CN111536948A - Direct sensor oriented photogrammetric camera - Google Patents

Abstract

The invention discloses a direct sensor oriented photogrammetric camera, comprising: the device comprises a camera shell, an image sensor module, an attitude sensor module, a distance measurement sensor module and a power supply and communication module; the power and the communication module communicate with the upper computer through a USB cable and supply power for the system, each sensor module is rigidly connected, the inner orientation element and the eccentric component of the camera are obtained through system integration calibration, the upper computer controls each sensor to simultaneously acquire images, attitude angles and the skew distance of a plane to be measured through software, and time stamp alignment is carried out on data, and then the outer orientation element of the camera is corrected according to an integrated calibration result, finally, object space coordinates are resolved by using a direct sensor oriented photogrammetry model, and image-control-free planar photogrammetry is realized. The invention has the advantages of no image control, easy checking, low cost, modularization, easy integration, portability and easy use.

Description

Direct sensor oriented photogrammetric camera

Technical Field

The invention relates to the technical field of close-range photogrammetry, in particular to a photogrammetry camera with a direct sensor orientation.

Background

The photogrammetry technology is a one-door non-contact type measurement technology formed along with the development of a computer vision technology, and compared with the traditional measurement means, the photogrammetry technology has the advantages of large measurement range, more measurement information acquisition, small limitation of working environment, no interference to a measurement object and the like. The technique in which the geometric size or spatial position of an object is measured using a single image taken by a single camera is called single-camera photogrammetry or monocular vision measurement in the field of close-range photogrammetry and machine vision, respectively. The device has the advantages of simple structure, easy calibration, convenient operation and the like, and is widely applied to non-contact plane measurement in industrial detection and mapping engineering. However, the mapping relationship from the three-dimensional world coordinate to the two-dimensional image coordinate is irreversible due to the lack of depth information in the imaging process of a single image, and a coplanar constraint condition is usually required to establish a reversible coordinate transformation relationship between the image plane and the object plane.

In the field of close-range photogrammetry, the prior art mostly depends on image control points laid on site to establish a coordinate transformation relation. For the scenes such as the water surface of a river, the outer vertical surface of a building and the like, the arrangement of the image control points has great safety risk, wastes time and labor, and the quantity and the arrangement mode of the image control points can directly influence the precision of the measurement result. In the field of machine vision, the conventional image-control-free measuring method mainly depends on geometric characteristic information such as regular parallel lines, circles and the like in an image, is usually only suitable for a specific scene, and is difficult to apply to the condition that the characteristics are too complicated or missing or needs to be calibrated again.

With the development of sensors and information fusion technology, a positioning and Orientation system is utilized to measure the position and the attitude of a camera in real time, and then the Direct Sensor Orientation (DSO) or (DSG) technology for coordinate calculation is applied to the field of aerial photogrammetry in an exploratory manner in recent years, image control-free measurement in a range of several square kilometers can be realized, the precision reaches the level of decimeter, and the efficiency and the safety of measurement are obviously improved. The main bottleneck of the prior art is that the high dynamic measurement accuracy of the sensor is insufficient, so that the high maneuvering motion error of the loading platform is overlarge. Generally, roll angle and pitch angle errors of an Inertial Measurement Unit (IMU) are required to be not greater than 0.01 °, heading angle errors are not greater than 0.02 °, and recording frequency is required to be higher than 50 Hz; the positioning accuracy of a Global Positioning System (GPS) is to be centimeter level, and the minimum sampling interval is generally within 1s, so a receiver usually adopts a high-accuracy dynamic carrier phase differential mode (DGPS). The high-precision POS in the existing aerial photogrammetry system not only greatly improves the system cost and volume, but also brings higher complexity to the integrated calibration of the system by six degrees of freedom (exterior orientation elements) of the multi-sensor, and the regular aerial calibration is usually carried out by using a calibration field distributed on the ground.

