Method and apparatus for producing timber

Abstract

To provide a method for processing a tree trunk by which a manufactured timber has required quality and good yield of the timber is obtained.SOLUTION: A method for separating and processing a tree trunk 1 comprising a spatial arrangement of sub-products and main products, forming a substantially flat surface 10 of the main products and sub-products, performing a quality inspection of the surface 10 in order to identify defect characteristics of the timber, and producing timber from the tree trunk 1 divided into at least two main product boards or two sub-product boards 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for producing timber from tree trunks. [Background technology]

[0002] In industrial timber processing, tree trunks are processed, inter alia, into boards, and it is desirable to obtain the highest possible timber yield. To this end, the trunks to be processed are generally examined for their dimensions, and a so-called cutting scheme is determined. This cutting scheme indicates the possible arrangement of the timber relative to the trunk's dimensions. The aim is to obtain the desired high timber yield by processing the trunks according to this cutting scheme.

[0003] The cutting method is generally determined by scanning the trunk with a profile sensor during the feed motion. The shape and dimensions of the trunk are determined based on the measurement data obtained, and the arrangement of the boards to be obtained is determined based on the shape and dimensions. The so-called main product boards are generally located in a cross-sectional area that is on the inside of the trunk, while the by-product boards are located in a cross-sectional area that is on the outside of the main product boards. Summary of the Invention [Problem to be solved by the invention]

[0004] One problem is that tree trunks can have various quality defects that are not visible from the outside and cannot be taken into account when determining the cutting method based on the external shape and dimensions of the trunk. Therefore, although processing tree trunks according to a cutting method generally results in a high lumber yield, it is possible to produce boards that do not have the desired quality.

[0005] The object of the present invention is to propose a means by which tree trunks can be processed with a good timber yield and the timber produced has the required quality. [Means for solving the problem]

[0006] This problem is solved by a method according to claim 1 and a device according to claim 10. Advantageous developments are the subject of the dependent claims.

[0007] The method according to the invention is used to produce timber from tree trunks and comprises the following method steps: A) determining a first cutting scheme for a trunk, comprising the spatial arrangement of by-products and main products; B) separating and processing the trunk according to a first cutting method, in which a substantially flat surface of the main product or by-product is formed; C) performing a surface quality inspection to identify at least one timber defect and / or timber defect characteristic; D) determining a second cutting scheme depending on the identified timber defects and / or timber defect characteristics, wherein at least one area of ​​the main product or the by-product is divided into at least two main product boards or two by-product boards according to the first cutting scheme and / or the division of the at least two main product boards or the at least two by-product boards is changed relative to the first cutting scheme; E) A step of separating and processing the trunk by a second cutting method.

[0008] The method according to the invention is based on the recognition that the trunk after the surface of the main product or by-product is formed is subjected to a quality inspection to determine a second cutting method that can achieve a good timber yield and the desired board quality compared to the first cutting method. This is achieved in particular by sorting into a plurality of main product or by-product boards or modifying an already existing sorting in the first cutting method according to the detected timber defects and / or timber defect characteristics, without the need to reject areas with main product or by-product defects.

[0009] It is important that the decision on the second cutting method be made in response to timber defects and / or timber defect characteristics. This is based on the recognition that the quality of the main product board or by-product board and therefore the attainable market price will fundamentally depend on whether the board has timber defects, how many timber defects there are, and to what extent the defects are. This is important to the present invention because optimizing the first cutting method described herein may involve reducing the width of the main product board or by-product board by deciding on the second cutting method, which generally involves economic losses.

[0010] However, economic analysis has surprisingly shown that the market value of the main or by-product boards can be advantageously increased if they are produced in relatively narrow dimensions, particularly narrow widths, according to quality. The achievable increase in market value of such main or by-product boards, particularly by reducing lumber defects, can be greater than the corresponding decrease in market value due to a reduction in size, particularly width. At the same time, the lower-quality, separated main or by-product boards, respectively, can be used in applications that do not necessarily require high quality, which can also provide economic benefits.

