Image analysis – Color image processing
Reexamination Certificate
1998-08-25
2001-12-18
Tran, Phuoc (Department: 2621)
Image analysis
Color image processing
C382S165000
Reexamination Certificate
active
06332036
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a color extraction apparatus and method for extracting a particular color from an input color image signal. For example, the invention is applied to realizing, in an entertainment robot or an imaging system, a function of recognizing a target object having a particular color and following it automatically.
2. Description of the Related Art
As disclosed in, for instance, Japanese Unexamined Patent Publication No. Hei. 8-51564, in conventional target following apparatuses and the like in which the imaging direction is controlled by detecting the movement of a target from an image taken by a television camera, it is operated to follow a target by using color information of a color image signal in addition to shape information of a target.
As proposed in Japanese Patent Application Nos. Sho. 59-12481 and Hei. 5-329272, a color extraction technique is known in which a color is extracted by normalizing input chrominance signals by an input luminance signal and comparing normalized signals with a preset value.
However, this conventional color extraction technique including normalization has a limitation that color models in a luminance/chrominance space are restricted.
The assignee of the present application has proposed a technique in which a high-order color model is introduced and a judgment is made by calculating the distance between a model and an input image with a microcomputer (Japanese Patent Application No. Hei. 9-48786). However, in this type of technique in which limitations on models are eliminated by using a microcomputer, the execution speed and the capability of accommodating a plurality of colors are insufficient because an input image is processed by the microcomputer.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a color extraction apparatus and method which can not only reduce the load of a signal processing means for image processing but also increase the extendability of a color model to thereby enable high-speed, simultaneous extraction of multiple colors by using a more flexible model.
The invention provides a color extraction apparatus comprising input signal processing means for obtaining a luminance signal and chrominance signals from an input image signal; color table managing means for producing, as a reference, a signal indicating a color area by searching a preset table based on a signal level of the luminance signal; color area comparing means for judging whether a color of the input image signal belongs to the reference color area by comparing the signal indicating the reference color area with signal levels of the chrominance signals; storing means for accumulating a color extraction result for the input image signal that is obtained as a comparison output of the color area comparing means; and control means for setting in advance the table corresponding to signal levels of the luminance signal in the color table managing means.
The above color extraction apparatus may be configured in such a manner that the control means sets a plurality of color models in tables of the color table managing means; the color table managing means produces, as references, signals indicating color areas for the respective color models by searching the tables in which the plurality of color models are set based on the signal level of the luminance signal; the color area comparing means judges whether the color of the input image signal belongs to the reference color areas by comparing the signals indicating the reference color areas with the signal levels of the chrominance signals; and the storing means accumulates color extraction results for the input image signal that are obtained as comparison outputs of the color area comparing means, the color extraction results being combined as unit data for each position in an image.
The above color extraction apparatus may further comprise means for calculating, for each of the color models, the number of color extraction results indicating that the color of the input image signal belongs to the reference color area; and means for calculating, for each of the color models, positional information and distribution information of in the image based on the number of color extraction results indicating that the color of the input image signal belongs to the reference color area and positions of those color extraction results in the image, wherein the storing means may store calculation results independently for the respective color models.
The above color extraction apparatus may further comprise logic operation means for performing a logic operation on color extraction results for a plurality of color models indicating that the color of the input image signal belongs to the reference color area, the color extraction results being obtained at a certain position in the image; and means for setting the logical operation, wherein the storing means may store operation results of the logical operation means independently for the respective color models.
The invention also provides a color extraction method comprising the steps of storing a color model of an extraction object; reading out an area of the stored color model based on a luminance signal level of an input image signal; comparing a signal indicating the read-out area with chrominance signal levels of the input image signal; and accumulating a comparison result as a color extraction result.
The above color extraction method may be such that the storing step sets a plurality of color models in tables; the reading step produces, as references, signals indicating color areas for the respective color models by searching the tables in which the plurality of color models are set based on the luminance signal level of the input image signal; and the comparing step judges whether a color of the input image signal belongs to the reference color areas by comparing the signals indicating the reference color areas with the chrominance signal levels of the input image signal, whereby color extraction is performed on the input image signal.
According to the invention, color extraction can be performed at high speed according to a color model that represents a particular distribution in a color difference space. At the same time, such information as size and position of an extracted color region can also be detected. Extended application to circuits in which detections are simultaneously performed for multiple color models can be done easily. Further, models can be set freely and can be extended by introducing a new operation such as combining models.
Therefore, in the color extraction apparatus and method according to the present invention, color extraction can be performed at high speed for multiple colors by using flexible models and, at the same time, such information as areas and centers of gravity for the respective colors in an image can also be extracted. This makes it possible to reduce the load of a CPU relating to a pre-process for image recognition.
REFERENCES:
patent: 4991223 (1991-02-01), Bradley
patent: 5087965 (1992-02-01), Torre-Bueno
patent: 5227871 (1993-07-01), Funada et al.
patent: 5313275 (1994-05-01), Daly et al.
patent: 5917938 (1999-06-01), Funada et al.
patent: 6011595 (2000-01-01), Henderson et al.
patent: 6047085 (2000-04-01), Sato et al.
Bell Boyd & Lloyd LLC
Sony Corporation
Tran Phuoc
LandOfFree
Color extraction apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Color extraction apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color extraction apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2596637