In the field of close-range photogrammetry, such as water surface flow field measurement, ground target positioning and speed measurement, building facade dimension measurement and other applications, the position and attitude of a camera are usually fixed, and a measurement object is a plane. Such single-camera planar relative coordinate and distance measurement applications do not require acquisition of absolute coordinates of the object point relative to the geodetic coordinate system, but only concern its relative positional relationship. Therefore, the existing direct sensor directional photogrammetry system can be optimized, and the practicability of the system is improved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a photogrammetric camera with a direct sensor orientation, which is free from image control, easy to check, low in cost, modularized, easy to integrate, portable and easy to use.

To solve the above technical problem, the present invention provides a direct sensor oriented photogrammetric camera comprising: the device comprises a camera shell, an image sensor module, an attitude sensor module, a distance measurement sensor module and a power supply and communication module; the power supply and the communication module communicate with the upper computer through a USB cable and supply power to the system, each sensor module is rigidly and fixedly connected, the inner orientation element and the eccentric component of the camera are obtained through system integration check, the parameters between the modules and the module are checked and calibrated after the modules in the system are integrally assembled together through the integration check, the upper computer controls each sensor to simultaneously acquire images, attitude angles and the slant distance of a plane to be measured through software, the data are aligned in a timestamp mode, then the outer orientation element of the camera is corrected according to the integration check result, finally, the object space coordinate is resolved by using a direct sensor oriented photogrammetry model, and image-control-free plane photogrammetry is realized.

Preferably, the camera shell is a cuboid and consists of a front panel, a hollow tube and a rear panel; the front panel is made of iron, a C-port lens holder is arranged on the left side and used for connecting a camera lens, four upright posts which are distributed in a central symmetry mode are arranged on the inner side of the lens holder and used for mounting an image sensor module, the horizontal and vertical distances of the upright posts are both 34mm, and the centers of the upright posts are screw holes of M2; a square groove with the size of 26mm multiplied by 12mm is arranged on the right side of the front panel and is used for installing a distance measuring instrument module; the centers of the lens mount and the square groove are aligned in the vertical direction, so that the optical center of the camera and the reference point of the distance meter are positioned at the same elevation; the middle through hole is made of aluminum, screw holes are formed in four corners of two ends of the middle through hole and used for mounting the front panel and the rear panel, an 1/4' through hole is formed in the center of the bottom of the middle through hole and used for mounting a camera support nut, and M2 screw holes are formed in the positions 3mm away from the two sides of the through hole and used for mounting a fixing screw of the support nut; the rear panel is iron, and a male four-core aviation plug is installed at the center and is used for connecting a USB cable.

Preferably, the image sensor module is arranged at the rear end of a lens mount of a front panel of a camera shell, is a first layer circuit board, has the size of 38mm multiplied by 38mm, is provided with a CMOS image sensor at the center, and is provided with a PH2.0mm packaged four-core wiring terminal at the rear end for leading out a USB interface; the module is powered by a 5V power supply provided by a USB interface, and the working current is less than 200 mA; the module supports a universal USB Video Class (UVC) protocol, can output images in MJPEG and YUV formats, and has a maximum frame rate higher than 30 fps.

Preferably, the attitude sensor module is arranged at the rear end of the image sensor module in parallel by adopting four upright posts, is a second layer circuit board and has the size of 38mm multiplied by 38 mm; the center of the module is a three-axis attitude sensor, the Z axis of the three-axis attitude sensor is vertical to the plane of the image sensor, and the X, Y axis of the three-axis attitude sensor is respectively parallel to the X, Y axis of the plane of the image sensor; the output data comprises three-axis (X, Y, Z) acceleration and two-axis (X, Y) inclination angles, the output frequency is 0.1 Hz-100 Hz, the output interface is a TTL serial port, and the Baud rate range is 9600B-115200B; the range of the acceleration is +/-16 g, and the error is 0.01 g; the inclination angle range is +/-90 degrees, the static error is 0.05 degrees, and the dynamic error is 0.1 degrees; the module can be powered by 3.3V-5V voltage, and the working current is less than 10 mA.