[0011] In principle, when carrying out the method of the present invention, it is not important whether the surface inspected in method step C) corresponds to a main product or a sub-product. Thus, the aforementioned advantages are obtained regardless of whether the determination of the second cutting method includes dividing the main product or the sub-product. However, it may be advantageous to divide the main product into at least two main product plates and / or change the division according to the first cutting method after performing a quality inspection of the surface of the main product. Similarly, it may be advantageous to divide the sub-product into at least two sub-product plates and / or change the division according to the first cutting method after performing a quality inspection of the surface of the sub-product. In other words, the main product obtained by the first cutting method may comprise at least one first main product plate, which may be divided into at least second and third main product plates by the second cutting method.

[0012] Correspondingly, the by-product from the first cutting method can comprise at least one first by-product slab, and the second by-product slab can be divided into at least second and third by-product slabs by the second cutting method.

[0013] Method step A) may be performed by moving the trunk along the feed direction until it reaches and crosses the detection area of ​​one or more profile sensors. The profile sensors may be laser or light section sensors or similar sensors capable of determining three-dimensional data at least partially representative of the trunk geometry. In particular, the profile sensors may be fixedly positioned in relation to the feed movement of the trunk. The trunk geometry is preferably determined as a function of the trunk feed speed.

[0014] The determined trunk geometry can be in the form of a three-dimensional model, in particular based on a point cloud, from which one or more cross-sectional shapes of the trunk can be deduced. The first cutting scheme determined in method step A) preferably indicates, based on the determined trunk geometry, how the main product and the by-products, in particular the main product slabs and by-product slabs they comprise, are arranged relative to the trunk or the determined trunk geometry in relation to said geometry. In particular, according to the first cutting scheme, the main product can comprise one or more main product slabs, and the by-product can comprise one or more by-product slabs. In particular, according to the first cutting scheme, multiple main product slabs and / or by-product slabs can be present per bundle. According to the first cutting scheme, at least two main product slabs or at least two by-product slabs can be arranged in pairs in the same plane extending essentially parallel to the long sides of the main product or by-product slabs, respectively. It is also within the scope of the present invention that the first cutting scheme determined in method step A) does not comprise the division of the main product or by-product boards, but only indicates possible arrangements of the main product or by-product boards relative to the trunk, which can be divided in particular in method step D) in order to define the dimensions and arrangement of the main product or by-product boards to be obtained relative to the trunk.

[0015] Method step B) can be carried out by separating the bark region from the trunk by sawing a portion of the trunk or by milling the bark region into wood chips. It is essential that method step B) results in the formation of at least one straight side surface forming the surface of the main product or by-product present on the trunk. In particular, the surface of the main product or by-product is the long side of at least one main product plank or at least one by-product plank. As mentioned above, such a main product or by-product plank can be one that has already been included in the first cutting method determined in step A).

[0016] It is within the scope of the invention that one or more flat surfaces are formed in method step B). In particular, the trunk after carrying out method step B) can be a so-called timber or model, which has two or four straight sides distributed over the periphery of the timber or model and which are separated from one another in particular by rounded edge regions in pairs. Since the surfaces of the main or by-products in method steps B) and C) are not the final surfaces of the main or by-product boards to be produced, it is within the scope of the invention that these surfaces can be reworked, for example by planing, especially after method step D).

[0017] Method step C) comprises a quality inspection of the surface of the main product or the sub-product, which may be performed using one or more optical inspection systems, each equipped to obtain two-dimensional and / or three-dimensional image data of the surface of the main product or the sub-product.

[0018] In particular, during the quality inspection in method step C), a geometric profile and / or a two-dimensional inspection image is determined. The geometric profile may indicate three-dimensional geometrical characteristics of the surface of the main product or by-product and may be determined in particular as a function of the feed speed of the trunk. In particular, the optical inspection system may comprise a profile sensor that is configured to be identical or at least equivalent to the profile sensor used to determine the trunk geometrical characteristics. The inspection image may comprise a two-dimensional distribution of grayscale values ​​and / or in particular red, green, and blue color values ​​on the image plane. In particular, the two-dimensional data does not comprise a profile of the surface extending perpendicularly to the surface. The optical inspection system is preferably positioned relative to the trunk in such a way that the depth of field, in particular extending parallel to the focal plane of the optical inspection system, extends essentially parallel to the inspected surface of the main product or by-product during the implementation of method step C).

[0019] Timber defects may comprise branch channels and / or knotholes and / or splits and / or warping and / or discolouration and / or decay and / or sapwood and / or insect damage. Timber defect characteristics may describe the specifications of the timber defect, in particular any one of the aforementioned timber defects, such as the spatial location on the surface of the main product or by-product and / or the spatial extent of the timber defect.

