CN102196148A - Image processing method, image processing equipment and image scanning equipment - Google Patents
Image processing method, image processing equipment and image scanning equipment Download PDFInfo
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- CN102196148A CN102196148A CN2010101166275A CN201010116627A CN102196148A CN 102196148 A CN102196148 A CN 102196148A CN 2010101166275 A CN2010101166275 A CN 2010101166275A CN 201010116627 A CN201010116627 A CN 201010116627A CN 102196148 A CN102196148 A CN 102196148A
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Abstract
The invention provides an image processing method, image processing equipment and image scanning equipment. The method can correct the shadow in the binding part on a scanned image of an opened book. The image processing method comprises the following steps of: determining the binding part, namely determining the binding part on the scanned image; generating a shadow data mapping graph, namely generating the shadow data mapping graph formed by the shadow data of the determined binding part according to the pixel value in the top part and the pixel value in the bottom part of the determined binding part; and correcting, namely correcting the shadow in the determined binding part by using the generated shadow data mapping graph. The implementation of the method is very quick, easy and cheap, and good correcting performance can be realized.
Description
Technical field
The present invention relates to a kind of image processing method, image processing equipment and image scanning apparatus, relate in particular to image processing method, image processing equipment and the image scanning apparatus of the shade in the bookbinding part on the scan image of the books that can proofread and correct expansion.
Background technology
Image reading apparatus (image scanning apparatus) is widely used in many occasions, and is particularly useful in office, library etc.A problem that exists in the normal image scanner is, when the bookbinding document of scanner scanning books type (following will be called " books "), rise above the flat of scanner in the bookbinding zone of books, that is, leave the focal plane of scanner and erect.As a result, the part (following will being called " bookbinding part ") corresponding to the bookbinding zone of books distorts, has shade and fuzzy on the scan image.Especially true for thick relatively books.
As one of current disclosed technology about shadow removal, United States Patent (USP) discloses for No. 6839459 a kind of by using the one dimension grading function that is weighted based on the relative distance from the position determined to the bookbinding center line to proofread and correct the technology of the shade the bookbinding part on the scan image of books of expansion.Described grading function calculates according to page boundary and bookbinding center line.The shortcoming of this method is in order to estimate accurate grading function, must very accurately detect page boundary and bookbinding center line.Yet, when on page boundary, interference being arranged (for example when the area of the book cover of books greater than page time), will be difficult to accurately detect page boundary.In addition, when the condition such as lighting condition in the bookbinding zone of the head portion of books and bottom part (this may because books cause in scanning, be pushed the time) not simultaneously, can't shadow model be described by single grading function.
United States Patent (USP) 6041146 has proposed a kind of method that is used for by using additional reference pressing plate to come the shade on the correct scan image, and described additional reference pressing plate is arranged on the position that is different from document surfaces, in order to record reference background information.Yet this additional reference pressing plate will increase hardware cost, and this method can not be used to handle by not having the scan image of this scanner acquisition with reference to pressing plate.
US patent application publication discloses a kind of equipment that is used for the shade on the fine correction scan image No. 20080024845.In this equipment, analyze the pixel value of view picture input picture, to determine dash area, and analyze away from the dash area of top page edge and bottom margin edge than upper section with than the pixel value of below part, make by considering that two above analysis results determine the inclination of input picture.After determining and having adjusted the inclination of input picture, utilize the corrected value that produces from the analysis result of view picture input picture, in each row, implement treatment for correcting.By utilizing the analysis result of view picture input picture is proofreaied and correct shade in No. 20080024845 disclosed method of US patent application publication, thus very complicated, and spend a large amount of calculating.In addition, the method is not used usually the margin shadow information as a setting of less top that is interfered and lowermost end.
Summary of the invention
The processing of partly proofreading and correct (removal) shade for the bookbinding from scan image, when removing shade effectively, keep the literal that prints on the books and picture and not drop-out be important.
The present inventor notices, for the page-images of majority from books, the top of page part and lowermost end part always have more white space than the interior section of the page, and most books even at the top of the page partly and the lowermost end margin that partly has complete blank.Can very well indicate about the background luminance background information of (it can be represented by pixel value) corresponding to the blank parts in the scan image of the white space in the books, it only depends on that the lighting condition of scanning light source and books are placed on the mode on the flat, and with books in the content of printing irrelevant.Therefore, top part in the bookbinding part and the blank parts in the lowermost end part can be very useful in this background information of extraction, because these parts less are subjected to the interference of the content of printing in the books.
In addition, the present inventor is also noted that the shade that occurs does not generally have unexpected variation in scan image, and the pixel value of scan image is especially very mild and near linear to the variation of bottom from the top.
Consider the technical problem that in above-mentioned prior art, exists and above-mentioned inventor's observation, image processing method, image processing equipment and the image scanning apparatus of the shade in the bookbinding part on the scan image of the books that can proofread and correct expansion is provided.According to the present invention, generate the shadow data mapping graph that is used for this bookbinding part according to top part in the bookbinding part of scan image and the pixel value (expression brightness) in the lowermost end part, remove shade according to the shadow data mapping graph that is generated from the bookbinding part then.
According to an aspect of the present invention, a kind of image processing method is provided, described image processing method can be proofreaied and correct the shade in the bookbinding part on the scan image of books of expansion, described image processing method comprises the steps: to bind the part determining step, determines the bookbinding part on the scan image; The shadow data mapping graph generates step, according to pixel value in the determined bookbinding top part partly and the pixel value in the lowermost end part, generates the shadow data mapping graph that is made of determined bookbinding shadow data partly; And aligning step, by using the shadow data mapping graph that is generated, proofread and correct the shade in the determined bookbinding part.
