Method for determining restored scanning position

Abstract

A method for position restoration. By comparing the graphic data and the restored graphic data, the graphic data closest to the restored graphic data is selected. Therefore, the graphic data scanned subsequently is correctly connected to the restored graphic data to avoid the missing line or repetition of graphic data.

Description

FIELD OF THE INVENTION

The invention relates in general to a method for determining restored position, and more particular, to a restoration method to avoid missing line and image repetition.

RELATED ART OF THE INVENTION

Due to advancing and fast-developing electronic techniques, the electronic industry has become one of the most important industries in modern society. Many high performance calculating systems are consequently being produced, and more and more electronic products are being used in daily life. In recent years, the growing processing speed and data storage capacity of the processor has greatly enhanced the performance of image processing, while the image processor such as the optical scanner or digital camera have become widely applied.

In the current operating process of the scanner, the graphic data generating speed is far faster than the data transmission speed between the scanner and the host, and therefore the graphic data scanned by the scanner requires a place for temporary storage. Such place for temporary storage is called a buffer, which ranges between about 32 Kbytes to about 512 Kbytes.

The faster the graphic data is generated; the more graphic data is stored in the buffer. When the buffer is full of the graphic data, the scanner has to stop scanning. If the scan continues under such circumstances, the graphic data will be lost, or operation problems may occur.

When the scanner head is performing scanning, the scanning process has to be stopped if the buffer is filled with the graphic data. Generally speaking, the stopped position is called the restored position. To allow each area of the document to have the same exposure time, the scanner head has a constant speed during scanning. Thus, the scanner head has to move backward with a certain distance. When the is completely emptied, the scanner head proceeds to the previously stopped position, that is, the restored position, to continue scanning. The scanning speed has to reach the previous scanning speed to result in a stable performance.

The procedure from filling the buffer with the graphic data, stopping scanning, the scanner head moving backward and restoring to the restored position and starting scanning is called smearing.

The smearing procedure is normally determined by the low transmission speed of interface connected to the host, such as the SCSI, USB and EPP. Alternatively, it also occurs when the computer host is too busy with other operation processes to read data from the interface. As a result, the graphic data is accumulated in the buffer until it is completely filled to cause smearing.

In the above smearing procedure, while returning to the restored position after moving backward, the scanner head may not return to the exact restored position due to the inertia effect or mechanic error of the scanner; therefore missing line and repetition of graphic data may occur.

SUMMARY OF THE INVENTION

The present invention provides a method for determining the restored position to avoid missing line and image repetition.

The method for determining the restored position provided by the present invention includes the following steps. In the first step, a scanner head moves along a first direction to scan a document. In the second step, the scanner head stops moving, and the position where the scanner head stops is defined as a restored position. Meanwhile, the data of the document located at the restored position is scanned by the scanner head, while the scanned data is defined as the restored graphic data. In the third step, the scanner head moves to a second direction opposing to the first direction with a first distance. In the fourth step, the scanner head moves along the first direction with a second distance to reach an initial scanning position, where the second distance is smaller than the first distance. In the fifth step, after moving along the second direction with the second distance, the scanner head proceeds in a stepping manner to scan a plurality of corresponding graphic data. In the sixth step, being compared to the restored graphic data, the scanned graphic data closest is selected and defined as the connecting graphic data. In the seventh step, the graphic data subsequent to the connecting graphic data is connected to the restored data.

According to one embodiment of the present invention, an additional step for erasing the scanned graphic data prior to the connecting graphic data is required, while the connecting graphic data can be used to replace the restored graphic data. In addition, while performing the third step, the first distance includes 36 steps. That is, the scanner head moves 36 steps along the second direction. While performing the fourth step, the scanner head moves 34 steps along the first direction.

In one embodiment of the present invention, the restored graphic data comprises a plurality of standard pixels, and each scanned graphic data comprises a plurality of pixels. While performing the sixth step, a part of the standard pixels is used as the comparison reference to compare with a part of the pixels of each graphic data in the corresponding positions. Alternatively, while performing the sixth step, all the standard pixels can be used as the comparison reference to compare to the pixels of each of the graphic data in the corresponding position.

