluate the image by means of a pattern recognition system or classifier for detecting a defect on the surface of the object or in the object volume. For this purpose, the pattern recognition system can be trained to detect defects by presenting images that show surfaces that have defects. In a practice following practice, the pattern recognition system may detect defects that are similar to the defects presented in training.

The control electronics can also be designed to record irregularities in the illuminations individually per individual image and to correct them for each pixel (shading correction). This intensity evaluation can also be used for automatic brightness adjustment to detect the total brightness per frame and to control it by varying the activation time of the sensor exposure and / or the illumination.

According to one embodiment, the illumination device of the inspection device may comprise an element group with five illumination elements formed as straight light segments, with the common radiation modes: orientation perpendicular, radiation characteristic directed or diffuse.

A first lighting element can emit red light, with the light field bright field, direction of reflected light, angle of incidence about 10 degrees. Advantageously, coatings or textures can thus be made visible in the object surface.

A second lighting element can emit blue light, dark-field light, direction of incident light, angle of incidence about 40 degrees. Advantageously, so that grooves or scratches on glass surfaces can be made visible.

A third lighting element can emit green light, with dark field light, direction of incident light, angle of incidence about 70 degrees. Advantageously, it can also be made visible grooves or scratches in the object surface by a resolution of the depth.

A fourth lighting element can emit pink light, dark-field light, direction of incident light, angle of incidence about 110 degrees. Advantageously, defects in the glass can be made visible thereby.

A fifth lighting element can emit yellow light, with dark-field light, direction of transmitted light, angle of incidence about 140 degrees. Advantageously, thus scattering effects such as bubbles or voids can be made visible.

The device can thus be combined with each other in a very simple manner different lights. In this way, it is particularly advantageous to detect different errors or types of errors on the object or in the object volume almost simultaneously, in particular even if a specific error can only be identified with one, another with another type of illumination.

Likewise, it is also possible to identify faults which can only be determined reliably with a specific combination of different types of lighting. In this way, an error on or in an object that can not be identified at all or not reliably by only one type of illumination can be determined and located in a particularly favorable manner.

According to one embodiment, the illumination device of the inspection device may comprise two, three or four element groups, each having three, coaxially arranged, designed as semi-circular or semi-cylindrical lighting segments, lighting elements open to the object. The illumination elements can have the following common radiation modes: orientation parallel, emission characteristic directed or diffuse, direction transmitted light.

A first lighting element can emit yellow light with dark-field illumination.

A second lighting element can emit blue light with dark-field light.

A third lighting element can emit red light with bright-field brightfield.

• 1. in einem ersten Takt jeweils die ersten Beleuchtungselemente EIN und die anderen AUS sind,
• 2. in einem zweiten Takt jeweils die zweiten Beleuchtungselemente EIN und die anderen AUS sind, und
• 3. in einem dritten Takt jeweils die dritten Beleuchtungselemente EIN und die anderen AUS sind.

The lighting elements can be switched on and off timed, wherein

• 1. in a first cycle the first lighting elements are ON and the other OFFs respectively,
• 2. in a second clock, the second lighting elements are ON and the other OFFs respectively, and
• 3. in a third clock, the third lighting elements are ON and the other OFFs respectively.

The three bars can be repeated cyclically.

• – von Flach- und Rohrglas, das Defekte, insbesondere Blasen, Knoten, Schlieren, Steine, oder Kratzer, aufweist, und/oder
• – von Stahlbauteilen, die Defekte, insbesondere Riefen, Lunker, Rattermarken, aufweisen, und/oder
• – von Folien, die Defekte, insbesondere Blasen, Verschmutzungen, Löcher, aufweisen, und/oder
• – von Fasern aus Glas oder Kunststoff, welche Blasen, Verschmutzungen oder inhomogene Materialzusammensetzungen aufweisen und/oder
• – von Silizium-Wafern oder -Bauteilen, welche Risse im Volumen, Materialverunreinigungen oder Riefen auf der Oberfläche aufweisen können.

