GB2113056A — Real time video perspective digital map display

Claim 1

Independent Claim 154 words

A digital information storage and read-out system for use in a system producing a perspective display, comprising: memory means for storing digital data representing a two-dimensional elevational pattern of information in pixel form in addressable memory locations; means for generating signals representing the parameters of the desired perspective display including the height and location of the viewing point and the angle of the display with respect to the two-dimensional pattern; read-out control means for reading pixel data out of said memory means from selected addressable memory locations through generation of address signals and application of said address signals to said memory means; and perspective transform means responsive to said signal generating means for transforming the address of each pixel of data read out of said memory means from the address of that pixel in the twodimensional pattern to the address of the position to be occupied by that pixel in the perspective 55 display.

Claim 2

Dependent Claim 154 words

A digital information storage and read-out system for use in a system producing a perspective display, comprising: memory means for storing digital data representing a two-dimensional elevational pattern of information in pixel form in addressable memory locations; means for generating signals representing the parameters of the desired perspective display including the height and location of the viewing point and the angle of the display with respect to the two-dimensional pattern; read-out control means for reading pixel data out of said memory means from selected addressable memory locations through generation of address signals and application of said address signals to said memory means; and perspective transform means responsive to said signal generating means for transforming the address of each pixel of data read out of said memory means from the address of that pixel in the twodimensional pattern to the address of the position to be occupied by that pixel in the perspective 55 display.

Claim 3

Dependent Claim 59 words

A digital information storage and read-out system according to claim 1, wherein said digital data is stored in said memory means with said pattern having a fixed orientation, said read-out control means including means for selectively generating said address signals so as to read out pattern information in a direction which may be selectively different from said fixed orientation.

Claim 4

Dependent Claim 101 words

A digital information storage and read-out system according to claim 2, wherein said perspective transform means includes means for generating a signal AE representing the difference in height between the viewing point of the perspective display and each pixel in said elevational pattern, means for generating a signal R representing the distance parallel to said fixed orientation between 13 GB 2 113 056 A 13 each pixel and the viewing point in said two-dimensional elevational pattern, and means for generating a signal AW representing the distance between each pixel and a line through the viewing point parallel to said fixed orientation.

Claim 5

Dependent Claim 82 words

A digital information storage and read-out system according to claim 3, wherein said perspective transform means further includes means for generating transformed addresses a,b for each 5 pixel according to the relationship: a = K AE sin a - R cos a and AE cos a - R sin a) b K AW AE cos a + R sin a where a is the angle of the perspective display with respect to said twodimensional elevational 10 pattern and K is a constant.

Claim 6

Dependent Claim 220 words

A digital information storage and read-out system for use in generating a perspective display of terrain over which a vehicle is moving on the basis of digital data representing a two-dimensional elevational terrain pattern in pixel form which is addressable in relation to the coordinate position of each pixel in said terrain pattern, comprising: a scene memory for storing said pixei data representing at least a portion of the terrain pattern of15 the terrain over which the vehicle is passing; signal supplying means for providing signals representing the angle of heading of said vehicle with respect to a fixed geographical orientation, the angle of the perspective display with respect to said two-dimensional elevational terrain pattern, and the elevation and current position of said vehicle with respect to said terrain; read-out control means responsive to the signals from said signal supplying means for reading pixel data out of said scene memory through generation of address signals and the application of said address signals to said scene memory; and perspective transform means responsive to the signals from said signal supplying means for transforming the address of each pixel read out of said scene memory from the address of that pixel in 25 the two-dimensional terrain pattern to the address of the position to be occupied by that pixel in said perspective display.

Claim 7

Dependent Claim 220 words

A digital information storage and read-out system for use in generating a perspective display of terrain over which a vehicle is moving on the basis of digital data representing a two-dimensional elevational terrain pattern in pixel form which is addressable in relation to the coordinate position of each pixel in said terrain pattern, comprising: a scene memory for storing said pixei data representing at least a portion of the terrain pattern of15 the terrain over which the vehicle is passing; signal supplying means for providing signals representing the angle of heading of said vehicle with respect to a fixed geographical orientation, the angle of the perspective display with respect to said two-dimensional elevational terrain pattern, and the elevation and current position of said vehicle with respect to said terrain; read-out control means responsive to the signals from said signal supplying means for reading pixel data out of said scene memory through generation of address signals and the application of said address signals to said scene memory; and perspective transform means responsive to the signals from said signal supplying means for transforming the address of each pixel read out of said scene memory from the address of that pixel in 25 the two-dimensional terrain pattern to the address of the position to be occupied by that pixel in said perspective display.