According to an aspect of the present invention, a kind of image processing equipment is provided, described image processing equipment can be proofreaied and correct the shade in the bookbinding part on the scan image of books of expansion, and described image processing equipment comprises: the bookbinding part is determined device, is used for determining the bookbinding part on the scan image; Shadow data mapping graph generating apparatus is used for generating the shadow data mapping graph that is made of determined bookbinding shadow data partly according to the pixel value of determined bookbinding top part partly and the pixel value in the lowermost end part; And means for correcting, be used for the shadow data mapping graph generated by using, proofreaies and correct the shade in the determined bookbinding partly.
According to an aspect of the present invention, provide a kind of image scanning apparatus, comprising: read control device, the image of books that is used to read expansion is to generate scan image; And aforesaid image processing equipment.
According to a preferred embodiment of the present invention, can be for example by at first top part by using determined bookbinding part and the pixel value in the lowermost end part estimate determined bookbinding partly the top and the shadow data of bottom, generate the top of determined bookbinding part and other shadow datas outside the bottom thereby then determined shadow data of binding top partly and bottom is carried out interpolation, generate whole determined bookbinding shadow data mapping graph partly.
According to a further advantageous embodiment of the invention, each row for determined bookbinding part, N the pixel the brightest central pixel corresponding pixel value of N pixel of search and the top of these row and lowermost end respectively, and the use described pixel value corresponding with the brightest described pixel is respectively as the shadow data of the top and the bottom of these row, wherein row are and determined bookbinding left border or the parallel pixel column of right side boundary partly, and N is predetermined positive integer.
According to a further advantageous embodiment of the invention, after estimating shadow data, handle the top of determined bookbinding part and the shadow data of bottom, make that the misdata in estimated shadow data is corrected for each row.
According to a further advantageous embodiment of the invention, in order to generate the shadow data mapping graph, at first generate the blank shadow data mapping graph that has identical size with determined bookbinding part, then the estimated shadow data of the bottom of the estimated shadow data on the top of the determined bookbinding part of filling, determined bookbinding part and the shadow data that generates from described interpolation in blank shadow data mapping graph.
Preferably, can be before the shadow correction, during the shadow correction or the geometric distortion of correct scan image after the shadow correction.
The image processing method that is used to proofread and correct shade according to the present invention is fully based on scan image data itself, and the auxiliary equipment without any need for additional does not require yet and accurately detects page boundary.
Further, according to the image processing method that is used for proofreading and correct shade of the present invention only the top part and the lowermost end part of the determined bookbinding part of analysis scan image.Specifically, the pixel value (expression brightness) that does not need to analyze in the whole determined bookbinding part is identified for proofreading and correct whole determined shadow data mapping graph of binding the shade in the part, but only based on determined top part and lowermost end this shadow data mapping graph of calculated for pixel values partly of binding part.Therefore, according to the method that is used to proofread and correct shade of the present invention fast, not expensive and implement easily.
From following description with reference to accompanying drawing, other property features of the present invention and advantage will become clear.
Description of drawings
Be incorporated in the specification and constitute the accompanying drawing diagram embodiments of the invention of a specification part, and with describe one and be used from explanation principle of the present invention.
Fig. 1 is the block diagram that the hardware configuration of the computer system 1000 that can implement embodiments of the invention is shown.
Fig. 2 is the block diagram that illustrates according to the image processing equipment 2000 of the shade of the bookbinding part of the scan image of the books that are used for proofreading and correct expansion of the present invention.
Fig. 3 is the flow chart of the processing of the shade in the bookbinding part that illustrates on the scan image of proofreading and correct the books that launch.
Fig. 4 is the flow chart that the exemplary process of the bookbinding part on the scan image of books of definite expansion according to a preferred embodiment of the invention is shown.
Fig. 5 illustrates the example for the determined books border of the scan image of the books that launch.
Fig. 6 illustrates the determined bookbinding part in the scan image of books of expansion of the example shown in Fig. 5.
Fig. 7 is the flow chart that the exemplary process of generation shadow data mapping graph according to a preferred embodiment of the invention is shown.
Fig. 8 is the schematic diagram that the example of error recovery shadow data is shown.
Fig. 9 illustrates the example of the shadow data mapping graph that generates for the determined bookbinding part in the example shown in Figure 6.
Figure 10 illustrates by the shadow correction data shown in Fig. 9 being applied to the example of the scan image behind the shadow correction that determined bookbinding part shown in Figure 6 obtains.
Embodiment
Describe embodiments of the invention in detail hereinafter with reference to accompanying drawing.
Note that similar project in similar Reference numeral and the character indicator diagram, and in case in a width of cloth figure, defined a project, then not need after figure in it is discussed.
At first, will the implication of some terms under the linguistic context of the present invention be described.
Term " books " is meant the document by the bind type that a plurality of sheet stitchings are formed together.Term " bookbinding zone " is meant the zone that comprises bookbinding center line and periphery thereof of the books of expansion.Term " bookbinding part " is meant the part corresponding to the bookbinding zone of these books of scan image of the books of expansion.
Term " top part " is meant the part comprising at least a portion of the top margin of books in the scan image.Term " lowermost end part " is meant the part comprising at least a portion on the border, bottom of books in the scan image.
