Method for determining a state of a driver monitoring device and driver monitoring device

Patent metadata

Field	Value
Publication number	US-12494069-B2
Application number	US-202318859081-A
Country	US
Kind code	B2
Filing date	Apr 19, 2023
Priority date	Apr 22, 2022
Publication date	Dec 9, 2025
Grant date	Dec 9, 2025

Abstract

A method for determining a state of a driver monitoring device includes generating a first image. The first image is based on an image of an interior illuminated by means of an illumination device. The method includes dividing the first image into multiple image sections. The method includes determining a maximum intensity of pixels of a first group of image sections of the first image and an average intensity of a second group of image sections of the first image and determining a difference in illumination of the first image by dividing the maximum intensity of the first group by the mean intensity of the second group. The method includes determining whether or not a diffuser is functional and properly arranged and activating or deactivating the illumination device for driver monitoring if the difference in illumination of the first image is smaller or greater than a lower threshold value.

First claim

The invention claimed is:

1 . A method for determining a state of a driver monitoring device, the device comprising an illumination device for illuminating an interior of a vehicle, a diffuser ( 120 ) arranged in a beam path of the illumination device in the correct state of the driver monitoring device for scattering a light emitted by the illumination device, and an image capturing device for capturing an image of the interior, the method comprising:
illuminating, by the illumination device, the interior, and generating at least one first image of at least one section of the interior, wherein said first image being based on an image of the interior which is illuminated by means of the illumination device, wherein said image is captured by the image capturing device; dividing the at least one first image into a left upper image section, a right upper image section, a left middle image section, a right middle image section, a left lower image section and a right lower image section; determining a maximum intensity of pixels of a first group of image sections of the at least one first image, wherein said first group comprising the left middle image section and the right middle image section; and determining an average intensity of a second group of image sections of the at least one first image, wherein said second group comprising the left upper image section, the right upper image section and the right lower image section or the left upper image section, the right upper image section and the left lower image section; determining a difference in illumination of the at least one first image by dividing the maximum intensity of the first group of image sections of the at least one first image by the mean intensity of the second group of image sections of the at least one first image; and determining that the diffuser is functional and properly arranged in the beam path of the illumination device and activating the illumination device for driver monitoring if the difference in illumination of the at least one first image is smaller than a lower threshold value, or determining that the diffuser is not functional and properly arranged in the beam path of the illumination device and deactivating the illumination device if the difference in illumination is greater than an upper threshold value.

2 . The method as claimed in claim 1 , further comprising:
applying a Laplace filter to the at least one first image if the difference in illumination is greater than the lower threshold value and smaller than the upper threshold value so as to obtain a modified at least one first image; capturing at least one edge in the modified at least one first image; setting an intensity value of pixels of the modified at least one first image which have no section of the at least one edge to a maximum intensity value, and setting the intensity value of pixels of the modified at least one first image which do have a section of the at least one edge to a minimum intensity value so as to obtain a modified at least one first image; applying a median filter to the modified at least one first image so as to obtain a filtered at least one first image; removing one or more sections of the filtered at least one first image, wherein at least one section contains an image of at least one section of a steering wheel area of the vehicle so as to obtain a test image section of the filtered at least one first image; determining a number of pixels with maximum intensity in the test image section of the filtered at least one first image; determining, based on the number of pixels with maximum intensity in the test image section of the filtered at least one first image, whether or not the diffuser is functional and properly arranged in the beam path of the illumination device; and storing a piece of corresponding information in a storage unit of a control unit of the vehicle.

3 . The method as claimed in claim 2 , further comprising:
generating at least one second image of the at least one section of the interior, said second image being based on an image captured by the image capturing device while the interior is not illuminated by means of the illumination device; dividing the at least one second image into a left upper image section, a right upper image section, a left middle image section, a right middle image section, a left lower image section and a right lower image section; determining a maximum intensity of pixels of a first group of image sections of the at least one second image, said group comprising the left lower image section and the right lower image section, and determining an average intensity of a second group of image sections of the at least one second image, said group comprising the left upper image section, the right upper image section and the right lower image section or the left upper image section, the right upper image section and the left lower image section; determining a difference in illumination of the at least one second image by dividing the maximum intensity of the first group of image sections of the at least one second image by the mean intensity of the second group of image sections of the at least one second image; applying a Laplace filter to the at least one second image if the difference in illumination is greater than the lower threshold value and smaller than the upper threshold value so as to obtain a modified at least one second image; capturing at least one edge in the modified at least one second image; setting an intensity value of pixels of the modified at least one second image which have no section of the at least one edge to a maximum intensity value; setting the intensity value of pixels of the modified at least one second image having a section of the at least one edge to a minimum intensity value so as to obtain a modified at least one second image; applying a median filter to the modified at least one second image so as to obtain a filtered at least one second image; removing one or more sections of the filtered at least one second image, wherein at least one section contains an image of at least one section of a steering wheel area of the vehicle so as to obtain a test image section of the filtered at least one second image; determining a number of pixels with maximum intensity in the test image section of the filtered at least one second image; and determining, based on the number of pixels with maximum intensity in the test image section of the filtered at least one first image and the number of pixels with maximum intensity in the test image section of the filtered at least one second image, whether or not the diffuser is functional and properly arranged in the beam path of the illumination device.

4 . The method as claimed in claim 3 , further comprising:
generating a first image based on an image captured by the image capturing device with a first exposure time of preferably 36 μs; generating another first image based on an image captured by the image capturing device with a second exposure time of preferably 640 μs; generating a second image based on an image captured by the image capturing device with the first exposure time; generating another second image based on an image captured by the image capturing device with the second exposure time; and determining, based on the number of pixels with maximum intensity in the test image section of the filtered one first image, the number of pixels with maximum intensity in the test image section of the filtered other first image, the number of pixels with maximum intensity in the test image section of the one filtered second image and the number of pixels with maximum intensity in the test image section of the filtered other second image, whether or not the diffuser is functional and properly arranged in the beam path of the ill

Assignees

• Valeo Schalter & Sensoren Gmbh

Inventors

• Putz Thomas
• Tamam Mahmoud
• Haebig Thomas

Classifications

• H04N23/56

  provided with illuminating means · CPC title

• G06V30/1431

  Illumination control · CPC title

• G06V10/141

  Control of illumination · CPC title

• G06V10/14

  Optical characteristics of the device performing the acquisition or on the illumination arrangements · CPC title

• G06V20/597 Primary

  Recognising the driver's state or behaviour, e.g. attention or drowsiness · CPC title