Preferably, the distance measuring sensor module adopts a phase type single-point laser distance measuring sensor, the light source is 635nm red laser, and the power is less than 1 mW; the indoor range is 0.05-100 m, and the outdoor range is 0.05-50 m; the precision of the distance measurement is +/-1 mm + dx0.05%, the repetition precision is +/-1 mm, and the resolution is 1 mm; the output frequency is 1 Hz-20 Hz, the output interface is a TTL serial port, and the baud rate range is 9600B-115200B; the module is powered by 5V voltage, and the working current is less than 120 mA; setting the optical front end of the distance measuring sensor as a measuring reference, and embedding the protective cover in a square groove of a front panel of a camera shell to be coplanar with the objective lens end of the camera optical lens; the circuit board of module is fixed in the backup pad that leads to the bottom in the camera shell through four high accurate adjustable stands, carries out the parallelism of optical axis and examines the school during integration, finely tunes the stand height through observing the position of laser facula in the image for the optical axis of range finding sensor is on a parallel with the optical axis of camera optical lens, is the perpendicular to image sensor plane promptly.

Preferably, the power supply and communication module is arranged at the rear end of the attitude sensor module in parallel by adopting four upright posts, is a third layer of circuit board and has the size of 38mm multiplied by 38 mm; the module takes a four-channel USB2.0 concentrator circuit as a core and comprises a host end and four extension ends, wherein the host end is connected with an upper computer through a four-core aviation plug 11 on a rear panel of a shell, the highest transmission rate is 480Mbps, and a 5V power supply with the maximum working current of 500mA is provided for the whole system; the expansion end 1 is connected with the image sensor module, and the working current is about 200 mA; the extension end 2 is connected with the attitude sensor module through the USB-to-TTL serial port circuit 1, and the working current is about 20 mA; the extension end 3 is connected with the distance measuring sensor module through the USB-to-TTL serial port circuit 2, and the working current is about 130 mA; the expansion end 4 is a reserved port.

Preferably, the main chip of the four-channel USB2.0 hub circuit is GL850G, the host end and the expansion end both have 500mA self-recovery fuses, and support the USB 2.0/1.1 interface protocol, and the host end and the expansion end both support high-speed and full-speed interface speeds; the main chip is provided with an on-chip 8-bit microprocessor, a 64B RAM and a 2KB mask ROM, and supports reading of an external EEPROM to realize downlink expansion port configuration; the four extension ends of the main chip support an Indvidual/Ganged mode, and the four extension ends are operated by operating the I/O port, so that the host end can independently control a certain extension end or simultaneously control a plurality of extension ends to work.

Preferably, a main chip of the USB-to-TTL serial port circuit is CH340, supports a USB2.0 protocol, adopts a full-duplex serial port communication mode, and has a communication baud rate of 50 bps-2 Mbps; the USB-to-TTL serial port circuit comprises a circuit 1 and a circuit 2; the circuit 1 completes the function of converting the TTL level and the USB level output by the attitude sensor module, and the circuit 2 completes the function of converting the TTL level and the USB level output by the ranging sensor module.

The invention has the beneficial effects that: (1) image control is avoided, and the method is easy to check: compared with the common industrial camera, the invention rigidly and fixedly connects the image sensor with the attitude sensor and the distance measuring sensor module, and obtains the internal orientation element and the eccentric component of the camera through system integration calibration, thereby realizing the tight coupling between the modules; the object space coordinates can be solved by using a direct sensor oriented photogrammetry model, image control-free planar photogrammetry is realized, control points and calibration fields do not need to be arranged on site, and the measurement efficiency and safety are obviously improved; (2) the cost is low: the invention takes the projection point of the camera on the plane of the object to be measured as the origin to establish an object coordinate system, and adopts a relative positioning and orientation scheme based on the laser ranging sensor and the two-axis tilt sensor to replace an absolute positioning and orientation scheme based on IMU/DGPS in the existing system, thereby obviously reducing the hardware cost; (3) modularization and easy integration: the circuit board is designed by adopting the standard size of 38mm multiplied by 38mm, is compatible with a plurality of image sensor modules supporting UVC protocols on the market, and realizes synchronization by adopting a timestamp alignment mode to replace a hardware triggering mode, so that a hardware system can be constructed by utilizing the existing modules, and the complexity of system integration is greatly simplified; (4) the portable easy-to-use: the camera shell is smaller than 100mm 80mm 50mm in volume, can be directly powered through a single USB cable and is communicated with an upper computer, and plug and play is supported.