Term " parallel " is meant substantially parallel.In the present invention, if two straight lines are called as " parallel ", this is meant the angle of their formation less than predetermined threshold.Term " quadrature " is meant quadrature basically.In the present invention, if two straight lines are called as " quadrature ", the difference between this angle and 90 that is meant that they form is spent is less than predetermined threshold.Above-mentioned loose definition for term " parallel " and " quadrature " is especially useful for the image of distortion.
Term " level " is meant substantial horizontal, and term " vertically " is meant perpendicular.In particular, the term " level " that uses in the file and picture of distortion is meant direction parallel with line of text in original document.For example, term " horizontal line " is meant that the line corresponding to this line is parallel with the line of text in the original document in original document.Similarly, the term " vertically " in the file and picture of distortion is meant in the original document in correspondence and the line of text quadrature.For example, term " vertical line " is meant in original document corresponding to the line of this line and the line of text quadrature in the original document.
Term " left side ", " right side ", " top " and " end " indication direction when the common mode when normally reading as people is watched books.
Term " shadow data mapping graph " is meant the mapping between each pixel in the bookbinding part on shadow information and the scan image.Be noted that the shadow data mapping graph can have various forms.For example, the shadow data mapping graph can have the form of form or mapping graph, and its shadow data by each pixel in the part of the bookbinding on the scan image constitutes, and is used to proofread and correct shade.The shadow data of a pixel can be the data of the estimated background pixel value (expression brightness) of this pixel of indication.Described pixel value for example can be in 0～255 scope.Scheme as an alternative, the shadow data mapping graph can have the form of shadow data function, and wherein shadow data is represented as mathematic(al) representation but not each single numerical value.As another alternative, the shadow data mapping graph can have the form of correction function, and when the input of correction function is that the original image with shade is when (for example being represented by pixel value), as the output of described correction function, with the image that generates after proofreading and correct.In addition, shadow data can be the estimated pixel value of former state, perhaps also can be by the normalized pixel value of the pixel value that presets.In brief, the notion of shadow data mapping graph should not be limited aspect its concrete form.
In this manual, unless point out with other modes, all sizes (such as length or width) are unit with " pixel ".
In the present invention, when mention between two line segments apart from the time, it indicates these two line segments to be regarded as distance therebetween under the situation parallel to each other.Not lucky when parallel to each other when these two line segments, distance therebetween for example can be by the distance definition from the mid point of a line segment to another line segment.
Fig. 1 is the block diagram that the hardware configuration of the computer system 1000 that can implement embodiments of the invention is shown.
As shown in Figure 1, computer system comprises computer 1110.Computer 1110 comprises processing unit 1120, system storage 1130, fixed non-volatile memory interface 1140, removable non-volatile memory interface 1150, user's input interface 1160, network interface 1170, video interface 1190 and the output peripheral interface 1195 that connects via system bus 1121.
Fixed non-volatile memory 1141 such as hard disk is connected to fixed non-volatile memory interface 1140.Fixed non-volatile memory 1141 for example can storage operating system 1144, application program 1145, other program module 1146 and some routine data 1147.
Removable nonvolatile memory such as floppy disk 1151 and CD-ROM drive 1155 is connected to removable non-volatile memory interface 1150.For example, floppy disk can be inserted in the floppy disk 1151, and CD (CD) can be inserted in the CD-ROM drive 1155.
Input equipment such as mouse 1161 and keyboard 1162 is connected to user's input interface 1160.
Output peripheral interface 1195 is connected to printer 1196 and loud speaker 1197.
Computer system shown in Figure 1 only is illustrative and never is intended to any restriction to invention, its application, or uses.
Computer system shown in Figure 1 can be incorporated in any embodiment, can be used as stand-alone computer, also can be used as the treatment system in the equipment, can remove one or more unnecessary assemblies, also can add one or more additional assemblies to it.
Fig. 2 is the block diagram that illustrates according to the image processing equipment 2000 of the shade of the bookbinding part of the scan image of the books that are used for proofreading and correct expansion of the present invention.As shown in Figure 2, image processing equipment 2000 comprises: the bookbinding part is determined device 2100, is used for the bookbinding part on definite scan image; Shadow data mapping graph generating apparatus 2300 is used for generating the shadow data mapping graph that is made of determined bookbinding shadow data partly according to the pixel value of determined bookbinding top part partly and the pixel value in the lowermost end part; And means for correcting 2500, be used for the shadow data mapping graph generated by using, proofreaies and correct the shade in the determined bookbinding partly.
Preferably, described shadow data mapping graph generating apparatus 2300 comprises: top estimation unit 2310, be used for pixel value by the top part of using determined bookbinding part, and estimate the shadow data on the top of determined bookbinding part; Bottom estimation unit 2330 is used for the pixel value by the lowermost end part of using determined bookbinding part, estimates the shadow data of the bottom of determined bookbinding part; And interpolating apparatus 2350, be used for interpolation is carried out on the top of determined bookbinding part and the shadow data of bottom, thereby generate the top of determined bookbinding part and other shadow datas outside the bottom.
Preferably, described bookbinding part determines that device 2100 comprises: be used for the top margin of definite books that launch and the device 2110 on border, bottom; And be used for determining the left border of described bookbinding part and the device 2130 of right side boundary, the top margin or border, the bottom quadrature of the described left border of determined bookbinding part and the books of right side boundary and described expansion.
