COLOR CALIBRATION OF COLOR IMAGE RENDERING DEVICES

• US 20160057399A1
• Filed: 11/05/2015
• Published: 02/25/2016
• Est. Priority Date: 08/31/2005
• Status: Active Grant

• Current Assignee: RAH Color Technologies LLC
• Original Assignee: RAH Color Technologies LLC
• Inventors: HOLUB, RICHARD A.
• Granted Patent: US 9,516,288 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01J 2003/2866 Markers; Calibrating of scan
• CPC Class Codes: G01J 2003/466 Coded colour; Recognition of predetermined colour; Determining proximity to predetermined colour
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0202 Mechanical elements; Supports for optical elements
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0262 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/0289 Field-of-view determination; Aiming or pointing of a spectrometer; Adjusting alignment; Encoding angular position; Size of measurement area; Position tracking
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/18 using diffraction elements, e.g. grating gratings per se G02B
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 3/462 Computing operations in or between colour spaces; Colour management systems
• CPC Class Codes: G01J 3/463 Colour matching
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 3/506 measuring the colour produced by screens, monitors, displays or CRTs
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G03B 27/547 colour mixing heads
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/20072 Graph-based image processing
• CPC Class Codes: G06T 7/80 : Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
• CPC Class Codes: G06T 7/90 : Determination of colour characteristics
• CPC Class Codes: G09G 2320/0285 : using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0626 : for control of overall brightness
• CPC Class Codes: G09G 2320/0666 : for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2320/0693 : Calibration of display systems
• CPC Class Codes: G09G 2330/021 : Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 : the light being ambient light
• CPC Class Codes: G09G 2360/147 : the originated light output being determined for each pixel
• CPC Class Codes: G09G 3/3413 : Details of control of colour illumination sources
• CPC Class Codes: G09G 5/02 : characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: H04N 1/6033 : using test pattern analysis H04N1/6055 takes precedence
• CPC Class Codes: H04N 1/6052 : Matching two or more picture signal generators or two or more picture reproducers
• CPC Class Codes: H04N 17/02 : for colour television signals
• CPC Class Codes: H04N 17/045 : Self-contained testing apparatus
• CPC Class Codes: H04N 23/13 : with multiple sensors
• CPC Class Codes: H04N 23/88 : for colour balance, e.g. white-balance circuits or colour temperature control
• CPC Class Codes: H04N 9/12 : Picture reproducers H04N9/11 takes precedence
• CPC Class Codes: H04N 9/3182 : Colour adjustment, e.g. white balance, shading or gamut white balance per se H04N9/73; control of amplitude of colour signals H04N9/68; colour control circuits for displays in general G09G5/02, G09G3/2003, G09G3/3607
• CPC Class Codes: H04N 9/3194 : including sensor feedback
• CPC Class Codes: H04N 9/68 : for controlling the amplitude of colour signals, e.g. automatic chroma control circuits H04N9/71, H04N9/73 take precedence; camera processing pipelines for controlling the colour saturation of colour signals H04N23/86
• CPC Class Codes: H04N 9/73 : Colour balance circuits, e.g. white balance circuits or colour temperature control camera processing pipelines for colour balance H04N23/88

Abstract

Color calibration of color image rendering devices, such as large color displays, which operate by either projection or emission of images, utilize internal color measurement instrument or external color measurement modules locatable on a wall or speaker. A dual use camera is provided for a portable or laptop computer, or a cellular phone, handset, personal digital assistant or other handheld device with a digital camera, in which one of the camera or a display is movable with respect to the other to enable the camera in a first mode to capture images of the display for enabling calibration of the display, and in a second mode for capturing image other than of the display. The displays may represent rendering devices for enabling virtual proofing in a network, or may be part of stand-alone systems and apparatuses for color calibration. Improved calibration is also provided for sensing and correcting for non-uniformities of rendering devices, such as color displays, printer, presses, or other color image rendering device.

Claims

1-22. -22. (canceled)

23. A hand-held multifunctional digital apparatus comprising:

a controller comprising at least one programmable processor;

memory for storing control programs for operating said apparatus and enabling a user interface, application programs for providing multifunctional capability, and data, wherein said data comprises at least location information, and images and audio data in digital form;

a plurality of cameras, wherein at least one of said cameras is operable to capture one or more of said images;

an illumination source associated with one of said cameras;

a color video display operable to present menus of said user interface, a viewfinder for displaying images captured by said at least one camera, and one or more of text and graphics associated with execution of one or more of said application programs;

an audio unit comprising one or more speakers and one or more microphones, said audio unit enabling said user interface to operate by a user speaking to the apparatus and the apparatus speaking to the user;

a transmitter and a receiver for enabling, via an antenna, one or more of cellular telephony, and communication with an external system using one or more network protocols;

a connector for interfacing said apparatus with an external device;

software comprising at least;

an operating program that controls the functions of said apparatus responsive, in part, to inputs through the user interface;

one or more programs providing said user interface that renders on said color video display graphic representations of functions for user selection and that employs speech recognition and computer generated speech to implement spoken interaction between the user and said apparatus using said audio unit, whereby said apparatus assists said user in performing a task by utilizing one or more measurements and guiding user performance through spoken directions responsive, in part, to values of said one or more measurements;

one or more programs for converting at least one of said images in a plurality of color channels into digital image data and for storing said digital image data in a file having a header and fields of data that enable a receiver of said file to interpret said digital image data; and

one or more programs that operates at least one of said cameras to capture a series of images as video data.

