Patents by Inventor Petrus De Greef

Petrus De Greef has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20080094346
    Abstract: A method for processing a frame of image data, wherein the image data is amplified by a gain factor determined in dependence of a number of sub-pixels within said frame of image data having a luminance above a first threshold value. The resulting gain factor allows for optimal amplification of the image data without loss of local detail. This leads to a better perceived image quality. In a preferred embodiment, the gain factor is simultaneously used for reducing the backlight intensity in a backlit LCD device. Thereby, the perceived image quality is similar to that of the unprocessed image data, however the power consumption of the LCD backlight is reduced substantially.
    Type: Application
    Filed: May 4, 2005
    Publication date: April 24, 2008
    Applicant: Koninklijke Philips Electronics N.V.
    Inventor: Petrus De Greef
  • Publication number: 20070223018
    Abstract: A method for processing color image data that enables to optimally render a color image on a target device. The method incorporates a color gamut mapping step, where the amount of gamut mapping is adapted dynamically, in dependence of at least a color saturation value of the input pixel. Preferably, also a luminance value of the input pixel is used. The adaptive gamut mapping incorporates correction of saturation, and preferably also hue and white point, of the image data. The color gamut of the target device is used to the fullest possible extent, while clipping and loss of local details in highly saturated areas of the input image is largely prevented.
    Type: Application
    Filed: May 4, 2005
    Publication date: September 27, 2007
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS, N.V.
    Inventors: Matheus Lammers, Petrus De Greef, Wei Lee, Erik Van Der Tol, Michiel Klompenhouwer, Erno Hermanus Langendijk
  • Publication number: 20070159490
    Abstract: A display method comprises the steps of generating (1) images comprising source data (SDA) and source frame synchronization instants (SSI) having a source frame rate (SFR). The source data (SDA) is stored (2) in a frame memory (5) under control of a first address pointer (AP I) having a start address (DSA) being determined by the source frame synchronization instants (SSI). During a read period (RP), display data (DDA) is read (2) from the memory (5) under control of a second address pointer (AP2) having a start address (SSA) being determined by display frame synchronization instants (DSI) having a display frame rate (DFR). The display data (DDA) is displayed (3) on a matrix display (4). The source frame rate (SIR) or the display frame rate (DFR) is controlled (2) to obtain, in a stable situation, the first address pointer (AP I) and the second address pointer (AP2) starting with an offset in time (TO) which has a fixed polarity during the read period (RP).
    Type: Application
    Filed: January 20, 2005
    Publication date: July 12, 2007
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventor: Petrus De Greef
  • Publication number: 20060066592
    Abstract: The present invention relates to a method of scanning lines in a display, a device for scanning lines and a portable electronic device including such a device. Driving luminance information for each pixel within a frame is divided into subfields (90, 92, 94, 96, 98, 100). Subfields are selected for scanning in a set of scanning cycles (Scan 0, Scan 1, Scan 2, Scan 3, Scan 4, Scan 5) equivalent to the existing number of subfields, lines are scanned consecutively and selection of subfield is varied from line to line in each scanning cycle such that no two consecutive line scans use the same subfield and no line is scanned using the same subfield twice during the set. Image flicker caused by the subfields is reduced.
    Type: Application
    Filed: October 22, 2003
    Publication date: March 30, 2006
    Inventor: Petrus De Greef
  • Publication number: 20050253784
    Abstract: The invention relates to a video circuit (1) for processing video signals which show images on a display panel with linear light transition, comprising a gamma correction circuit (3), a quantizer (11) and a sub-field generator circuit (8). To save computing time, a random-access memory (7) replaces the quantizer (64).
    Type: Application
    Filed: July 24, 2003
    Publication date: November 17, 2005
    Inventors: Petrus De Greef, Rob Beuker
  • Publication number: 20050219270
    Abstract: The invention concerns a device and method for converting and supplying a display driving unit with luminance values as well as a portable electronic device and a display unit including the converting device. The device includes an input (33, 35, 37), which receives a first value representing a luminance level with a first word length. It also includes a conversion unit (34, 36 38), that converts the first value into second and third values. These values together represent the luminance level represented by the first value and have a second word length. The second word length is shorter than the first word length. The device also includes a subfield control unit (32), which supplies the second and third values to the display driving unit during a frame period of the display. The time taken up by each converted value is a subfield of the frame. The subfield of the third value is longer than the subfield of the second value.
    Type: Application
    Filed: February 25, 2003
    Publication date: October 6, 2005
    Inventors: Petrus De Greef, Rob Beuker, Petrus Van De Sande
  • Publication number: 20050093775
    Abstract: The present invention relates to driving a plasma display panel including discharge cells each corresponding to a pixel in response to a video signal including fields wherein each field is formed by a plurality of subfields, wherein a sustain-level signal (AS) is applied (Q) to cause a sustaining discharge in a discharge cell for emitting light therefrom, and an error diffusion process is carried out. In the error diffusion process (Q?1, ST, F, A), sustain-level quantization errors of the current filed are detected (Q?1, ST) and transferred (F, A) to a next field, in which the sustain-level quantization errors are preferably compensated for.
    Type: Application
    Filed: January 14, 2003
    Publication date: May 5, 2005
    Inventors: Petrus De Greef, Age Van Dalfsen
  • Publication number: 20050083250
    Abstract: The present invention relates to a method and a device for addressing cells of a display panel, in particular discharge cells of a plasma display panel (PDP), each cell corresponding to a pixel in response to a video signal, wherein the addressing of those cells which are identified as being not active is skipped by an adaptive line skip unit (ALS).
    Type: Application
    Filed: December 18, 2002
    Publication date: April 21, 2005
    Applicant: Koninklijke Philips Electronics N.V.
    Inventor: Petrus De Greef
  • Publication number: 20050035928
    Abstract: The present invention relates to a method and a device for driving a display panel, in particular a plasma display panel (PDP), including cells each corresponding to a pixel in response to a video signal including fields wherein each field is formed by a plurality of subfields, wherein during the processing of a current field the number of subfields per field is adjusted (RU) for a next field in accordance with predetermined parameters.
    Type: Application
    Filed: January 15, 2003
    Publication date: February 17, 2005
    Inventor: Petrus De Greef