Claim 8

Dependent Claim 94 words

A digital information storage and read-out system according to claim 5, wherein said perspective transform means includes means for generating a signal AE representing the difference in elevation between the vehicle and each pixel in said terrain pattern, means for generating a signal R 30 representing the distance parallel to the vehicle heading between each pixel position and the vehicle position in said terrain pattern, and means for generating a signal AW representing the distance between each pixel and a line through the vehicle position parallel to the vehicle heading in said terrain pattern.

Claim 9

Dependent Claim 83 words

A digital information storage and read-out system according to claim 6, wherein said perspective transform means includes further means for generating transformed addresses a,b for each pixel according to the relationships a = K AE sin a - R cos a and LE cos a - R sin a) AW b = K AE cos a + R sin a where a is the angle of the perspective-display with respect to said two- dimensional elevational terrain 40 pattern and K is a constant.

Claim 10

Dependent Claim 61 words

A digital information storage and read-out system according to claim 5, wherein said terrain pattern of data is stored in said scene memory with a fixed geographical orientation, and said read-out means includes means for selectively generating said address signals so as to read out pattern information in a direction which may be selectively different from said fixed geographical orientation. 45

Claim 11

Dependent Claim 77 words

A digital information storage and read-out system according to claim 5, wherein said terrain pattern of data is stored in said scene memory with a north-up orientation, and wherein said read-out means includes means for selectively generating said address signals so as to scan said pixel data in said scene memory either in a north-south or an east-west direction depending on which is closest to the direction of heading of the vehicle with respect to said terrain.

Claim 12

Dependent Claim 74 words

A digital information storage and read-out system according to claim 5, wherein said read out means includes means for selectively generating said address signals so as to scan an area of said scene memory in successive lines which extend from a line through the pixel position corresponding to the position of the vehicle in the general direction of heading of the vehicle with respect to the terrain. 14 GB 2 113 056 A 14

Claim 13

Dependent Claim 95 words

A digital information storage and read-out system according to claim 5, wherein said readout means includes means for selectively generating said address signals so as to scan a generally diamond-shaped area of said scene memory, said area being positioned within said scene memory with one edge thereof being substantially transverse to the direction of vehicle heading with respect to said terrain pattern and the scanning of said area being in the direction parallel or transverse to the geographical orientation of said data in the scene memory, whichever makes the smallest angle with said vehicle heading.

Claim 14

Independent Claim 241 words

A system for generating a perspective display of terrain over which a vehicle is moving, comprising: a scene memory for storing digital data representing a two-dimensional elevational terrain pattern10 in pixel form which is addressable in relation to the coordinate positon of each pixel with respect to a selected geographical orientation; signal supplying means for providing signals representing the heading angle of said vehicle with respect to said selected geographical orientation, the angle of the desired perspective display with respect to said two-dimensional elevational terrain pattern, and the elevation and current position of 15 - said vehicle with respect to said terrain; read-out control means responsive to the signals from said signal supplying means for reading pixels of elevation data out of said scene memory through generation of address signals and the application of said address signals to said scene memory; perspective transform means responsive to the signals from said signal supplying means for 20 transforming the address of each pixel read out of said scene memory from the address of that pixel in the scene memory to the address of the position to be occupied by that pixel in said perspective display; display memory means for storing the pixel data read out of said scene memory in a matrix of memory positions forming storage locations corresponding to said transformed addresses; and 25 display means for displaying the pixel data stored in said display memory means to produce said perspective display.

Claim 15

Independent Claim 241 words

A system for generating a perspective display of terrain over which a vehicle is moving, comprising: a scene memory for storing digital data representing a two-dimensional elevational terrain pattern10 in pixel form which is addressable in relation to the coordinate positon of each pixel with respect to a selected geographical orientation; signal supplying means for providing signals representing the heading angle of said vehicle with respect to said selected geographical orientation, the angle of the desired perspective display with respect to said two-dimensional elevational terrain pattern, and the elevation and current position of 15 - said vehicle with respect to said terrain; read-out control means responsive to the signals from said signal supplying means for reading pixels of elevation data out of said scene memory through generation of address signals and the application of said address signals to said scene memory; perspective transform means responsive to the signals from said signal supplying means for 20 transforming the address of each pixel read out of said scene memory from the address of that pixel in the scene memory to the address of the position to be occupied by that pixel in said perspective display; display memory means for storing the pixel data read out of said scene memory in a matrix of memory positions forming storage locations corresponding to said transformed addresses; and 25 display means for displaying the pixel data stored in said display memory means to produce said perspective display.