Drawings

FIG. 1 is a diagram of hardware functional modules according to the present invention.

Fig. 2 is a schematic diagram of a hardware three-dimensional structure according to the present invention.

FIG. 3 is a diagram illustrating the internal structure of the hardware according to the present invention.

FIG. 4 is a schematic diagram of a four-channel USB2.0 hub circuit according to the present invention.

Fig. 5 is a schematic diagram of the USB to TTL serial circuit according to the present invention.

Wherein, 1, a front panel; 2. leading to middle; 3. a rear panel; 4. a lens mount; 5. a square groove; 6. a camera lens; 7. an image sensor module; 8. a ranging sensor module; 9. an attitude sensor module; 10. a power supply and communication module; 11. a four-core aviation plug; 12. a USB cable; 13. a host end; 14. an upper computer; 15. a first extension end; 16. a second extension end; 17. a third extension end; 18. and a fourth expansion terminal.

Detailed Description

As shown in fig. 1, a direct sensor oriented photogrammetric camera comprising: the device comprises a camera shell, an image sensor module, an attitude sensor module, a distance measurement sensor module and a power supply and communication module; the power supply and the communication module communicate with the upper computer through a USB cable and supply power to the system, each sensor module is rigidly and fixedly connected, the inner orientation element and the eccentric component of the camera are obtained through system integration check, the parameters between the modules and the module are checked and calibrated after the modules in the system are integrally assembled together through the integration check, the upper computer controls each sensor to simultaneously acquire images, attitude angles and the slant distance of a plane to be measured through software, the data are aligned in a timestamp mode, then the outer orientation element of the camera is corrected according to the integration check result, finally, the object space coordinate is resolved by using a direct sensor oriented photogrammetry model, and image-control-free plane photogrammetry is realized.

The hardware three-dimensional structure and the internal structure schematic diagram of the direct directional vision measurement camera are respectively shown in fig. 2 and fig. 3.

The camera shell is a cuboid and consists of a front panel 1, a through 2 and a rear panel 3; the front panel 1 is made of iron, the left side of the front panel is provided with a C-port lens holder 4 for connecting a camera lens 6, the inner side of the lens holder 4 is provided with four upright posts which are distributed with centers symmetrical and used for mounting an image sensor module 7, the horizontal and vertical distances of the upright posts are both 34mm, and the centers of the upright posts are M2 screw holes; a square groove 5 with the size of 25mm multiplied by 12mm is arranged at the right side of the front panel 1 and is used for installing a distance measuring sensor module 8; the centers of the lens mount 4 and the square groove 5 are aligned in the vertical direction, so that the optical center of the camera 6 and the reference point of the ranging sensor module 8 are positioned at the same elevation; the middle through 2 is made of aluminum, four corners at two ends of the middle through 2 are provided with screw holes for mounting the front panel 1 and the rear panel 3, the center of the bottom is provided with an 1/4' through hole for mounting a camera bracket nut, and the positions 3mm away from the through hole are respectively provided with an M2 screw hole for mounting a fixing screw of the bracket nut; the rear panel 3 is made of iron, and a male four-core aviation plug 11 is installed at the center and used for connecting a USB cable 12.

