EP0177058A2
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EP
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A method and a device for calculating a histogram
Assignee: International Business Machines Corp
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Filing: 1985-10-04
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Granted: —
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Expires: 2005-10-04
Abstract
Abstract Histograms of large volume data, e.g. image data, are calculated in at least two phases under the control of a computer (1), using a first histogram storage (29) with a wast address space and short word length and a second histogram storage (25) with a limited address space but a long word length. In one or several first phases, a preliminary histogram is generated in the first histogram storage; simultaneously, possible overflow items are identified using the second histogram storage. In a final phase, the overflow items are processed in the second histogram storage to update the preliminary histogram in the first histogram storage.
Inventors
- 👤 Yoshio Tozawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 14:37
CPC Classifications
G; G06; G06F; G06F17/00; G06F17/10; G06F17/18
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
178 words
A method for calculating a histogram, wherein the items to be histogrammed are mapped to the locations of a histogram storage for incrementing a count value in the selected location on occurrence of the corresponding item, characterized by the steps of: - creating, in at least one first phase, a first preliminary histogram by mapping all items to the locations of a first histogram storage (29), whose address range is equal or bigger than the number of different items, and whose word length is too short to accommodate the maximum item frequency; - identifying, in the first phase, overflow items occurring with a frequency higher than the word length of the first histogram storage can accommodate; - creating, in a second phase, a second preliminary histogram by mapping the overflow items, to the locations of a second histogram storage (25) with an address range smaller than the number of different items and with a word length that is sufficient to accommodate the maximum item frequency; - merging the first and second preliminary histograms to create the final histogram.
Claim 2
Independent Claim
178 words
A method for calculating a histogram, wherein the items to be histogrammed are mapped to the locations of a histogram storage for incrementing a count value in the selected location on occurrence of the corresponding item, characterized by the steps of: - creating, in at least one first phase, a first preliminary histogram by mapping all items to the locations of a first histogram storage (29), whose address range is equal or bigger than the number of different items, and whose word length is too short to accommodate the maximum item frequency; - identifying, in the first phase, overflow items occurring with a frequency higher than the word length of the first histogram storage can accommodate; - creating, in a second phase, a second preliminary histogram by mapping the overflow items, to the locations of a second histogram storage (25) with an address range smaller than the number of different items and with a word length that is sufficient to accommodate the maximum item frequency; - merging the first and second preliminary histograms to create the final histogram.
Claim 3
Dependent Claim
88 words
The method of claim 1, characterized in that each item represents n color values of a point in an image, that the first preliminary histogram is generated by applying, in sequence, a first phase to each of n equal subparts of the total color value range, that in each of the first phases the frequency distribution of color values in one of the color axes is determined, and that in the second phase the frequency distributions on the color axes are evaluated to generate the second preliminary histogram.
Claim 4
Dependent Claim
61 words
The method of claim 2, characterized in that the mapping of items in the second histogram storage is performed according to the formula: with wherein: ℓ = storage address E 1 = a selectable offset on 1st axis n. = ordinal number of the overflow projection on the i-th axis C i = total number of overflow projections on i-th axis
Claim 5
Dependent Claim
134 words
Device for calculating a histogram including a storage containing count values for the items to be histogrammed and computing means (1), to carry out the method of the claims 1 to 3, characterized in that there are provided: - a first histogrammer (29) including a first histogram storage, whose address range is equal or bigger than the number of different items and whose wordlength is insufficient to accommodate the maximum item frequency; - a second histogrammer (25) including a second histogram storage whose address range is smaller than the number of different items, and whose wordlength is sufficient to accommodate the maximum item frequency; - selection means (21-23) to select specified items for processing in the second histogrammer and - computing means (1) connected to the first and second histogrammer and the selection means.
Claim 6
Dependent Claim
56 words
The device of claim 4, characterized in that the computing means conditions the selecting means (21-23) in a first processing phase to enter selected items for mapping and storage in the second histogrammer and that the computing means evaluates the results of the first processing phase to condition the selecting means for a second processing phase.
Claim 7
Dependent Claim
25 words
The device of claim 4 or 5, characterized in that the first histogram storage is the video refresh buffer (6) of a display system (8).
References Cited (Backward Citations)
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