Device for detecting the presence of objects

• US 20030141762A1
• Filed: 12/17/2002
• Published: 07/31/2003
• Est. Priority Date: 02/18/2000
• Status: Active Grant

• Current Assignee: Ficosa North America Corporation (Panasonic Holdings Corporation)
• Original Assignee: Ficosa North America Corporation (Panasonic Holdings Corporation)
• Inventors: Daura Luna, Francesc, Crespi, Bruno, Bande Martinez, Daniel, Tecchiolli, Giampietro, Sartori, Alvise, Tarrago Pujol, Jose Maria
• Granted Patent: US 6,911,642 B2
• Time in Patent Office: Days
• US Class Current: 307/10.1
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06V 20/58 Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads
• CPC Class Codes: G08G 1/167 Driving aids for lane monitoring, lane changing, e.g. blind spot detection

Abstract

An object presence detection device, of the type mounted to a motor vehicle having at least one blind spot, where the detection device is for detecting an object situated in the blind spot, comprises: a receiver for detecting electromagnetic waves, comprising a focussing device, and a light detector converting said received electromagnetic waves into electrical signals; an electronic circuit converting the electrical signals into digitized signals; a logic circuit analyzing the digitized signals to analyze the presence of objects in the blind spot which are moving relative to the vehicle, and emitting variable output signals depending on the result of the analysis; indicator members activated by the output signals, suitable to be perceived by the driver.

Claims

1. - An object presence detection device, of the type mounted to a motor vehicle, said vehicle having at least one blind spot, where said detection device is for detecting an object situated in said blind spot, comprising:

[a] a receiver (7) for detecting electromagnetic waves, said receiver (7) comprising a focussing device, and a light detector converting said received electromagnetic waves into electrical signals, said light detector defining an image surface, [b] an electronic circuit (9) converting said electrical signals into digitized signals, [c] a logic circuit (15) analyzing said digitized signals to analyze the presence of objects in the blind spot which are moving relative to said vehicle, and generating variable output signals depending on the result of said analysis, [d] indicator members activated by said output signals.

2. - The detection device according to claim 1, wherein said light detector is constituted by active sensor elements having a dynamic range equal or superior to six decades on one same image surface, and wherein one same sensor element has a dynamic range equal or superior to the six decades between two consecutive images.

3. - The detection device according to claim 1 or claim 2, wherein said light detector is constituted by photodiodes for converting said electromagnetic waves into an electrical current.

4. - The detection device according to claim 3, wherein said electrical current is converted into an electrical voltage and because said electrical voltage is amplified.

5. - The detection device according to at least one of claims 1 to 4, wherein said light detector comprises a two-dimensional matrix of said sensor elements defining a number of rows of sensor elements, where each of said rows extends in a first direction and is parallel to the remaining rows, and where the group of rows forms said image surface.

6. - The detection device according to claim 5, wherein said electronic circuit (9) makes a selection of each of said sensor elements by activating the corresponding row and the corresponding position in said row, it being possible in this way to select any sensor element after any sensor element.

7. - The detection device according to claim 5, wherein said electronic circuit (9) simultaneously converts all said electrical signals from a row of sensor elements to digitized signals.

8. - The detection device according to at least one of claims 1 to 7, wherein said electronic circuit (9) comprises an amplifier stage (11) and a digitization stage (ADC).

9. - The detection device according to at least one of claims 5 to 8, wherein each row is provided with at the most 512 active sensor elements for processing, and is provided with at the most 512 active rows of sensor elements for processing the image.

10. - The detection device according to at least one of claims 5 to 8, wherein each row is provided with at the most 320 active sensor elements for processing the image, and is provided with at the most 256 active rows of sensor elements for processing the image.

11. - The detection device according to at least one of claims 1 to 10, wherein said logic circuit (15) carries out a mathematical convolution along the entire said image surface of the digitized signal.

12. - The detection device according to claim 11, wherein said mathematical convolution over the entire said image surface is carried out by means of a convolution kernel appropriate for a movement detection.

13. - The detection device according to at least one of claims 1 to 12, wherein said logic circuit (15) is for detecting movement in at least one direction, said direction being adjustable depending on the location of said focussing device, and wherein said logic circuit (15) is capable of determining the relative speed of said movement in said direction.