The image sensor module 7 is arranged at the rear end of the lens mount 4 of the front panel 1 of the camera shell, is a first layer circuit board, has the size of 38mm multiplied by 38mm, is provided with a CMOS image sensor at the center, and is provided with a PH2.0mm packaged four-core wiring terminal leading out a USB interface at the rear end of the module; the module is powered by a 5V power supply provided by a USB interface, and the working current is less than 200 mA; the module supports a universal USBVideo Class (UVC) protocol, can output images in MJPEG and YUV formats, and has a maximum frame rate higher than 30 fps. The installation-free additional driving program can be identified and called by the upper computer software.

The attitude sensor module 9 is arranged at the rear end of the image sensor module 7 in parallel by adopting four upright posts, is a second layer circuit board and has the size of 38mm multiplied by 38 mm; the center of the module adopts a three-axis attitude sensor WT-31, the module adopts a high-precision gyroscope accelerometer LIS3DH, the Z axis of the module is vertical to the plane of the image sensor, and the X, Y axis of the module is respectively parallel to the X, Y axis of the plane of the image sensor; an arithmetic unit integrated in the module can read the measurement data of the LIS3DH, the output data comprises three-axis (X, Y, Z) acceleration and two-axis (X, Y) inclination angles, the three-axis acceleration and the two-axis inclination angles are sequentially arranged in one frame of data, the output frequency is 0.1-100 Hz, an output interface is a TTL serial port, and the baud rate range is 9600B-115200B; the range of the acceleration is +/-16 g, and the error is 0.01 g; the inclination angle range is +/-90 degrees, the static error is 0.05 degrees, and the dynamic error is 0.1 degrees; the module can be powered by 3.3V-5V voltage, and the working current is less than 10 mA.

The distance measuring sensor module 8 adopts a phase type single-point laser distance measuring sensor HI50, the light source is red laser with 635nm, and the power is less than 1 mW; the indoor range is 0.05-100 m, and the outdoor range is 0.05-50 m; the precision of the distance measurement is +/-1 mm + dx0.05%, the repetition precision is +/-1 mm, and the resolution is 1 mm; the output frequency is 1 Hz-20 Hz, the output interface is a TTL serial port, the Baud rate range is 9600B-115200B, the output data is 8-bit data, and no check bit exists; the module is powered by 5V voltage, and the working current is less than 120 mA; setting the optical front end of the distance measuring sensor module 8 as a measuring reference, and embedding a protective cover of the distance measuring sensor module in a square groove 5 of a front panel 1 of a camera shell to be coplanar with the objective end of a camera lens 6; the circuit board of module is fixed in the backup pad of 2 bottoms of leading to in the camera shell through four high accurate adjustable stands, carries out the parallelism of optical axis and examines the school during integration, finely tunes the stand height through observing the position of laser facula in the image for the optical axis of range finding sensor module 8 is on a parallel with the optical axis of camera lens 6, is the perpendicular to image sensor module 7 plane promptly.

The power supply and communication module 10 is arranged at the rear end of the attitude sensor module 9 in parallel by adopting four upright posts, is a third layer circuit board and has the size of 38mm multiplied by 38 mm; the module takes a four-channel USB2.0 concentrator circuit as a core and comprises a host end 13 and four extension ends, wherein the host end 13 is connected with an upper computer 14 through a four-core aviation plug 11 on a rear panel of a shell, the highest transmission rate is 480Mbps, and a 5V power supply with the maximum working current of 500mA is provided for the whole system; the first extension end 15 is connected with the image sensor module 7, and the working current is about 200 mA; the second extension end 16 is connected with the attitude sensor module 9 through the USB-to-TTL serial port circuit 1, and the working current is about 20 mA; the third extension end 17 is connected with the distance measuring sensor module 8 through the USB-to-TTL serial port circuit 2, and the working current is about 130 mA; the fourth expansion port 18 is a reserved port.

