Method of detecting presence and motion for door control devices and door control devices implementing such a demand

• US 8,068,006 B2
• Filed: 12/22/2005
• Issued: 11/29/2011
• Est. Priority Date: 12/23/2004
• Status: Expired due to Fees

• Current Assignee: Celec Conception Electronique En Abrege Celec
• Original Assignee: Celec Conception Electronique
• Inventors: Martin, Christian
• Primary Examiner(s): Mehmood; Jennifer
• Assistant Examiner(s): SMALL, NAOMI J
• Application Number:
  US11/791,714
• Publication Number:
  US 20080117020A1
• Time in Patent Office: 2,168 Days
• Field of Search: 340/5.7
• US Class Current: 340/5.7
• CPC Class Codes: B66B 13/26 between closing doors
• CPC Class Codes: G06T 7/269 using gradient-based methods
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
• CPC Class Codes: H04N 7/186 Video door telephones

Abstract

A method of detecting presence and motion for door control devices, and a door control device implementing the method. On receipt of a door opening command (24), at least a portion of at least one image captured by a digital camera of the floor area is compressed (28) and the compressed image is compared (32) with at least one active presence criterion to inhibit or not inhibit the door closure command (34).

Claims

1. A method of detecting presence and motion for door control devices implementing a camera (4) for capturing, in at least one spectral zone of visible light or infrared light, digital images including at least one image plane and in analysing the information in at least one image or image plane, comprising:

capturing (26;

60, 66;

80) at least one digital image, of at least one floor area (56) in which the door installation is disposed, in a digital memory in a form of at least one two-dimensional matrix of pixel values which is representative of at least one image signal component (Y;

R, G, B;

Y, Cr, Cb);

executing a compression (28;

62;

86) of at least one captured image or image plane so as to adapt the captured image or image plane to a given memory capacity and to a given resolution in the floor area;

executing a comparison (32;

72;

92;

116) of at least one portion of the compressed image or image plane with at least one comparison value established on the basis of an active presence criterion to produce (34;

74;

94;

118, 120) an inhibition signal controlling at least one door control device; and

deducing from this a door control device control decision,

wherein a floor area determination step includes;

determining door pillars by producing at least two lines (52, 54) representing the pillars;

determining a line joining ends of the reproducing lines (52, 54) representing the pillars; and

dimensioning in the orthogonal direction (58) a rectangle determining the floor area (50).

2. The method according to claim 1, wherein the compression step includes a step for selecting determined dimensions of an individual block based on the requested resolution at least in a floor area, the aperture of the image sensor and the dimensions of the image field, and the available memory size.

3. The method according to claim 2, wherein the compression step consists in calculating the average value of a characteristic of an image signal in each individual block.

4. The method according to claim 1, wherein the comparison step includes a step for calculating the inter-block difference of the reference image and the second image.

5. The method according to claim 4, wherein the comparison step also includes a step for comparing at least one inter-block difference value with a predetermined threshold value, Threshold:

Δ

Y>

Threshold, such that if the inter-block difference value exceeds the predetermined threshold “

Threshold”

, a signal detecting motion in the second image is produced.

6. The method according to claim 5, wherein said threshold value is adjusted according to the relation:

Threshold=Threshold_—

0+tl*K

in which the brightness ratio tl is determined by the relation;

7. The method according to claim 1, wherein the image capture is sequential and in that the reference image is reloaded periodically.

8. The method according to claim 1, wherein the method includes a step for calculating a gradient (88) in the compressed image of the floor area (50).

9. The method according to claim 8, wherein the active presence detection step includes a step (92) for comparing at least one gradient value in the compressed image of the floor area with a predetermined threshold.

10. The method according to claim 9, wherein the step for comparing at least one gradient value is preceded by a threshold calculation and/or adaptation step (90).

11. The method according to claim 8, wherein the gradient calculation step includes a step for calculating two gradients (100, 102) in orthogonal directions to detect forward and/or sideways motions.

12. The method according to claim 11, wherein the detection of forward and/or sideways motions is executed by searching (108, 110) for the positions of the maxima of the two gradients (104, 106), then by calculating the variations (dx, dy) of the positions (i, j) of the maxima at predetermined reference values (i0, j0) and by comparing the two position variations (dy>

dx) to deduce from this whether the motion in the image is forward or sideways to deduce from this a decision to inhibit a closure command.

13. The method according to claim 12, wherein the method includes a step for calculating reference values (I0, j0) by assigning, in a sequence of processed images, at least one value captured previously for each of the positions (i, j) of the maxima of the gradients.

14. The method according to claim 1, wherein the method includes determining a combination of at least one of the active presence detection criteria:

detection of presence (60-74);

detection of motion (80-94);

detection of forward or sideways motion (100-120).

18. The method according to claim 3, wherein the characteristic of the image signal is brightness.

15. A method of detecting presence and motion for door control devices implementing a camera (4) for capturing, in at least one spectral zone of visible light or infrared light, digital images including at least one image plane and in analysing the information in at least one image or image plane, comprising:

capturing (26;

60, 66;

80) at least one digital image, of at least one floor area (56) in which the door installation is disposed, in a digital memory in a form of at least one two-dimensional matrix of pixel values which is representative of at least one image signal component (Y;

R, G, B;

Y, Cr, Cb);

executing a compression (28;

62;

86) of at least one captured image or image plane so as to adapt the captured image or image plane to a given memory capacity and to a given resolution in the floor area;

executing a comparison (32;

72;

92;

116) of at least one portion of the compressed image or image plane with at least one comparison value established on the basis of an active presence criterion to produce (34;

74;

94;

118, 120) an inhibition signal controlling at least one door control device; and

deducing from this a door control device control decision,

wherein the method is executed for each component of the image signal (R, G, B;

Y, Cr, Cb) and in that it consists in determining a decision by majority vote on each parameter drawn from each component of the image signal.

16. The method according to claim 15, wherein the method includes associating, in one and the same plane of a given resolution, at least two components of resolutions at most equal to the given resolution then in executing the steps on the basis of said image planes.

17. A door control device including at least one digital image matrix sensor coupled with a two-dimensional memory of pixel values, comprising:

at least one processor for executing the compression of the captured image in memory;

at least one processor for producing a decision signal to execute the door control device command on the basis of a predetermined active presence decision criterion;

a circuit controlling the closure of the door control device sensitive to an active presence decision signal that is produced; and

a memory for each image plane, the image signal components of lower resolutions being associated in one and the same image plane, and the device includes a means for executing decisions on majority vote for all of the image planes processed.