CN108961333B

CN108961333B - Efficient calculation method for pixel area of image area

Info

Publication number: CN108961333B
Application number: CN201810641311.4A
Authority: CN
Inventors: 刘瑜
Original assignee: Hangzhou Jingyi Intelligent Science and Technology Co Ltd
Current assignee: Zhejiang Ruitest Technology Co ltd
Priority date: 2018-06-21
Filing date: 2018-06-21
Publication date: 2021-05-14
Anticipated expiration: 2038-06-21
Also published as: CN108961333A

Abstract

Discloses an efficient calculation method for the pixel area of an image region, namely, the center point C (x) of the image region in a known binary image I_c,y_c) The method is realized by the following steps: 1. setting linked list L = { a =_i(p, q) } and a table-tail pointer ep; 2. the center point C (x)_c,y_c) Storing surrounding pixel points into a linked list L; 3. judging the quadrant position of the elements in the linked list L relative to the central point C, entering the corresponding step, if the table tail pointer ep is 0, obtaining the pixel area value s of the image area, and ending the process; 4. searching outwards from the center in the first quadrant, and accumulating the number of pixels; 5. searching outwards from the center in the second quadrant, and accumulating the number of pixels; 6. searching outwards from the center in the third quadrant, and accumulating the number of pixels; 7. searching from the center outwards in the fourth quadrant, the number of pixels is accumulated.

Description

Efficient calculation method for pixel area of image area

Technical Field

The invention relates to a method for efficiently calculating the pixel area of an image area, and belongs to the field of image processing.

Background

Computer vision has become more and more widely used, and has been developed from simple video recording to image recognition and analysis, such as license plate recognition, face recognition, human body tracking, binocular stereo vision, and the like. Therefore, the importance of the image processing algorithm is highlighted, and the rapid development of the algorithms such as image denoising, image transformation, image segmentation, image compression, image enhancement, image blurring processing and the like is promoted.

Disclosure of Invention

The invention provides a high-efficiency calculation method for the pixel area of an image region, which adopts a method for searching pixel points in the region from a central point spirally outwards.

The technical scheme adopted by the invention for solving the technical problems is as follows:

an efficient calculation method for pixel area of an image area is known as a binary image I (x, y), wherein x = 1-M, y = 1-N, M is the maximum number of pixels in the x-axis direction, N is the maximum number of pixels in the y-axis direction, the image area I (x, y) is equal to 1, x = 1-M, y = 1-N, M is the maximum number of pixels in the x-axis direction, N is the maximum number of pixels in the y-axis direction, and a central point is C (x, y)_c,y_c) The method is realized by the following steps:

(1) setting linked list L = { a =_iIn which a is_i= (p, q), i =1,2,3.. the pointer ep is set to point to the position of the latest data in the linked list L, the initial value is 0, the pixel area s of the interest region is set, and the initial value is 1;

(2) initialize the linked list L if I (x)_c+1,y_c) Equal to 1, s = s +1, ep = ep +1, a_ep=(x_c+1,y_c)，I(x_c+1,y_c) = 0; if I (x)_c,y_c+1) is equal to 1, then s = s +1, ep = ep +1, a_ep=(x_c,y_c+1)，I(x_c,y_c+1) = 0; if I (x)_c-1,y_c) Equal to 1, s = s +1, ep = ep +1, a_ep=(x_c-1,y_c)，I(x_c-1,y_c) = 0; if I (x)_c,y_c-1) equals 1, then s = s +1, ep = ep +1, a_ep=(x_c,y_c-1)，I(x_c,y_c-1)=0；

(3) For the linked list L, if ep is equal to 0, the calculation is completed, a pixel area value s of the image area is obtained, and the process is ended; if a is_ep.p-x_c>0, and a_ep.q-y_cIf the value is more than or equal to 0, executing the step 4; if a is_ep.p-x_cIs ≦ 0, and a_ep.q-y_c>0, executing the step 5; if a is_ep.p-x_c<0, and a_ep.q-y_cIf not more than 0, executing the step 6; if a is_ep.p-x_cIs not less than 0, and a_ep.q-y_c<0, executing the step 7;

(4) establishing temporary variables (m, n) with m = a_ep.p，n=a_ep.q, then ep = ep-1; if I (m +1, n) is equal to 1, s = s +1, ep = ep +1, a_ep= (m +1, n), I (m +1, n) = 0; if I (m, n +1) is equal to 1, s = s +1, ep = ep +1, a_ep= (m, n +1), I (m, n +1) = 0; returning to the step 3;

(5) establishing temporary variables (m, n) with m = a_ep.p，n=a_ep.q, then ep = ep-1; if I (m-1, n) is equal to 1, s = s +1, ep = ep +1, a_ep= (m-1, n), I (m-1, n) = 0; if I (m, n +1) is equal to 1, s = s +1, ep = ep +1, a_ep= (m, n +1), I (m, n +1) = 0; returning to the step 3;

(6) establishing temporary variables (m, n) with m = a_ep.p，n=a_ep.q, then ep = ep-1; if I (m-1, n) is equal to 1, s = s +1, ep = ep +1, a_ep= (m-1, n), I (m-1, n) = 0; if I (m, n-1) is equal to 1, s = s +1, ep = ep +1, a_ep= (m, n-1), I (m, n-1) = 0; returning to the step 3;

(7) establishing temporary variables (m, n) with m = a_ep.x，n=a_ep.y, then ep = ep-1; if I (m +1, n) is equal to 1, s = s +1, ep = ep +1, a_ep= (m +1, n), I (m +1, n) = 0; if I (m, n-1) is equal to 1, s = s +1, ep = ep +1, a_ep= (m, n-1), I (m, n-1) = 0; and returning to the step 3.