[0020] Method step C) may comprise a data processing step in which the collected image data is evaluated to determine timber defects and / or timber defect characteristics. Preferably, the data processing step comprises image processing, in particular filtering and / or edge detection and / or segmentation and / or morphological processing and / or feature extraction and / or pattern recognition and / or pattern classification and / or texture analysis and / or histogram analysis, in order to detect timber defects and / or timber defect characteristics. Furthermore, it is within the scope of the present invention for the data processing step to comprise the use of analysis algorithms based on AI and / or machine learning.

[0021] Method step D) comprises determining a second cutting scheme, which includes different specifications for the main product and the secondary product compared to the original first cutting scheme. In this case, it is possible to separate the main product board or secondary product board determined in the first cutting scheme into at least two main product boards or two secondary product boards, or to change, for example, the size ratio, particularly the width ratio, or the respective positional relationship to the trunk, of two adjacent main product boards or secondary product boards already separated. In particular, the main product or secondary product is separated into at least two main product or secondary product boards such that a separation plane is defined that is essentially perpendicular to the inspected surface of the main product or secondary product, or such that the separation between the two main product boards or secondary product boards is changed, and such a separation change is carried out by shifting, particularly by offsetting such separation plane in a parallel manner, so that the width, particularly of the main product or secondary product, is changed.

[0022] The separating process according to method step E) is carried out in accordance with the second, optimized cutting strategy determined in method step D) and comprises in particular the production of separate main-product and by-product plates, in which two rounded edge regions adjacent to the surfaces of the main-product and by-product are milled, and the separate main-product and by-product plates can be separated from each other or from the trunk by one or more saw cuts.

[0023] In an advantageous development, in method step C), defects in the timber are detected spatially resolved on the surface and the defect location and / or spatial defect extent are determined.

[0024] The spatially resolved detection of timber defects makes it possible to determine the position of the timber defect relative to the trunk or detected trunk geometry and, in particular, to derive a second cutting strategy depending on said position.In a simple embodiment, an optical inspection system usable in method step C) may be calibrated so that it is able to determine and detect the position and / or extent of the defect on the surface, in particular relative to the trunk geometry, directly on the basis of the collected inspection data.

[0025] In an advantageous development, defects in the timber, in particular their location and / or extent relative to the trunk, can be detected spatially resolved in relation to the rounded edges and / or rounded edge regions which laterally delimit the surface of the main product or by-product, respectively, whereby the rounded edges and / or rounded edge regions are detected before and / or during method step C).

[0026] The aforementioned development is based on the realization that the edge of a trunk, in particular a timber or a model, and / or the edge of a trunk area can be used to simplify the spatially resolved detection of timber defects and / or timber defect characteristics in relation to the trunk, in particular a timber or a model. In this case, the edge of a trunk represents a profile extension along the trunk axis that occurs during the separate processing of the trunk in method step B) and directly limits the lateral surface of the main or by-product. The edge of a trunk area is directly adjacent to the edge of a trunk and represents the geometrical shape of the trunk's outer surface as it naturally grows, or, in the case of a timber or a model, particularly a part of this shape. The edge of a trunk, as well as the edge of a trunk area, can have a corresponding individual extension due to the individual growth of the trunk, which can be used as a criterion for the location of timber defects and / or the extent of the timber defect relative to the trunk or timber or model.

[0027] In particular, the stem geometry detected for method step A) may contain rounded edges and / or rounded edge areas, which can be used as a reference for determining the defect location and / or extent in relation to the trunk or timber or model stem geometry. It is therefore advantageous to use the stem geometry, which comprises rounded edges and / or rounded edge areas, detected before and / or during method step A) for determining the first cutting strategy.

[0028] In particular, in method step D), a comparison is made between the three-dimensional extension of the rounded edge area contained in the trunk geometry determined in method step A) and the three-dimensional extension of this rounded edge area contained in the inspection result of the three-dimensional inspection in method step C), and it is possible to accurately determine the position and / or extent of the defect in relation to the trunk, in particular the timber or model.

