JPH02236116A - Horizontal line detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a horizon detection device used in an image processing device of an automatic navigation system for a ship or the like.

Therefore, three images of the front, the right direction, and the left direction are input, the horizontal line position is detected in each image, and the angle is detected based on the amount of swing of the imaging device and the change in the horizontal line position.

[Problems to be Solved by the Invention] However, as described above, the imaging device is oscillated, a plurality of images are processed, a horizontal line candidate is obtained from each image, and the horizon line is determined from the relationship with the oscillation angle. The method of calculating the angle has disadvantages in that it requires swing control of the imaging device, which makes the device complicated, and that it requires a large amount of calculation because it requires processing multiple images.

The present invention was made in view of the above-mentioned circumstances, and it is possible to detect the angle and position of the horizon from a single image without reducing detection accuracy, and it is possible to detect the horizon line by simplifying the imaging device and image processing circuit. The purpose is to provide a detection device.

[Means for Solving the Problems] The present invention digitizes an analog video signal captured by an imaging device using an A/D converter, divides it into regions according to frameless, and divides a horizontal line into each divided region. After the detection is performed and each detection result is temporarily stored in the horizontal line position memory, the horizontal line angle calculation circuit calculates the angle using the least squares method.

[Operation] With the above configuration, one digital image is divided into small areas, the horizontal line is detected in each area, and the angle of the horizontal line is calculated from the detection results by the method of least squares. In particular, the position and angle of the horizon can be detected with high precision without complicating the device or processing circuit.

[Embodiment] An imaging device that performs the following, 12 is an analog video signal output from the imaging device 11, l3 is an A/D converter that digitizes the video signal l2 with a predetermined sampling clock and quantization bit number, and l4 is an The digital image data that is the output of the A/D converter l3, l5 is the digital image data l4 that is the output of the A/D converter l3.
1B is the digital image data read out from the frame memory 15; 1B is the address generation circuit that generates the specified address of the divided area of the digital image data 1G; 1B is the address generation circuit 1
Specified address where 7 occurred, 191-19. is a horizontal line position detection circuit that detects the horizontal line position in each segmented area of digital image data l[i according to a specified address l8;
20 is a horizontal line position detection circuit 19. Horizontal line positions 201 to 20N, 21, which are the detection results of ~19N, are horizontal line position memories that store horizontal line positions 20t to 20N, 22 is a horizontal line position read from the horizontal line position memory 2l, and 23 is a horizontal line position that is at least two times the horizontal line position 22. A horizon angle calculation circuit 24 calculates the angle of the horizon using multiplication, and numeral 24 is the horizontal angle calculated by the horizon angle calculation circuit 23.

FIG. 2(a) shows the division of image areas by the address generation circuit 17, in which the image for one screen is vertically divided into N equal parts from area 1 to area N. Address generation circuit l7
By outputting the specified address l8 of these divided areas to the horizontal line position detection circuit 19l''=19H, it is temporarily held in the horizontal line position detection circuit 19. to frame memory l5 in units of one screen.The frame memory l5 is read out. The digital image data te is sent to the horizontal line position detection circuits 191 to 1.
9N, respectively, to the horizontal line position detection circuit 19. .about.19N detect the horizontal line position of the image data in the area divided according to the designated address l8 from the address generation circuit l7.

For one data F (x, y) 1B, first DFY (x. y) −F (x. y+1) −F
Perform the differentiation (x. y) − (1).

For the DFY (x, y) (differential image data) obtained in this way, calculations are performed to obtain a further marginal distribution.

The calculation result SDFY (x, V) (marginal distribution data) is then subjected to calculation to obtain a movement difference. In the obtained DY(y) (moving difference data), all zero-crossing points are found, and the coordinates of the zero-crossing point where the difference between the positive peak and the negative peak sandwiching the crossing point is the maximum are stored as the horizontal line position in the horizontal line position memory 21. Output.

The horizontal line angle calculation circuit 2 calculates the horizontal line position 22 of each segmented area which has been temporarily stored in the horizontal line position memory 21 and read out.
3, the angle and position of the horizontal line are calculated using the least squares method, digitized in the next stage processing circuit (not shown), temporarily stored in frame memory, and then image processed to determine the horizontal line from the video signal. In a horizon detection device that detects
The digital image data read from the frame memory is divided into regions according to the instruction address of the address generation circuit, and horizontal line detection is performed for each divided region,
After each detection result is stored in the horizontal line position memory, the horizontal line angle calculation circuit uses the least squares method to calculate the horizontal line position and angle. A horizon line detection device that can detect with precision can be provided.

[Brief explanation of drawings]

FIG. 2 is a diagram showing an input image by a conventional horizon detection device. 11...Imaging device, l2...Video signal, l3...
・A/D conversion 3, l4...Digital image data, l5
...Frame memory, IG...Digital image data, l7...Address generation circuit, l8...Specified address, 19, to 19. ...Horizontal line position detection circuit, 201
~20N...Horizontal line position, 2l...Horizontal line position memory, 22...Horizontal line position, 23...Horizontal line angle calculation circuit, 24...Horizontal line angle.

Claims (1)

[Claims] A horizontal line detection device that digitizes an analog video signal captured by an imaging device using an A/D converter, temporarily stores it in a frame memory, and then performs image processing to detect a horizontal line from the video signal. an address generation circuit that generates a specified address for vertically dividing digital image data into areas in the frame memory; and image data of each divided area read out from the frame memory by the specified address of the address generation circuit. A horizontal line position detection circuit that detects the horizontal line, a horizontal line position memory that stores each detection result of this horizontal line position detection circuit, and a least squares method using the horizontal line position of each divided area stored in this horizontal line position memory. 1. A horizontal line detection device comprising: an arithmetic circuit that calculates a horizontal line angle using a calculation circuit.