24. The apparatus according to claim 23 wherein said location information comprises at least GPS coordinates.

25. The apparatus according to claim 23 wherein said color video display comprises an array of pixels that are visually resolvable with the aid of a magnifier.

26. The apparatus according to claim 25 further comprising a magnifier attachable to said apparatus and adjustable by a user to enable said user to visualize detail on said color video display.

27. The apparatus according to claim 23 wherein said operating program controls said apparatus responsive to a comparison of a measured spatial pattern with a stored reference.

28. The apparatus according to claim 23 wherein said software further comprises a program that applies a correction for spatial non-uniformity of brightness and color across the surface of said color video display.

29. The apparatus according to claim 28 wherein said program that applies a correction for spatial non-uniformity of rendering utilizes one or more spatial non-uniformity correction tables, wherein a single said table comprises a two-dimensional array whose inputs are spatial coordinates upon the surface of said color video display and whose output for each input is a correction value for at least one color channel.

30. The apparatus according to claim 29 wherein said spatial non-uniformity correction tables are prepared with the aid of an image capture device that is calibrated for approximately colorimetric and uniform spatial response and that is used to measure the surface of said color video display.

31. The apparatus according to claim 23 wherein said one or more programs for storing said digital image data in a file stores said digital image data in a JPEG file having EXIF-compatible fields of data describing properties of said digital image data.

32. The apparatus according to claim 23 wherein said software further comprises one or more programs that alter rendering upon said color video display, responsive to measurement of ambient illumination by a sensor incorporated with said apparatus, in accord with user preferences expressed through said user interface.

33. The apparatus according to claim 31 wherein said one or more programs for converting at least one of said images in a plurality of color channels into digital image data provide said digital image data in accordance with one or more color transformations that map colors of said at least one of said images to coordinates of a color space having a defined relationship to CIE colorimetric values and that compensate at least for differences between the illuminant of image capture and that for viewing of a reproduction.

34. The apparatus according to claim 33 further comprising a program that transforms said digital image data to comprise colors not representable in said color space having a defined relationship to CIE colorimetric values in accordance with gamut expansion in preparation for rendering on an output device with at least increased saturation realizable on said output device.

35. The apparatus according to claim 23 wherein said one or more measurements utilized in said assistance to said user in performing said task are based upon at least said digital image data.

36. The apparatus according to claim 35 wherein said color video display when presenting said viewfinder displays said video data.

37. The apparatus according to claim 35 wherein said software further comprises a program that provides indications of progress in performing said task while comparing features of said digital image data with digital information of a reference image.

38. The apparatus according to claim 37 wherein said software further comprises a program that communicates with an external computer that provides one or both of data or computation to assist in said guiding of user performance.

39. The apparatus according to claim 23 wherein one of said one or more programs that operates at least one of said cameras to capture said video data enables a video conference in which images of at least one conversant are displayed on said color video display.

40. The apparatus according to claim 39 wherein the screen of said color video display is split to enable display of images of one or both conversants in said video conference or data related to said video conference comprising at least a textual selection from a document or numerical data from a spreadsheet.

41. The apparatus according to claim 33 wherein said software further comprises one or more programs that enable a user to modify variables of color reproduction of said digital image data interactively through menu selections and to observe the results of said selections on display of said digital image data on said color video display.

42. The apparatus according to claim 23 further providing an interface to external devices comprising one or more of Bluetooth, Firewire, Universal Serial Bus, and infrared signaling.

43. The apparatus according to claim 23 wherein said software further comprises a program that communicates with an external computer that provides one or both of data or computation to assist in said guiding of user performance.

44. A hand-held multifunctional digital apparatus comprising:

a controller comprising at least one programmable processor;

memory for storing control programs for operating said apparatus and enabling a user interface, application programs for providing multifunctional capability, and data, wherein said data comprises at least location information, and images and audio data in digital form;

a plurality of cameras, wherein at least one of said cameras is operable to capture one or more of said images in a plurality of color channels;

an illumination source associated with at least one of said cameras;

a color video display operable to present menus of said user interface, a viewfinder for displaying images captured by said at least one camera, and one or more of text and graphics associated with execution of one or more of said application programs;

an audio unit comprising one or more speakers and one or more microphones;

a transmitter and a receiver for enabling communication with an external system using one or more network protocols;

a connector for interfacing said apparatus with an external device;

software comprising at least;

an operating program that controls the functions of said apparatus responsive, in part, to inputs through the user interface;

one or more programs providing said user interface that renders on said color video display graphic representations of functions for user selection and that employs speech recognition and computer generated speech to implement spoken interaction between the user and said apparatus using said audio unit;

one or more programs for converting at least one of said images in a plurality of color channels into digital image data and for storing said digital image data in a file having a header and fields of data that enable a receiver of said file to interpret said digital image data; and

one or more programs that operates at least one of said cameras to capture a series of images as video data and enables a video conference in which the screen of said color video display is partitioned to display images of one or more conversants in said video conference or data related to said video conference comprising at least a textual selection from a document or numerical data from a spreadsheet.

45. A method for detecting color differences between a source digital image and a reproduction by a rendering device of said source digital image comprising the steps of:

measuring spatial non-uniformities of a rendering upon a display surface by said rendering device;

rendering upon said display surface a reproduction of said source digital image which one of uses one or more spatial non-uniformity correction functions, or simulates the effects of said spatial non-uniformities;

capturing a digital image of said reproduction of said source digital image;

producing one or more histograms from each of said source digital image and said digital image of said reproduction of said source digital image; and

comparing corresponding histograms of said each of said source digital image and said digital image of said reproduction of said source digital image from said producing step to determine color differences.