Four-channel USB2.0 hub circuit, its characterized in that: the main chip is GL850G, the host end and the expansion end are both provided with a 500mA self-recovery fuse, the USB 2.0/1.1 interface protocol is supported, and the host end and the expansion end both support high-speed and full-speed interface speeds; the main chip is provided with an on-chip 8-bit microprocessor, a 64B RAM and a 2KB mask ROM, and supports reading of an external EEPROM to realize downlink expansion port configuration; the four extension ends of the main chip support an Indvidual/Ganged mode and are operated by operating the I/O ports, so that the host end can independently control a certain extension end or simultaneously control a plurality of extension ends to work.

USB changes TTL serial ports circuit, its characterized in that: the main chip is CH340 and supports a USB2.0 protocol, the communication mode is full-duplex serial communication, and the communication baud rate is 50 bps-2 Mbps; a level conversion device is additionally arranged outside the circuit, and TTL serial port signals such as RS232, RS485, RS422 and the like are supported; the USB-to-TTL serial port circuit comprises a circuit 1 and a circuit 2; the circuit 1 completes the function of converting the TTL level and the USB level output by the attitude sensor module 9, and the circuit 2 completes the function of converting the TTL level and the USB level output by the distance measuring sensor module 8.

The four-channel USB2.0 hub circuit is shown in fig. 4 and includes a control chip U1. Pin 23 of U1 is connected to VCC, and pin 15 is connected to ground; pin 16 of U1 is grounded after being connected in series with capacitor C18; a starting oscillation circuit consisting of a crystal oscillator X1 and capacitors C8 and C9 is connected with pins 6 and 7 of the U1; pin 4 of U1 is grounded after being connected in series with resistor R3, i.e. the RREF end of GL850G is grounded, and the voltage reference point of the internal reference voltage circuit can be set as ground; pin 17 of U1 is a power supply mode determination pin, and is directly connected to pin 2 of pin header P2; in operation, pin 1 and pin 2 of pin header P2 are connected, that is, the PSELF terminal of GL850G is connected to a high level, the power supply mode may be set to a self-power mode, and similarly, the PSELF terminal needs to be grounded to supply power to the bus. The pin 18 of the U1 is connected to the pin 16 through a series-parallel circuit formed by a resistor R4, a resistor R2 and a diode LED 1; by the connection method, the working mode of the extension end of the GL850G can be set to be a Ganged mode, and the function of unified operation of the host computer on the extension port can be realized in the mode; a filter circuit formed by capacitors EC1, C15 and an inductor LB2 is connected with pins 24 and 1 of U1; the pin 1, the pin 5 and the pin 10 of the U1 are connected in parallel, and are connected in series with a parallel circuit formed by capacitors C5, C6, C17, C23 and C24 and then grounded; pin 2 and pin 3, pin 8 and pin 9, pin 25 and pin 26, and pin 27 and pin 28 of U1 are four groups of extension channels, where pin 2 and pin 3 are connected to USB to TTL serial circuit 2, pin 8 and pin 9 are reserved ports, pin 25 and pin 26 are connected to the image sensor module, and pin 27 and pin 28 are connected to USB to TTL serial circuit 1.

The USB to TTL serial circuit is shown in fig. 5, and is composed of a power supply, two chips, two crystal oscillators, and eight capacitors; a pin 19 of the control chip U3 is connected with a power supply VC1, and a capacitor C2 is connected between the pin 19 and the ground in series to realize stable power supply input; a pin 5 of the control chip U3 is grounded after being connected in series with a capacitor C1, and a pin 8 is directly grounded, namely, the 3V voltage input end of the CH340 is set to be in a closed state; a starting oscillation circuit consisting of a crystal oscillator Y1 and capacitors C3 and C4 is connected with pins 9 and 10 of a control chip U3; pins 6 and 7 of the control chip U3 are USB signal terminals, and the two pins are respectively connected with pins 28 and 27 of a four-channel USB2.0 hub circuit control chip U1; pins 3 and 4 of the control chip U3 are connected to a serial data transmission end of the attitude sensor module; a pin 19 of the control chip U4 is connected with a power supply VC2, and a capacitor C16 is connected between the pin 19 and the ground in series to realize stable power supply input; a pin 5 of the control chip U4 is grounded after being connected in series with a capacitor C14, and a pin 8 is directly grounded, namely, the 3V voltage input end of the CH340 is set to be in a closed state; a starting oscillation circuit consisting of a crystal oscillator Y2 and capacitors C19 and C20 is connected with pins 9 and 10 of a control chip U4; pins 6 and 7 of the control chip U4 are respectively connected with pins 3 and 2 of a four-channel USB2.0 hub circuit control chip U1; the 3 and 4 pins of the control chip U4 are connected to the serial data transmission terminal of the distance measuring sensor module.

