DE19961635A1 - Optical sensor for dynamic monitoring of surfaces has dynamically operating color surface sensor using color changes as evaluation, switching criteria remote control parameter setting path - Google Patents

Abstract

The sensor has a dynamically operating color surface sensor that uses color changes as evaluation and switching criteria. The detection field and other sensor parameters can be programmed via a wireless/ light, a conductor-less or a wired or light conductor-based remote control path. The sensor can optionally transmit information to the remote controller to enable interactive operation.

Description

Task

A sensor is described, the color changes on a too monitoring area recognizes. This area to be monitored should be by the user can be defined (programmed) quickly and with simple means on site.

The sensor works passively, i. H. a suitable source of lighting is available or must be created. The sensor works dynamically, i. H. a Monitoring area on which nothing changes for a long time is taught in; Changes and movements are detected and displayed. Programmed sensor parameters are retained even in the event of a power failure.  

State of the art / description and criticism

The common methods are listed here, which are similar Fulfill the task, d. H. Area sensors with dynamic or static Evaluation method.

1. Ultrasonic sensors

Ultrasonic sensors are active sensors based on the Doppler principle or work according to the sound transit time method. The two weak points of this Procedures are the severely restricted setting (touch panel) and Susceptibility to faults when using several sensors of the same type. There is in the Practice also problems with wind / air currents and noise.

2. Radar sensors

Inexpensive radar sensors work on the Doppler principle. Various Materials such as plastic, wood or ceramic are not recognized and here too the differentiated setting option of the touch pad is not possible. Like Sensors affect each other.

3. Passive infrared sensors

With this type of sensor, the heat radiation difference of bodies is compared evaluated the environment. A rough setting of the touch pad is possible however, objects without their own heat source are not recognized.

4. active infrared sensors

A basic unit of this sensor type consists of an IR transmitter and an IR Receiver. The signal evaluation is divided into two again different procedures. Method 1: The changes in intensity of the Receive signals are evaluated (dynamic intensity button). Method 2: transmitter and receiver optics have a defined distance from each other; the point of impact of the transmitter image on the receiver element, which is behind the receiving optics is detected; Changes lead to a switching signal (triangulation method).

With such a basic unit, only a very small area in size can be created monitor the transmitter image. For larger surveillance fields, that too correspondingly many basic units are still to be programmable in integrated a sensor. If e.g. B. an area of 2 m.2 m with a resolution of 10 cm.10 cm should be monitored, you would have 400 basic units need. The disadvantages of this method can be derived from these considerations deduce. This type of sensor is either very expensive or the resolution is very high low.  

Functional description according to block diagram 1

There is a two-dimensional color area sensor behind the optics (Module 0). This color area sensor consists of a large number of single photosensitive cells (PIXEL), usually in rows and columns are arranged. These pixels are in a repeating pattern Color filters covered. With a related group of PIXEL different color wavelength sensitivity, colors can be recognized; with a grid of these related PIXEL groups can be Color images that are imaged on the color area sensor into electrical Translate analog signals. The individual PIXEL can be controlled (Module 1) address, with which the corresponding analog signal on the color Area sensor can be tapped. This analog signal is sent through an A-D converter (Module 2) digitized and can be read in by the computer 1 CPU (Module 3) and are processed. The CPU can use the remote control receiver (module 5) (Module 3) which PIXEL groups are to be used for further evaluation are relevant, d. H. the shape of the detection field can be programmed with this. This type of remote control receiver can be used to carry out any type of commands on the surface Monitoring sensor are transmitted, which if necessary in the data storage (Module 4). As soon as the color area sensor an object in the valid Detection field detects; can he use the related information about output the output module (module 7). In the simplest case, this can be one YES / NO information that is output electrically. If necessary, it can (Module 7) also output more complex information such as object size, object color, Object position, signal-to-noise ratio, illuminance and self-test Information. As soon as a subject is recognized in the valid detection field, this becomes signaled with module 6 (switching status display). This function is for the simple checking of the set detection field makes sense. The Block diagram 1 describes the functional arrangement of the modules and not real ones Components. So there are z. B. CPU's with integrated A-D converter and integrated Data storage accordingly (module 4). There are also color area sensors (e.g. CCD sensors and CMOS image sensors), the A-D converter and Control circuits included. All of these possible, real assignment variants are covered by this description. The evaluation procedure is analyzed Color changes in the detection area if these color changes are a exceed the specified and permissible threshold, this results in a switching signal. The The properties described in the Task chapter can be used with the Satisfy sensor according to block diagram 1.

Claims (10)

1. The invention is characterized in that in a dynamically operating color area sensor (block diagram 1) that uses color changes as an evaluation and switching criterion, the detection field and other sensor parameters via a wireless / fiber-optic or a wired / fiber-optic remote control link can be programmed. 2. As an option, it is also possible that the sensor has its own Remote control transmitter transmits information to the external remote control, which makes interactive setting processes possible. 3. The transmission medium between sensor and external remote control can via cable, light guide, radio, modulated infrared radiation, modulated light Radiation, sound and induction loops take place. 4. Disturbing optical reflections can be fixed or rotated Reduce the polarization filter in front of the receiver optics. 5. The dynamic range (lighting insensitivity) of the sensor can be with interchangeable panels, motorized panels, against each other rotatable polarizing filters, phototropic glasses and a variable Change the integration time of the image sensor (module 0). 6. The sensor can be equipped with a test input, which is both via the remote control and alternatively or simultaneously via an electric one Input signal can be controlled. Such a control signal causes a self test of the sensor; the test result can be found in modules 6/7 be issued. 7. To improve the self-test, one or more, controllable auxiliary transmitters can be arranged so that they directly on the image sensor (Module 0) light up; these auxiliary transmitters can be single color, multicolor or white his. 8. To prevent condensation on the optical outer surface, a Window heating can be provided. 9. To reduce contamination of the optical outer surface, you can optical outer surfaces can be provided with a coating that is antistatic works and / or has a high self-cleaning power in the rain. 10. The real image sensors (module 0) often have a restricted one Temperature working range; this disadvantage can be solved in the sensor Fix built-in and regulated heating and / or cooling.