Preferably, described top estimation unit 2310 comprises: be used for each row for determined bookbinding part, search and N pixel of the top of these row the brightest central pixel corresponding pixel value, and the use described pixel value corresponding with the brightest described pixel is as the device 2311 of the shadow data on the top of these row, wherein row are and determined bookbinding left border or the parallel pixel column of right side boundary partly, and N is predetermined positive integer; And/or be used for after estimating shadow data for each row, handling the shadow data on determined bookbinding top partly, make the device 2313 that misdata in estimated shadow data is corrected.
Preferably, described bottom estimation unit 2330 comprises: be used for each row for determined bookbinding part, search and N pixel of the lowermost end of these row the brightest central pixel corresponding pixel value, and the use described pixel value corresponding with the brightest described pixel is as the device 2331 of the shadow data of the bottom of these row, wherein row are and determined bookbinding left border or the parallel pixel column of right side boundary partly, and N is predetermined positive integer; And/or be used for after estimating shadow data for each row, handling the shadow data of determined bookbinding bottom partly, make the device 2333 that misdata in estimated shadow data is corrected.
Preferably, described shadow data mapping graph generating apparatus 2300 also comprises: be used to generate with determined bookbinding part and have the device 2370 of the blank shadow data mapping graph of identical size, and be used for filling the estimated shadow data of bottom of the estimated shadow data on the top of determined bookbinding part, determined bookbinding part and the device 2390 of the shadow data that generates from described interpolation at blank shadow data mapping graph.
Preferably, described image processing equipment 2000 also comprises distortion correction device 2700, is used for the geometric distortion of correct scan image.
More than device is the exemplary and/or preferred module that is used to implement the following process that will describe.The module that is used to implement each step is not below at large described.Yet,, just can be useful on the functional module or the device of the correspondence of implementing same process as long as the step of certain process of execution is arranged.The technical scheme that all combinations by step described below and the device corresponding with these steps limit all is included in the application's the disclosure, as long as these technical schemes that their constitute are complete and applicable.
In addition, the said system that is made of various devices can be used as functional module and is incorporated in the hardware unit of scanner or photocopier and so on.Except these functional modules, scanner or photocopier certainly have other hardware or software part.
Exemplary and/or preferred embodiment according to image processing method of the present invention below will be described.
Fig. 3 is the flow chart that the processing of the shade in the bookbinding part of scan image of the books that proofread and correct to launch is shown.
In step S301, the scan image of the books that input launches.
In step S303, the bookbinding part on the scan image of definite books that launch.A lot of prior art documents have proposed by for example utilizing the estimation of the distribution of the pixel value of bookbinding center line or whole scan image to be determined or locate bookbinding the whole bag of tricks partly in the scan image of books of expansion.The technology of any definite bookbinding part well known in the prior art all can be used.Especially,, determine that the method for bookbinding part also can use at this therefore only roughly because the present invention does not need accurately the determining of bookbinding part, and can sharp ground influence technique effect.
In step S305,, generate the shadow data mapping graph for determined bookbinding part by using the determined top part of part and the pixel value in the lowermost end part of binding.For example can generate the shadow data mapping graph by determined bookbinding part being divided into a plurality of little parts and generating shadow data respectively in these little parts each.In a preferred embodiment, with top part and lowermost end part in a plurality of zones in each zone in pixel in the middle of the brightest pixel corresponding pixel value can be used to generate determined bookbinding shadow data mapping graph partly.
In step S307, remove (correction) determined shade of binding in the part by using the shadow data mapping graph that is generated.
By this way, obtain to have the scan image of shadeless bookbinding part.
Below, some preferred embodiments will be described.It should be noted that following preferred embodiment can implement individually, perhaps also can implement with any combination.
As mentioned above, the present invention can adopt the bookbinding method partly of the scan image of rough definite books that launch.Below provide a kind of be used for determining the simple of bookbinding part and mode easily, it does not need to estimate to bind the distribution of the pixel value of center line or view picture scan image.
Fig. 4 is the flow chart that the exemplary process of the bookbinding part on the scan image of books of definite expansion according to a preferred embodiment of the present invention is shown.The exemplary process of the process that is used for execution in step S303 has been described in processing in this flow chart shown in Fig. 4, and can carry out after step S301.
In step S401, the books border in the scan image of definite books that launch.Disclose the various technology that are used at image locating rectangle object in the prior art, any such technology all is used in this and determines the books border.Books border in the scan image of books that for example, can following definite expansion.
At first, by utilizing general edge detection method, the edge detection method such as utilizing Sobel operator or Canny operator etc. produces edge image from scan image.Then, the long level curve of selecting the top in the edge image is as books border, top, and select in the edge image below long level curve as books border, bottom.After this, the long vertical line of selecting the leftmost side in the edge image is as books border, left side, and the long vertical line of the rightmost side in the selection edge image is as books border, right side.Thereby, from scan image, detect the whole border of books.Generation and utilization to edge image are being known in the art, and therefore will here not describe in detail.
Also can use the additive method that is used for determining the books border.For example, books border, left side and books border, the right side not vertical line from edge image are detected, but can consider books border, top and books border, bottom towards determining with the end.In this case, can only use about books border, top and books border, bottom towards with the information of end, and need not to produce or estimate books border, left side and books border, right side.
Fig. 5 illustrates the example for the determined books border of the scan image of the books that launch.