Another aspect of the invention relates to a use of the above-described inspection device for testing and / or sorting

• - Of flat and tube glass, the defects, in particular bubbles, knots, streaks, stones, or scratches, and / or has
• - Of steel components, the defects, in particular grooves, voids, chatter marks, have, and / or
• - Of films that have defects, especially bubbles, dirt, holes, and / or
• - Of fibers of glass or plastic, which have bubbles, soils or inhomogeneous material compositions and / or
• - Silicon wafers or components which may have cracks in the volume, material contamination or scoring on the surface.

The object may include materials from the group of metals, plastics, glasses, ceramics or glass ceramics, wood, paper or silicon. The object can also be produced completely continuously, for example as a glass or metal strip or generally as a web or tape product, and tested during a transport, for example via a conveyor or transport path, in a production environment with the inspection device.

The surfaces of the object may comprise wholly or partially diffusing, smooth, textured, reflective or even surfaces of other nature. The object can also be completely or partially transparent or semi-transparent.

Particularly advantageously, the inspection device can also be formed by one or more detectors and one or more lighting elements or element groups such that it can be configured for testing different objects.

In this case, for example, a set of parameters, comprising control parameters for the signals and the trigger pulses and for the transport speed of the transport path, can be defined for the different objects to be tested and stored in a memory of the control electronics. This parameter set can be specified by an operator and selected or adjusted depending on the objects.

As a result, the inspection device is particularly well suited to test different objects with low system complexity. For example, non-transparent, isolated objects in which the surface finish is to be measured, but also transparent and continuously manufactured objects such as a glass ribbon, in which contaminants are to be measured in volume, are measured by means of an identically or similarly configured device, wherein only the parameter sets can differ.

According to a further embodiment of the invention, the illumination device can also comprise a plurality of detectors, each of which images a specific area of an object. In this way, a camera line can be formed, which may include the camera line of various detectors. From the control electronics, an overall picture can be generated from this.

In this case, the detectors can also be designed particularly cost-effectively as a monochrome line scan camera which can each record a specific image area along a camera line.

It is also possible to use detectors which can record multi-line images.

In a further embodiment, the illumination elements can also emit electromagnetic radiation in the infrared or ultraviolet range in order, for example, to increase visibility, to be able to check temperature differences in or on the object, or cracks in glass surfaces. For this purpose, the detector can be advantageously designed as an IR or UV camera.

In a further development of the invention, a lighting element can emit coherent, expanded laser light. As a result, speckle patterns or granulation patterns can be generated on the object surface. In this way, for example, tensions in the object or very small spatial changes between lighting element and object can be checked.

In a further development, a lighting element can also emit X-rays. The illumination device can thus also comprise an X-ray tomograph, whereby sectional images of the object can be generated.

In yet another embodiment, the. Lighting device and optical grids or diffraction grating include. These can be used for monochromatization of the radiation and / or for analysis in the context of optical testing.

Furthermore, a lighting element of the lighting device may comprise diffractive optical elements in order to shape or divide the emitted radiation, preferably laser radiation. By shaping, for example, an approximately uniform intensity distribution can be achieved.

The invention will be explained in more detail by means of embodiments and with reference to the drawings. The same reference numbers refer to the same or corresponding elements. The features of various embodiments may be combined.

The drawings show:

1 A first embodiment of an inspection device,

2 A second embodiment of an inspection device,

3 A third embodiment of an inspection device,

4 A fourth embodiment of an inspection device,

5 an illustration of a schematic structure of an imaging device,

6 a timing diagram for the detector control,

7 the operating status of detector and lighting elements in the time sequence

8th Overall picture of an object, whereby the object in

Brightfield incident light is irradiated,

9 Overall picture of an object, whereby the object is irradiated in the dark field incident light,

10 Overall picture of an object, whereby the object is irradiated in bright field transmitted light, and

11 Overall picture of an object, created by ordered composition of m super pictures.

In general, different defects in the surfaces of products with cameras can be detected using adapted illumination.

