Edge dependent motion blur reduction

• US 20050190164A1
• Filed: 05/21/2003
• Published: 09/01/2005
• Est. Priority Date: 05/23/2002
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: De Haan, Gerard, Klompenhouwer, Michiel Adriaanszoon, Velthoven, Leo Jan
• Granted Patent: US 7,643,019 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20008 Globally adaptive
• CPC Class Codes: G06T 2207/20201 Motion blur correction
• CPC Class Codes: G06T 5/003 Deblurring; Sharpening vibration or motion blur correction for cameras comprising an electronic image sensor H04N23/682
• CPC Class Codes: G06T 5/20 using local operators
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/106 Determination of movement vectors or equivalent parameters within the image
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51
• CPC Class Codes: H04N 5/20 Circuitry for controlling amplitude response
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo

Abstract

The invention relates to a method and a circuit arrangement to reduce motion blur of images shown in non-stroboscopic display devices, in particular Liquid Crystal Display Panels (LCDs). Thin Film Transistor Displays (TFTs), Colour Sequential Displays. Plasma Display Panels (PDPs), Digital Micro Mirror Devices or Organic Light-Emitting Diode (OLED) displays, in which motion vectors depending on moving components in each image of an input video, signal are calculated, in which anti-motion blur filtering of the input video signal is performed based on the calculated motion vectors to produce an output video signal, and in which images are generated on said display device depending on said output video signal. In order to provide an improved spatial filtering with less noise enhancement and less noise modulation, it is proposed that edge characteristics in each image of the input video signal are determined and that anti-motion blur filtering is further based on said determined edge characteristics. In this way, spatial filtering is concentrated on significant parts of an image only, and both noise enhancement and noise modulation are reduced.

Claims

1. Method to reduce motion blur of images shown in non-stroboscopic display devices, in particular Liquid Crystal Display Panels (LCDs), Thin Film Transistor Displays (TFTs), Colour Sequential Displays, Plasma Display Panels (PDPs), Digital Micro Mirror Devices or Organic Light-Emitting Diode (OLED) displays, in which motion vectors depending on moving components in each image of an input video signal are calculated, in which anti-motion blur filtering of the input video signal is performed based on the calculated motion vectors to produce an output video signal, and in which images are generated on said display device depending on said output video signal, characterized in that edge characteristics in each image of the input video signal are determined and that anti-motion blur filtering is further based on said determined edge characteristics.

2. Method according to claim 1, characterized in that said edge characteristics are length and/or orientation of edge vectors and/or the presence of an edge.

3. Method according to claim 2, characterized in that said length and/or orientation of the edge vectors are derived from zero-crossings of the absolute values of the first derivatives of the image signal in two orthogonal directions subtracted by fixed thresholds.

4. Method according to claim 3, characterized in that low and narrow edges are not considered in the calculation of length and orientation of said edge vectors.

5. Method according to claim 2, characterized in that the presence of edges is detected by sampling the edge vectors into binary signals.

6. Method according to claim 5, characterized in that the presence of edges is smoothed out over space by dilating and/or corroding and/or low-pass filtering said binary signals.

7. Method according to claim 1, characterized in that anti-motion blur filtering is performed

by filtering the input video signal with a spatial filter,

by subsequently combining the filtered input video signal with the input video signal itself to produce an intermediate video signal,

by multiplying the intermediate video signal with gain factors to produce an amplified intermediate signal, and

by combining said amplified intermediate signal with said input video signal to produce an output video signal.

8. Method according to claim 7, characterized in that the spatial filter applied to the input video signal is a high spatial frequency boosting filter.

9. Method according to claim 8, characterized in that the filter coefficients of the high spatial frequency boosting filter and the direction of the frequency characteristic of this filter depend on the motion vectors and

that the gain factors depend on the length of the motion vectors and the presence of edges.

10. Method according to claim 8, characterized in that the filter coefficients of the high frequency boosting filter and the direction of the frequency characteristic of the filter depend on the motion vectors and

that the gain factors depend on the inner product of edge vectors and motion vectors normalised to the length of the edge vectors.

11. Method according to claim 8, characterized in that the direction of the frequency characteristic of the high spatial frequency boosting filter depends on the orientation of the edge vectors,

that the filter coefficients of the high spatial frequency boosting filter depend on the motion vectors,

and that the gain factors depend on the motion vectors and/or the edge vectors.

12. Method according to claim 8, characterized in that the direction of the frequency characteristic of the high spatial frequency boosting filter depends on the orientation of the edge vectors,

that the filter coefficients of the high spatial frequency boosting filter depend on the edge vectors,

and that the gain factors depend on the motion vectors and/or the edge vectors.

13. Method according to claim 8, characterized in that a fixed set of filter coefficients for the high spatial frequency boosting filter is used, that the direction of the frequency characteristic of the spatial filter depends on the orientation of the edge vectors and that the gain factors depend on the motion vectors and/or the edge vectors.

14. Method according to claim 11, characterized in that the gain factors depend on the length of the motion vectors and the presence of edges.

15. Method according to claim 11, characterized in that the gain factors depend on the inner product of edge vectors and motion vectors normalised to the length of the edge vectors.

16. Non-stroboscopic display device, in particular a Liquid Crystal Display (LCD), Thin Film Transistor Display (TFT), Colour Sequential Display, Plasma Display Panel (PDP), Digital Micro Mirror Device or Organic Light-Emitting Diode (OLED) display,

with means to calculate motion vectors in each image of an input video signal, with means to filter the input video signal depending on said calculated motion vectors to produce an output video signal, and

with means to display the images of the output video signal on a display panel,

characterized in that means to determine the edge characteristics of each image of the input video signal are provided and

that means to filter the input video signal depending on both the calculated motion vectors and the determined edge characteristics are provided.