1. A display device comprising:
a connecting block rotatably fastened to an end of a stand assembly;
a head mount vertically movable with respect to the connecting block; and
a locking unit that selectively locks the motion of the head mount as the connecting block rotates.
2. The display device of claim 1, wherein the locking unit comprises a cam provided on a rotation shaft of the stand assembly; and a cam follower selectively locked to the head mount, being contacted with the cam.
3. The display device of claim 2, wherein the cam follower comprises a first cam follower having an end contacted with the cam; and a second cam follower having an end rotatably connected to the first cam follower and the other end selectively locked to the head mount.
4. The display device of claim 3, wherein the motion direction of the first cam follower is oblique to the motion direction of the second cam follower at a predetermined angle.
5. The display device of claim 4, further comprising a guide unit that guides the motion of the second cam follower.
6. The display device of claim 5, wherein the guide unit comprises a guide hole formed at the second cam follower and a guide pin provided in the guide hole.
7. The display device of claim 6, further comprising a guide bracket that guides the motion of the cam follower.
8. The display device of claim 7, wherein the guide pin is provided at the guide bracket.
9. The display device of claim 3, further comprising an elastic member that elastically supports the second cam follower.
10. The display device of claim 3, wherein a first engaging part is provided at the second cam follower and a second engaging part is provided at the head mount to be selectively engaged to the first engaging part.
11. The display device of claim 10, wherein the first engaging part and the second engaging part are rack gears, respectively.
12. The display device of claim 3, wherein a cam roller is provided at a lower end of the first cam follower.
13. The display device of claim 2, wherein the head mount and the can follower are engaged each other in the same direction as the rotation direction of the connecting block.
14. The display device of claim 13, further comprising a guide unit that guides the rotation of the cam follower.
15. The display device of claim 14, wherein the guide unit comprises a guide hole formed at the cam follower and a guide pin provided in the guide hole.
16. The display device of claim 1, wherein the locking unit comprises a motion part that moves in accordance with the rotation of the connecting block and a guide part that changes a motion direction of the motion part.
17. The display device of claim 16, wherein the motion part comprises a cam and at least one cam follower contacted with the cam.
18. The display device of claim 17, wherein the cam follower comprises a first cam follower having an end contacted with the cam; and a second cam follower having an end rotatably connected to the first cam follower and the other end selectively locked to the head mound.
19. The display device of claim 16, wherein the guide part comprises a guide hole formed on the motion part and a guide pin provided in the guide hole.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for computing a distance metric for a document page collection comprising:
obtaining a document page collection, each document page in the collection having one or more features, the one or more features defining a page layout attribute;
extracting information from the one or more features on each document page;
constructing a feature vector for the one or more features on each document page;
assigning a feature weight to each feature; and
computing a distance metric based on the feature weight and the feature vector.
2. The method of claim 1 wherein the one or more features is a paragraph.
3. The method of claim 1 wherein the information extracted from the one or more features is information selected from the group consisting of the number of paragraphs on each document page, the total area of the paragraphs on each document page, the coordinates of the paragraphs on each document page, the width of the paragraphs on each document page, the height of the paragraphs on each document page, the number of textboxes per paragraph on each document page and the font size of the paragraphs on each document page.
4. The method of claim 1 wherein the one or more features is an image.
5. The method of claim 1 wherein the information extracted from the one or more features is information selected from the group consisting of the number of images on each document page, the total area of the images on each document page, the width of the images on each document page, the height of the images on each document page and the number of SVG-type images on each document page.
6. The method of claim 1 wherein the one or more features includes a paragraph and an image.
7. The method of claim 1 wherein the feature weights are assigned a value based on formulating constraints.
8. A method for evaluating a generated clustering for a document page collection comprising:
obtaining a document page collection, each document page in the collection having one or more features, the one or more features defining a page layout attribute;
choosing a sample of document pages from the collection;
computing a reference clustering for the sample of document pages;
extracting information from the one or more features on each document page in the sample;
constructing a feature vector for the one or more features on each document page;
assigning a feature weight to each feature;
computing a distance metric between any two pages in the sample of document pages based on the feature weight and the feature vector;
clustering the sample of document pages using the distance metric in a clustering algorithm to obtain a generated clustering for the sample of document pages; and
comparing the reference clustering to the generated clustering.
9. The method of claim 8 wherein the one or more features is a paragraph.
10. The method of claim 8 wherein the information extracted from the one or more features is information selected from the group consisting of the number of paragraphs on each document page, the total area of the paragraphs on each document page, the coordinates of the paragraphs on each document page, the width of the paragraphs on each document page, the height of the paragraphs on each document page, the number of textboxes per paragraph on each document page and the font size of the paragraphs on each document page.
11. The method of claim 8 wherein the one or more features is an image.
12. The method of claim 8 wherein the information extracted from the one or more features is information selected from the group consisting of the number of images on each document page, the total area of the images on each document page, the width of the images on each document page, the height of the images on each document page and the number of SVG-type images on each document page.
13. The method of claim 8 wherein the one or more features includes a paragraph and an image.
14. The method of claim 8 wherein the feature weights are assigned a value based on formulating constraints.
15. The method of claim 8 wherein the reference clustering is computed by a user browsing the sample of document pages and clustering the sample by hand.
16. The method of claim 8 wherein the generated clustering and the reference clustering are found to be similar.
17. The method of claim 8 wherein the generated clustering and the reference clustering are found to be dissimilar.
18. The method of claim 17 further comprising:
adjusting the feature weight to each feature;
computing a distance metric between any two pages in the sample of document pages based on the adjusted feature weight and the feature vector;
clustering the sample of document pages using the distance metric in a clustering algorithm to obtain a generated clustering for the sample of document pages; and
comparing the reference clustering to the generated clustering.
19. The method of claim 18 wherein the steps are repeated until the generated clustering and the reference clustering are similar.
20. A method for clustering a document page collection comprising:
obtaining a document page collection, each document page in the collection having one or more features, the one or more features defining a page layout attribute;
extracting information from the one or more features on each document page and constructing a feature vector;
computing a distance metric based on an assigned feature weight for each feature; and clustering the document page collection using the distance metric.