For the inspection of z. B. web or large discs, for example, line scan cameras are used. For these applications different line lighting is available on the market. In general, the line lights have a preferred direction. The appearance, especially the contrast, of defects depends strongly on the direction from which they are illuminated. So it may be that one type of lighting is well suited for one type of fault, but another type of fault is poor or even not visible in this lighting.

The invention provides a line illumination in which multiple switchable lights are combined.

The 1 shows a first embodiment of the inspection device according to the invention 12 for the optical examination of an object 18 , This is a glass object that is in a transport direction 18 is moved. The optical inspection is performed to detect a defect, damage or defect in the surface of the object.

• – eine Beleuchtungsvorrichtung 10, welche Licht auf das Objekt 18 ausstrahlt, und
• – einen Detektor 14, der von dem Objekt gestreutes oder transmittiertes Licht zum Erzeugen eines Bildes erfasst.

The inspection device 12 includes

• A lighting device 10 which light on the object 18 radiates, and
• - a detector 14 which detects light scattered or transmitted by the object to form an image.

The lighting device comprises a plurality of lighting elements, which are each designed as line emitters. By means of a lighting element, light is directed to at least a part of a surface of the object.

The function of a lighting element may be characterized by a color and a plurality of radiation modes of the light emitted by the lighting element.

The lighting elements differ from each other by the color and at least one radiation mode. A combined radiation generated by the illumination device is scattered and / or transmitted and / or reflected by the object and / or emitted as luminescent radiation to enable examination of the object by means of an analysis of the image generated by the detector.

• 21 Rot, senkrecht, Hellfeld, Auflicht
• 22 Blau, senkrecht, Dunkelfeld, Auflicht
• 23 Grün, senkrecht, Dunkelfeld, Auflicht
• 24 Pink, senkrecht, Dunkelfeld, Durchlicht
• 25 Gelb, senkrecht, Hellfeld, Durchlicht
• 26 Pink, senkrecht, Dunkelfeld, Durchlicht
• 27 Grün, senkrecht, Dunkelfeld, Auflicht
• 28 Blau, senkrecht, Dunkelfeld, Auflicht

The lighting elements 21 - 28 in 1 have the following colors and radiation modes:

• 21 Red, vertical, brightfield, reflected light
• 22 Blue, vertical, darkfield, reflected light
• 23 Green, vertical, dark field, reflected light
• 24 Pink, vertical, dark field, transmitted light
• 25 Yellow, vertical, brightfield, transmitted light
• 26 Pink, vertical, dark field, transmitted light
• 27 Green, vertical, dark field, reflected light
• 28 Blue, vertical, darkfield, reflected light

The lighting element 21 makes it easier to visualize coatings in a reflection.

The lighting element 22 , which is located at a steep angle, makes it easier to make grooves on metal bands visible.

The lighting element 23 has the same function as the lighting element 22 , but a changed preferred direction, for example, to distinguish the depth.

The lighting element 24 makes it easier to visualize scattering defects such as bubbles.

The lighting element 25 makes it easier to visualize dark defects in the glass.

The lighting device consists of switchable lighting elements, which are formed as a linear lighting segment. Each light segment can have different properties, in terms of wavelength, diffused or directed light or direction of illumination.

The lighting device is advantageously designed as a modular system, by means of which a suitable for the application system can be configured.

The switchable light segments are generally switchable perpendicular to the scan line. For some applications, it may also be useful to switch the light segments parallel to the scan line.

According to 1 the object is illuminated from several illumination angles. Here are the colors for different types of lighting. The colors can also stand for the physical color of the lighting element.

The 2 shows a second embodiment of the inspection device according to the invention 12 for the optical examination of an object 18 , In this embodiment, the lighting device comprises three element groups, in each of which three lighting elements 29 . 30 . 31 are arranged. The lighting elements 29 . 30 . 31 are formed as semicircular or semi-cylindrical lighting segments, arranged coaxially, open to the object. The illumination elements have the following common radiation modes: orientation parallel, radiation characteristic directed or diffuse, direction transmitted light.