[0029] Alternatively or additionally, in method step D), a comparison is made between the two-dimensional extension of the rounded edge area contained in the profile cross-section of the trunk geometry determined in method step A) and the two-dimensional extension of this rounded edge area contained in the inspection result of the two-dimensional inspection in method step C). In particular, the profile cross-section extends essentially parallel to the trunk axis. This makes it possible to accurately determine the location and / or extent of the defect in the trunk, in particular in the timber or model.

[0030] In an advantageous development, one optical measuring device or several different optical measuring devices are used for the image inspection of the surface of the main product or by-product before and / or during method step C) and for the detection of the rounded edges and / or rounded edge regions.

[0031] In a possible embodiment of the aforementioned preferred development, the optical measuring device may comprise an imaging camera that detects not only the surface of the main product or by-product but also the rounded edge and / or rounded edge region adjacent to said surface. This makes it possible to determine with high precision, spatially resolved, the position and extent of timber defects that are detectable using only one surface image, in relation to the geometry of the trunk, in particular as a function of the rounded edge and / or rounded edge region. In particular, the at least one optical measuring device may be configured to inspect the surface of the main product or by-product only two-dimensionally, in particular without providing any estimates regarding the geometric profile of the inspected surface.

[0032] In one possible embodiment of the preferred development described above, multiple optical measuring devices can be used to detect the surface and the rounded edge and / or rounded edge regions of the main product or by-product, respectively, separately. This allows the optical measuring devices to be optimized for the measurement task to be performed. In particular, the measuring devices have relative positions relative to one another, which allow the detected rounded edge or rounded edge region and the surface image to be spatially correlated with each other. In particular, it is within the scope of this embodiment for the rounded edge and / or rounded edge region to be determined by a profile sensor and for the surface of the main product or by-product to be inspected by an imaging sensor. In this case, it is possible for the profile sensor to at least partially detect the surface, but not use the surface profile data collected in this process for quality inspection.

[0033] In an advantageous development, method step D) is performed in response to a defect-dependent quality parameter, in particular such that at least one of the main-product or by-product boards separated by method step D) differs from the respective other separated main-product or by-product board with respect to one or more timber defects and / or defect characteristics. It is also within the scope of preferred developments that the main-product or by-product boards are separated so that they do not differ with respect to the quality parameter. This can be advantageous if the total number of defects detected on the surface of the main-product or by-product can be evenly distributed over the separated main-product and by-product boards by separating by the second cutting method, thereby achieving a desired ratio of the number of defects or timber defect characteristics to the width dimension of the separated main-product or by-product board.

[0034] The quality parameter can be considered as at least one characteristic value that contains information about how pronounced a quality-related characteristic is in the surface of the main product or by-product or in a single sheet of the separated main product or by-product. In particular, the surface of the main product or by-product before method step D) can have a first quality parameter, and the separated sheets of the main product and by-product, respectively, can have a second quality parameter.

[0035] This advantageous development is not limited by the definition of the quality parameter. The quality parameter can be user- or device-dependent and may conceivably depend on the timber defect and / or the timber defect characteristics. In particular, it may be an indication of the presence or absence of a timber defect and / or the extent of the timber defect characteristics. In particular, it is possible to determine a plurality of quality parameters for carrying out method step D), in particular position-dependently in relation to the surface inspected in method step C).

[0036] The quality parameter relates to the surface of the main or by-product from method step C) and may for example indicate the number of timber defects detected and / or the relationship between the timber defect properties and the surface dimensions.

[0037] In particular, threshold values ​​can be defined for carrying out method step D), the quality parameters of which must not be above or below which the separation of the main product or by-products is carried out and in particular the dimensions and positions of the separated main product and by-product plates according to the second cutting method are determined.

[0038] Thus, in a simple example, the quality parameter can be the number of timber defects on the surface of the by-products, determined and detected in method step C), where said number exceeds a threshold number of timber defects.It is then conceivable to carry out a second, optimized cutting strategy for separating the main product or the by-products such that one board of the main product or the by-product has no timber defects and the respective other board of the by-product has all the detected timber defects.

[0039] Similarly, it is conceivable that the separated main or by-product boards do not differ with respect to the number of timber defects, based on the recognition that the main or by-product boards should be assigned to the same quality class after separation or rescaling, or may be characterized by the same quality parameters, but may be valued higher due to the separation cut compared to larger, unseparated boards.

