Category Archive: Visibility measurement for car industry

Sep
16

Visibility Measurement for Road Safety

Visibility Measurement for Road Safety by NEXYAD

INTRODUCTION

Visibility is one of the structural elements of road safety. Indeed, the sense of sight is the only one that let us perceived the future path of the vehicle and then let us act on it : the driver “can see” in front of the vehicle, he predicts where the vehicle will go, and he can act on the controls (brake, steering wheel, …) in order to control the trajectory.

No other way allows us to anticipate.

If we model the task of driving with an automatic control engineering scheme, then we can notice that vision is used quite everywhere :

Set Point of Trajectory Modification

Vision plays a critical role in driving task, and what sizes the efficiency of this sense is « visibility ».

Visibility can be affected by many kinds of factors:
. the absence or insufficience of light (that is why the infrastructure is sometimes illuminated at night, and why vehicles are equipped with lighting.
. rain deposited on the windshield (that is why vehicles are equipped with wipers)
. mist on the windshield (that is why vehicles are equipped with demisting systems)
. humidity, fog or mist suspended in the air in the road scene.

Experts of road infrastructure add elements to enhance the visibility of the path :
. lane markings (white lines), reflective elements.

Similarly, automobile experts equip their vehicle with systems enabling them to improve visibility for the driver, but also allowing the vehicle to be more easily seen by other drivers.

We then understand that measurement of visibility is an important area of potential improvement of road safety in via ADAS.

VISIBILITY MEASUREMENT

The founders of the company NEXYAD have been working since the 80s on the measurement of visibility, early on military applications.
Indeed, it is the military who have studied since the 60’s which criteria allow human visual perception system to detect objects on their clutter.

For the military, the constant search for stealth (camouflage, for example) requires modeling the performance of the detection by human, depending on the light of a scene in the visible wavelength.

The work carried out tests on panels of thousands of soldiers, and led to predictive models for human vision of the ability to detect objects or not, depending on the image quality.
NEXYAD is one of the very few companies in the world to hold these models and have experience of their implementation for more than 20 years.
In simplified terms, we can consider that our eyes and brain need, depending on the size of the objects to be detected, a different contrast level.
We can then compare the contrast available in a scene (eg a road scene) with needed contrast to detect, , for each size of objects.

The comparison results in two scores :
. the apparent size of the smallest detectable object : as the apparent size of an object decreases with distance, it can then be deduced the maximum distance of detection for a reference object (a car, a truck, a pedestrian). Distances will obviously be different for every object because they don’t have the same size. Johnson criteria give let also estimate the maximum distance for object recognition, and the maximum distance for object identification.
. ease of interpretation of the visual scene. NEXYAD summarized this in a score computed from available and needed contrast: the Visual Quality Score (VQS).

This measure of visibility enables automotive application objectify the subjective. NEXYAD has developed two product lines from the same technology :

. a visibility test bench : VisiNex Lab http://nexyad.net/Automotive-Transportation/?page_id=159

VisiNex Lab

Place a vehicle on a test bench and VisiNex Lab measuring visibility among time. If there are disturbs of visibility from rain, for example (using NEXYAD RainNex rain machine, or another rain machine), then we see scores for degraded visibility. If one starts the vehicle visibility restoration systems (eg in the case where the disturbance is the rain : the wipers), then we measure the performance of the visibility restoration.
VisiNex Lab is used by the automotive industry and is still the only tool for measuring the performance of wipers, demisting system, lighting system, …

. an embedded module for ADAS : VisiNex Onboard http://nexyad.net/Automotive-Transportation/?page_id=438
VisiNex Onboard measures the image quality and predicts the detection power of the driver and onboard artificial vision modules. So we get a rating of confidence for artificial vision systems.
Again, NEXYAD is the only non military company to dispose of this technology.

Road Scene

CONCLUSION

Every tier one company or car manufacturer should use NEXYAD modules VisiNex in order to measure performance, robustness, and reliability of their wipers, lighting, and of their camera-based ADAS.
VisiNex Onboard is currently under implementation into the asynchronous real time framework RT-MAPS.

For more information : sales@nexyad.net

Sep
14

Visibility Measurement for ADAS and Autonomous Vehicle

Visibility measurement for ADAS and Autonomous Vehicle
By NEXYAD

Advanced Driver Assistance Systems (ADAS), and partial or total delegation of car control systems will integrate more and more cameras. Those cameras are used to capture video and images are inputs for obstacle detection algorithms, road detection algorithms, detection of pedestrians systems, …

However, a camera can “see” only under certain conditions, and the algorithms used to exploit image need a certain level of image quality. It is possible that some algorithms test themselves if they are in a case of good image quality or not, but in the general case, they don’t, and it is then prudent to have a qualification system that is independent of the detection systems.

The company NEXYAD has worked for years on atmospheric visibility measurement for military application, and was able to develop predictive models of the ability for a human to detect objects. This work can be easily set to pass from a performance prediction of the human vision to a prediction of performance for a machine vision system.

The models consist in comparing the contrast in the scene with the required contrast for detection and / or pattern recognition.
Such a system requires that is respected a compromise between several characteristics of the image:
. number of different gray levels (for a digital camera, it depends on the number of bits)
. size of the objects to be detected
. contrast of objects from their background

Note for Automotive engineers : a performance specification for a camera-based detection system, without giving the minimum contrast, le maximum number of pixels, the number of bits … does NOT have any sense. It is important to know that fact in order to make applications that work and application that know when they work.
For instance, we are all able to detect stars in a dark night sky : the size of objects is very small, the number of Grayscale is very low (pure black and pure white), and the contrast of objects from the background is huge.

