REAL-TIME DIGITAL IMAGE PROCESSING ARCHITECTURE

• US 20110007183A1
• Filed: 12/18/2008
• Published: 01/13/2011
• Est. Priority Date: 03/12/2008
• Status: Active Grant

• Current Assignee: Siemens Healthineers Nederland BV (Siemens AG)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kahlman, Josephus Arnoldus Henricus Maria
• Granted Patent: US 8,537,237 B2
• Time in Patent Office: Days
• US Class Current: 348/229.1
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20182 Noise reduction or smoothing in the temporal domain; Spatio-temporal filtering
• CPC Class Codes: G06T 2207/30072 Microarray; Biochip, DNA array; Well plate
• CPC Class Codes: G06T 5/002 Denoising; Smoothing noise processing or correction adapted to be used in an image pickup device containing and electronic image sensor H04N23/81, H04N25/60 - H04N25/67
• CPC Class Codes: G06T 5/70 Denoising; Smoothing

Abstract

The invention relates to a digital image processing architecture, particularly for processing digital images provided by a camera (101) of a biosensor reader (100). The architecture comprises a pixel processing unit (112) for evaluating a stream of image values (I(x,y,t)) with respect to a given set of processing spots (PS_i(t) in the image area, thus determining characteristic parameters like the integral (E_i(t) of pixel values in the processing spots (PS_i(t). The pixel processing unit (112) communicates with a higher-level digital control unit (130) that sets the processing spots (PS_i(t) to be evaluated and that reads out and post-processes the results of the pixel processing unit (112).

Claims

1. A digital image processing device (100) for real-time evaluation of a sequence of image frames (I_t) provided by a camera (101), comprising:

a) a digital pixel processing unit (112) for determining at least one characteristic parameter (E_i, σ

′

_i) of a set of processing spots (PS_i, PS_a, PS_b) in the image area from a stream of image values (I(x,y,t));

b) a higher-level digital control unit (130) in communication with the pixel processing unit (112) for setting the set of processing spots and for reading out and post-processing the determined characteristic parameters.

2. The image processing device (100) according to claim 1,

characterized in that the processing spots relate to a rectangular image region (PS_i, PS_a, PS_b).

3. The image processing device (100) according to claim 1,

characterized in that the set of processing spots (PS_i, PS_a, PS_b) comprises a single processing spot only, a plurality of processing spots from an image stripe (S_j), and/or a plurality of processing spots from the whole image area.

4. The image processing device (100) according to claim 1,

characterized in that the characteristic parameter comprises the integral (E_i) of all image values (I(x,y,t)) in a processing spot (PS_i) and/or the integral (σ

′

_i) of a function of their deviation from a reference value (ê

_i).

5. The image processing device (100) according to claim 4,

characterized in that the reference value (ê

_i) and/or its changing rate (dÊ

_i/dt) is determined by the digital control unit (130) based on characteristic parameters (E_i) of previous frames.

6. The image processing device (100) according to claim 1,

characterized in that it comprises at least one shadow register (120-124) for storing data to be exchanged between the pixel processing unit (112) and the digital control unit (130).

7. The image processing device (100) according to claim 1,

characterized in that the set of processing spots (PS_i, PS_a, PS_b) is set once before the evaluation of a sequence of frames, at the beginning of each frame, at the beginning of a sub-frame (S_j), and/or on demand of the pixel processing unit (112).

8. The image processing device (100) according to claim 1,

characterized in that the digital control unit (130) iteratively adapts at least one processing spot (PS_a, PS_b) to the image position of a marker (AM).

9. The image processing device (100) according to claim 1,

characterized in that it comprises a focusing module (143) for changing the focus of the camera (101) based on the characteristic parameter (E_i, σ

′

_i), particularly based on a function of the deviation of all image values (I(x,y,t)) from a reference value (ê

_i) in a processing spot (PS_a, PS_b).

10. The image processing device (100) according to claim 1,

characterized in that it comprises a status indicator (141) for signaling the detection of an exceptional state in at least one image frame (I_t), particularly of a deteriorated optical quality.

11. The image processing device (100) according to claim 1,

characterized in that the post-processing of the digital control unit (130) comprises a temporal filtering of the characteristic parameters (E_i(tε

S_d)) that have been obtained for a selected subset of the image frames (I_t).

12. The image processing device (100) according to claim 11,

characterized in that the filtered characteristic parameter (<

E_i>

) is related to—

preferably subtracted from—

the corresponding characteristic parameters (E_i(tε

S_b)) obtained for image frames (I_t) that do not belong to the selected subset.

13. The image processing device (100) according to claim 1,

characterized in that it comprises a controllable illumination unit (102) by which the exposure conditions can selectively be set for different image frames (I_t).

14. A method for evaluating a sequence of image frames (I_t) provided by a camera (101), comprising

a) determining with a pixel processing unit (112) at least one characteristic parameter (E_i, σ

′

_i) of a set of processing spots (PS_i, PS_a, PS_b) in the image area from a stream of image values (I(x,y,t));

b) determining a set of processing spots (PS_i, PS_a, PS_b) and post-processing at least one characteristic parameter with a higher-level digital control unit (130);

c) exchanging data between the digital control unit (130) and the pixel processing unit (112) after the latter has completed processing of a current set of processing spots (PS_i, PS_a, PS_b) for one frame.

15. A computer program product for enabling carrying out a method according to claim 14.