For vertical switching, grooves that are exactly perpendicular to the transport direction would provide little contrast. To avoid such errors are in this embodiment, the lighting elements 29 . 30 . 31 parallel to the scan line of the detector designed as a camera 14 arranged.

The object 18 , which in the present case is a glass plate, moves out of the plane of the paper.

Each color represents a time switching state (3 channels). In the first bar, the yellow area lights up in the second and the red one in the third.

The 3 shows a third embodiment of the inspection device according to the invention 12 in which a combined switching is performed. In this figure, the object moves 18 , which is formed as a glass plate, out of the plane of the drawing.

A combination of lighting elements with the orientations parallel and perpendicular advantageously has a high flexibility.

• Takt 1 nur die gelbe Fläche leuchtet.
• Takt 2 nur die rote Fläche leuchtet.
• Takt 3 nur die blaue Fläche leuchtet.
• Takt 4 nur die grüne Fläche leuchtet.
• Takt 5 nur die pinke Fläche leuchtet.
• Takt 6 nur die orangefarbene Fläche leuchtet.

Each color is representative of a temporal switching state (6 channels).

• Clock 1 only the yellow area lights up.
• Clock 2 only the red area lights up.
• Clock 3 only the blue area lights up.
• Clock 4 only the green area lights up.
• Clock 5 only the pink area lights up.
• Bar 6 only the orange area lights up.

Here are the lighting elements in each bar 32 - 37 controlled in such a way that in the cycles 1 to 3 in the radiation mode "parallel" and in the bars 4 to 6 in the radiation mode "perpendicular" light to the object 18 radiate.

The 4 shows a fourth embodiment of the inspection device according to the invention 12 in which a combined switching is performed. This will be an inspection of scratches in the surface of the object 18 , which is formed as a glass plate performed.

For scratches on glass, the contrast of the scratches depends on the angle of illumination. A multi-directional lighting has proven to be very beneficial. This lighting is achieved by means of a reflector 16 realized in the left picture the 4 becomes the reflector 16 , which can be regarded as a "light tunnel", illuminated from below. Part of the light shines through the glass 18 and then passes through an opening of the reflector to the camera 14 from which it is detected, with the associated radiation modes being "transmitted light" and "bright field". Another part of the light shines through the glass 18 , reaches the reflector 16 from which it is on the glass 18 is scattered back from the glass 18 to the opening of the reflector 16 scattered and then passes through an opening in the reflector 16 to the camera 14 from which it is detected, with the associated radiation modes being a combination of "transmitted light", "incident light" and "bright field".

In the right picture the 4 becomes the reflector 16 illuminated from below. Part of the light shines through the glass 18 and then gets to the camera 14 from which it is detected, with the associated radiation modes being "transmitted light" and "bright field". Another part of the light is from the glass 18 reflected, reaches the reflector 16 from which it is on the glass 18 backscattered, the glass shines through 18 and then gets to the camera 14 , wherein the associated radiation modes are a combination of "transmitted light", "dark field" and "bright field".

In 5 a construction of a lighting device is shown comprising a detector 14 , a control electronics 57 with a frame grabber 58 as well as several lighting elements 21 . 22 and 23 a lighting device. The detector is designed as a monochrome line scan camera.

In the present case, the object to be tested is a continuous glass band 18 which is transported by a transport device 56 is promoted in the direction of the arrow.

The control electronics controls by means of signals 53 the operating state of the lighting elements 21 . 22 and 23 the lighting device. The control electronics also control by means of signals 51 the detector 14 ,

Furthermore, the control electronics receives over the signal path 52 Information about the speed of the transport device 56 , which by means of an encoder 55 be determined. The control electronics can use this information to select the signal frequency for controlling the detector and / or the lighting elements from a stored in a database parameter set the speed of the transport route.

