Device for digital display of a video image
View Patent ↗The present invention relates to a device for digital display of a video image using time-division modulation. This device is intended to display a video image during a video frame comprising a plurality of consecutive subfields distributed within at least two separate identical time segments. According to the invention, the pixels of the video image change state at most once during each time segment and the video image to be displayed is saved in the image memory in the form of information identifying, for each subfield, the pixels changing state.
1. A digital display device serving to display a video image during a video frame comprising a plurality of consecutive subfields distributed within at least two separate identical time segments, each pixel of the video image being able selectively to take an on state or an off state during each subfield of the said video frame and each pixel of the video image changing state at most once during each time segment, the device comprising:
a matrix of elementary cells for displaying the pixels of the video image; and,
an image memory for storing the video image before its display by the matrix of elementary cells, said memory comprising N memory areas each associated with a subfield and saving the coordinates of the pixels of the video image changing state during the associated subfield.
2. The device device according to claim 1 , wherein the said at least two time segments of the video frame are identical and comprise the same number of subfields.
3. The device according to claim 1 , wherein it comprises means for generating, from the information stored in the image memory, binary planes for each subfield.
4. The device Devise according to claim 1 , wherein it comprises means for determining the coordinates of a pixel of the video image changing state in the course of the video frame and for appending thereto an address in the memory area referring to the subfield during which said pixel changes state.
5. The device according to claim 1 , wherein, the pixels of the video image being organized in rows and columns in the video image, the pixel coordinates saved in the image memory consist, for each pixel, of a row coordinate and a column coordinate.
6. A digital display device serving to display a video image during a video frame comprising a plurality of consecutive subfield distributed within at least two separate identical time segments each pixel of the subfield of the said video frame and each pixel of the video image changing state at most once during each time segment, the device comprising:
a matrix of elementary cells for displaying the pixels of the video image;
an image memory for storm the video image before its display the matrix of elementary cells, said memory comprising N memo areas each associated with a subfield and saving the coordinates of the pixels of the video image changing state during the associated subfield; and,
means for calculating, for each video level of the pixels of the video image, its number of occurrences in the video image, which numbers of occurrences are supplied to the memory address and pixel coordinate generating means so as to determine the addresses to be appended to the pixel coordinates.
7. A digital display device serving to display a video image during a video frame comprising a plurality of consecutive subfields distributed within at least two separate identical time segments, each pixel of the video image being able selectively to take an on state or an off state during each subfield of the said video frame and each pixel of the video image changing state at most once during each time segment, the device comprising:
a matrix of elementary cells for displaying the pixels of the video image;
an image memory for storing the video image before its display by the matrix of elementary cells, said memory comprising N memory areas each associated with a subfield and saving the coordinates of the pixels of the video image changing state during the associated subfield;
the pixels of the video image are organized in rows and columns in the video image, and,
each area of the image memory encloses for all the pixels belonging to one and the same row of said image and changing state during the associated subfield, a common row coordinate and, for each of said pixels, a column coordinate.
8. A digital display device serving to display a video image during a video frame comprising a plurality of N consecutive subfields distributed within at least two separate identical time segments, each time segment comprising P subfields arranged in the same order, each pixel of the video image being able selectively to take an on state or an off state during each subfield of the said video frame and each pixel of the video image changing state at most once during each time segment and each pixel changing state during the subfields of same order in the said at least two time segments, the device comprising:
a matrix of elementary cells for displaying the pixels of the video image; and,
an image memory for storing the video image before its display by the matrix of elementary cells, said memory comprising P memory areas each associated with one of the P subfields and saving the coordinates of the pixels of the video image changing state during the associated subfield, each memory area of said image memory then being read once per time segment to display the video image.
9. The device according to claim 8 , wherein it comprises means for generating, from the information stored in the image memory, binary planes for each subfield.
10. The device according to claim 8 , wherein it comprises means for determining the coordinates of a pixel of the video image changing state in the course of the video frame and for appending thereto an address in the memory area referring to the subfield during which said pixel changes state.
11. A digital display device serving to display a video image during a video frame comprising a plurality of N consecutive subfields distributed within at least two separate identical time segments, each time segment comprising P subfields arranged in the same order, each pixel of the video image being able selectively to take an on state or an off state during each subfield of the said video frame and each pixel of the video image changing state at most once during each time segment and each pixel changing state during the subfields of same order in said at least two time segments, the device comprising:
a matrix of elementary cells for displaying the pixels of the video image;
an image memory for storing the video image before its display by the matrix of elementary cells, said memory comprising P memory areas each associated with one of the P subfields and saving the coordinates of the pixels of the video image changing state during the associated subfield, each memory area of the said image memory then being read once per time segment to display the video image;
means for determining the coordinates of a pixel of the video image changing state in the course of the video frame and for appending thereto an address in the memory area referring to the subfield during which the said pixel changes state; and,
means for calculating, for each video level of the pixels of the video image, its number of occurrences in the video image, which numbers of occurrences are supplied to the memory address and pixel coordinate generating means so as to determine the addresses to be appended to the pixel coordinates.
12. The device according to claim 8 , wherein, the pixels of the video image being organized in rows and columns in the video images the pixel coordinates saved in the image memory consist, for each pixel, of a row coordinate and a column coordinate.
13. A digital display device serving to display a video image during a video frame comprising a plurality of N consecutive subfields distributed within at least two separate identical time segments, each time segment comprising P subfields arranged in the same order, each pixel of the video image being able selectively to take an on state or an off state during each subfield of the said video frame and each pixel of the video image changing state at most once during each time segment and each pixel changing state during the subfields of same order in said at least two time segments, the device comprising:
a matrix of elementary cells for displaying the pixels of the video image;
an image memory for storm the video image before its display by the matrix of elementary cells, said memory comprising P memory areas each associated with one of the P subfields and saving the coordinates of the pixels of the video image changing state during the associated subfield, each memory area of the said image memory then being read once per time segment to display the video image;
the pixels of the video image are organized in rows and columns in the video; and,
each area of the image memory encloses, for all the pixels belonging to one and the same row of said image and changing state during the associated subfield, a common row coordinate and, for each of said pixels, a column coordinate.