EP0370829A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Diagnostic imaging apparatus
Assignee: Philips Nuclear Medicine Inc
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Filing: 1989-11-24
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Granted: —
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Expires: 2009-11-24
Abstract
Abstract A CT scanner (10) generates views of data such as equal angular increment detector fan views (Figure 2A) which are convolved or filtered by an array processor (24). A combined backprojector and forward projector (28) backprojects the data from the array processor into an output memory (30) and forward projects lines of image representation data from an input memory (26) to the output memory. Each view representation may again be an equal angular increment detector fan format view (Figure 2A), a parallel ray format view (Figure 2B), an equal linear increment source fan format view (Figure 2D), a source fan format view (Figure 2C), an equal angular incremental detector fan format view (Figure 2E), an equal linear increment detector fan format view (Figure 2F), or an equal angular increment source fan format view (Figure 2G). In a backprojector mode, the projector is addressed by line and row addresses of a pixel of the output memory. A look-up table (76) and a multiplier (82) generate a weighting function (W). A multiplier (78) and an adding means (80) along with the look-up table convert the memory addresses into an appropriate address for a line of view data stored in a projector memory (60). An element of view data retrieved in response to the received address is multiplied (84) by the weighting function. In a forward projector mode, a parallel ray forward projection configuration (92) is provided. A view format transform assembly (90) transforms other format view designations and addresses into the corresponding parallel ray format view designations and addresses.
Inventors
- 👤 Carl J. Brunnett
- 👤 Holly C. Heiple
- 👤 Allen B. Zachary
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 16:06
CPC Classifications
G; G06; G06T; G06T12/00; G06T12/20
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
80 words
A diagnostic imaging apparatus comprising: a CT scanner (10) for generating views of radiation intensity data, each view including view data elements which correspond to an intensity of radiation along a corresponding ray through a scan circle (14); and an array processor means (24) for processing a plurality of views; characterised by a combined backprojector and forward projector means (28) for backprojecting processed views into an image representation and for forward projecting data of an image representation into view representations.
Claim 2
Dependent Claim
80 words
A diagnostic imaging apparatus comprising: a CT scanner (10) for generating views of radiation intensity data, each view including view data elements which correspond to an intensity of radiation along a corresponding ray through a scan circle (14); and an array processor means (24) for processing a plurality of views; characterised by a combined backprojector and forward projector means (28) for backprojecting processed views into an image representation and for forward projecting data of an image representation into view representations.
Claim 3
Dependent Claim
93 words
An apparatus according to Claim 1 further including: a non-invasive examination means (50) for generating diagnostic data indicative of interior regions of a subject; an image reconstruction means (52) for reconstructing the diagnostic data into an image representation, the reconstruction means (52) being operatively connected with an input memory (26) which is connected with an input of the combined backprojector and forward projector means (28) for selectively loading the image representation into the input memory (26), whereby image representations from scanners other than CT scanners can be converted into CT scanner view representations.
Claim 4
Dependent Claim
85 words
An apparatus according to Claim 1 or Claim 2 further including a view representation adjusting means (42) for adjusting view representations in accordance with a preselected algorithm, the view representation adjusting means (42) being operatively connected with an output memory means (30) for receiving forward projected view representations therefrom and being operatively connected with at least one of the array processor (24) and combined backprojection and forward projection means (28) for supplying the adjusted view representations thereto to be backprojected into an adjusted image representation.
Claim 5
Independent Claim
77 words
An apparatus according to any preceding claim wherein the combined backprojector and forward projector means (28) includes: a projector memory means (60) for receiving lines of data, in a backprojecting mode the lines of data being view data lines and in a forward projecting mode the lines of data being lines of the image representation; and a weighting function multiplying means (84) for multiplying each data value retrieved from the projector memory by a weighting function (W).