6 shows a possible timing diagram, which includes the timing of the various signals or switching operations.

In the example, within a sequence A, 1 to n frames can be generated. After the signal for a superimage defined with A1, after a delay (delay) the detector ( 61 ) is activated for a duration. For frame 1, the beginning is indicated by A1 and the end by A2. Likewise, the lighting device and / or one or more lighting elements ( 62 ) and / or one or more element groups.

The signal defined with A2 also marks the beginning of the frame 2.

At the same time, the state of the outputs, for. B. a bit pattern at the digital outputs (IO status, 63 ) To be defined. This signal is delayed analogously to the detector for a time and activated for a period of time. The other individual images can be parameterized analogously.

The timing of the operating states of the detector 14 and the lighting elements of the lighting device 7 ,

The operating states of the lighting device 1 to n are controlled by the control electronics and alternately assume the operating states ON and OFF.

Likewise, the detector assumes the operating state ON or OFF. The operating state ON of the detector identifies the time span within which an exposure takes place. Shown are the respective switching states of the components of the lighting device.

The 8th . 9 and 10 each show an overall picture of an object with a different lighting. at 8th The detector receives transmitted light, which was generated by a lighting element in the bright field. The picture of the 9 also shows transmitted light, where the object was irradiated in a dark field illumination. In 10 the detector receives reflected light, whereby the object was irradiated in the bright field (reflection).

The 11 shows the overall picture of an object, as it results from the ordered assembly of the recorded super pictures: The recorded sequence consists of 1 to n frames ( 71 . 72 . 73 . 74 ), which contain the measurement object or parts of the measurement object in different illumination states and to the superimage no. 1 (FIG. 75 ). The resulting 1 to m super images of the measurement object ( 75 . 76 ) are arranged in order according to the chronological order of their formation to the overall picture of the object to be measured. 75 So embodies the superimage 1 of the object, whereas 76 the superimage m of the object is embodied and in which a total of 1 ... m super-images are generated by the object. In this case, a superimage comprises in each case n partial images of the object in the different illumination states. A further resorting of partial information from the individual image channels is eliminated.

LIST OF REFERENCE NUMBERS

10

lighting device

12

inspection device

14

detector

16

reflector

18

object

20

transport direction  Illuminating elements with the following colors and radiation modes, where LI = linear luminous segment, GE = curved luminous segment, PK = point-shaped illumination element

21

LI, red, vertical, brightfield, reflected light

22

LI, blue, vertical, darkfield, reflected light

23

LI, green, vertical, darkfield, reflected light

24

LI, Pink, vertical, dark field, transmitted light

25

LI, yellow, vertical, brightfield, transmitted light

26

LI, Pink, vertical, dark field, transmitted light

27

LI, green, vertical, darkfield, reflected light

28

LI, blue, vertical, darkfield, reflected light

29

GE, yellow, parallel, darkfield, transmitted light

30

GE, blue, parallel, darkfield, transmitted light

31

GE, red, parallel, darkfield, transmitted light

32

PK, yellow, vertical, darkfield, transmitted light

33

PK, red, vertical, darkfield, transmitted light

34

PK, blue, vertical, darkfield, transmitted light

35

PK, green, parallel, darkfield, transmitted light

36

PK, Pink, parallel, darkfield, transmitted light

37

PK, orange, parallel, darkfield, transmitted light

38

LI, yellow, vertical, brightfield, transmitted light

39

LI, yellow, parallel, brightfield, transmitted light

51

Control signals to the detector

52

Control signals to the control electronics

53

Control signals to the lighting element

56

transport device

57

control electronics

58

Frame grabber

61

Circuit of the detector

62

Circuit of a lighting element

63

bit pattern

70

Complete representation of the object

71

Representation in lighting state 1

72

Representation in lighting condition 2

73

Representation in lighting condition 3

74

Representation in lighting condition n

75

Super picture No. 1

76

Superpicture No. m

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102008022292 A1 [0005]
• WO 2009/112204 A2 [0006]
• US 2007/0132759 A1 [0007]
• US 2006/0091825 [0008, 0009]
• US 6392754 B1 [0010]
• AT 507018 A1 [0011]
• EP 1477793 A2 [0012]

