TW544643B - Method for cropping area of license plate from vehicle image - Google Patents

Abstract

The present invention provides a method for cropping area of license plate from the vehicle image, which includes the following steps: using the CCD camera with associated lens and the image capturing card to take the vehicle image on the lane; using the vehicle image reading unit to read out the image captured by the image capturing card; next, using the logarithmic gray level operation unit for pixels to calculate the logarithmic gray levels for each pixel in the vehicle image; then, using the horizontal gradient operation unit for logarithmic gray levels to calculate the horizontal gradients of the logarithmic gray levels on each pixel; and, using the binary operation unit for horizontal gradients to convert the real number of the horizontal gradients into binary values, 0 or 1; finally, using the searching unit for the most dense area of binary horizontal gradient to search the area with the highest sum of binary horizontal gradients in the whole vehicle image according to the default length and width values of the license plate, and cropping out the area as the location of the license plate area.

Description

Employees' Consumption Cooperative Press of the Intellectual Property Bureau of the Ministry of Economic Affairs: t

15 20 10 [Technical field] Especially the method of cutting out the license plate area of the car, equipped with a five-access control license plate area, a motion recognition system, traffic monitoring, and vehicle light. [Previous technology] A method of extracting a vehicle image from a car law area. The identification and extraction of the license plate area in the second image is the automatic overall performance of the license plate. In addition, among the management personnel who ## 心 +… It seems that the license plate number 2 of the vehicle is cut and displayed on the license plate area of the moving f license plate, and it will be seen by two people like Zhong Gong. Therefore, how to automatically and effectively find out the location of a license plate from a vehicle image and cut it out is an important issue such as automatic license plate identification and reduction, traffic monitoring, and vehicle access control. The positioning and cutting of the license plate area in the T-shirt image is generally directly obtained by using the pixel gray level value to calculate the result. However, this method is prone to the error caused by the grayscale value calculation result due to the light and shadow. Positioning error. The gray scale of the mother pixel in the color image is obtained by multiplying the two components (brightness and reflection intensity of the object) (Muwplication) (refer to Digitanmage pr0⑽, co-authored by Rafad c_ Gonzalez and Richard R Woods, 1993) ; Brightness is determined by the intensity of the external light, and the reflection intensity of the object really reflects the image characteristics of the object itself. It can be seen that there are still many shortcomings in the above-mentioned custom items, which is not a good one! !! · Equipment · 1 丨 (Please read the precautions on the back first—greedy) J I J J ..

If nn 94 δ— un 9— 'The paper size is in accordance with Chinese National Standards (CNS) A4 Regulations (210 x 297 male f \ σ), and it is urgent to improve the Q Law Institute ’s view of the above The license plate area of the sister ’s image: the various shortcomings of the birth of 'is eager to improve and innovate, and after suffering from multiple cars, and finally successfully developed the car that completed the image of this vehicle [invention purpose] is to provide —Edition of the vehicle «image plate area 10 :: knife extraction method 'can be applied to the method of automatic license plate identification and traffic monitoring, and the vehicle license plate area extraction method of the two-door vehicle image. [Technical content] 15 We can achieve the purpose of the job The vehicle image of the license plate area is obtained from the camera. The position of the license plate area in the entire vehicle image is searched from the horizontal gradient distribution of the gray record of each rider. The invention of the license plate region is taken from the invention. The invention includes a CCD camera with a lens, an image capture r and a vehicle image reading unit, a logarithmic grayscale value calculation unit for pixels, a horizontal gradient operation unit for f-number grayscale values, and a horizontal gradient two Valued operations Early 7L, binarized horizontal gradient most dense area search unit and other modules. 20 The grayscale value of each pixel in an image is obtained by multiplying the two components such as brightness and reflection intensity of the object (refer to D. a.U.M. Processing, 1993, C. G_I_ Rlchard E. W〇〇dS ); Brightness is determined by the intensity of the light in the ', and the reflection intensity of the object really reflects the image characteristics of the object itself. Logarithmic gray obtained by logarithmic gray scale rendering Logarithmic illumination and logarithmic reflection are strong 544643