Claim 6
Dependent Claim
142 words
An apparatus according to Claim 4 wherein the combined backprojector and forward projector means (28) further includes: first and second inputs for receiving projected data line designations and data addresses (u, v or t, 0) for a data element within each projected line for one of an image data line and a view data line; a memory address generating means (78) operatively connected with the inputs for generating an address of a data element in the other of the image data and view data line stored in the projector memory means (60); and, a weighting function generating means (76, 82 or 100) operatively connected with the first and second inputs for generating a weighting function (W) from the projected line designations and addresses, the weighting function generating means (76, 82 or 100) being operatively connected with the weighting function multiplying means (84).
Claim 7
Dependent Claim
140 words
An apparatus according to Claim 4 further including: a look-up table means (100, 102) which is addressed by a view angle designation to retrieve values 1/cos0 and tan0, the look-up table means (100) being operatively connected with the weighting function multiplying means (84) for conveying the 1/cos0 value thereto; a second multiplying means (78) for multiplying a view data element address designation (t) by the 1/cos0 term; a third multiplying means (82) for multiplying the tan0 term by a function (S) of a position of an image data line stored in the projector memory means (60) relative to the image representation; and, an adding means (80) operatively connected with the second and third multiplying means (78, 82) for adding the outputs thereof and being operatively connected with the projector memory means (60) for addressing the line of image data therein.
Claim 8
Dependent Claim
75 words
An apparatus according to Claim 6 wherein the view angle designation is an indication of an angle of a parallel ray format view and the view data element address (t) is a designation of one of the parallel rays of the view and further including a view format transforming means (90) for transforming view designations and addresses of other view formats into an equivalent of a parallel ray format view designation and data element addresses.
Claim 9
Dependent Claim
84 words
An apparatus according to Claim 7 wherein the view format transforming means (90) includes at least one of: a means for transforming equal linear increment fan format view designations and addresses into parallel ray format view designations and addresses; a means for transforming equal angular increment detector fan format view designations and addresses into parallel ray format view designations and addresses; and, a means for transforming equal angular increment source fan format view designations and addresses into parallel ray format view designations and addresses.
Claim 10
Dependent Claim
100 words
An apparatus according to Claim 4 further including: in a backprojecting configuration, first and second inputs for receiving image memory row and column addresses (u, v); a memory address generating means (78) for generating addresses of view elements of each view data line stored in the projector memory means (60) from the image memory row and column addresses (u, v); a weighting function generating means (76, 82) for generating the weighting function (W) from the image memory row and column addresses (u, v), the weighting function generating means (76, 82) being operatively connected with the weighting function multiplying means (84).
Claim 11
Dependent Claim
152 words
A combined backprojector and forward projector for CT scanner type data, the combined projector comprising: a memory means (60) for storing at least one of (1) a line of view data and (ii) a line of image date; a first multiplying means (84) operatively connected with the memory means (60) for multiplying a retrieved data element by a weighting function (W); a memory address generating means (78) for generating addresses of data elements of the line of data stored in the memory means, the address generating means (78) being operatively connected with the memory means (60) and with first and second inputs (u,v or t,0); and, a weighting function generating means (76, 82 or 100) operatively connected with at least one of the first and second inputs (u, v or t,0) for generating the weighting function (W) therefrom and with the first multiplying means (84) for supplying the weighting function (W) thereto.
Claim 12
Dependent Claim
152 words
A combined backprojector and forward projector for CT scanner type data, the combined projector comprising: a memory means (60) for storing at least one of (1) a line of view data and (ii) a line of image date; a first multiplying means (84) operatively connected with the memory means (60) for multiplying a retrieved data element by a weighting function (W); a memory address generating means (78) for generating addresses of data elements of the line of data stored in the memory means, the address generating means (78) being operatively connected with the memory means (60) and with first and second inputs (u,v or t,0); and, a weighting function generating means (76, 82 or 100) operatively connected with at least one of the first and second inputs (u, v or t,0) for generating the weighting function (W) therefrom and with the first multiplying means (84) for supplying the weighting function (W) thereto.