Claim 16

Dependent Claim 73 words

A system according to claim 12, further including: buffer storage means for storing the pixel data read out of said scene memory including the transformed address of each pixel in storage locations corresponding to the storage locations occupied 30 by said pixel data in said scene memory; and means for transferring said pixel data from said buffer storage means to storage locations in said display memory means in accordance with said transformed address.

Claim 17

Dependent Claim 70 words

A system according to claim 13, wherein said read-out means includes means for selectively generating said address signals so as to scan a generally diamond-shaped area of said scene memory 35 along lines substantially parallel or transverse to said selected geographical orientation depending on which makes the smallest angle with the vehicle heading, said area being positioned within said scene memory with one edge thereof transverse to said vehicle heading.

Claim 18

Dependent Claim 44 words

A system according to.claim 13, wherein said read-out means includes means for selectively generating said address signals so as to scan a generally diamond-shaped area of said scene memory 40 - along parallel lines substantially in the direction of the heading of the vehicle.

Claim 19

Dependent Claim 52 words

A system according to claim 15, wherein said buffer storage means includes a column buffer memory having a plurality of columns for storing respective lines of pixel data read out of said scene memory by said read-out means in positions corresponding to the locations of said pixel data in said scene memory.

Claim 20

Dependent Claim 86 words

A system according to claim 16, wherein each column in said column buffer memory has a capacity to store at least the number of pixels which occupy the diagonal of said generally diamond shaped scan area of said scene memory, and further including start/stop means for storing the address locations for each column of said column buffer memory at which pixel data begins and ends and means responsive to said start/stop means for reading plural pixel data from adjacent columns of said 50 column buffer memory.

Claim 21

Dependent Claim 100 words

A system according to claim 16, wherein said transferring means includes buffer control means for reading out plural pixel data including the transformed addresses thereof in groups from adjacent columns of said column buffer memory by scanning said columns, line writing logic means responsive to the pixel data read out of said column buffer memory for generating additional pixels of 55 elevation data representing pixels occupying positions extending along lines between the pixels of each group in accordance with the transformed addresses thereof, and means for transmitting said pixel data and said additional pixel data in said display memory means.

Claim 22

Dependent Claim 82 words

A system according to claim 18, wherein said transferring means includes inhibiting means responsive to the elevation data of each pixel to be transferred to said display memory means for inhibiting such transfer in connection with any pixel along a given column in said matrix of memory positions of said display memory means which has an elevation value which is less than the elevation value of a pixel from the same column which has already been transferred to said display memory means.

Claim 23

Dependent Claim 144 words

A system according to claim 19, wherein said inhibiting means includes a column max 65 GB 2 113 056 A 15 memory for storing an elevation value for each column of data stored in said display memory means, means for comparing the elevation value for each pixel read out of said column buffer memory and for each pixel generated by said line writing logic means with the elevation value stored in the column max memory for that column in which the pixel is to be written into said display memory means, means responsive to said comparing means for storing in the column max memory the elevation value of the 5 pixel when that value is greater than the value previously stored and for inhibiting transfer of said pixel to said display memory means when the elevation value thereof is less than that previously stored.

Claim 24

Dependent Claim 105 words

2 1. A system according to claim 18, wherein said line writing logic means includes storing means for storing the transformed addresses of two adjacent pixels, means for incrementing one of said addresses in first and second coordinate directions toward said other address by calculated stepping 10 values, means for generating an additional pixel at each incremented step taken by said incrementing means, and means for controlling said buffer control means to store the transformed addresses of the next pixels read out of said column buffer memory into said storing means when the one address has been incremented until it corresponds to said other address.

Claim 25

Dependent Claim 75 words

A system according to claim 2 1, wherein said storing means stores the transformed 15 addresses of four adjacent pixels read out of said column buffer memory, and said incrementing means includes means to compare said addresses in predetermined combinations of pairs, and means to increment said addresses in said predetermined combinations of pairs only when said comparison thereof indicates that the one address of the pair has a selected relationship to the other address.

Claim 26

Dependent Claim 41 words

A system according to claim 22, wherein said comparing means includes means for determining whether the line extending between the pair of pixels will face in a predetermined direction with respect to the orientation of data in said display memory means.

