A kind of double lens image acquisition and processing unit for DPM code readersTechnical field
The present invention relates to direct part mark（Direct Part Marking are abbreviated as DPM）Code identification field, is specifically related toA kind of and double lens image acquisition and processing unit for DPM code readers.
Background technology
Data capacity that Quick Response Code possesses is big, error correcting capability is strong, high reliability causes its application increasinglyExtensively, as planar bar code technology develops rapidly, the continuous extension of application, the lasting depth of Quick Response Code automatic identification technology researchEnter, build and be specific to industrial DPM (Direct Part Mark direct part mark) code automatic recognition system and by its industryThe requirement of change is increasingly strong.
Conventional two-dimensional bar code substantially realized using printing means, this kind of Quick Response Code easily with the abrasion of printed matter,It is fuzzy and become unreadable, easy to be lost, exist do not support Life cycle retrospect ability, it is irredundant the shortcomings of.DPM codes are then logicalCross laser-induced thermal etching, machine is beaten the industrial means such as shock, electrochemical corrosion and made in the direct mark code in the surface of part, rather than by code systemOn an other carrier.These means reflect the characteristics of maximum of DPM codes：Permanently.This causes product in lifeIn producing line in production process and it is offline after the trackings of logistics links be possibly realized.
DPM code generating methods and can be by illumination shadow using the diversity two-dimensional barcode image that causes actual acquisition to arrive of materialThe influence of situations such as sound, complex background interference, inclination of the bar code shot, this brings huge be stranded to follow-up identification workHow difficulty, therefore, research accurately and rapidly identify that the device of DPM codes has become an important field of research.
Quick Response Code code reader general at present is mainly by light source, reception device, photoelectric conversion part, decoding unit and calculatingMachine interface forms, and basic functional principle is：The light sent by light source by irradiation optical system to bar code symbol above, due toThe wavelength of the visible ray of the object reflection of different colours is different, and white object can launch the visible ray of various wavelength, black objectThe visible ray of various wavelength is then absorbed, the light being reflected back on optical-electrical converter, is allowed to produce by optical system imagingElectric signal, signal voltage is related to being irradiated to the light intensity being reflected back on bar code symbol, amplification of the electric signal through oversampling circuit, thenAfter filtering, shaping, square-wave signal corresponding with analog signal is formed, decoded unit decoding, completes the full mistake that bar code distinguishes readingJourney.General DPM codes reader is single-lens at present, and the present invention provides a kind of double lens image acquisition and processing unit, twoIndividual camera lens can have different optical parametrics, this advantage not having with single-lens device.Code reader presses scan modeTo divide, contact and contactless two kinds can be divided into.Contact type code reader must contact with bar code, can be only achieved reading dataPurpose.As long as contactless bar code code reader, in effective field depth, light source irradiation Quick Response Code can be automatically performed scanning.Contactless code reader three reads greatly the type of skill：Planar array scanning system, laser scanner based on image, line scanningSystem, most common of which is the planar array scanning system based on image, and it forms as shown in Figure 1.This face battle array based on imageScanning reading system uses a camera device, and shoots DPM code images from front.It is single-lens to be typically only capable to receiving plane letterBreath, and spatial information can not be obtained, therefore for directly playing shock, electrochemical corrosion etc. in material surface laser-induced thermal etching, machineThe DPM code resolution capabilities that industrial means are realized are not high.In addition, compared to the Quick Response Code of black and white printing, the picture contrast of DPM codesRelatively low, when this system of application is to identify DPM Quick Response Codes, its recognition capability is very low.
The content of the invention
Present invention aim to address the defects of prior art, there is provided a kind of twin-lens image for DPM code readersCollection and processing unit, the technical scheme of use are as follows：
A kind of double lens image acquisition and processing unit for DPM code readers, including the shooting dress being electrically connected to each otherPut, image pre-processing unit and main control unit, the camera device there are two, installation spaced apart, two shooting dressesThe optical lens optical axis put is angled；The camera device is under the control of main control unit from different angles to DPMCode is shot, and the image photographed is sent into image pre-processing unit；Described image pretreatment unit receives shooting dressPut the DPM codes of shooting and image is handled, so as to the DPM code images corrected.
