Scepter Scientific Inc. Integrated Vision Technologies

 

Non-Contact Slab Measurement and Position Measurement System

 

The slab dimensional and position measurement system utilizes state of the art CCD cameras and electronic imaging technology in conjunction with structured light techniques to measure the dimensions and position of steel slabs in motion on the depiling and charging tables of a hot strip mill.  Comprised of two separately functional systems, one for measuring slab length, width, and thickness and a second for measuring slab position in the furnace charge area. The functional components of both systems are nearly identical and, they utilize the same techniques for measurement, but, requirements of the two systems is quite different.

 

Both systems capture video images geometrically digitized on the camera CCD and transmitted as an analog signal in standard RS-170 format. Per the standard, the camera transmits 30 frames per second in an interlaced format, the odd field (odd scan lines), then the even field (even scan lines) of the frame or image. A video acquisition board in the system converts this signal into discrete digital values and loads these values into a specialized computer accessible memory area called a frame buffer.

 

The computer analyzes this image as an array of image elements or pixels, each an eight bit binary value between 0 and 255 (decimal). From this mathematical picture the computer generates a measurement based on relative pixel position.  These results are then converted to values based on conversion factors determined through the calibration process.

 

Of the two systems the slab dimensional measurement system is the simpler. It processes sequential images from only one camera, searching for a valid object and measuring it.To expand the range of measurement beyond the field of view of the single camera, this system utilizes a limited bank of high resolution photosensors in a Vernier technique.  The photosensors are used to detect a rough measurement of+/- 10 feet while the camera image is used to measure the remaining 0 to 10 feet to a resolution of +/-0.25 inches.

 

In the case of the slab position measurement system, the system must respond to the images from several cameras. The system does this by multiplexing the inputs from the cameras one at a time. The computer is responsible for not only determining which camera to select for input from but must also effectively control the timing of the operation and manage the limited number of buffers available for image storage.

 

The large image area provides enough measurement range to satisfy position measurement requirements but this system also utilizes a bank of photosensors to detect approaching slabs and verify calibration constants. In addition there are environmental sensors at each camera and laser to detect equipment damaging or failure inducing conditions.

 

 

Hot Rolled Steel Automated Plate Layout System

 

In this system, plates are received from the rolling mill transfer table hot rolled to the correct gauge. When the plate exits the leveler section, it is scanned by a CCD camera and pyrometer to obtain a temperature corrected profile. Once the profile map is complete, the plate moves to a Telesis marking station which identifies the plate with the appropriate charge number.

 

The profile map is corrected for thickness and rotated to register one edge of the plate. The corrected map along with the plate temperature and gauge/calibration constants are transmitted to a MicroVAX computer for further processing. The MicroVAX computer performs an optimized sub-plate layout of the required pattern plate sizes.

 

Plates are then moved from the cooling table and registered on the layout table in front of the shear. A computer controlled display presents a sequenced plate Que. to the layout station operator with a cursor pointing to the current plate identification number. If there are no error indications, and the layout is acceptable, the operator will initiate the automatic marking and shearing process.

 

 

 

Non-Woven Web Inspection

 

The web inspection system, designed to detect defects on continuous non-woven materials, uses a CCD line scan array camera with up to 4,096 picture elements. The CCD camera and illumination system are configured to view the cross web intensity profile of the continuously moving web. The inspection system processes the camera picture elements at a 10 million pixel per second rate looking for light or dark pixels that might represent defects. The potentially defective areas are linked together using a 68000 multibuss microprocessor with specific support hardware and software algorithms to accumulate, characterize, and classify defects at extraordinary speeds exceeding 5,000 objects per second.

 

Objects classified as defects are tracked by a flagging device mounted at a distance following the inspection station. The defects are flagged in programmable cross web zones providing the appropriate defect flagging for web slitting operations using multiple flaggers.  Defect data is sent to a host computer, typically an IBM-PC, for full color defect display. The data can be presented to the operator in a variety of formats and or archived for future reference. Inspection summaries, shift reports, and other data base operations are provided to meet specific customer requirements.

 

Inspection parameters are stored in the host computer under product codes. Parameters specific to the product code are down loaded to the inspection system matching the inspection requirements to the specific characteristics of the product. Product code files are easily generated or updated using a menu entry system selecting well known product related parameters.

 

 

 

 

 

Formation Measurement System

 

The formation measurement system is a non contact vision system designed to determine the formation quality of paper or other non woven materials during the manufacturing process.   This system provides a real time formation profile across a 300 inch wide web at speeds of up to 3000 feet per minute.

 

The formation system uses a 2048 element CCD camera that is configured to view transmitted light passing through the product. The light source contains multiple fluorescent aperture tubes and light guide assemblies to produce an intense uniform line of diffused light over the entire backside width of the web.

 

The formation signal processor was developed to accept the camera video at a rate of 10 million pixels per second and process the pixel information into a formation index which is proportional to the magnitude of the variations in web uniformity. The 68000 central processor that computes the formation index produces a continuous web formation index profile indicating the real time web uniformity.

 

The formation processor can be programmed to specific characteristics of the product including minimum and maximum floc size, cross web reporting resolution, and average measurement intervals. A novel algorithm computes the web speed from a web tachometer and varies the formation parameters to produce speed independent formation measurements. The same processor performs a frequency analysis of the formation data to discriminate against external noise sources such as stray illumination powered at 60 Hz.

 

The output of the formation processor is sent to a host computer, typically an IBM-PC, for full color profile displays and histograms. The data can be presented to the operator in a variety of formats and or archived for future reference. This very flexible customer interface can be customized to meet specific customer requirements without affecting the formation system performance.

 

Formation parameters are stored in the host computer under product codes. Parameters specific to the product code are down loaded to the formation processor matching the formation measurement index to the specific characteristics of the product. Product code files are easily generated or updated using a menu entry system selecting well known product related parameters.