JPH06315110A - Video picture calibration system - Google Patents

Abstract

PURPOSE: To automatically provide a video obtaining module and configuration information with video processing electronic device of a video measurement system by adapting a camera so as to be joined to a video processing means to receive the configuration information for correction and forming a second output signal useful for an object. CONSTITUTION: In an image system 10 with a video camera 20 to look into the object, a camera is provided with an output including both video information to display the object to be looked into and the configuration information which is provided with at least one of both electronic characteristics and optical characteristics of the camera. The camera is suitable to be connected with the video processing electronic device with a correction facility by the correction information which is down loaded in future, the video camera 20 is changeable with another video camera 20 with different correction information. A multiplexer 40 is coupled with a camera output signal to couple the correction information and video output of the camera and provided with the output capable of being connected with the video processing electronic device. The correction information is stored in memory located in a camera.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to improvements in the electrical and optical calibration of video imaging systems. More particularly, the present invention relates to an apparatus and method for storing optical and electrical calibration information in an endoscope and transmitting the information to a calibration display electronics.

[0002]

2. Description of the Related Art Modern borescopes and endoscopes have a miniaturized optical assembly and a CCD image sensor spread at the end of the optical assembly, which is convenient for the user. To use a full color video display system. It is possible to provide the output of the imager to a system that includes display electronics, video measurement systems, computers, video modems, and information storage devices. An acceptor of video information from a borescope imager is commonly referred to herein as "video processing electronics." For use with borescopes and endoscopes for measuring inaccessible remote objects, eg in addition to common assignee US patent N
o. It is necessary to accurately determine the distance from the viewing lens to the object, as taught in 5,070,401. In order to achieve this, the video processing electronics must take into account the optical properties of the particular optical assembly and additionally compensate for the electronic features of the CCD imager so that the final display or Similar results are corrected for personality. As used herein, the term "optical feature" used in reference to the video acquisition element of a video system, as adjustments, corrections, or compensations may be required by the video processing electronics to provide an accurate representation of the object viewed. ”,“ Electrical characteristics ”and“ electro-optical characteristics ”include size, field of view, lens distortion, pixel type, color balance, signal level,
Reference is made respectively to electronic and optical parameters such as contrast, brightness, etc. As used herein, the term "configuration information" refers to the outline of the electronic and optical characteristics of the video acquisition elements of a video system required by video processing electronics.

It is an existing practice to standardize the output signal of CCD sensors, and it is also customary to match electrical features to video processing electronics by analog devices such as jumpers and potentiometers. Such a method works ideally well, and the amplification gain of the CCD device can be compensated for drift, aging, frequency response variation, blooming effects, etc. However, individually adjusting each assembly in manufacturing is an intensive, slow and expensive labor.

Other known methods of providing video camera or imager configuration information to video processing electronics include configuration switches, jumpers and shorting pins, and potentiometers. A commercial video measurement unit is programmed to interface with a borescope with a known contour of configuration information. If borescopes with different component contours are required to work interchangeably with the measurement system, it may be necessary to modify the video processing electronics. This can be done, despite the inconvenience, by changing the hardware using switches or jumpers, or by changing to memory devices, such as PROMs, that incorporate special borescope configuration information in detail. Another solution is to access a library or table of borescope configurations in software, where the operator selects the appropriate borescope from a menu on the screen. The latter approach risks operator error and requires software maintenance whenever a new borescope is introduced into the system.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to automatically provide configuration information about a video acquisition module, such as a borescope, to the video processing electronics of a video measurement system. Another object of the present invention is to provide an improved video measurement system in which the video acquisition module with a variety of configuration information contours can be conveniently replaced.

Yet another object of the present invention is to provide an improved borescope which provides electronic symbols to the video processing electronics of the video measurement system containing the necessary configuration information. A further object of the present invention is to eliminate the hardware and user-reciprocal software required by conventional video measurement systems to adapt the configuration of the video acquisition module to video processing electronics.