Claim 27

Dependent Claim 48 words

A system according to claim 13, wherein said transferring means includes means for writing into said display memory means along successive scanning lines only those pixels which represent a different value of slope from the previous pixel stored in said display memory means on the same scanning line.

Claim 28

Dependent Claim 49 words

A system according to claim 24, wherein said display means includes means for reading pixel data out of said display memory means, including means for generating pixels for storage locations containing zero information in accordance with the value of the last pixel read out along the same scanning line.

Claim 29

Dependent Claim 42 words

A system according to claim 25, wherein said display memory means includes first and second display memories, and means for writing pixel data into one of said first and second display memories while pixel data is being read out of the other.

Claim 30

Dependent Claim 230 words

A digital information storage and read-out system for use in generating a real-time perspective display of terrain over which a vehicle is moving on the basis of stored digital data 35 representing a two-dimensional elevational terrain pattern and signals indicating the instantaneous heading, geographic location and elevation of the vehicle and the desired angle of view of the resultant perspective display, comprising: a scene memory for storing said digital data in pixel form in addressable coordinate positions related to a selected geographic orientation of the terrain; read-out control means responsive to said signals representing heading, geographic location and angle of view for reading pixel data out of said scene memory through generation of address signals to address a selected area of said scene memory on the basis of the heading and geographic location of the vehicle and the desired angle of view with respect to the terrain represented by said digital data; perspective transform means responsive to the signals representing heading, elevation, geographic location and angle of view for transforming the address of each pixel read out of said scene memory from the addresses of that pixel in the two-dimensional terrain pattern to the address of the position to be occupied by that pixel in said perspective display; and display means responsive to the addresses generated by said perspective transform means for generating a real-time perspective display of said terrain.

Claim 31

Dependent Claim 230 words

A digital information storage and read-out system for use in generating a real-time perspective display of terrain over which a vehicle is moving on the basis of stored digital data 35 representing a two-dimensional elevational terrain pattern and signals indicating the instantaneous heading, geographic location and elevation of the vehicle and the desired angle of view of the resultant perspective display, comprising: a scene memory for storing said digital data in pixel form in addressable coordinate positions related to a selected geographic orientation of the terrain; read-out control means responsive to said signals representing heading, geographic location and angle of view for reading pixel data out of said scene memory through generation of address signals to address a selected area of said scene memory on the basis of the heading and geographic location of the vehicle and the desired angle of view with respect to the terrain represented by said digital data; perspective transform means responsive to the signals representing heading, elevation, geographic location and angle of view for transforming the address of each pixel read out of said scene memory from the addresses of that pixel in the two-dimensional terrain pattern to the address of the position to be occupied by that pixel in said perspective display; and display means responsive to the addresses generated by said perspective transform means for generating a real-time perspective display of said terrain.

Claim 32

Dependent Claim 32 words

A system according to claim 27, wherein said perspective transform means includes means for varying said transformed addresses in response to selected variations in the signal representing the desired angle of view.

Claim 33

Dependent Claim 89 words

A system according to claim 27, wherein said perspective transform means includes means for generating a signal AE representing the difference in elevation between the vehicle and each pixel 55 in said terrain pattern, means for generating a signal R representing the distance parallel to the vehicle heading between each pixel position and the vehicle position in said terrain pattern, and means for generating a signal AW representing the distance between each pixel and a line through the vehicle position parallel to the vehicle heading in said terrain pattern.

Claim 34

Dependent Claim 107 words

A system according to claim 29, wherein said digital data stored in said scene memory represents for each point in the terrain an elevation value E, equal to the actual elevation of that point reduced by a base elevation Eb, and said means for generating the signal AE includes first means for multiplying the elevation value E, read from said scene memory by a scale factor Sf and for adding to the result of said multiplication the base elevation Eb and second means for subtracting the output of said first means from the signal representing the elevation of said vehicle. 16 GB 2 113 056 A 16

Claim 35

Dependent Claim 73 words

A system according to claim 29, wherein said perspective transform means includes further means for generating transformed addresses a,b for each pixel according to the relationships a = K AE sin a - R cos a and LE cos a R sin a) AW b = K ( LE cos a + R sin a where a is the desired angle of view with respect to the horizontal and K is a constant.

Claim 36

Dependent Claim 96 words

A digital information storage and read-out system according to claim 27, wherein said readout means includes means for selectively generating said address signals so as to scan a generally diamond-shaped area of said scene memory, said area being positioned within said scene memory with one edge thereof being substantially transverse to the direction of vehicle heading with respect to said terrain pattern and the scanning of said area being in the direction parallel or transverse to the 10 geographical orientation of said data in the scene memory, whichever makes the smallest angle with said vehicle heading.