The present invention is shot using two independent camera devices to DPM codes, and every camera device is for mesh to be capturedMark has different imaging angles, and when concavo-convex DPM codes imaging to material surface be present, left side camera device can obtain moreInformation on the left of target, right side camera device can obtain information on the right side of more targets.Read relative to the DPM codes of a camera deviceDevice is read, the present invention can increase light-inletting quantity, strengthen shooting effect during insufficient light；Also, the light of at least one filming apparatusLearn camera lens optical axis and be not orthogonal to material surface where DPM codes, the mode of this tilt breaches to be stood from vertical angle shootingThe limitation of body target, while image is gathered from different angles, more target three-dimensional spatial informations can be obtained, improve system pairThe resolution capability of DPM codes.The pretreatment that image pre-processing unit is carried out to image is strong to be merged into each other and being compensated to imageJust, it is necessary to which explanation, image pre-processing unit of the invention, which has, uses what software algorithm photographed to each camera deviceImage is merged, compensated and corrected, and has software algorithm that is many maturations or increasing income, art technology in image processing fieldPersonnel can select or change as needed these existing software algorithms and image is merged, compensated and corrected.
Preferably, present invention additionally comprises the auxiliary lighting apparatus electrically connected with main control unit, the floor light dressPut installed in the periphery of two camera devices, it illuminates DPM code targets under main control unit control.
Preferably, present invention additionally comprises the auxiliary lighting apparatus electrically connected with main control unit, the floor light dressAmong two camera devices, it illuminates DPM code targets under main control unit control.
DPM codes are directly formed on the surface of part by the industrial means such as laser engraving, mechanical stipple, electrochemical corrosionIdentification code, material surface convex-concave information is so just only existed on surface, be different from the high-contrast optics letter of common printed bar codeBreath, the picture quality for being collected sharp picture using common barcode reader imaging device or being collected is poor, and the present invention is logicalCross between optical lens and optical lens periphery sets auxiliary lighting apparatus, and floor light is controlled by main control unitThe target area for the light irradiation that device is sent, making it, heart district domain forms a hot spot for being different from ambient lighting, mesh in the targetThe light of mark regions scatter projects on two imaging devices respectively by camera lens, so, it becomes possible to collect the convex of material surfaceRecessed information, image quality is improved, improves follow-up DMP codes recognition accuracy.The light source of auxiliary lighting apparatus be feux rouges or green glow orWhite LED light source.
Preferably, the optical axis included angle scope of the optical lens of the camera device is 0 degree to 150 degree.
Preferably, described two camera devices use optical parametric identical camera lens.
Preferably, described two camera devices are using the different camera lens of optical parametric.
Preferably, the camera device includes the optical lens and imaging device set gradually, the imaging device isCcd image sensor or cmos image sensor, are electrically connected with main control unit.
Compared with prior art, beneficial effects of the present invention：
1st, the present invention is shot using two sets of independent camera devices to DPM codes, and light-inletting quantity greatly improves, can be lowImage quality is improved under luminous environment, and the image of two camera devices compensates fusion, it is possible to reduce the noise of image, improve letterMake an uproar ratio.
2nd, two sets of camera devices have different imaging angles for target to be captured, bumps be present to material surfaceWhen DPM codes are imaged, relative to the system of a camera device, the present invention can obtain more object space depth informations, significantlyImprove recognition capability of the reader system to DPM codes.
3rd, two sets of independent camera devices can use the optical lens of different focal and different exposure parameters to be shot,Obtain the different image of two width to be merged, compensated and corrected by image processing algorithm, DPM codes reader can be made to have biggerThe identification depth of field and adapt to more complicated photoenvironment.
Brief description of the drawings
Fig. 1 is the structural representation of traditional planar array scanning system based on image；
Fig. 2 is the system structure diagram of the embodiment of the present invention 1；
Fig. 3 is the profile of the twin-lens of the embodiment of the present invention 1；
Fig. 4 is the fundamental diagram that IMAQ is carried out using general lighting technology；
Fig. 5 is the fundamental diagram that the embodiment of the present invention 1 carries out IMAQ；
Fig. 6 is the internal system attachment structure schematic diagram of the embodiment of the present invention 2.
Embodiment
The present invention is described in further detail with reference to the accompanying drawings and examples.
Embodiment：
Embodiment 1：As shown in Figures 2 and 3, a kind of double lens image acquisition and processing unit for DPM code readers,Including the camera device, image pre-processing unit and main control unit being electrically connected to each other, the camera device has two, interval oneSet a distance is installed, and the optical lens optical axis of two camera devices is angled；Control of the camera device in main control unitDPM codes are shot from different angles under system, and the image photographed is sent to image pre-processing unit；Described imagePretreatment unit receives the DPM codes of camera device shooting and correction is merged into each other and compensated to image, so as to be correctedDPM code images.