These and other objects of the invention are achieved by an imaging system, which comprises a video camera for looking into an object. The camera has an output that includes both video information representing the object viewed and configuration information that comprises at least one of the electronic and optical characteristics of the camera. The camera is adapted to interface with video processing electronics having calibration equipment according to the calibration information to be downloaded. The video camera can be replaced with another video camera having different calibration information. In one aspect of the invention, a multiplexer is coupled to the camera output signal for combining the calibration information and the video output of the camera, the multiplexer having an output connectable to video processing electronics. The calibration information may be stored in memory located on the camera. In another aspect of the invention, the video camera is used in a borescope or endoscope.

According to another feature of the invention, the imaging system comprises a borescope having an electro-optical system forming a first output signal for displaying an image of the object viewed.
The borescope incorporates electronic circuitry that produces a second output signal indicative of configuration information comprising at least one of the electronic and optical features of the camera. The video processing electronics receives the first and second output signals from the borescope and further forms a third output signal that is beneficial to the object. The video processing electronics includes a calibration circuit that operates according to the configuration information. The borescope can be exchanged for another borescope with different configuration information.

According to another feature of the invention, the circuit forming the second output signal comprises a programmed microcomputer having a non-volatile memory containing configuration information. In one embodiment, there is a multiplexer coupled to the first output signal and the second output signal, the multiplexer having an output connected to the video processing electronics.

[0010]

For a better understanding of these and other objects of the invention, reference numerals have been made to the detailed description of the invention which should be read in conjunction with the following figures. Returning to FIG. 1, a system 10 for delivering calibration information to video processing electronics is shown. The system is a video camera 2
0, which in the preferred embodiment is located at the end of the borescope or the insertion tube of the endoscope. Along with this, the common assignee, Danner et al., Disclosed in US Pat. No. 4,491,865, and further incorporated herein by reference numeral, may be incorporated into camera 20. The optical part 22 has a field of view 12
Is provided on a photosensor 24 for projecting an image of a charge coupled device (CCD), which preferably has a known pixel type. CCDs with 488 vertical pixels and 510 horizontal pixels are adapted to the NTSC video convention and can be used with the present invention. The sensor 24 is connected to a power source (not shown) via line 26, and along with the required bias and line or bus 27 along with a clock signal. The output signal is typically analog,
However, it may be digital and is guided by the line 28 from the sensor 24. Microcomputer 30 and memory 32 for storing calibration information are coupled to reset circuit 35. The microcomputer 30 is triggered by the reset circuit and outputs the configuration information stored as data in the memory 32. The multiplexer 40 is further connected to the output of the microcomputer 30 and to the video output line 28. The signal processed by multiplexer 40 is output to video processing electronics (not shown), which is arranged to receive both the video signal and configuration information. Such video processing electronics are well known in the art. For example, Sarophine et al., US Pat. No. 4,546,379, discloses a device for balancing the primary color image in a video system. Video processing details, such as signal level control, image size, color balance,
Distortion correction etc. will therefore not be discussed further here.

In effect, memory 32, microcomputer 30, reset circuit 35, and multiplexer 40 may be implemented on a single integrated circuit chip. FIG. 2 will be described. The above system will be described in more detail. The microcomputer or microprocessor 30 is Motorola
It is implemented as a MC68HC05 CPU, and is provided with a small-scale RAM 33 and a booting ROM 34 for general use. The memory 32 comprises stored configuration data and suitable programs for the microprocessor 30,
It is realized by EPROM with 12-bit memory,
The serial I / 0 port 36 has lines 56, 56 for communication.
A multiplexer 40 is provided via the. An A / D converter 39 is attached to port 41 and accesses the analog signal of sensor 24 via line 28. The bus 37 is a memory 32, a ROM 33, an I / O port 34, an A / D converter 3
9 and CPU 38 are connected. The control timing for the microphone computer 30 is provided in the oscillator 44 at the frequency controlled by the crystal circuit 43. The oscillator is coupled to the computer via frequency divider 58. The timer 45 is also coupled to the oscillator section 44 and asserts that the signal resets the computer, but the line RESET 4
7 is held high through resistor 48. Further control of the processor is provided on the interrupt line IRQ 49, which is connected to the bus 27 leading from the video processing electronics, thereby ensuring access to the bias and clock signals. Power source 46 provides the DC voltage required by the computer.