Based on the four-channel USB2.0 concentrator circuit and the USB-to-TTL serial port circuit, the three sensor modules are connected with the four-channel USB2.0 concentrator circuit in different modes; the data terminals D + and D-of the image sensor module are respectively connected with the pin 9 and the pin 8 of the chip U1; the power supply end and the grounding end of the attitude sensor module are respectively connected with VCC and GND; the data end of the attitude sensor module is connected with a pin 3 and a pin 4 of a chip U1; the power supply end and the ground end of the ranging sensor module are connected with VCC and GND; the RX and TX terminals of the ranging sensor module are connected to pin 3 and pin 4 of chip U1, respectively.

Claims (8)

1. A direct-sensor-oriented photogrammetric camera, characterized in that it comprises: the device comprises a camera shell, an image sensor module, an attitude sensor module, a distance measurement sensor module and a power supply and communication module; the power and the communication module communicate with the upper computer through a USB cable and supply power for the system, each sensor module is rigidly connected, the inner orientation element and the eccentric component of the camera are obtained through system integration calibration, the upper computer controls each sensor to simultaneously acquire images, attitude angles and the skew distance of a plane to be measured through software, and time stamp alignment is carried out on data, and then the outer orientation element of the camera is corrected according to an integrated calibration result, finally, object space coordinates are resolved by using a direct sensor oriented photogrammetry model, and image-control-free planar photogrammetry is realized.

2. The direct sensor oriented photogrammetry camera of claim 1, wherein the camera housing is a cuboid comprised of a front panel, a center pass, and a back panel; the front panel is made of iron, a C-port lens holder is arranged on the left side and used for connecting a camera lens, four upright posts which are distributed in a central symmetry mode are arranged on the inner side of the lens holder and used for mounting an image sensor module, the horizontal and vertical distances of the upright posts are both 34mm, and the centers of the upright posts are screw holes of M2; a square groove with the size of 26mm multiplied by 12mm is arranged on the right side of the front panel and is used for installing a distance measuring instrument module; the centers of the lens mount and the square groove are aligned in the vertical direction, so that the optical center of the camera and the reference point of the distance meter are positioned at the same elevation; the middle through hole is made of aluminum, screw holes are formed in four corners of two ends of the middle through hole and used for mounting the front panel and the rear panel, an 1/4' through hole is formed in the center of the bottom of the middle through hole and used for mounting a camera support nut, and M2 screw holes are formed in the positions 3mm away from the two sides of the through hole and used for mounting a fixing screw of the support nut; the rear panel is iron, and a male four-core aviation plug is installed at the center and is used for connecting a USB cable.

3. The direct-sensor directed photogrammetry camera of claim 1, wherein the image sensor module is mounted on the rear end of the lens mount of the front panel of the camera housing as a first layer of circuit board, 38mm x 38mm in size, with a CMOS image sensor centered thereon, and the rear end of the module has a ph2.0mm packaged four-core terminal leading out USB interface; the module is powered by a 5V power supply provided by a USB interface, and the working current is less than 200 mA; the module supports a universal USB Video Class protocol, outputs images in MJPEG and YUV formats, and has a maximum frame rate higher than 30 fps.