In step S403, after having determined the books border, the geometric distortion of correct scan image before proofreading and correct shade.It should be noted that this step is optional, because geometric distortion is to almost not influence of the present invention.In addition, even books were put in scan period with being tilted, also can implement the present invention and do not make decreased performance.That is to say that some geometric distortions also are acceptables, and do not make performance degradation of the present invention.Scheme as an alternative, the correction of geometric distortion also can enforcements after removing shade, and this and relation of the present invention are little, will be not in this description.
In step S405, determine that left border determines that position and right side boundary determine the position, wherein said left border determine the position on books border, left side the right side of (the perhaps left end on top or books border, bottom), and apart from books border, left side (the perhaps left end on top or books border, a bottom) W pixel, described right side boundary determine the position on books border, right side the left side of (the perhaps right-hand member on top or books border, bottom), and apart from books border, right side (the perhaps right-hand member on top or books border, a bottom) W pixel, wherein W is given threshold value, and equal certain ratio (for example books width * 0.3) of books width, wherein said books width is defined as the distance between books borders (the perhaps left end on top or books border, bottom), left side and books border, right side (the perhaps right-hand member on top or books border, bottom).
At step S407, determine the bookbinding portion boundary.
Particularly, for the scan image that has been corrected geometric distortion, books border, top is two parallel straightways with books border, bottom, and they are set as the top margin and the border, bottom of bookbinding part.Produce pass respectively above-mentioned left border determine position and right side boundary determine the position and with two parallel lines of top margin and border, bottom quadrature, as the left border and the right side boundary of described bookbinding part.
For the scan image that is not corrected geometric distortion, be similar to from the books border, top of distortion and books border, bottom and two straight lines obtaining are set up as bookbinding top margin and border, bottom partly.Produce pass respectively above-mentioned left border determine position and right side boundary determine the position and with the top margin of bookbinding part and border, bottom in two parallel lines of one of at least quadrature, as the left border and the right side boundary of described bookbinding part.
Then, after top margin, border, bottom, left border and the right side boundary of having determined the bookbinding part, described bookbinding part is determined.
Fig. 6 illustrates the determined bookbinding part in the scan image of books of expansion of example shown in Figure 5.
Fig. 7 is the flow chart that the exemplary process of generation shadow data mapping graph according to a preferred embodiment of the present invention is shown.The exemplary process of the processing that is used for execution in step S305 has been described in processing in the flow chart shown in Fig. 7, and can carry out after step S303.
In step S701, partly estimate the shadow data on the top of determined bookbinding part by the top that uses determined bookbinding part.The top part of determined bookbinding part can be defined as in the determined bookbinding part, be equal to or less than whole pixels of N pixel to the distance of determined bookbinding top margin partly, wherein N is the positive integer of being scheduled to.For example, this threshold value can be set as N ≈ 0.1* books height, and wherein said books height is defined as the top margin of determined bookbinding part and the distance between the border, bottom.
Preferably, can be to classify the shadow data on the determined bookbinding of estimated by unit top partly as.At this, " row " are meant left border or the parallel pixel column of right side boundary with determined bookbinding part.For each row of determined bookbinding part, the brightest pixel corresponding pixel value in the top part of search and these row, and the brightest resulting and described pixel corresponding pixel value is reserved as the shadow data on the top of these row.By this way, each row has the data point of conduct for the shadow data on the top of these row.
In the middle of the shadow data that is used for the top that is obtained, some row may have wrong shadow data.The shadow data of mistake may be that noise or form line etc. cause.In order to proofread and correct the shadow data of possible mistake, preferably can use post-processing step here.For example, the shade by in the scan image of observing the books that launch can obtain following criterion: the shade on the bookbinding center line is the darkest, and along with the both sides that move to determined bookbinding part from the bookbinding center line, it is more shallow that shade becomes.Described reprocessing can be carried out possible wrong shadow data and proofread and correct, so that can satisfy above criterion or similar criterion.
For example, in described reprocessing, check estimated shadow data, removal does not meet the above criterion or the data point of similar criterion, and replace the data point of being removed by the value of the data point in the adjacent row or by the value (for example, the mean value of the value of the data point in the adjacent row on the adjacent row on the left side and the right) of the data point calculation from adjacent row.Fig. 8 is the schematic diagram of example that the shadow data of error recovery is shown.The correct data point of the circle symbolic representation shadow data among Fig. 8, triangle symbol is represented the data point of mistake, it has the higher value of value than the adjacent row of more approaching bookbinding center line, and square symbols represents for the data after the correction of the data point of mistake, and the data after the described correction are to obtain by the value of the data point in the adjacent row on the adjacent row in left side and right side is asked on average.
Scheme in order to proofread and correct the mistake in the top shadow data partly, also can be applied to the other technologies such as curve fit these data points as an alternative, to suppress the irregular variation in the shadow data.
In step S703, partly estimate the shadow data of the bottom of determined bookbinding part by the lowermost end that uses determined bookbinding part.The lowermost end part of determined bookbinding part can be defined as in the determined bookbinding part, be equal to or less than whole pixels of N pixel to the distance on determined bookbinding border, bottom partly, wherein N is the positive integer of being scheduled to.For example, this threshold value can be set as N ≈ 0.1* books height, and wherein said books height is defined as the top margin of determined bookbinding part and the distance between the border, bottom.