Accordingly, the present invention compares the scanned graphic data with the restored graphic data to select the graphic data closest to the restored graphic data. The selected graphic data scanned subsequently can thus be connected with the restored graphic data correctly.

BRIEF DESCRIPTION OF THE DRAWINGS

These, as well as other features of the present invention, will become more apparent upon reference to the drawings wherein:

FIGS. 1 and 2 are process flows showing the method for determining restored position according to the present invention;

FIG. 3 is a schematic drawing showing the arrangement of the standard pixels of the restored graphic data in one embodiment of the present invention; and

FIG. 4 is a schematic drawing showing the arrangement of the pixels of the graphic data.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, schematic diagrams illustrating a method to determine restored position in one preferred embodiment of the present invention are shown. In FIG. 1, when the scanner (not shown) is scanning, the scanner head moves along a first direction 180, where the movement of the scanner head is in a stepping manner. The scanned graphic data is then stored in the buffer (not shown) of the scanner. When the buffer has insufficient capacity, the scanner head stops moving. The position where the scanner head stops is defined as the restored position 110. The data of the document scanned by the scanner head at the restored position 110 is defined as the restored graphic data.

The scanner head then moves with a first distance along a second direction to reach an initial position 130. For example, in a stepping manner, the scanner head moves 36 steps to reach the initial position 130. The second direction 190 is an opposite direction to the first direction 180 in this embodiment.

Referring to FIG. 2, after the scanner head reaches the initial position 130, the scanner head moves along the first direction 180 with a second distance 140 to reach an initial scanning position 150. The second distance 140 is smaller than the first distance 120. The scanner head obtains a graphic data by scanning at the initial scanning position 150, and such graphic data is defined as the initial graphic data. It is appreciated that before reaching the initial scanning position 150, sufficient capacity of the buffer of the scanner is required to store the subsequent scanned graphic data. For the relationship between the remaining capacity of the buffer and the movement of the scanner head refer to the Taiwanese Patent No. 432861; whereby the scanning speed can be increased.

After the scanner head moves with the second distance 140 along-the first direction 180, the scanner head continues moving along the first direction 180 and scans the document 110 until he buffer is again short of capacity. The scanner head proceeds in a stepping manner. A graphic data is scanned for each step that the scanner head steps forward. In one embodiment, the scanner head steps many steps to various positions such as the first to eighth positions 152, 154, 156, 158, 160, 162, 164 and 166. Corresponding to the first to eighth positions 152 to 166, first to eighth graphic data are scanned, respectively.

After the scanner head starts scanning, a comparison step is performed. That is, the scanned graphic data such as the first to the eighth graphic data are compared to the restored graphic data, respectively, among which the one closest to the restored graphic data, for example, the second graphic data, is selected as the connecting graphic data.

After realizing that the second graphic data is the one closest to the restored graphic data, the third graphic data is connected to the restored graphic data. The initial graphic data, the first graphic data and the second graphic data are removed. Therefore, the subsequently scanned graphic data can be correctly connected to the previously scanned graphic data without the problems of missing line and image repetition. Alternatively, the restored graphic data can also be replaced by the second graphic data.

Referring to FIGS. 3 and 4, FIG. 3 schematically shows arrangement of the standard pixels of the restored graphic data, and FIG. 4 schematically shows arrangement of the pixels of the scanned graphic data. As shown in FIG. 3, the restored graphic data 200 comprises a plurality of standard pixels 202, while in FIG. 4, each of the scanned graphic data 300 comprises a plurality of pixels 302. During the comparison procedure, a part of the standard pixels 202 can be used as the comparison reference to respectively compare a part of the pixels 302 for each of the graphic data 300. The part of the pixels to be compared includes parts of the pixels of the initial graphic data, the first to the fourth graphic data, while the pixels 302 to be compared to the standards pixels 202 are in the positions corresponding to those of the standard pixels 302, respectively. For example, the one hundredth to two hundredth pixels 302 are compared to the one hundredth to the two hundredth standard pixels 202. Alternatively, all of the standard pixels 202 can also be used as the comparison reference to respectively compare each of the pixels 302 of each graphic data. Again, the pixels 302 are compared to the standard pixels 202 in the corresponding positions.