4. The direct-sensor directed photogrammetry camera of claim 1, wherein the attitude sensor module is mounted in parallel at the rear end of the image sensor module using four posts, being a second layer of circuit board, having dimensions 38mm x 38 mm; the center of the module is a three-axis attitude sensor, the Z axis of the three-axis attitude sensor is vertical to the plane of the image sensor, and the X, Y axis of the three-axis attitude sensor is respectively parallel to the X, Y axis of the plane of the image sensor; the output data comprises three-axis (X, Y, Z) acceleration and two-axis (X, Y) inclination angles, the output frequency is 0.1 Hz-100 Hz, the output interface is a TTL serial port, and the Baud rate range is 9600B-115200B; the range of the acceleration is +/-16 g, and the error is 0.01 g; the inclination angle range is +/-90 degrees, the static error is 0.05 degrees, and the dynamic error is 0.1 degrees; the module is powered by 3.3V-5V voltage, and the working current is less than 10 mA.

5. The direct-sensor directed photogrammetry camera of claim 1, wherein the ranging sensor module employs a phase-type single-point laser ranging sensor, the light source is a 635nm red laser, the power is <1 mW; the indoor range is 0.05-100 m, and the outdoor range is 0.05-50 m; the precision of the distance measurement is +/-1 mm + dx0.05%, the repetition precision is +/-1 mm, and the resolution is 1 mm; the output frequency is 1 Hz-20 Hz, the output interface is a TTL serial port, and the baud rate range is 9600B-115200B; the module is powered by 5V voltage, and the working current is less than 120 mA; setting the optical front end of the distance measuring sensor as a measuring reference, and embedding the protective cover in a square groove of a front panel of a camera shell to be coplanar with the objective lens end of the camera optical lens; the circuit board of module is fixed in the backup pad that leads to the bottom in the camera shell through four high accurate adjustable stands, carries out the parallelism of optical axis and examines the school during integration, finely tunes the stand height through observing the position of laser facula in the image for the optical axis of range finding sensor is on a parallel with the optical axis of camera optical lens, is the perpendicular to image sensor plane promptly.

6. The direct sensor directed photogrammetry camera of claim 1, wherein the power and communication module is mounted in parallel at the rear end of the attitude sensor module using four posts, being a third layer of circuit board, having dimensions 38mm x 38 mm; the module takes a four-channel USB2.0 concentrator circuit as a core and comprises a host end and four extension ends, wherein the host end is connected with an upper computer through a four-core aviation plug on a rear panel of a shell, the highest transmission rate is 480Mbps, and a 5V power supply with the maximum working current of 500mA is provided for the whole system; the expansion end 1 is connected with the image sensor module, and the working current is about 200 mA; the extension end 2 is connected with the attitude sensor module through the USB-to-TTL serial port circuit 1, and the working current is about 20 mA; the extension end 3 is connected with the distance measuring sensor module through the USB-to-TTL serial port circuit 2, and the working current is about 130 mA; the expansion end 4 is a reserved port.

7. The direct-sensor directed photogrammetry camera of claim 6, wherein the main chip of the four-channel USB2.0 hub circuit is GL850G, the host and extension terminals both have 500mA self-recovery fuses, support the USB 2.0/1.1 interface protocol, and both support high-speed and full-speed interface speeds; the main chip is provided with an on-chip 8-bit microprocessor, a 64B RAM and a 2KB mask ROM, and supports reading of an external EEPROM to realize downlink expansion port configuration; the four extension ends of the main chip support an Indvidual/Ganged mode, and the four extension ends are operated by operating the I/O port, so that the host end can independently control a certain extension end or simultaneously control a plurality of extension ends to work.

8. The direct-sensor directed photogrammetry camera of claim 6, wherein the main chip of the USB to TTL serial circuit is CH340, supports the USB2.0 protocol, the communication mode is full-duplex serial communication, and the communication baud rate is 50 bps-2 Mbps; the USB-to-TTL serial port circuit comprises a circuit 1 and a circuit 2; the circuit 1 completes the function of converting the TTL level and the USB level output by the attitude sensor module, and the circuit 2 completes the function of converting the TTL level and the USB level output by the ranging sensor module.

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