[0040] The density of defects, the location of defects or the type of defects can also be used to determine the aforementioned quality parameters, and here again it is fundamentally immaterial how these parameters are determined and how they are taken into account when classifying the main or sub-products.

[0041] In an advantageous development, in method step C), the defects detected in the timber are at least partly formed by branch passages, which extend from the surface through at least the main product or by-product.

[0042] In particular, the defects detected in timber may comprise a cross section of a branch passage or a part of said cross section and / or the location of the branch passage formation. Within the scope of the invention described herein, the term "branch passage (Ast)" may mean a part extending into the interior of the trunk or timber, and in particular may refer to a part extending from the surface of the main product or by-product into the interior of the trunk.

[0043] Research has shown that branch passages can be a timber defect that affects the quality of the board as well as the economic value of the board. However, it is not necessary to reject or exclude from reprocessing main- or by-product boards affected by branch passage formation. Rather, it is advantageous to reprocess the main- or by-product boards affected by branch passage formation in a way that adds value to them. Although such boards will usually have lower quality than boards not affected by branch passage formation, they may be suitable for technical uses that have relatively low requirements for board quality.

[0044] In an advantageous development, in method step B) at least one first by-product board is separated from the trunk by a first cutting method, thereby obtaining a flat surface of the by-product on the trunk, on which surface at least method step C) is carried out.

[0045] According to the aforementioned development, the by-product obtained by the first cutting method in method step A) may comprise a bundle of multiple by-product boards. In this case, the separating process in method step B) is carried out by removing not only the bark region of the trunk but also one by-product board of the by-product bundle, thereby exposing the surface of the underlying by-product board of the by-product bundle, which is then inspected in method step C). Preferably, the inspected by-product board in method step C) is separated into two by-product boards in method step D), which are then separated from the trunk in method step E).

[0046] It is known that the first by-product boards of a bundle of by-products usually have particularly small width dimensions compared to the boards of the underlying by-products. This is because the width of the trunk decreases in the radial direction due to its round cross section, and the width of the boards of the outer by-products is correspondingly smaller. Therefore, from an economic point of view, it is not worth considering the outer by-product boards in the second, optimized cutting scheme. If the first by-product boards are divided, it is possible to obtain two partial boards, one of which has fewer wood defects than the other. However, since the width dimension of the first by-product boards is generally narrow, further dividing them into two partial boards does not bring about significant economic benefits. In other words, it is advantageous to determine the second, optimized cutting scheme in relation to the surface based on the boards of the underlying by-products, in particular the boards of the second by-product, rather than based on the cutting scheme of method step A) in relation to the first by-product board.

[0047] In an advantageous development, in method step D) the main product or the sub-product is separated in such a way that a separation plane is formed which extends essentially perpendicular to the surface of the main product or the sub-product and separates the two main product sheets or the two sub-product sheets and / or is offset.

[0048] The separation surface indicates the spatial separation between two main or sub-product sheets in the second cutting mode according to method step A) or in the second, optimized cutting mode according to method step D). The separation surface can be an imaginary area that separates the main or sub-product sheets in order to separate the two main or sub-product sheets from each other in method step D).

[0049] In method step E), a cleft is formed in the by-product, which extends in particular along the separation plane and then separates the two by-product plates thus separated from one another from the trunk by a separation cut. This makes it possible to process the trunk in a simple manner according to the second optimized cutting strategy. The formation of the cleft can be carried out by means of a scoring saw, which spatially divides the by-product into at least two by-product plates by engaging with the trunk during the feeding movement of the trunk to separate them at the surface of the by-product.

[0050] As mentioned above, the problem is also solved by an apparatus for producing timber. The apparatus comprises conveying means for conveying tree trunks along their trunk axes in a main conveying direction and at least one profile sensor arranged to determine the trunk geometry during the conveying movement of the trunk. The apparatus further comprises a data processing unit, which is signal-technically coupled to the profile sensor and is configured to determine a first cutting strategy depending on the trunk geometry. The first separating means is configured to engage the trunks for separation during the conveying movement and to form an essentially flat main product or by-product surface by the determined cutting strategy. At least one quality sensor is arranged to inspect the surface of the main product or by-product and is configured to determine at least one timber defect and / or timber defect characteristic in the surface. The quality sensor and the data processing unit are signal-technically coupled to each other, and the data processing unit is configured to determine a second cutting strategy depending on the timber defect. In this case, the main product or the sub-product is divided into at least two main product plates or two sub-product plates and / or the division of the cutting scheme of the two main product or sub-product plates is modified with respect to the first cutting scheme, and the second separating means is arranged and configured to engage the trunk for machining during the conveying movement and to process the trunk according to the optimized cutting scheme.

