US5218647A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method to convert between 2 color space on a 32 bit μ-processor
Assignee: Ricoh Co Ltd
•
Filing: 1990-12-12
•
Granted: 1993-06-08
•
Expires: 2010-12-12
Abstract
Abstract An improved method for converting between two color spaces such as the RGB and YIQ color on a 32 bit microprocessor. The present invention only requires in total number of operations three table look-ups, two adds, two barrel shifts and two masking operations. In terms of speed it is believed that the present invention is optimal for microprocessors such as 32 bit microprocessors.
Inventors
- 👤 Steven M. Blonstein
- 👤 James D. Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:02
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6016; H04N1/6019
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
222 words
A method for converting between RGB and YIQ color spaces comprising the steps of: generating first, second and third look-up tables, each having a predetermined number of precalculated entries of a certain number of bit locations corresponding to said RGB color space, dividing each of the bit locations into at least three compartments of a lesser number of bit locations, such that each compartment corresponds to a YIQ color space component, looking up a first bit location number corresponding to the R (red) component, looking up a bit number location for the G (green) component and adding the two bit number locations together, looking up a bit location for the B (blue) component and adding to the previous bit total to form a calculated bit result such that the Y, I and Q components have been calculated simultaneously, masking off a certain number of low order bits to obtain the Y component value of said second color space, shifting the bit number a predetermined number of times and masking off the low order bits using a single barrel shift and mask operation to form the I component, shifting the bit number a certain number of times more to the right and masking off the bottom low order bits to form the Q component, thereby increasing the speed of the color space conversion.
Claim 2
Independent Claim
222 words
A method for converting between RGB and YIQ color spaces comprising the steps of: generating first, second and third look-up tables, each having a predetermined number of precalculated entries of a certain number of bit locations corresponding to said RGB color space, dividing each of the bit locations into at least three compartments of a lesser number of bit locations, such that each compartment corresponds to a YIQ color space component, looking up a first bit location number corresponding to the R (red) component, looking up a bit number location for the G (green) component and adding the two bit number locations together, looking up a bit location for the B (blue) component and adding to the previous bit total to form a calculated bit result such that the Y, I and Q components have been calculated simultaneously, masking off a certain number of low order bits to obtain the Y component value of said second color space, shifting the bit number a predetermined number of times and masking off the low order bits using a single barrel shift and mask operation to form the I component, shifting the bit number a certain number of times more to the right and masking off the bottom low order bits to form the Q component, thereby increasing the speed of the color space conversion.
Claim 3
Dependent Claim
18 words
The method of claim 1 wherein said certain number of bit locations of said precalculated entries is thirty-two.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the greatest of said lesser number of bit locations is greater than eight.
Claim 5
Dependent Claim
29 words
The method of claim 3 wherein the Q and I components have at least 9 bits of resolution, and the Y component has at least 8 bits of resolution.
Claim 6
Dependent Claim
18 words
The method of claim 4 wherein said certain number of bit locations of said precalculated entries is thirty-two.
Claim 7
Independent Claim
165 words
A method for converting image data between a first color space having a certain number of components and a second color space having a certain number of components comprising the steps of: generating one look-up table for each component of said first color space, each table having a predetermined number of precalculated entries of a certain number of bit locations, each entry of each table corresponding to a particular value of a particular component of said first color space, each entry of each table being divided up into a number of compartments of a lesser number of bit locations, said number of compartments being at least as large as said certain number of components of said second color space; looking up certain entries in said tables corresponding to values of components of said first color space; adding said certain entries to form a sum; and performing barrel shifting and masking operations to extract the values of components of said second color space from said sum.
Claim 8
Independent Claim
165 words
A method for converting image data between a first color space having a certain number of components and a second color space having a certain number of components comprising the steps of: generating one look-up table for each component of said first color space, each table having a predetermined number of precalculated entries of a certain number of bit locations, each entry of each table corresponding to a particular value of a particular component of said first color space, each entry of each table being divided up into a number of compartments of a lesser number of bit locations, said number of compartments being at least as large as said certain number of components of said second color space; looking up certain entries in said tables corresponding to values of components of said first color space; adding said certain entries to form a sum; and performing barrel shifting and masking operations to extract the values of components of said second color space from said sum.
Claim 9
Dependent Claim
69 words
The method of claim 6 wherein said barrel shifting and masking operations step is comprised of: for each component of said second color space performing the step of masking off a number of low order bits of said sum to obtain the value of each component of said second color space; for each component of said second colr space except one, performing the step of barrel shifting said sum.
Claim 10
Dependent Claim
20 words
The method of claim 7 wherein said certain numbers of components of said first and second color spaces is three.
Claim 11
Dependent Claim
19 words
The method of claim 8 wherein the greatest of said lesser number of bit locations is greater than eight.
Claim 12
Dependent Claim
18 words
The method of claim 8 wherein said certain number of bit locations of said precalculated entries is thirty-two.
References Cited (Backward Citations)
US4747154A
Cited
US4998286A
Cited
US4974071A
Cited
US5038202A
Cited
US4951139A
Cited
US4951129A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-07 | 1996-12-07 | 1997-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-07 | 2000-12-07 | 2001-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-07 | 2004-12-07 | 2005-06-08 | $7700.00 | Window Closed / Lapsed |