Contrast

Similarly, we are able to distinguish clouds over gray sky : the size of objects is very large, and even on edges there is no detail (no high frequency / contours), and the number of different gray levels is very large (gradual grey scale from black to white).

Clouds

Between these two extremes are all possible cases, and in particular with all traffic scenes that may vary greatly from one to another :
. sunny day, overcast day, dark night, undergrowth, sunset, night in headlights, fog, rain, etc …

Visibility_Measurement

In addition to these technical compromise, there are criteria (eg criteria Johnson) that allow to objectify the subjective.

NEXYAD has developed a tool called VisiNex that integrates models and criteria described above, which led to two products:

. VisiNex Lab : test bench for visibility measurement. It sets a vehicle with calibrated visibility disturbances (rain machine, fog machine, …), and VisiNex Lab measures the evolution of the available visibility during the disturbance and during activation of visibility restoration systems (lighting, demisting, wiping, …).
VisiNex Lab is used to adjust the rain sensors, the wiper systems, the lighting systems. VisiNex is a world leader on this type of use : http://nexyad.net/Automotive-Transportation/?page_id=159

VisiNex_Banc

. VisiNex Onboard : NEXYAD took his model into onboard applications to apply and qualify road visibility along the route running (important place to qualify for the road safety applications).
VisiNex Onboard is currently being integrated into the framework for asynchronous real-time applications development RT-MAPS, and will soon be in the NEXYAD vision modules pack for ADAS and driving delegation applications.

VisiNex Onboard
Standard visibility on a highway scene.                             Degraded visibility when approaching a tunnel

VisiNex Onboard can be used in automotive application on the following topics :
. visibility measurement to control Visibility restoration systems (wiper, lighting, …)
. qualification of visibility conditions where an obstacle detection or road detection system will work properly.

The second point is important because road safety applications require to maximize the reliability of vision systems.

To know more :sales@nexyad.net

Oct
07

Poster publication of the Visibility measurement research project (SURVIE – Mov’eo) conclusions at the “carrefours du PREDIT”, in Paris, Palais Broigniart (October 7-8, 2013)

The project SURVIE was headed by NEXYAD with the research partners AXIMUM, CETE, IFSTTAR, OKTAL, SAINT GOBAIN, VALEO.

The goal of this project was to validate standard measurement protocols for different testing usages of the test bench tool VisiNex (developed by NEXYAD : click HERE to know more) : measurement of the performance of every system in a car that was made to restore visibility : lighting, wipers, demist, defrost, hydrophobic windshield, …

SURVIE was a collaborative research program of the competitive cluster Mov’eo.






Jun
13

Closing meeting of the collaborative research project SURVIE : 2012 June 28 in Paris (June 13, 2012)

The closing meeting of the collaborative research project SURVIE will take place the 28th of June 2012, in the Région Ile de France office in Paris.

SURVIE dealt with measurement of visibility during recovery (wipers, lights, demist, defrost, etc …). Measurement was performed using the onl device in the worl that can measure visibility for a human being ; VisiNex Developed par the company Nexyad.

The project gathered Saint Gobain, Valeo, CETE Lyon laboratory (Clermont Ferrand Lab), Oktal, Aximum, Nexyad.

Project Purpose: Research on the technical ways to improve or restore visibility to the driver, and development of new functionalities of VisiNex.

Several innovative measurement functionalities could be integrated to VisiNex by Nexyad, allowing partners to improve their understanding of visibility recovery in many cases of real world scenes.

This research program got the label of the French competitive cluster on automotive and transportation mov’eo.

May
10

New release of the NEXYAD VisiNex (May 10, 2012)

A new release of the NEXYAD VisiNex™ (*) tool is available and brings more functionalities : can deal with vibrations (due to artificial wind for instance), can deal with occultations (dirt, frost, …), geographical mapping of visibility (that lets show the dynamic of visibility recovery), measurements with the car lightning as light source.

(*) : visibility measurement for automotive and transportation applications : wipers, lightning, windshield, sign marks, …)

Jan
09

Wipers and Lightning benchmarks under rain and fog, for VALEO, using VisiNex (January 9, 2012)

Wipers and Lightning benchmarks under rain and fog, for VALEO, using VisiNex™.

Visinex-VALEO

Dec
29

Cross calibration of VisiNex using the tool EVALIS, of AXIMUM (December 29, 2011)

Cross calibration of VisiNex™ using the tool EVALIS, of AXIMUM

Visinex-AXIMUM

Dec
05

Visibility measurement, for CETE Lyon (December 5, 2011)

Visibility measurement, for CETE Lyon (Lab Clermont Ferrand), using VisiNex™, and comparison with the subjective marks of a sensorial analysis human panel.

Visinex-CETE

Visinex-CETE

Nov
29

Hydrophobic winshields benchamrk under rain, for SAINT GOBAIN , using VisiNex. (November 29, 2011)

Hydrophobic winshields benchamrk under rain, for SAINT GOBAIN , using VisiNex™.

Visinex-St_Gobain

Aug
16

Visibility measurement through a windshield with fog and frost (August 16, 2011)

New release of VisiNex available (visibility measurement using a camera), allowing to draw a visibility map (visibility in every part of the A zone of the windshield, for instance) among time. Application of this new version of VisiNex at the French laboratory UTAC, for Saint Gobain: efficiency test and benchmark of new windshield defogging and defrosting systems.


UTAC-VISINEX

UTAC-VISINEX

UTAC-VISINEX

Older posts «