2. Description of invention A7 B7 PA890608.AiVn, 5 /; The sum of the Logarithmic reflectance of the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. The resolution of the image screen is M * N㈣ pixels, and the gray value of the &lt; pixel at the coordinate position (X, y) is g (x, y), 0 &lt; X &lt; M + bu0 &lt; The values of y, N · τ1, g (x, y) can be read directly from the output values of the CCD camera. If the bright g% i (x, y) and the reflection intensity of the pixel at the coordinate position (x, y) are r (x, y) ', then g (x, yH (x, y) X r (x, y), The value of i (x, y) and r (x, y) cannot be read from the output value of the CCD camera. After the logarithmic operation, the logarithmic grayscale value is milk x, y), and the logarithmic brightness is r ( x, y), the logarithmic reflection intensity is r, (x, y), that is 10 gf (x? y) = In g (x? y) = 111 i (x, y) + In r (x, y) i '(x, y) + r' (x, y), 0 &lt; x &lt; m + bu 〈y <N + 1. We take [g, (x + 1, y) / 2 i as the horizontal gradient of the logarithmic grayscale value of the pixel at the coordinate position (x, y), and b [g? (X + l? Y) &lt; gHx- l ^ y)] / 2 [if (x + i? y) + Γϊχ + Ι, ν), iT (x.1? y) ^ f! (x. l, y)] / 2; The difference in brightness is very small, so the value of 奸 (i-iT (xl, y) is very small and can be ignored; therefore, the logarithmic gray-scale straight horizontal gradient of the pixel at the coordinate position (x, y) is very close to ^ kiss Han. In this way, the effect of light changes or shadows on the image is eliminated. The 20 series of the present invention applies a logarithmic operation to the pixel grayscale value and uses the logarithmic grayscale value to calculate the location of the license plate, so it will not The positioning of the license plate area is incorrect due to changes in gray levels due to light changes or shadows. (The main f of the present invention is to capture the vehicle image by the camera with a lens CCD camera and image capture, and read from the vehicle image. The unit adapts the image capture paper size to the national standard (CNS) XT ^ 袼 (2if ^ winter) 1 -------- t-III! Lotus! Ti! ----- I * (Please read the precautions on the back before filling this page) 544643 A7 B7 P A890608.AM1-6/12 Description of Invention 10 Member of Intellectual Property Bureau, Ministry of Economic Affairs

15 The scene taken by the foot card ^ (The image reads out I, and then the logarithmic gray scale of the pixel! Direct transport difference: Wulai calculates the logarithmic gray scale value of each pixel in the vehicle image, = put The horizontal gradient computing unit of Gray 1 and 3 then calculates the horizontal gradient of the straight gray 13 for each pixel, and then the binary computing unit of the horizontal gradient converts the value of == money to ^ or ㈣ binary value. Finally According to the binarized horizontal gradient densest area search unit, according to the preset length and width of the license plate, the total sum of the horizontal gradients of the two companies in the ㈣ region of the vehicle image is the highest, and the ^ side area is cut out to the location of the license plate area. Brief description of the drawings] ▲% Mai read the following detailed description of a preferred embodiment of the present invention and its 4 drawings. You can further understand the technical content of the present invention and its purpose. The drawings of this embodiment are as follows: ^ This is an embodiment of the method for the peak area of the license plate region of the vehicle material of the present invention—a rough schematic diagram of the binarized horizontal gradient densest area search unit; and a detailed search method of the squared horizontal gradient densest area search unit不 \ 艺 、 图. [Main department Representative symbol] i CCD camera 2 image capture card 3 vehicle shadow reading unit 4 prime logarithmic gray level calculation unit 5 logarithmic level horizontal gradient operation unit. Degree applicable to China] (Please read the precautions on the back first Fill out this page again) t-1 1 ni 3 —fl 1 n xi ^ Install SI i II- &quot; -δ, enin Φ n »1 —fl Is t— ϋ n