14. - The detection device according to at least one of claims 11 to 13, wherein said logic circuit (15) comprises a specialized electronic circuit including:

[a] a Von Neumann type sequential central processing unit (CPU), [b] a parallel coprocessor (TOT), specialized in the calculation of said convolution over the entire said image surface, said coprocessor including at least 32 parallel accumulator multipliers with a high calculation speed for calculating said convolution directly on the image surface at such a calculation speed that the convolution is completed before a new image acquisition is initiated, and [c] a local RAM (SRAM).

15. - The detection device according to at least one of claims 11 to 14, wherein said convolution is calculated in a time no greater than 100 ms.

16. - The detection device according to at least one of claims 1 to 15, wherein it is adapted to distinguish a vehicle from other objects.

17. - The detection device according to claim 16, wherein said distinguishing is effected by recognizing arrises, clearly marked in the vertical and horizontal directions on the road surface, in an image.

18. - The detection device according to claim 16 or claim 17, wherein if it has detected a vehicle, it analyzes said relative speed from the following image.

19. - The detection device according to at least one of claims 1 to 18, wherein it divides said image surface in at least two portions (25, 27, 29), and wherein in each of said portions (25, 27, 29) it uses different analysis techniques.

20. - The detection device according to claim 19, wherein in one of said portions (25, 29) said technique consists of recognizing said arrises and the follow-up thereof through various images to calculate said relative speed.

21. - The detection device according to claim 19 or claim 20, wherein in at least one of said portions (27, 29) a technique is used based on a phase difference to obtain an estimate of the optical flow in one direction.

22. - The detection device according to at least one of claims 1 to 21, having an action radius of at least 15 meters.

23. - The detection device according to at least one of claims 1 to 22, wherein said focussing device comprises at least one lens.

24. - The detection device according to at least one of claims 1 to 23, wherein said focussing device comprises an electromagnetic wave transmission guide for guiding the electromagnetic waves from a first area, facing said blind spot, to a second area, where said electronic circuit (9) is accommodated.

25. - The detection device according to at least one of claims 1 to 24, wherein said electromagnetic waves are visible waves.

26. - The detection device according to at least one of claims 1 to 25, wherein said electronic circuit (9) is CMOS, DMOS, MOS, Si-Ge or BiCMOS technology.

27. - The detection device according to at least one of claims 1 to 26, wherein said light detector is CMOS, DMOS, MOS, Si-Ge or BiCMOS technology.

28. - The detection device according to at least one of claims 1 to 27, wherein said electronic circuit (9) is SOI (silicon on insulator) technology.

29. - The detection device according to at least one of claims 1 to 28, wherein said light detector is SOI (silicon on insulator) technology.

30. - The detection device according to at least one of claims 1 to 29, wherein said light detector and said electronic circuit (9) are physically united in a multi-chip module (MCM) on a plastics material, glass fiber (FR4), ceramic or silicon substrate.

31. - The detection device according to at least one of claims 1 to 30, wherein said focussing device comprises a microlens integrated in an integrated circuit including said focussing device.

32. - The detection device according to at least one of claims 1 to 31, wherein said light detector is housed inside the vehicle external rear-view mirror unit.

33. - The detection device according to claim 32, having a light detector in each of the vehicle external rear-view mirrors.

34. - The detection device according to at least one of claims 1 to 33, additionally detecting whether said vehicle has initiated actions indicative of an approach to said object.

35. - The detection device according to claim 34, wherein said indicative actions comprise the activation of an indicator.

36. - The detection device according to one of claims 34 or 35, wherein said actions comprise turning a steering wheel.

37. - The detection device according to at least one of claims 1 to 36, wherein said indicative elements include luminous signals of at least two colors, where each color indicates a different warning level.

38. - The detection device according to at least one of claims 1 to 37, wherein said indicative elements include an output element allowing pictograms to be shown, where said output element is a matrix of LEDs or a screen.

39. - The detection device according to at least one of claims 1 to 38, where said vehicle is provided with doors having a safety lock, being adapted to act on said lock.

40. - The detection device according to at least one of claims 1 to 39, additionally comprising a driver drowsiness detection device.

41. - The detection device according to claim 40, wherein said drowsiness detection device shares said receiver (7), said electronic circuit (9) and said logic circuit (15) with said object presence detection circuit.

42. - The detection device according to one of claims 40 or 41, wherein said drowsiness detection device emits an alarm signal depending on the position of said motor vehicle relative to marking lines.