Claim 13
Dependent Claim
260 words
A projector according to Claim 10 wherein in a backprojecting mode: the first and second inputs receive image memory row and column addresses (u, v); the memory address generating means (78) generates a view data elment address from the image memory row and column addresses (u,v); and the weighting function generating means (84) generates the weighting function (W) from the image memory row and column addresses (u, v). 12. A projector according to Claim 11 wherein the weighting function generating means (76, 82) includes a look-up table means (76) connected with one of the inputs for retrieving a value D/(D-v) in response to being addressed by a value v, where v is a received one of the row and column addresses and D is a diameter from a center of a scan circle (14) to a corresponding radiation detector (16), the look-up table means (76) being connected with a second multiplying means (82) for squaring the retrieved value, the second multiplying means (82) being operatively connected with the first multiplying means (84) to supply the squared value thereto; and the address generating means (78) includes a third multiplying means (78) operatively connected with the other input and operatively connected with the look-up table means (76) for multiplying the address received on the other input by the retrieved look-up table value and an adding means (80) for adding a centering constant to the product of the third multiplying means (78), the adding means (80) being operatively connected with the memory means (60) for addressing the memory (60) with the output thereof.
Claim 14
Dependent Claim
84 words
A projector according to Claim 10 wherein in a forward projection mode: a parallel ray format view designation (0) and a view data element address (t) which is a designation of one of the parallel rays of the designated parallel ray format view are received on the first and second inputs and further including a view format transforming means (90) for transforming view designations and addresses of other view formats into an equivalent of a parallel ray format view designation and data element addresses.
Claim 15
Dependent Claim
76 words
An apparatus according to Claim 13 wherein the view format transforming means (90) includes at least one of: a means for transforming equal linear increment fan format view designations and addresses into parallel ray format view designations and addresses; a means for transforming equal angular increment detector fan format view designations and addresses; and, a means for transforming equal angular increment source fan format view designations and addreses into parallel ray format view designations and addresses.
Claim 16
Dependent Claim
203 words
A projector according to Claim 10 wherein in a forward projection mode: a view designation (0) is received at one input and a view address (t) is received at the other input and a line of data from an image representation is stored in the memory means (60), the view designation being a view angle indicative of an angle of a parallel ray format view through the scan circle (14); the weighting function generating means (100) and the memory address generating means (78) include a look-up table means (100, 102) which is addressed by the view angle to retrieve values 1/cos0 and tan0, the 1/cos0 value being conveyed to the first multiplying means (84); a second multiplying means (78) for multiplying the view address (t) by the 1/cos0 value; a third multiplying means (82) for multiplying the tan0 value by an indication (S) of a position of the image data line stored in the memory means (60) relative to a remainder of the image representation; and, an adding means (80) for adding the product of the second and third multiplying means (78, 82), the adding means (80) being connected with the memory means (60) for addressing the memory (60) with the output thereof.
Claim 17
Dependent Claim
255 words
A backprojector for CT scanner type data comprising: first and second inputs which receive image memory row and columnm addresses u and v; a memory means (60) for storing a line of view data; a weighting function generating means (76, 82) operatively connected with at least one of the first and second inputs for generating a weighting function (W) therefrom, the weighting function generating means (76, 82) including a look-up table means (76) connected with one of the inputs for retrieving a value D/(D-v) in response to being addressed by v, where D is a diameter from a center of a scan circle (14) to a corresponding detector (16), the look-up table means (76) being connected with a first multiplying means (82) for squaring the retrieved look-up table value; a second multiplying means (84) operatively connected with the memory means (60) for multiplying a retrieved data element by the squared retrieved look-up table value from the first multiplying means (82); and, a memory address generating means (78) for generating addresses of view data elements of the line of view data stored in the memory means (60), the address generating means including a third multiplying means (78) operatively connected with the other input and operatively connected with the look-up table means (76) for multiplying the address u received on the other input by the retrieved look-up table value and an adding means (80) for adding a centering constant to the third multiplying means product, the adding means (80) being operatively connected with the memory means (60).