[0051] In particular, the device according to the invention is suitable for carrying out the method according to the invention or advantageous developments thereof. In particular, the method according to the invention or advantageous developments thereof can be carried out by the device according to the invention or advantageous developments thereof. In this respect, the above-mentioned remarks regarding the method apply accordingly with regard to possible embodiments of the device and the advantages thereby obtained. [Brief explanation of the drawings]

[0052] The advantages and possible embodiments of the present invention will be explained below on the basis of exemplary embodiments and drawings. [Figure 1] 1 shows the determination of the first cutting method for the trunk. [Figure 2] Figure 1 shows the surface profiling of by-products on the trunk depending on the cutting method. [Figure 3] Shows quality inspection of the surface of the by-product. [Figure 4] 1 shows the determination of a second, optimized cutting scheme for the trunk, in which the by-product boards are separated. DETAILED DESCRIPTION OF THE INVENTION

[0053] In industrial timber processing, tree trunks are generally processed into boards obtained from different cross-sectional areas of the trunk: boards obtained from the inner cross-sectional area of ​​the trunk are called main product boards, whereas boards obtained from the outer cross-sectional area are called by-product boards.

[0054] To achieve a good lumber yield, the trunk is typically scanned with a profile sensor, and the cutting method is determined based on the data obtained. The cutting method indicates how the main-product and by-product boards should be arranged and what their dimensions should be relative to the trunk's geometry to achieve a good lumber yield. To obtain the main-product and by-product boards, the trunk is typically first cut into lumber according to the cutting method, which creates a flat surface for the by-product, essentially a flat side, so that the surface can be profiled at the trunk. The problem is that trunk profile data often fails to identify all lumber defects and fully consider them when determining the cutting method, leading to a high percentage of poor-quality boards. Based on Figures 1 and 4, a method and the means necessary for implementing the method are described, which enable a high lumber yield to be achieved while maintaining the desired quality of the formable boards.

[0055] 1 shows a tree trunk 1, which has an essentially cylindrical basic geometry extending along its trunk axis 2. Due to the natural growth of the trunk, the trunk 1 has an irregular surface profile. For processing the trunk, the trunk 1 is conveyed in a feed direction 3 and reaches the detection area of ​​several profile sensors 4, of which only one profile sensor 4 is shown in the illustrated embodiment. The profile sensors 4 can, for example, each be configured as a laser-light section sensor.

[0056] The data detected by the profile sensor 4 is transmitted to the calculation unit 5, which determines the shape and dimensions of the trunk and a corresponding first cutting method 6, taking into account the relative movement between the trunk 1 and the profile sensor 4. As mentioned above, the first cutting method 6 includes a plurality of main product plates 7 arranged in a cross-sectional area on the inside of the trunk 1, and a plurality of by-product plates 8 arranged in a cross-sectional area on the outside of the trunk 1. For ease of understanding, only one main product plate 7 and one by-product plate 8 are labeled.

[0057] Figure 2 shows a trunk 1 being separated into regions according to the determined first cutting method 6. In this case, the trunk 1 is moved towards a cutter head 9 rotating along a feed direction 3, which engages the trunk 1 for separation. This separates the bark region from the trunk 1, forming a surface 10 of the by-product board 8 below the bark region. Instead of the cutter head 9 shown in Figure 2, it is also possible to provide a sawing means, which separates the bark region of the trunk 1 from the trunk 1 as a single unit, thereby forming the surface 10.

[0058] The processing of the trunk 1 shown in Figure 2 results in the formation of two rounded edges 11, which are adjacent to the surface 10 of the by-product board 8 and which, in the illustrated embodiment, extend essentially along the trunk axis 3. For clarity, only one of the rounded edges 11 is labeled. Opposite the rounded edges 11 extend respective rounded edge regions of the trunk 1, which are not labeled for clarity.