Preferably, can be to classify the shadow data of the determined bookbinding of estimated by unit bottom partly as.At this, " row " have the identical implication of implication with " row " described for the top of determined bookbinding part.For each row of determined bookbinding part, the brightest pixel corresponding pixel value in the lowermost end part of search and these row, and the brightest resulting and described pixel corresponding pixel value is reserved as the shadow data of the bottom of these row.By this way, each row has the data point of conduct for the shadow data of the bottom of these row.
In the middle of the shadow data that is used for the bottom that is obtained, some row may have wrong shadow data.The shadow data of mistake may be that noise or form line etc. cause.In order to proofread and correct the shadow data of possible mistake, preferably can here use and the similar post-processing step of describing for the top of post-processing step.For example, described reprocessing can be identical with above reprocessing for the top description.
Please note, though from the flow chart of Fig. 7, carry out after the estimation of the shadow data of bottom appeared in estimation to the shadow data on top, but can before estimation, carry out the estimation of the shadow data of bottom, perhaps can carry out concurrently to the estimation of the shadow data on top with to the estimation of the shadow data of bottom to the shadow data on top.That is to say that the present invention does not limit the time sequencing that is used to carry out to the estimation of the shadow data of top and bottom.
In step S705, interpolation is carried out on the top of determined bookbinding part and the shadow data of bottom, make to estimate to be in the determined top of part and the shadow data between the bottom of binding.
Particularly, each row for determined bookbinding part by interpolation is carried out on the top of these row and the shadow data of bottom, obtain to be in the top of these row and the shadow data between the bottom.
Utilize the interpolation of vertical direction, even books were tilted and the geometric distortion of scan image are not proofreaied and correct in scan period, the performance that the present invention still can obtain.
By this way, can obtain all shadow datas of all row in the determined bookbinding part.
In step S707, for example can generate the shadow data mapping graph in such a way.
At first, can generate blank shadow data mapping graph earlier.Described blank shadow data mapping graph can have and the identical size of determined bookbinding part, and each pixel on the described blank shadow data mapping graph is corresponding to the pixel on the same position on the determined bookbinding part.Then, for each row of blank shadow data mapping graph, in the shadow data of the top of determined bookbinding part and bottom is filled into corresponding top and bottom position on the blank shadow data mapping graph.Then, for each row of blank shadow data mapping graph, the shadow data in other parts beyond the top of bookbinding part that obtain as the result of interpolation, determined and the bottom, determined bookbinding part is filled in the corresponding position on the blank shadow data mapping graph.
By this way, generate for whole determined bookbinding shadow data mapping graph partly.Though more than described a kind of concrete mode that generates the shadow data mapping graph in detail, generated the method for shadow data mapping graph and the detailed formation of described shadow data mapping graph itself and be not limited to above-mentioned concrete mode.For example, in the foregoing description, at first described how to generate each shadow data, described that then shadow data is filled in each position in the blank shadow data mapping graph.Yet can the above-mentioned processing of following enforcement: at first generate blank shadow data mapping graph, every then next pixel ground generates a shadow data and also simultaneously a described shadow data is filled in the relevant position in the blank shadow data mapping graph.In addition, according to above description, the data point in the shadow data mapping graph is to be the estimated pixel value of pixel in the determined bookbinding part.Yet the data point in the shadow data mapping graph can also be by the normalized normalization pixel value of scheduled pixel value.In addition, as explained above, the shadow data mapping graph also can have the form of mathematic(al) representation.Therefore, the distribution in determined bookbinding part is just enough as long as the shadow data mapping graph can characterize shade.In addition, the shadow data mapping graph can be accepted such as the further processing that is used for correction error or enhancing picture quality.
Fig. 9 illustrates the example of the shadow data mapping graph that is generated for the determined bookbinding part in the example shown in Figure 6.As can be seen, the shadow data mapping graph has characterized the distribution of the shade of background, and does not comprise the literal or the relevant information of picture of printing in any and the books.
Below will describe according to a preferred embodiment of the present invention by using the shadow data mapping graph that is generated to remove the exemplary process of the shade in (correction) determined bookbinding part.This processing can be carried out in step S307, promptly carries out after step S305.
For example, can be according to the pixel value in the determined bookbinding part of following formula correction on hypographous scan image:
D(x，y)＝M*I(x，y)/S(x，y)
Wherein, D (x, y) be in the determined bookbinding part in the position (x, the pixel value (pixel value after the correction) of the pixel after the correction of y) locating, I (x, y) be at position (x in the determined bookbinding part, the pixel value (original pixel value) of the pixel before the correction of y) locating, (x is for position (x y) to S, the shadow data value of the pixel of y) locating, and M is the pixel value of representative " ideal " background pixel value.When (x, (x, (x in the time of y), that is to say, when the shadow data of this position equals the original pixel value of this position, this means that this position is in the background parts (blank parts) y) to equal I y) to locate S in certain position.In this case, the pixel value D after the correction (x, y) equal the expression " ideal " background pixel value M.Therefore, as can be seen, the method according to this invention is transformed into " ideal " pixel value M with the original pixel value in the background parts, regardless of its original pixel value.For example, the pixel value of the brightest pixel in the whole shadow data part before M can be set to proofread and correct.Scheme as an alternative, M also can be other predetermined pixel value.In this case, thereby also can adjust pixel value in the non-shaded portion in the scan image, make that the background pixel value after proofreading and correct has uniform value.
