Advanced drive support system (ADAS) more and more accurate, so that full automatic driving foreground appears no longer Yao cannot be reached. The core of ADAS is image sensor, because their action is right the integral efficiency of passivity and active ADAS is more and more important, because their functional sex safety is more and more important,mix be paid close attention to.

 

Standard of safety of ISO 26262 car and grade of automobile safety integrality (of ASIL) concept introduce the requirement that stressed pair of functional sex safety.

 

To car design personnel, understanding ASIL is very important, it is used at mixing to be concerned with the image sensor in ADAS. Understanding breakdown detects the influence with the safe sex of ADAS whole function that amend and accumulates pair of nicety of the influence that the property of technology, potential trouble and its logarithm occupy dependability, breakdown also is crucial.

 

Newest ADAS system includes many image sensor, can detect and identify of all kinds risk, include object of pedestrian, static state and car. Whether can sensor need to adopt any avoiding that act according to dangerous contrail identifies and corresponding. All systems that these are based on machine vision have to be nodded jointly, be sensor then all or partial breakdown may produce the potential consequence that endangers life badly even.

 

ASIL is seen without exception

 

Functional security or ASIL are the safe system that is based on a standard for a kind when car makes only / standard, its traceable ISO 61508, this is a kind of overall industrial safety level, but the standard that becoming independent as at present (ISO 26262) develops, the car technology that develops quickly in order to catch up with specific car wants sue for peace.

 

ISO 26262 covers installation to be produced group by group in “ in multiplying the ” that use a car electric with electronic system, a series of tests that although a lot of standards just are opposite,the product that has attestation must satisfy and condition ask compulsively, but ISO 26262 is a standard that is based on a risk. This meant it to limit a flow, evaluate hazardous condition risk and decide and carry out a safety precaution in order to control systematic breakdown. This method still hopes to detect and control random failure, or reduce its to affect as far as possible at least.

 

Image sends feeling breakdown kind

 

Typical image sensor is a relatively complex subsystem, contain a series of photosensitive element, will incident smooth transition becomes imitate telecommunication name. Digitlize these signal next, make they can be mixed to convey by memory, processing ADAS system, so that be analysed further, for example obstacle identifying.

 

Graph 1: Typical image sensor block diagram

 

In domain of functional sex safety, the breakdown ” with insecure “ is to may bring about ADAS system to make wrong and decision-making matter. This may be involved arrive from complete sensor breakdown of sensor individual resemble element, travel or list breakdown, or imitate / the problem in digital circuit. Typical breakdown may include “ to block ” to resemble effect of noise of element, report, be short of break travel, be short of break row, shift to resemble element, transmission mistake or color slanting.

 

 

Graph 2: The give typical examples of a breakdown in imitate circuit

 

As target detection algorithm more and more accurate, often detect small to 10×10 like element, lesser breakdown can system of “ misdirect ”ADAS. In fact, breakdown detects is a quite big challenge, the breakdown property that partial reason is imitate and digital domain and type are different, because contemporary sensor is tall like prime number,also be.

 

 

Detect the method of breakdown is mixed almost breakdown type is euqally much. For example, lead plane processor can detect easily give those who get stuck to resemble element, travel or kind, but the addition that resembles prime number as sensor, will become cost and cost a source. Through using inside the emitter that buy mistake checks and receiver, can detect – correct even – transmission mistake. This plan won’t bring to bear on to systematic processor laden, but the cost that can raise whole system.

 

Processor of use ADAS system detects breakdown has a lot of drawback. Above all, many subtle breakdown type cannot detect in systematic level, include to color slants or be based on the problem of noise. Another defect is the cost that systematic level breakdown detects; Of the resembles element, travel and kind amount of the measure that considers potential trouble type and need examination big, need very high-powered CPU, GPU and memory. Although charge can be accepted, the effectiveness that addition complexity also can affect whole ADAS system, answer and can effect.

 

This brought about systematic level breakdown to detect in the field that makes a person pay close attention to most – the time that runs all algorithmic place to need. Be when processor when computational number, car may be close to fraise quickly, or pedestrian, may cause disastrous consequence.

 

 

Contemporary image sensor includes a lot of compositive test functions, carry out a loop to be checked redundantly for example (the ability of CRC) transmits medium breakdown with detecting, or in computation frame, travel or more is carried out when resembling element enumerated ability, ensure thereby sent correct frame.

 

When system of functional sex security by inside when buy arrives in sensor, systematic action is simplified to be indicated to check status simply or register, these condition are indicated or register indicates trouble instantly, and did not drain systematic resource almost. This also is meant need high-powered CPU, GPU and memory no longer, reduced systematic cost and complexity thereby.

 

The barrier of hereat of a crucial index of system of low defer ADAS detects time-interval (FTDI) , it is ADAS system detects the magnanimity that breakdown place needs time, and fault tolerance time-interval (FTTI) is the time that the system answers place to need, make the system regains safe position.

 

 

Graph 3: The system detects FDTI(supports) comparative sensor detects FDTI(bottom)

 

If the graph is shown 3 times, should detect breakdown inside when buy arrives in sensor, detect time can shorten greatly, make the system has more time to regain safe position before dangerous incident may happen thereby.

 

Sensor of a contemporary image: AR0233AT

 

One of newest image sensor are the AR0233AT of An Sen beautiful semiconductor. This 2.6 million 1/2.5 resembling element inch parts of an apparatus is to be only include ADAS system inside a lot of cars apply and design.

 

This back takes form (BSI) technology uses 3 micron to resemble element, provide excellent crepuscular performance, second exposure exceeds sheet 95 decibel (DB) . Piece on tall dynamic limits (HDR) raises crepuscular function to come exceed 140 DB, or the 120 DB that restrains LED to twinkle.

 

Security is the core of this sensor, this parts of an apparatus accords with standard of ISO 26262 ASIL-B and AEC-Q100 Grade 2. A when have trouble of more than 8000 infuse complete safety is enclosed, can use for designing staff.

 

 

More influences in gaining ground to be designed in car increasingly as ADAS system are decision-making avoid risk with in order to, we more and more rely on them. Accordingly, they now the category of classify ISO 26262. ISO 26262 is to be aimed at take the functional sex security that uses a car standard, this standard asks to use “ first and last the method of ” will identify risk, reduce their effect as far as possible.

 

In view of the complexity of image sensor, and examinations of more and more need resembling element, impose a large number of probable breakdown conditions, the examination the job gives ADAS system gains a success unlikely, raise cost for certain instead.

 

Accordingly, the newest image sensor that is used at ADAS system used ego to detect technology, this accelerated breakdown to detect not only flow, the processing capability that still means all ADAS system is usable will make those who avoid risk is correct and decision-making, make our path more safe thereby.