The invention has the following beneficial effects: 1. the method is simple and high in efficiency, so that the operation speed is high; 2. the calculation result is accurate, and the error is small.

Drawings

Fig. 1 is a schematic diagram of an efficient calculation method of pixel area of an image area.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

referring to fig. 1, a method for efficiently calculating a pixel area of an image region is known as a binary image I (x, y), where x =1 to M, y =1 to N, M is a maximum number of pixels in an x-axis direction, N is a maximum number of pixels in a y-axis direction, the image region I (x, y) is equal to 1, other regions I (x, y) are equal to 0, and a central point is C (x, y)_c,y_c). The efficient calculation method is realized by the following steps:

(1) setting linked list L = { a =_iIn which a is_i= (x, y), i =1,2,3.. the pointer ep is set to point to the position of the latest data in the linked list L, the initial value is 0, the pixel area s of the interest region is set, and the initial value is 1;

step 1 provides for subsequent calculations. The linked list L is used to store the outermost pixels that are radially searched from the center to the periphery.

(2) Initialize the linked list L if I (x)_c+1,y_c) Equal to 1, s = s +1, ep = ep +1, a_ep=(x_c+1,y_c)，I(x_c+1,y_c) = 0; if I (x)_c,y_c+1) is equal to 1, then s = s +1, ep = ep +1, a_ep=(x_c,y_c+1)，I(x_c,y_c+1) = 0; if I (x)_c-1,y_c) Equal to 1, s = s +1, ep = ep +1, a_ep=(x_c-1,y_c)，I(x_c-1,y_c) = 0; if it is notI(x_c,y_c-1) equals 1, then s = s +1, ep = ep +1, a_ep=(x_c,y_c-1)，I(x_c,y_c-1)=0；

In step 2, the center point C (x) is used_c,y_c) As core, an initial search path is established as the center point C (x)_c,y_c) Adjacent points up, down, left, and right.

step 3 is an entry of the cyclic search, so that the judgment of the ending condition is firstly carried out, if ep is equal to 0, the calculation of the pixel area s of the image area is completed, and the process is ended; otherwise, the position of the latest data in the link list L is judged according to the position of the latest data relative to the central point C (x)_c,y_c) The quadrant positions of (a) are processed in different steps.

(6) establishing temporary variables (m, n) with m = a_ep.p，n=a_ep.q, then ep = ep-1; if I (m-1, n) is equal to1, then s = s +1, ep = ep +1, a_ep= (m-1, n), I (m-1, n) = 0; if I (m, n-1) is equal to 1, s = s +1, ep = ep +1, a_ep= (m, n-1), I (m, n-1) = 0; returning to the step 3;

(7) establishing temporary variables (m, n) with m = a_ep.p，n=a_ep.q, then ep = ep-1; if I (m +1, n) is equal to 1, s = s +1, ep = ep +1, a_ep= (m +1, n), I (m +1, n) = 0; if I (m, n-1) is equal to 1, s = s +1, ep = ep +1, a_ep= (m, n-1), I (m, n-1) = 0; and returning to the step 3.

Step 4, a searching method of the first quadrant, wherein the searching method is performed right first and then upward; step 5, a search method of a second quadrant, wherein the search method is performed leftwards and upwards; step 6, a search method of a third quadrant, namely, firstly, leftwards and then downwards; step 7 is a search method of the fourth quadrant, first right and then down. When all the paths reach the outermost periphery of the image area, the data in the linked list L are deleted one by one, no new data is added, finally ep is equal to 0, and the calculation process is ended.

Claims

1. An efficient calculation method for pixel area of an image area is known as a binary image I (x, y), wherein x = 1-M, y = 1-N, M is the maximum number of pixels in the x-axis direction, N is the maximum number of pixels in the y-axis direction, the image area I (x, y) is equal to 1, x = 1-M, y = 1-N, M is the maximum number of pixels in the x-axis direction, N is the maximum number of pixels in the y-axis direction, and a central point is C (x, y)_c,y_c) The method is characterized in that: the method is realized by the following steps:

(7) establishing temporary variables (m, n) with m = a_ep.x，n=a_ep.y, then ep = ep-1; if I (m +1, n) is equal to 1, s = s +1, ep = ep +1, a_ep= (m +1, n), I (m +1, n) = 0; if I (m, n-1) is equal to 1, s = s +1, ep = ep +1, a_ep=(m,n-1)，I(m,n-1) = 0; and returning to the step 3.