According to the above, the present invention selects a closest graphic data of a restored graphic data by comparing the scanned graphic data with the restored graphic data, such that the subsequently scanned graphic data can be correctly connected to avoid the missing line and data repetition.

Other embodiments of the invention will appear to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples are to be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

Claims

1.-6. (canceled)

7. A method, comprising: moving a scanning head in a first direction to obtain first image data; designating a portion of the first image data as connecting image data; moving the scanning head in the first direction to obtain second image data, the second image data including at least a portion of said connecting image data; and combining at least a portion of the first and second image data based, at least in part, on a comparison of the connecting image data included in said first image data with the connecting image data included in said second image data.

8. The method of claim 7, further comprising moving the scanning head in a second direction opposite said first direction prior to obtaining said second image data.

9. The method of claim 8, wherein at least a portion of the second image data includes image data that is also included in said first image data.

10. The method of claim 7, and further comprising determining said comparison by combining the connecting data of said first image data with the connecting data of said second image data.

11. The method of claim 10, wherein the combined first and second image data comprises third image data.

12. The method of claim 11, wherein the third image data comprises a complete image of the document.

13. The method of claim 7, wherein the first image data comprises a first plurality of pixel values, and the second image data comprises a second plurality of pixel values, and wherein comparing comprises comparing a portion of the second plurality of pixel values to a portion of the first plurality of pixel values.

14. The method of claim 7, wherein the connecting data comprises image data obtained near a stopping point of the scanning head.

15. A method, comprising: performing a first scan of a document to obtain first image data for a portion of the document; designating a portion of the first image data as connecting data; performing a second scan of the document to obtain second image data for a portion of the document, at least a portion of the second image data including the same image data as obtained from said first scan; and combining the first and second image data by use of the connecting data to form a third image.

16. The method of claim 15, wherein said combining comprises combining the first image data with the portion of the second image data not including the same image data as obtained from said first scan.

17. The method of claim 15, wherein the third image comprises a complete image of the document.

18. The method of claim 15, wherein the connecting data comprises image data obtained near a stopping point of a scanning head after the first scan.

19. An article comprising: a storage medium having stored thereon instructions that, when executed, result in: moving a scanning head along a first direction to obtain first image data; stopping the scanning head at a stopping point, and designating a portion of the obtained image data as connecting image data; moving the scanning head along the first direction to obtain second image data, the second image data including at least a portion of said connecting image data; comparing the connecting image data included in said first image data with the connecting image data included in said second image data; and combining at least a portion of the first and second image data based on the comparing.

20. The article of claim 19, wherein the instructions, when executed, further result in: moving the scanning head a second direction opposite said first direction prior to obtaining said second image data.

21. The article of claim 19, wherein the instructions, when executed, further result in: combining the connecting data of said first image data with the connecting data of said second image data.

22. The article of claim 19, wherein the combined first and second image data comprises third image data.

23. The article of claim 22, wherein the third image data comprises a complete image of the document.

24. The article of claim 19, wherein the first image data comprises a first plurality of pixel values, and the second image data comprises a second plurality of pixel values, and wherein the instructions, when further executed, further result in: comparing a portion of the second plurality of pixel values to a portion of the first plurality of pixel values.

25. The article of claim 19, wherein the connecting data comprises image data obtained near the stopping point.

26. An article comprising: a storage medium, having stored thereon instructions, that, when executed, result in: performing a first scan of a document to obtain first image data for a portion of the document; designating a portion of the first image data as connecting data; performing a second scan of the document to obtain second image data for a portion of the document, at least a portion of the second image data including the same image data as obtained from said first scan; and combining the first and second image data by use of the connecting data to form a third image.

27. The article of claim 26, wherein the instructions, when further executed, further results in: combining the first image data with the portion of the second image data not including the same image data as obtained from said first scan.

28. The article of claim 26, wherein the third image comprises a complete image of the document.

29. The article of claim 26, wherein the connecting data comprises image data obtained near the stopping point.