In the present embodiment, a kind of double lens image acquisition and processing unit for DPM code readers, in addition toThe auxiliary lighting apparatus of main control unit electrical connection, the auxiliary lighting apparatus is positioned at the centre of two camera devices and is arranged onThe periphery of two camera devices, it illuminates DPM code targets under main control unit control.
In the present embodiment, the optical axis included angle scope of the optical lens of the camera device is 0 degree to 150 degree.
In the present embodiment, described two camera devices use optical parametric identical camera lens.
In the present embodiment, the camera device includes the optical lens and imaging device set gradually, the imaging deviceFor ccd image sensor or cmos image sensor, electrically connected with main control unit.In wherein Fig. 3,21 and 22 be optical framesHead, 31 and 32 be imaging device.
In the present embodiment, by between optical lens and optical lens periphery sets the He of auxiliary lighting apparatus 12 respectively11, and the target area of the light irradiation sent by main control unit control auxiliary lighting apparatus 11 and 12, make it in the targetHeart district domain forms a hot spot for being different from ambient lighting, and the light of target area scattering projects corresponding take the photograph respectively by camera lensAs on device, it is possible to provide field range indicates and improved object illumination.The light source of auxiliary lighting apparatus 11 and 12 is feux rouges.
In the present embodiment, auxiliary lighting apparatus, camera device and image pre-processing unit are under the control of main control unitCooperate；Auxiliary lighting apparatus illuminates target area under the control of main control unit, and camera device is in main control unitThe image photographed is sent to image pre-processing unit under control, image is merged by image pre-processing unit, compensatedWith correction.
For common printed code, DPM codes are to play the industry such as shock, electrochemical corrosion by laser-induced thermal etching, machineMeans are formed in the direct mark code in the surface of part, and material surface convex-concave information is so just only existed on surface, and are not presentThe optics monochrome informatio of high-contrast, the picture quality for being difficult to collect sharp picture or collect using general lighting technologyDifference, the operation principle of its IMAQ is as shown in figure 4,20 be optical lens in figure, and 01 is material surface, and 02 is DPM codes concave surface,03 is material surface 01 and the interface of DPM codes concave surface 02, and 01,02,03 imaging corresponding part is 301,302 and 303, itsThe middle imaging 303 of interface 03 only has a very thin profile, it is difficult to differentiates.
And the present embodiment is shot using two independent camera devices to DPM codes, every camera device is for waiting to clapTaking the photograph target has a different imaging angles, and the operation principle of its IMAQ is as shown in figure 5,21 and 22 be two camera lens in figureHead, 04 is material surface, and 05 is DPM codes concave surface, and 06 is material surface 04 and the interface of DPM codes concave surface 05,04,05,06 instituteInto two images fusion after corresponding part be 301,302 and 303, it can be seen that the visual angle due to double camera devicesDifference, more target side-informations can be photographed, after two images are merged, the picture 306 corresponding to interface 06 hasLarger area and clearly profile, resolution capability greatly improve.When concavo-convex DPM codes imaging to material surface be present, left side is taken the photographAs device can obtain information on the left of more targets, right side camera device can obtain information on the right side of more targets.Relative to oneThe DPM code readers of individual camera device, the present embodiment can increase light-inletting quantity, strengthen shooting effect during insufficient light；Also, extremelyThe optical lens optical axis of a rare filming apparatus is not orthogonal to material surface where DPM codes, and the mode of this tilt is dashed forwardThe limitation that three-dimensional target is shot from vertical angle has been broken, while has gathered image from different angles, each image is merged into each other and mendedCorrection is repaid, more target three-dimensional spatial informations can be obtained, improves resolution capability of the system to DPM codes.
Embodiment 2：As shown in fig. 6, a kind of DPM code recognition devices based on twin-lens, including above-mentioned read for DPM codesThe double lens image acquisition and processing unit of device, in addition to decoding apparatus 5 are read, the decoding apparatus 5 receives image preprocessing dressPut the complete image of 4 processing and solve the information that DPM image in 2 D code is included.
The decoding apparatus 5 electrically connects with main control unit 7 and image preprocess apparatus 4 respectively, described image pretreatmentDevice 4 also electrically connects with main control unit 7.
Image preprocess apparatus is merged to image, after complementary and correction, under the control of main control unit, will be located in advanceManage the image that finishes and be sent to decoding apparatus, the information that DPM image in 2 D code included is solved by decoding apparatus.
The DPM code recognition devices based on twin-lens also include the communication device 6 electrically connected with main control unit 1.