[0059] Removing the bark region and forming surface 10 exposes defects 12, which in the illustrated embodiment are branch passages extending from the interior of the trunk through by-product planks 8 to trunk surface 10. While such branch passages inherently reduce the quality of by-product planks 8, within the scope of the embodiments described herein, they do not necessarily require the rejection of the by-product planks 8 for reprocessing. Instead, an optimized cutting strategy for trunk 1 is determined by determining the location of branch passage formations in the trunk, as described in detail with reference to Figures 3 and 4.

[0060] According to Fig. 3, a machined tree trunk 1 is image-inspected, which may be in the form of a timber with two straight surfaces 10 or a so-called model with four straight surfaces 10. A camera system 13 is used for this purpose. It is important that the surfaces 10 on the one hand and the rounded edge 11 on the other hand are within the detection field of the camera system 13 so that they can be detected.

[0061] In order to be able to determine the position of the defect 12 relative to the trunk geometry, the camera system 13 can be calibrated so that the position data can be determined as a function of the position and movement of the trunk 1 and the image information as well as the time of the image capture. In the embodiment shown here, the blunt edge 11 or blunt edge area is detected in addition to the surface 10, and in this case the position of the defect relative to the trunk 1 is determined as a function of the blunt edge extension.

[0062] It is possible to carry out a comparison of the two-dimensional extension of the rounded edge contained in the determined trunk geometry (see FIG. 1) as well as in the test result of the two-dimensional inspection of the surface 10 (see FIG. 3). Accordingly, the position of the defect in relation to the trunk (or timber or model) and / or the extent of the defect can be determined precisely by comparison, in particular, of the two-dimensional extension of the rounded edge contained in the profile cross-section of the determined trunk geometry and the two-dimensional inspection image of the surface 10. In particular, the profile cross-section extends essentially parallel to the trunk axis, as shown in the side view according to FIG. 3.

[0063] If a profile sensor (not shown) is used in addition to the camera system 13, the detection of the surface 10 and the detection of the rounded edge region can be performed separately, with the rounded edge region being detected three-dimensionally and the surface 10 being detected two-dimensionally. The detected rounded edge region can then be compared with the determined trunk geometry (see FIG. 1) to accurately determine the defect location and / or extent relative to the trunk (or timber or model) depending on the relative positions between the camera system and the profile sensor.

[0064] FIG. 4 illustrates the determination of an optimized cutting strategy according to the defect location 12. In this case, the by-product board 8, whose surface 10 has been inspected by imaging, is separated by a separation plane 14 extending essentially perpendicular to the surface 10. This separates the by-product board 8 into two by-product boards, which differ from each other in the determined timber defect, i.e., the number of branch channels, which is described here by way of example. The trunk 1 is then processed according to the optimized cutting strategy. For this purpose, a scoring saw (not shown in detail) is used, which separates the by-product 8 according to the determined separation plane 14. Furthermore, two rounded edge regions 15 adjacent to the by-product are milled, so that the separated by-product boards have essentially straight, parallel short sides. The by-product boards can then be separated from the trunk 1 by sawing.

[0065] The principle of separating main-product or by-product boards, as explained herein with reference to Figures 1 through 4, is based on the recognition that the quality of a main-product or by-product board, and therefore its attainable market price, can essentially depend on whether the board has timber defects, the number of timber defects, and / or the severity of the timber defects. While a reduction in the theoretically obtainable width of a main-product or by-product board generally entails an economic loss, economic analysis has surprisingly shown that the market price of a main-product or by-product board can be advantageously increased when it is produced at a relatively narrower dimension, particularly in width, depending on the quality. In particular, the increase in the attainable market price of such a main-product or by-product board, due to the reduction in timber defects, can be greater than the decrease in market price due to the reduction in dimension, particularly in width. At the same time, the lower-quality separated main-product or by-product board, respectively, can be used for applications that do not necessarily require high quality, thus similarly achieving economic benefits.

[0066] As an alternative to the implementation of the present invention described herein, during trunk processing, it is possible to first separate one of the by-product boards from the trunk, thereby exposing the surface of the underlying by-product boards and subjecting them to imaging inspection. This is advantageous because the first by-product board in a bundle of by-product boards usually has a smaller width than the underlying by-product boards. This results in the outer by-product boards having correspondingly smaller dimensions, which, from an economic point of view, are not worth considering in the second, optimized cutting strategy. Therefore, it is possible to determine the second optimized cutting strategy based not on the surface of the first by-product board, but on the surface of the underlying by-product board, in particular the second by-product board.