In operation, the low to high transition resets line RESET 47 when power is first applied to the camera. The reset circuit triggers execution of the user program stored in EPROM 32, as indicated by block 35, and causes the microcomputer 30 to execute EPROM 3
2 contents to video-data multiplexer 40 bus 3
7, serial I / O port 36, communication port 59, and lines 56, 56. The multiplexer 40 combines the data into unused portions of the video signal, such as vertical or horizontal blanking intervals. The combined output of multiplexer 40 is useful in video processing electronics for demultiplexing by well known techniques and for display or storage as desired. Although the prototype of FIG. 2 was implemented with relatively small RAM and EPROM memories 32, 33 having 128 and 2112 bits, respectively, these memories can be as large as required for certain applications.

It will be appreciated that the system can be adapted to borescopes having different fixed sets of optical properties (ie field of view, size, distortion, number of pixels, etc.). Since each borescope is incorporated into a copy of the system 10, it is feasible to replace borescopes with different electro-optical features with special video processing electronics modules or units, providing all the requirements within the video processing electronics. Internal calibration and adjustments occur automatically whenever new configuration information is downloaded from system 10.

A benefit of the above described multiplexed embodiment is that no additional signal need be provided to or by the system 10 or its video camera 20. The present invention can be implemented with existing video camera designs without changing the camera connections. To use this system, a borescope or other type of video camera is selected and connected to the plug compatible video electronics module. The system is powered, at which time the configuration information is automatically downloaded to the video electronics module and further adjustments are made to the circuit operating conditions to ensure faithful reproduction of the object viewed by the camera. The camera is used in the desired application. The camera may be separated from the video electronics whenever needed and may be replaced with yet another camera or borescope.

In FIGS. 3 and 4, like components have like reference numbers and a first alternative embodiment of the present invention is shown. This variant is useful when multiplexing is not desired, and operates similar to the first embodiment. However, the separation line 52 is provided to send data directly from the microcomputer 30 to the video processing electronics. Video output line 28 is separately connected to video processing electronics. In some applications it may be desirable to provide a data request line 51 to initiate the downloading of configuration information to the video processing electronics.

As shown in FIG. 4, the data output line 52 sends data from the bus 37 through the 16-bit capture / compare timer 31. The data request line 51 communicates with the bus 37 via the I / O port 53. Separate signal connections to the video processing electronics are required with this variant, but multiplexers and demultiplexers may be omitted. EPROM
It is not intended to limit the storage of configuration information in the. Any form of memory known for computer technology, such as a diskette, a fixed disk drive, or even an optical disk is used.

It has become possible to embed configuration information in an optical system such that electronic symbols are generated by a CCD or auxiliary electronic device, which information is captured by a computer and further downloaded, or without any intervention by a microcomputer. Even sent to the video processing electronics at time. In FIG. 6, the system 10 according to the invention
A second alternative embodiment of 0 is shown. In this variant, the microcomputer 30 has a video electronic module 160.
, Rather than in system 100. The configuration memory 132, which may be an EPROM or the like, contains configuration information and may be accessed by a microcomputer, which sends that information to a compensation circuit in the video electronic device described above. Only one microcomputer needs to be provided for this embodiment;
However, a special line to that system is generally required.

Examples Tables 1-4 are typical compilations of electro-optical data describing the video camera 10 and CCD sensor 24. A suitable binary representation of similar data was stored in a prototype memory 32 constructed in accordance with the present invention. The table is best understood with reference to FIG. 5 and has coordinates x = 0, y = 0 in the upper left hand corner and is divided into two regions of interest, shown as A and B. The direction of the display screen will be described.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

Table 4 contains display data that describes the pixel features for the video camera.