Claims (24)

Lighting device for non-contact optical testing of an object, comprising at least one detector with at least one imaging element, computer-aided control electronics and at least one lighting device, wherein the lighting device comprises one or more lighting elements which emit electromagnetic radiation, the object is wholly or partially in the beam path of the lighting device, the detector detects the radiation scattered and / or transmitted and / or reflected and / or emitted by luminescence by taking a single image, the control electronics controls the lighting device, the control electronics simultaneously controls the detector, and wherein an image of the object or a portion of the object can be generated by combining individual images with different illumination. Lighting device according to the preceding claim, characterized in that the detector is designed as an optical image sensor and one or more arranged image sensors and one or more imaging elements, wherein the image sensor may be formed on the basis of CCD, CMOS or hybrid chip technology for Detection of electromagnetic radiation. Lighting device according to the preceding claims, characterized in that the control electronics comprises a frame grabber. Lighting device according to the preceding claims, characterized in that the recording of a sequence of individual images is triggered by means of the control electronics or the frame grabber. Lighting device according to the preceding claims, characterized in that a single image comprises one or more lines, which the detector receives from the object or from a partial area of the object. Lighting device according to the preceding claims, characterized in that the recording time and the exposure time of the detector is set flexibly to each frame by means of the control electronics or the frame grabber. Lighting device according to the preceding claims, characterized in that by means of the control electronics and / or the frame grabber at the same time as the control of the detector for each frame, the operating state of one or more lighting elements with respect to starting time and lighting duration can be switched Lighting device according to the preceding claims, characterized in that by means of the control electronics and / or the frame grabber (master) further frame grabbers (slaves) are synchronized with their own connected detectors on this sequence. Lighting device according to the preceding claims, characterized in that the control electronics and / or the frame grabber assembles the individual images belonging to a sequence next to one another to form a superimage. Lighting device according to the preceding claims, characterized in that the control electronics and / or the frame grabber the super images below together one another to a complete and sorted by illumination state representation of the object or a portion of the object zusammenfügt. Lighting device according to the preceding claims, wherein the direction of the emitted radiation of a lighting element determines whether the object is irradiated in reflected light or transmitted light. Lighting device according to the preceding claims, wherein the radiation characteristic of the lighting element determines whether the object is diffused or irradiated directly or with direct radiation. Lighting device according to the preceding claims, wherein the lighting mode of the lighting element determines whether the object is irradiated in the bright field or in the dark field. Lighting device according to the preceding claims, characterized in that the illumination device comprises illumination elements, wherein the wavelength and / or the spectral width and / or the direction and / or the emission characteristic and / or the light emitting the emitted electromagnetic radiation of at least two illumination elements of each other. Lighting device according to one of the preceding claims, characterized in that the illumination elements differ from each other by the color and / or two, three or four radiation modes. Lighting device according to one of the preceding claims, wherein: - A lighting element is individually switchable to activate (operating state ON) or deactivate (operating state OFF) of the lighting element; A lighting element has a switching state indicating whether the lighting element is active or inactive; - Several lighting elements can be combined to form an element group; A lighting element has a switching pattern indicating a sequence of switching states in which the lighting elements of the element group are; - An element group is individually switchable for activating or deactivating the element group, preferably in accordance with the switching pattern of the element group; - The lighting elements are timed, periodically, on and off; A period comprises a predetermined number of cycles, wherein the switching states assumed during the period are repeated cyclically with each period; - For each clock, the lighting elements form an element group, preferably in accordance with the belonging to this clock switching pattern; - The belonging to different cycles of a period element groups each differ from each other, preferably in one color and / or at least one radiation mode. Lighting device according to one of the preceding claims, comprising: A lighting support