[0067] Similarly, although not shown, it is possible to separate the main product in the inner region of the trunk into two main product boards instead of separating the by-product. Unlike the embodiment described here, the separation process of the trunk 1 described in connection with Figure 2 comprises the removal of the entire by-product, not just the bark region. This can be done according to the previous embodiment in Figures 1 to 4, or by separating the by-product from the trunk according to the first cutting scheme, rather than separating the by-product.

Claims

1. A method for producing timber from a tree trunk (1) comprising the following method steps: A) determining a first cutting scheme for the trunk (1), comprising the spatial arrangement of by-products and main products; B) separating and processing the trunk (1) according to the first cutting method, in which substantially flat surfaces (10) of the main product and the by-product are formed; C) performing a quality inspection of said surface (10) to identify at least one defect (12) in the timber and / or at least one defect characteristic of the timber; D) determining a second cutting scheme depending on the identified timber defects (12) and / or timber defect characteristics, wherein the main product or the by-product is divided into at least two main product boards or two by-product boards (8) for the first cutting scheme and / or the division of the at least two main product boards or the at least two by-product boards (8) is changed for the first cutting scheme; E) Separating and processing the trunk (1) by the second cutting method.

2. 2. The method according to claim 1, characterized in that in method step C) defects (12) of the timber are identified spatially resolved on the surface and by determining the defect location and / or spatial defect extent.

3. 3. A method according to at least claim 2, characterized in that before and / or during method step C), rounded edges and / or rounded edge areas which laterally limit the surface of each main product or by-product are identified, and defects and / or their extent in the timber relative to the trunk are spatially resolved as a function of the rounded edges and / or rounded edge areas.

4. 4. The method according to claim 1, wherein the method step D) is performed as a function of at least one defect-dependent quality parameter.

5. 9. The method according to claim 8, characterized in that at least two of the separated main product or sub-product plates (8) have a different number of defects, and / or a different density of defects, and / or different positions of defects, and / or different types of defects.

6. 6. The method according to claim 1, wherein the timber defects (12) identified in method step C) are at least partly formed by branch passages extending from the surface (10) at least through the main product or the by-product, and the identified timber defects (12) are in particular cross sections of branch passages or parts of cross sections of branch passages at the surface of the main product or the by-product.

7. 7. The method according to claim 1, wherein in method step B) at least one first by-product board (8) is separated from the trunk by the first cutting method, thereby forming a flat surface (10) of the by-product on the trunk (1), and at least method step C) is carried out on said surface (10).

8. 8. The method according to claim 1, wherein in method step D) the main product or the sub-product is separated by forming and / or offsetting a separation plane (14) which extends substantially perpendicular to the surface (10) of the main product or the sub-product and which separates two main product or sub-product plates (8).

9. 9. The method according to any one of claims 1 to 8, characterized in that in method step D) at least one split is formed and two or more of the main product or by-product boards are separated from the trunk (1) by separating cuts.

10. An apparatus for producing timber from tree trunks (1), using a method in particular according to any one of claims 1 to 9, conveying means provided for conveying the tree trunk (1) along its trunk axis in a main conveying direction (3); a profile sensor (4) arranged to determine the geometry of the trunk (1) during its transport movement; a data processing unit (5) that is signal-technically coupled to the profile sensor (4) and is configured to determine a first cutting method depending on the geometry of the trunk; a first separating means (9) configured and arranged to engage the trunk (1) for separation during the conveying movement and to form a substantially flat surface (10) of the main product or by-product according to the first cut mode determined; a quality sensor (13) arranged to inspect the surface (10) of the main product or the by-product and configured to identify at least one timber defect (12) and / or timber defect characteristic on the surface (10), the inspection sensor (13) being signal-technically coupled to the data processing unit (5), the data processing unit (5) being configured to determine a second cutting scheme depending on the timber defect (12), and the main product or the by-product is divided into at least two main product boards (8) or two by-product boards (8) for the first cutting scheme and / or the division of the first cutting scheme of the two main product or by-product boards is changed; and at least one second separating means configured to engage said trunks for machining during said conveying motion and to process said trunks according to said second cutting manner.

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