[0023]

[Table 4]

Pixel and optical data are useful in the operation of video measurement systems in combination with the system.
While the present invention has been described with reference to the structures disclosed herein, it is not limited to the details disclosed and it is intended that the present application be protected by any variations and still fall within the scope of the claims. change.

[0025]

As described above, the present invention allows for automatically providing configuration information about the video acquisition module to the video processing electronics of a video measurement system.

[Brief description of drawings]

FIG. 1 is a block diagram of an image calibration system according to the present invention.

FIG. 2 is a partial schematic detail of the system shown in FIG.

FIG. 3 is a block diagram of a first alternative embodiment of an image calibration system.

FIG. 4 is a partial schematic detail of the system shown in FIG.

FIG. 5 is a diagram of a display screen useful in understanding the application of the present invention.

FIG. 6 is a diagram of a second alternative embodiment of the system.

[Explanation of symbols]

 10 ... System 20 ... Video camera 22 ... Optical part 24 ... Optical sensor 26 ... Line 27 ... Bus 30 ... Microcomputer 31 ... Timer 32 ... EPROM 34 ... Booting ROM 35 ... Reset circuit 36 ... Serial I / 0 port 37 ... Bus 39 ... A / D converter 40 ... Multiplexer 43 ... Crystal circuit 44 ... Oscillation unit 46 ... Power source 100 ... System 132 ... Configuration memory 160 ... Video electronic device

Claims (14)

[Claims] 1. A structure comprising a video camera for looking at an object and forming a first output signal for displaying an image of the object, the camera having at least one of an electronic characteristic and an optical characteristic of the camera. An imaging system comprising means for storing information, the camera being adapted to interface with video processing means for receiving the configuration information for calibration and for forming a second output signal useful for the object. 2. The imaging system of claim 1, wherein the video camera is replaceable with another video camera having different configuration information. 3. The multiplexer further comprising a multiplexer coupled to the means for storing the configuration information on the first output signal, the multiplexer having an output connectable to the video processing means. The image system described in. 4. The image system of claim 1, wherein the video camera further comprises microcomputer means for downloading the configuration information to the video processing means. 5. The imaging system of claim 1, wherein the video camera comprises a borescope or an endoscope. 6. A borescope having electronic optics means for forming a first output signal for remotely peeking at an inaccessible object and displaying an image of said object, said borescope comprising an electron of said electron optics means. Means for forming a second output signal indicative of configuration information comprising at least one of an optical characteristic and an optical characteristic, the first output signal from the borescope and the second output signal.
Image processing means for receiving a third output signal useful for the object and adjusting the video processing means according to the configuration information. 7. The imaging system of claim 6, wherein the borescope is replaceable with another borescope having different configuration information. 8. The image system of claim 6, wherein the means for forming the second output signal comprises a microcomputer having a memory containing the configuration information. 9. The image of claim 6, further comprising a multiplexer coupled to the first output signal and the second output signal, the multiplexer having an output connected to the video processing means. system. 10. The borescope further comprises means for storing the configuration information, the storage means being accessible to the means for forming the second output signal.
The image system described in. 11. An electronic device comprising a borescope having an output connectable to video processing electronics, said borescope forming a first output signal for peeping into a remotely inaccessible object and displaying an image of said object. Programmed to form a second output signal having optical means and disposed on the borescope for displaying configuration information comprising at least one of electronic and optical features of the borescope. An image acquisition device comprising a microcomputer, said microcomputer having means for storing said configuration information, whereby said configuration information and a warfare image are communicated to said video processing electronic device. 12. The image acquisition device according to claim 11, further comprising a multiplexer connected to the first output signal and the second output signal. 13. The image acquisition device according to claim 11, wherein the means for storing the configuration information comprises a non-volatile memory. 14. The image acquisition device according to claim 13, further comprising control means for activating the microcomputer to generate the second output signal.