Claim 18
Dependent Claim
255 words
A backprojector for CT scanner type data comprising: first and second inputs which receive image memory row and columnm addresses u and v; a memory means (60) for storing a line of view data; a weighting function generating means (76, 82) operatively connected with at least one of the first and second inputs for generating a weighting function (W) therefrom, the weighting function generating means (76, 82) including a look-up table means (76) connected with one of the inputs for retrieving a value D/(D-v) in response to being addressed by v, where D is a diameter from a center of a scan circle (14) to a corresponding detector (16), the look-up table means (76) being connected with a first multiplying means (82) for squaring the retrieved look-up table value; a second multiplying means (84) operatively connected with the memory means (60) for multiplying a retrieved data element by the squared retrieved look-up table value from the first multiplying means (82); and, a memory address generating means (78) for generating addresses of view data elements of the line of view data stored in the memory means (60), the address generating means including a third multiplying means (78) operatively connected with the other input and operatively connected with the look-up table means (76) for multiplying the address u received on the other input by the retrieved look-up table value and an adding means (80) for adding a centering constant to the third multiplying means product, the adding means (80) being operatively connected with the memory means (60).
Claim 19
Dependent Claim
171 words
A forward projector for CT scanner type data comprising: first and second inputs for receiving a parallel ray format view angle designation 0 and a view data element address (t); a memory means (60) for storing a line of an image representation; a look-up table means (100, 102) which is addressed by the view angle to retrieve values 1/cos0 and tan0; a first multiplying means (78) for multiplying the view address (t) by the 1/cos0 value; a second multiplying means (82) for multiplying the tan0 value by an indication (S) of a position of the image data line stored in the memory means (60) relative to the image representation; an adding means (80) for adding the product of the first and second multiplying means (78, 82), the adding means (80) being connected with the memory means (60) for addressing the memory means (60) to retrieve an image data element; and, a third multiplying means (84) for multiplying the image data element retrieved from the memory means (60) by the 1/cos0 value.
Claim 20
Dependent Claim
171 words
A forward projector for CT scanner type data comprising: first and second inputs for receiving a parallel ray format view angle designation 0 and a view data element address (t); a memory means (60) for storing a line of an image representation; a look-up table means (100, 102) which is addressed by the view angle to retrieve values 1/cos0 and tan0; a first multiplying means (78) for multiplying the view address (t) by the 1/cos0 value; a second multiplying means (82) for multiplying the tan0 value by an indication (S) of a position of the image data line stored in the memory means (60) relative to the image representation; an adding means (80) for adding the product of the first and second multiplying means (78, 82), the adding means (80) being connected with the memory means (60) for addressing the memory means (60) to retrieve an image data element; and, a third multiplying means (84) for multiplying the image data element retrieved from the memory means (60) by the 1/cos0 value.
Claim 21
Dependent Claim
152 words
A forward projector for projecting image data into any one of a plurality of CT scanner data view formats, the projector comprising: a means for receiving first format view designations and addresses (0, t); a memory means (60) for storing a line of image data; a memory address generating means (78) for generating addresses for the memory means (60) from the received first format view designations and addresses; a weighting function generating means (100) for generating weighting functions (W) from the received first format view designations and addresses; a combining means (84) for combining data retrieved from the memory means (60) with the generated weighting functions (W); and, a view format transforming means (90) for transforming other format view designations and addresses into equivalents of the first format designations and addresses (0, t), the view format transforming means (90) being operatively connected with the address and weighting function generating means (78, 100).
Claim 22
Dependent Claim
152 words
A forward projector for projecting image data into any one of a plurality of CT scanner data view formats, the projector comprising: a means for receiving first format view designations and addresses (0, t); a memory means (60) for storing a line of image data; a memory address generating means (78) for generating addresses for the memory means (60) from the received first format view designations and addresses; a weighting function generating means (100) for generating weighting functions (W) from the received first format view designations and addresses; a combining means (84) for combining data retrieved from the memory means (60) with the generated weighting functions (W); and, a view format transforming means (90) for transforming other format view designations and addresses into equivalents of the first format designations and addresses (0, t), the view format transforming means (90) being operatively connected with the address and weighting function generating means (78, 100).
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