Claim 37

Dependent Claim 146 words

A system according to claim 27, wherein said display means includes a column buffer memory having a plurality of columns for storing respective lines of pixel data, including both elevation data and the transformed address of each pixel read out of said scene memory by said read-out means, 15 in positions corresponding to the locations of said pixel in said scene memory; line writing logic means responsive to groups of the pixel data read out of said column buffer memory for generating additional pixel data representing the elevation and addresses of pixels extending along lines between the pixels of each group in accordance with the transformed address thereof; and display memory means for storing the elevation data of pixels processed by said line writing logic means and pixels read out of 20 said column buffer memory at locations corresponding to the transformed addresses of said pixels.

Claim 38

Dependent Claim 72 words

A system according to claim 33, wherein said display means further includes transferring means for transferring pixel data from said line writing logic means into said display memory means by scanning said display memory means in successive lines beginning with pixel data representing the bottom of the display, the storage locations in each line of pixel data in the display memory means forming columns with the corresponding positions in the other lines.

Claim 39

Dependent Claim 77 words

A system according to claim 34, wherein said transferring means includes inhibiting means responsive to the elevational data of each pixel to be transferred to said display memory means for inhibiting such transfer in connection with any pixel along a given column of said display memory means which has an elevational value which is less than the elevational value of a pixel of the same 30 column which has already been transferred to said display memory means.

Claim 40

Dependent Claim 137 words

A system according to claim 35, wherein said inhibiting means includes a column max memory for storing an elevation value for each column of data stored in said display memory means, means for comparing the elevation value for each pixel read out of said column buffer memory and for each pixel generated by said line writing logic means with the elevation value stored in the column max 35 memory for that column in which the pixel is to be written into said display memory means, means responsive to said comparing means for storing in the column max memory the elevation value of the pixel when that value is greater than the value previously stored and for inhibiting transfer of said pixel to said display memory means when the elevation value thereof is less than that previously stored.

Claim 41

Dependent Claim 104 words

A system according to claim 33, wherein said line writing logic means includes storing means 40 for storing the transformed addresses of two adjacent pixels, means for incrementing one of said addresses in first and second coordinate directions toward said other address by calculated stepping values, means for generating an additional pixel at each incremented step taken by said incrementing means, and means for controlling said buffer control means to store the transformed addresses of the next pixels read out of said column buffer memory into said storing means when the one address has 45 been incremented until it corresponds to said other address.

Claim 42

Dependent Claim 73 words

A system according to claim 37, wherein said storing means stores the transformed addresses of four adjacent pixels read out of said column buffer memory, and said incrementing means includes means to compare said addresses in predetermined combinations of pairs, and means to increment said addresses in said predetermined combinations of pairs only when said comparison thereof indicates that the one address of the pair has a selected relationship to the other address.

Claim 43

Dependent Claim 41 words

A system according to claim 38, wherein said comparing means includes means for determining whether the line extending between the pair of pixels will face in a predetermined direction with respect to the orientation of data in said display memory means.

Claim 44

Dependent Claim 93 words

A system according to claim 33, wherein said display means further includes sun angle logic means for generating, with respect to each pixel read out of said column buffer memory and each pixel generated by said line writing logic means, the slope at the point of the terrain represented by that pixel on the basis of the pixels around that pixel, and transferring means for transferring said slope data into said display memory means at addresses provided by said line writing logic means in successive lines. 17 GB 2 113 056 A 17

Claim 45

Dependent Claim 73 words

A system according to claim 40, wherein said sun angle logic means includes means for comparing each value of slope which is generated with the slope value previously generated for the preceding pixel, and inhibiting means responsive to said comparing means for controlling said transferring means to store in said display memory means only that pixel data which represents a 5 change in slope on a given scanning line in said display memory.

Claim 46

Dependent Claim 49 words

A system according to claim 41, wherein said display means includes means for reading pixel data out of said display memory means, including means for generating pixels for storage locations containing zeros in accordance with the value of the last non-zero pixel read out along the same scanning line.

Claim 47

Dependent Claim 57 words

A digital information storage and read-out system constructed and arranged to operate 10 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1983. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained

Claim 48

Dependent Claim 57 words

A digital information storage and read-out system constructed and arranged to operate 10 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1983. Published by the Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained

Real time video perspective digital map display

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