Three-dimensional imaging radar system and method based on a plurality of times of integral

• US 9,958,547 B2
• Filed: 07/30/2013
• Issued: 05/01/2018
• Est. Priority Date: 12/25/2012
• Status: Active Grant

• Current Assignee: Zhejiang Geniuspros Technologies Company Limited
• Original Assignee: Hangzhou Guangpo Intelligent Technology Co., Ltd.
• Inventors: Fu, Jian, Zhang, Xiuda, Lv, Jun, Gu, Yingjie
• Primary Examiner(s): Abraham, Samantha K
• Application Number:
  US15/039,453
• Publication Number:
  US 20160313446A1
• Time in Patent Office: 1,736 Days
• CPC Class Codes: G01S 17/18 wherein range gates are used
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 7/4861 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/4865 Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487

Abstract

This invention discloses a three-dimensional imaging radar system and method based on a plurality of times of integral. The system includes an LED light source, an optical band-pass filter, an image sensor, an electronic shutter, a data processor, and a display terminal. The LED light source generates a series of light pulse trains, and when the light pulse trains illuminate an object, the object reflects the light in succession. The reflected light is sensed by the image sensor through the optical band-pass filter, to form an image on the image sensor. The image sensor performs exposure imaging three times in succession for the reflected light of the same pulse under the action of the electronic shutter. The data processor analyzes the three images to obtain contour information and distance information about the object. Finally, the display terminal displays results.

Claims

1. A three-dimensional imaging radar system based on a plurality of times of integral, comprising:

an LED light source (1), an optical band-pass filter (2), an image sensor (3), an electronic shutter (4), a data processor (5), and a display terminal (6), wherein the optical band-pass filter (2) and the electronic shutter (4) are fixed to the image sensor (3), the LED light source (1) and the image sensor (3) are connected with the data processor (5), the data processor (5) is connected with the display terminal (6), the LED light source (1) generates a series of light pulse trains, when these light pulse trains illuminate an object, the object reflects the light in succession, the reflected light is sensed by the image sensor (3) through the optical band-pass filter (2), to form an image on the image sensor (3), the image sensor performs exposure imaging three times in succession for the reflected light of the same pulse under the action of the electronic shutter, the data processor (5) analyzes the three images to obtain contour information and distance information of the object, the display terminal (6) finally displays results, the LED light source (1) includes one or more light pulse generators capable of generating microsecond pulses and nanosecond pulses, and the light pulse generator is an LED or laser.

2. A three-dimensional imaging method based on a plurality of times of integral using the system according to claim 1, comprising:

(1) the LED light source (1) generating a light pulse, within exposure time controlled by the electronic shutter (4), the image sensor (3) continuously collecting three light waves reflected by the object at the same place to obtain successive three frame images, the collecting time interval being τ

, the pixel of the anterior two frame images being lower, the pixel of the posterior frame image being higher;

(2) fitting the third frame image to an image having the same pixel with the anterior two frame images via a pixel combining mode, to obtain a high-pixel image and a low-pixel image of the third frame image, the high-pixel image including more contour information of the object due to the high pixel;

(3) the data processor (5) processing the anterior two frame images and the low-pixel image of the third frame image, to obtain a distance information point of the object;

wherein the light intensity generated from the two frame images collected from the light with the wavelength λ

changes with the distance, and the changes satisfy the following;

I(S)=∫

_τ

^Tx(t−

2S/C)g(t)dt;

I(S′

)=∫

_τ

^T+τ

x(t−

2S′

/C)g(t)dt

S is a distance of the anterior frame, S′

is a distance of the posterior frame, C is a light speed, t is time, x(t−

2S/C) is a light pulse waveform of the anterior frame of the wavelength λ

, x is weight, x(t−

2S′

/C) is a light pulse waveform of the posterior frame of the wavelength λ

, g(t) is a waveform of the electronic shutter, T is integration time;

according to the above two formulas, the light intensity integration time of the reflected light of the object with the same distance on the image sensor (3) is different, the light intensity with the greater integration time has the greater integral, the light intensity with the shorter integration time has the smaller integral, the image sensor (3) performs the light intensity integral for the collected light waves during the three times of exposure, to obtain three integral curve graphs for the same pixel point, since the light wave collected by CCD is the convolution of the light intensity in the time domain, each integral curve graph has one top point, the three points determines a conic, further to determine a top point of the conic, the horizontal coordinate of the top point represents the round trip time of the signal light, that is, the distance information point of the object;

(4) the data processor (5) obtaining the detailed distance information of the object by combining the distance information point of the object acquired in the step (3) and the contour information of the third frame image, and the display terminal (6) finally displaying the information.