Patent EP0016629A2 successfully refreshed from Google Patents.
EP0016629A2
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EP
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System and method for restoring image signal levels and setting signal gain for image-viewing devices
Assignee: Xerox Corp
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Filing: 1980-03-19
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Granted: —
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Expires: 2000-03-19
Abstract
Abstract A system for restoring image signal levels and setting signal gain for image-viewing devices such as change- coupled devices (CCDs) (15). Following the last image signal (or'pixel') in a line of image data, a predetermined sequence of dark level signals (D) and light level signals (L) are shifted out of the CCD. The dark level signals are the absence of all image information, while the light level signals represent signals introduced at the appropriate time early in the shifting cycle. At the CCD output, the dark and light level signals are isolated and processed by an MPU (86) in accordance with pre-established functions to provide an offset potential end gain multiplicand. The offset potential and gain multiplicand determined are used to remove tne offset and set signal gain for the next succeeding line of image signals. The process is repeated as each line of image signals is output from the CCD.
Inventors
- 👤 Douglas Glenn Wiggins
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:21
CPC Classifications
H; H04; H04N; H04N25/00; H04N25/60; H04N25/67; H04N25/671; H04N25/70; H04N25/701
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
221 words
An image signal restoration and gain-control system for an image viewing device (15) having an array of photosensitive elements (12) for viewing an original image and generating image signals (49) in response thereto, the image signals each being comprised of an offset potential (50) and an image potential (51) proportional to the intensity of the image portion viewed by the array elements, at least one output register (18, 20) for receiving the image signals, and means (Ø 4 , Ø 5 ) for driving the register to serially output signals from the register characterized by: means for generating'dark' (54) and 'light' (55) signals in said register with a plurality of image signals; means (85) for separating said dark and light signals from the image signals as all the signals are output from said register.; processing means (86) for determining from said dark and light signals an offset potential and a signal gain factor required to bring the image signals to a preset signal level; signal-restoring means (92) for removing said offset potential from succeeding image signals output by said viewing device to restore succeeding image signals to a substantially absolute level; and gain-correcting means (94) for adjusting the potential level of said succeeding image signals in accordance with said gain factor to provide image signals at a preset signal level. -
Claim 2
Dependent Claim
221 words
An image signal restoration and gain-control system for an image viewing device (15) having an array of photosensitive elements (12) for viewing an original image and generating image signals (49) in response thereto, the image signals each being comprised of an offset potential (50) and an image potential (51) proportional to the intensity of the image portion viewed by the array elements, at least one output register (18, 20) for receiving the image signals, and means (Ø 4 , Ø 5 ) for driving the register to serially output signals from the register characterized by: means for generating'dark' (54) and 'light' (55) signals in said register with a plurality of image signals; means (85) for separating said dark and light signals from the image signals as all the signals are output from said register.; processing means (86) for determining from said dark and light signals an offset potential and a signal gain factor required to bring the image signals to a preset signal level; signal-restoring means (92) for removing said offset potential from succeeding image signals output by said viewing device to restore succeeding image signals to a substantially absolute level; and gain-correcting means (94) for adjusting the potential level of said succeeding image signals in accordance with said gain factor to provide image signals at a preset signal level. -
Claim 3
Dependent Claim
60 words
The system of Claim 1 further characterised by: analog-to-digital converter (84) for converting the dark and light signals output by said viewing device to digital signals prior to input tc said processing means; and digital-to-analog converters (88, 90) for converting signals from said processing means to analog signals for use by said signal restoring means and said gain correcting means.
Claim 4
Dependent Claim
109 words
The system of Claim 1 or 2, further characterized by: buffer means (81, 82) for storing said dark and light signals for use by said processing means in determining the potential derived from said viewing device and said signal gain factor; means (100) for routing the signal output of said viewing device into two paths, one path being to said buffer means, and the second path being to said signal-restoring means and said gain-correcting means; and means (103) for removing said dark and light signals from the image signals in said second path so that only image signals are input to said signal restoring means and said gain-correcting means.
Claim 5
Dependent Claim
24 words
The system of Claim 3, further characterised by subtractor means (92) in said second path for subtracting said offset potential from said image signals.
Claim 6
Dependent Claim
30 words
The system of Claim 4 further characterised by multiplier means (94) in said second path for multiplying said image signals, said multiplier means being downstream of said subtractor means (92).
Claim 7
Independent Claim
237 words
The method of image signal restoration and gain control for an image viewing device (15) having an array (11) of image viewing elements (12), and at least one parallel in/serial out register (18, 20) coupled to said viewing elements in parallel for receiving image signals generated by said viewing elements and serially transferring said image signals along said register to an output of said register, characterized by the steps of: a) generating dark (54) and light (55) level signals to said shift register with each block of image signals (49); b) clocking (Ø 4 , Ø 5 ) said shift register to transfer said block of image signals together with said dark and light level signals serially along said shift register to the shift register output (28); c) separating (85, 103) said dark and light level signals from said block of image signals as said signals are output from said shift register; d) determining (86) from said dark and light level output signals the restoration potential required to restore the image signals to an absolute signal level and the gain factor required to produce an image signal output at a predetermined potential level; e) removing (92) said restoration potential from the next successive block of image signals to restore said image signals to said absolute signal level, and f) multiplying (94) the image signals by said gain factor to provide image signals at said predetermined potential level.
Claim 8
Independent Claim
237 words
The method of image signal restoration and gain control for an image viewing device (15) having an array (11) of image viewing elements (12), and at least one parallel in/serial out register (18, 20) coupled to said viewing elements in parallel for receiving image signals generated by said viewing elements and serially transferring said image signals along said register to an output of said register, characterized by the steps of: a) generating dark (54) and light (55) level signals to said shift register with each block of image signals (49); b) clocking (Ø 4 , Ø 5 ) said shift register to transfer said block of image signals together with said dark and light level signals serially along said shift register to the shift register output (28); c) separating (85, 103) said dark and light level signals from said block of image signals as said signals are output from said shift register; d) determining (86) from said dark and light level output signals the restoration potential required to restore the image signals to an absolute signal level and the gain factor required to produce an image signal output at a predetermined potential level; e) removing (92) said restoration potential from the next successive block of image signals to restore said image signals to said absolute signal level, and f) multiplying (94) the image signals by said gain factor to provide image signals at said predetermined potential level.
Claim 9
Dependent Claim
110 words
The method according to Claim 6 characterised by the steps of: g) separating (103) the signals output by the shift register into a first signal stream comprised of said dark and light level signals, and a second signal stream comprised of image signals only; h) buffering (81, 82) said first signal stream for use in determining a restoration potential and a gain factor; i) using the restoration potential to restore the absolute image signal levels to the image signals in said second stream, and j) using the gain factor to set the signal gain of the image signals in said second stream to provide a uniform image signal output level.
References Cited (Backward Citations)
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