structure having slots, each providing a supply voltage and / or switching signals and to which each lighting elements and / or element groups can be mounted by means of plug-in connections for creating the lighting device, - a lighting support structure with a matrix of: fixing points for receiving the lighting elements, for example, to be able to fasten glass fibers, glass fiber bundles, fiber cross-section transducers, individual LEDs, LED line lights, LED surface lights or lasers, A common wiring several lighting elements for a common control, A common control of several lighting elements and / or detectors by a switching logic and / or further frame grabbers, A reflector and / or a scattering body, on which the light of the illumination elements is emitted so that it is diffused or directed by the reflector onto the object. Lighting device according to one of the preceding claims, wherein - The lighting elements are arranged in a luminous matrix, which spans a flat or curved luminous surface; - The luminous surface forms a partial surface of a rotating body, in particular a ball or a cylinder. Inspection device for the optical inspection of an object, comprising A lighting device according to one of the preceding claims, which radiates electromagnetic radiation to the object, A detector that detects and generates an image of the object scattered and / or transmitted and / or reflected and / or generated by luminescence and - A control electronics and / or a frame grabber for controlling and controlling the lighting device and the detector. Inspection device according to the preceding claim, characterized by an electronic control unit coupled to the illumination device and the detector, which is designed to record irregularities in the illuminations per frame and to correct them for each pixel, as well as an automatic brightness adjustment of the total brightness by varying the activation duration of the illumination Sensorbelichtung and / or make the lighting. Inspection device according to one of the preceding two claims, characterized in that the control electronics and / or the frame grabber is designed to To determine the control parameters for controlling the lighting device by means of the optical properties of the object, and / or To control the lighting device by means of the control parameters, and / or - Evaluate the image by means of a pattern recognition system or classifier for detecting a defect on the surface of the object or in the object volume. Use of an inspection device according to one of the preceding claims for sorting out - Of flat or tube glass, the defects, in particular bubbles, knots, streaks, stones, or scratches, or - Of steel components, the defects, in particular grooves, voids, chatter marks have, or - Of films that have defects, especially bubbles, dirt, holes, or Fibers of glass or plastic which have defects, in particular bubbles, soiling or inhomogeneous material compositions, or - Silicon wafers or components that have cracks in the volume, material contamination or grooves on the surface. An inspection method for optically examining an object by means of: a lighting device with a plurality of illumination elements which radiates electromagnetic radiation onto the object; and at least one detector on which the radiation scattered and / or transmitted and / or reflected and / or produced by luminescence is directed by the object for at least partially detecting the object and for producing an image, wherein - the function of a lighting element is characterized by one color and several radiation modes, - comprising the following steps: a) determining the colors and radiation modes of the lighting elements, preferably by an operator or by control electronics such that at least two illumination elements are different from each other by the color and at least one radiation mode; b) controlling the detector by the control electronics and / or the frame grabber, c) controlling the lighting device or the lighting elements by the control electronics and / or the frame grabber, d) arranging or moving the object or a portion of the object in the beam path or a Proportion of the beam path of one or more illumination elements, e) illumination of at least a part of the object by the illumination device on the basis of the control parameters; f) detecting the radiation scattered and / or transmitted by the object and / or reflected and / or produced by luminescence by the detector; g) transmitting the recorded individual images as a digital single-frame signal to the control electronics and / or the frame grabber and h) combining the individual image signals into a superimage of the object. Inspection method according to the preceding claim, wherein - A plurality of lighting elements is combined to form an element group, wherein the lighting device comprises a plurality of element groups; - Each one lighting element or element group is switched individually to enable or disable the lighting element or the element group; - The lighting elements and / or element groups are each individually or in groups, simultaneously or successively, periodically recurring in a predetermined clock, switched; - The image is analyzed by a pattern recognition system or classifier and evaluated to detect a defect on the surface of the object or in the object.

Images