Above-mentioned formula has provided about how using the shadow data mapping graph to proofread and correct the example of the pixel value in the hypographous bookbinding part.Yet, use the concrete grammar of described shadow data mapping graph not limited by above-mentioned formula.Can use weight coefficient W (x, y), make by to I (x, y) weighting obtain D (x, y).Also can utilize the shadow data mapping graph proofread and correct before, during or afterwards, use other processing as required.
Figure 10 illustrates the example by the scan image behind the shadow correction that the shadow correction data shown in Fig. 9 is applied to the determined bookbinding part acquisition shown in Fig. 6.From Figure 10 as seen, the shade that takes place in the bookbinding part of the scan image of the books that launch is removed well.
Can use above image processing method and equipment to proofread and correct shade in the bookbinding part of scan image of books of expansion.Described image processing method and equipment can be configured to the equipment that separates with scanner (image scanning apparatus), perhaps can be structured in the scanner.When image processing method according to the present invention and equipment were structured in the scanner, they can be configured to the part of the image processing part of scanner, and can be stored in according to the form of program in the storage device of scanner and use for controller.In this case, above-mentioned image processing equipment can constitute the functional module of scanner.Reading reading images (scan image) that control part obtained the books that launch afterwards, then can carry out above-mentioned image processing method according to image processing equipment of the present invention, with the shade in the bookbinding part of correct scan image.Thus, the user of scanner can from scanner obtain immediately behind the shadow correction (behind the shadow removal) image and without any need for the effort of further processing image.Be incorporated at scanner under the situation of photocopier, the shade of the image of the books that the user of photocopier can obtain wherein to launch is corrected the copy of (shade is removed).
In addition, certainly, also can before the image processing method according to the present invention, during or afterwards, carry out other image processing process such as geometric distortion correction.
Can implement method and apparatus of the present invention by many modes.For example, can implement method and apparatus of the present invention by software, hardware, firmware or its any combination.The order of above-mentioned method step only is illustrative, and method step of the present invention is not limited to above specifically described order, unless otherwise offer some clarification on.In addition, in certain embodiments, the present invention can also be implemented as the program that is recorded in the recording medium, and it comprises the machine readable instructions that is used to realize the method according to this invention.Thereby the present invention also covers the recording medium that storage is used to realize the program of the method according to this invention.
Though by the example detail display specific embodiments more of the present invention, it will be appreciated by those skilled in the art that above-mentioned example only is intended that exemplary and does not limit the scope of the invention.It should be appreciated by those skilled in the art that the foregoing description to be modified and do not depart from the scope and spirit of the present invention.Scope of the present invention is to limit by appended claim.
Claims (19)
1. image processing method, described image processing method can be proofreaied and correct the shade in the bookbinding part on the scan image of books of expansion, and described image processing method comprises the steps:
Bookbinding part determining step is determined the bookbinding part on the scan image;
The shadow data mapping graph generates step, according to pixel value in the determined bookbinding top part partly and the pixel value in the lowermost end part, generates the shadow data mapping graph that is made of determined bookbinding shadow data partly; And
Aligning step by using the shadow data mapping graph that is generated, is proofreaied and correct the shade in the determined bookbinding part.
2. image processing method according to claim 1, wherein said shadow data mapping graph generates step and comprises the steps:
The top estimating step by the pixel value in the top part of using determined bookbinding part, is estimated the shadow data on the top of determined bookbinding part;
The bottom estimating step by the pixel value in the lowermost end part of using determined bookbinding part, is estimated the shadow data of the bottom of determined bookbinding part; And
Interpolation procedure is carried out interpolation to the top of determined bookbinding part and the shadow data of bottom, thereby generates the top of determined bookbinding part and other shadow datas outside the bottom.
3. image processing method according to claim 1, wherein said bookbinding part determining step comprises the steps:
Determine the top margin and the border, bottom of the books of expansion; And
Determine the left border and the right side boundary of described bookbinding part, the top margin or border, the bottom quadrature of the described left border of determined bookbinding part and the books of right side boundary and described expansion.
4. image processing method according to claim 2, wherein said top estimating step comprises the steps:
Each row for determined bookbinding part, search and N pixel of the top of these row the brightest central pixel corresponding pixel value, and the use described pixel value corresponding with the brightest described pixel is as the shadow data on the top of these row, wherein row are and determined bookbinding left border or the parallel pixel column of right side boundary partly, and N is predetermined positive integer.
5. image processing method according to claim 4, wherein said top estimating step further comprises the steps:
After estimating shadow data for each row, handle the shadow data on the top of determined bookbinding part, make that the misdata in estimated shadow data is corrected.
6. image processing method according to claim 2, wherein said bottom estimating step comprises the steps:
Each row for determined bookbinding part, search and N pixel of the lowermost end of these row the brightest central pixel corresponding pixel value, and the use described pixel value corresponding with the brightest described pixel is as the shadow data of the bottom of these row, wherein row are and determined bookbinding left border or the parallel pixel column of right side boundary partly, and N is predetermined positive integer.
7. image processing method according to claim 6, wherein said bottom estimating step further comprises the steps:
After estimating shadow data for each row, handle the shadow data of the bottom of determined bookbinding part, make that the misdata in estimated shadow data is corrected.
8. according to each described image processing method among the claim 2-7, wherein, described shadow data mapping graph generates step and further comprises the steps:
Generate the blank shadow data mapping graph that has identical size with determined bookbinding part, and
In blank shadow data mapping graph, fill the estimated shadow data of the estimated shadow data on the top of determined bookbinding part, determined bookbinding bottom partly and the shadow data that generates from described interpolation.
9. according to each described image processing method among the claim 1-7, further comprise:
The distortion correction step, the geometric distortion of correct scan image.
10. image processing equipment, described image processing equipment can be proofreaied and correct the shade in the bookbinding part on the scan image of books of expansion, and described image processing equipment comprises:
The bookbinding part is determined device, is used for the bookbinding part on definite scan image;
Shadow data mapping graph generating apparatus is used for generating the shadow data mapping graph that is made of determined bookbinding shadow data partly according to the pixel value of determined bookbinding top part partly and the pixel value in the lowermost end part; And
Means for correcting is used for the shadow data mapping graph generated by using, proofreaies and correct the shade in the determined bookbinding partly.
11. image processing equipment according to claim 10, wherein said shadow data mapping graph generating apparatus comprises:
The top estimation unit is used for the pixel value by the top part of using determined bookbinding part, estimates the shadow data on the top of determined bookbinding part;
The bottom estimation unit is used for the pixel value by the lowermost end part of using determined bookbinding part, estimates the shadow data of the bottom of determined bookbinding part; And
Interpolating apparatus is used for interpolation is carried out on the top of determined bookbinding part and the shadow data of bottom, thereby generates the top of determined bookbinding part and other shadow datas outside the bottom.
12. image processing equipment according to claim 10, wherein said bookbinding determine that partly device comprises:
Be used for the top margin of definite books that launch and the device on border, bottom; And
Be used for determining the left border of described bookbinding part and the device of right side boundary, the top margin or border, the bottom quadrature of the described left border of determined bookbinding part and the books of right side boundary and described expansion.
13. image processing equipment according to claim 11, wherein said top estimation unit comprises:
Be used for each row for determined bookbinding part, search and N pixel of the top of these row the brightest central pixel corresponding pixel value, and the use described pixel value corresponding with the brightest described pixel is as the device of the shadow data on the top of these row, wherein row are and determined bookbinding left border or the parallel pixel column of right side boundary partly, and N is predetermined positive integer.
14. image processing equipment according to claim 13, wherein said top estimation unit further comprises:
Be used for after estimating shadow data, handling the shadow data on determined bookbinding top partly, make the device that misdata in estimated shadow data is corrected for each row.
15. image processing equipment according to claim 11, wherein said bottom estimation unit comprises:
Be used for each row for determined bookbinding part, search and N pixel of the lowermost end of these row the brightest central pixel corresponding pixel value, and the use described pixel value corresponding with the brightest described pixel is as the device of the shadow data of the bottom of these row, wherein row are and determined bookbinding left border or the parallel pixel column of right side boundary partly, and N is predetermined positive integer.
16. image processing equipment according to claim 15, wherein said bottom estimation unit further comprises:
Be used for after estimating shadow data, handling the shadow data of determined bookbinding bottom partly, make the device that misdata in estimated shadow data is corrected for each row.
17. according to each described image processing equipment among the claim 11-16, wherein, described shadow data mapping graph generating apparatus further comprises:
Be used to generate the device that has the blank shadow data mapping graph of identical size with determined bookbinding part, and
Be used for filling the estimated shadow data of bottom of the estimated shadow data on the top of determined bookbinding part, determined bookbinding part and the device of the shadow data that generates from described interpolation at blank shadow data mapping graph.
18., further comprise according to each described image processing equipment among the claim 10-16:
The distortion correction device is used for the geometric distortion of correct scan image.
19. an image scanning apparatus comprises:
Read control device, the image of books that is used to read expansion is to generate scan image; And
According to each described image processing equipment among the claim 10-18.
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| CN108292433A (en) * | 2015-11-23 | 2018-07-17 | 光学实验室成像公司 | The detection and verification of shade in intravascular image |
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| US6330050B1 (en) * | 1997-07-24 | 2001-12-11 | Ricoh Company, Ltd | Image processing device for providing correction of a curvature distortion of a bound portion of a spread book |
| US20030053681A1 (en) * | 2001-09-19 | 2003-03-20 | Jia Charles Chi | Method and apparatus for three-dimensional shadow lightening |
| JP2005109807A (en) * | 2003-09-30 | 2005-04-21 | Brother Ind Ltd | Image processing method, image processor, image forming device and image processing system |
| US20080024845A1 (en) * | 2006-07-28 | 2008-01-31 | Canon Kabushiki Kaisha | Image reading apparatus |
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| US6330050B1 (en) * | 1997-07-24 | 2001-12-11 | Ricoh Company, Ltd | Image processing device for providing correction of a curvature distortion of a bound portion of a spread book |
| JPH11195107A (en) * | 1998-01-05 | 1999-07-21 | Ricoh Co Ltd | Method for preserving and developing non-rectangular image data |
| US20030053681A1 (en) * | 2001-09-19 | 2003-03-20 | Jia Charles Chi | Method and apparatus for three-dimensional shadow lightening |
| JP2005109807A (en) * | 2003-09-30 | 2005-04-21 | Brother Ind Ltd | Image processing method, image processor, image forming device and image processing system |
| US20080024845A1 (en) * | 2006-07-28 | 2008-01-31 | Canon Kabushiki Kaisha | Image reading apparatus |
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| CN108292433A (en) * | 2015-11-23 | 2018-07-17 | 光学实验室成像公司 | The detection and verification of shade in intravascular image |
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