i IB ϋ ί I '* 1 i n 6- 544643 A7

10 Wisdom Wealth of the Ministry of Economic Affairs. Summer [printed by Fei Hexu Co. 2ϋ 6 binarization operation unit of horizontal degree 7 binarization level gradient most dense area search unit [preferred embodiment] Please refer to the question-'this The block diagram of the vehicle license plate area of the vehicle image provided by the invention = an embodiment block diagram 'is composed of a ccd camera with a lens 1, a capture card 2 and a vehicle image reading unit 3, and the logarithmic gray scale value of the pixel is moved- Logarithmic gray level straight horizontal gradient operation unit 5, horizontal ladder production: valued operation unit 6, binarized horizontal gradient most dense area search unit 7, etc .: = composition :, where 'this lens is used to input camera 1 and image capture The image is read by the vehicle image reading unit 3, and then the logarithm of the pixel is called. The logarithmic difference is used to punch each pixel in the image of the handle image. [The gray scale value range of the service I 噼 格 &quot; is from 0 to 255, which is &lt; the math that does not perform logarithmic operation on 0 ^^ «grey _... makes grey two: = operation: = = :::: r operation Unit 5 then calculates == 'the logarithmic gray value of the pixel at the right coordinate position ㈣ for each pixel is p, y' The horizontal gradient of the logarithmic gray scale value of the element is ca l, y)] / 2; Then, the skin's mystery 洚 ', "Gai's Fen number $ / again ~ the nasal transport unit 6 will be the horizontal degree or 1 two Here, the conversion side ... the largest one hundredth and the smallest one hundredth; the maximum Γ is set from the flat gradient to the binarized horizontal gradient of the remaining pixels. The vertical level The gradient densest area searching unit 7 searches for the entire wheel shadow edge to make the two straightened water of the whole area I! I! The back i! II φ fills the I page according to the preset tile magic straight! order

544643 ΡΑ89ϋ608 ΑΜ1-3/12 Intellectual Property Bureau of the Ministry of Economic Affairs P, printed by the Industrial and Consumer Cooperatives A7 B7 i 5. Description of the invention (6) ϊ! The flat gradient summator [ij ′ cuts out the edge area as the location of the license plate area. ί | · | The binarization horizontal gradient densest area search unit 7 is divided into two steps: coarse search and fine search. Figure 2 shows the rough search method of searching for the densest area of the second childhood level. The search method is based on the rough search method of the unit. The length and width a of the license plate are each twice the range! 5 As the range window for calculating the sum of the gradients, In the vehicle image, the mobile window calculates the range window frame of the sum of gradients and calculates the sum of all binarization levels in each range; the range window of the calculated gradient sum moves horizontally one at a time: | 値 The length of the license plate or Move the width of a license plate vertically. From each movement i find a range where the sum of the binarized horizontal gradients is the largest, and this range is the rough search result of the bin | 10 binarized horizontal gradient densest area search unit 7. ί Figure 3 shows the detailed search method of the binarized horizontal gradient densest area search unit. Perform a detailed search on the range defined by the coarse search result of the search unit of the second-horizontal horizontal gradient densest area: use the license plate length and width as the range window to calculate the sum of the degrees. 15 Move the range to calculate the range window frame of the sum of gradients and calculate the sum of all binarized horizontal gradients in each range. The range window to calculate the sum of gradients moves one pixel horizontally or one pixel vertically every time. From each move, find the one-touch range where the sum of the binarized horizontal gradients is the largest. This range is the fine search result of the search unit 7 for the densest region of the binarized horizontal gradients. The range of I 20 is the license plate. region. ί | [Features and effects] | The method for extracting the license plate area of the vehicle image provided by the present invention has the following advantages when compared with other conventional techniques: j I The present invention applies a logarithmic operation to the pixel grayscale value (Logarithmic

I! -8- ί (Please read the precautions on the back before filling out this page)

Use Chinese country (2i〇 ~ x ^? Mm); ~~~

D4404J A7 B7 V. Description of the invention (f PA890608 AMI _ 9/1 9

10 opemtion) in order to get the logarithmic gray scale, and then the effect of brightness, and calculate the m 4 reels / money. Clouds in addition to the light changes to t or the shadow makes the heterogeneous it iterating 'so it will not cause the license plate area due to} The setting is wrong. The above detailed description is a specific description of one of the inventions that can be implemented by J. Ding, but the embodiment is not intended to limit the patent scope of the invention, and any equivalent implementation or implementation that does not depart from the technical spirit of the invention or Changes should be included in the patent scope of this case. To sum up, this case is not only technically innovative, but also can be used to enhance the above-mentioned multiple effects. It should have fully met the requirements of novelty and progressive azole's statutory invention patents, and applied in accordance with the law. To approve this case, to encourage invention, to the utmost convenience. (Please read the notes on the back before filling out this page) · Binding-·

ϋ ϋ 12 I Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs

Claims (1)

5 10 2. 15 Scope of patent application 1. License plate and peak material. The main camera uses the lens 4 and the material card to lightly capture the vehicle image. The image reading unit reads the image recorded by the shadow capture card and then the pixel logarithmic gray. A straightening operation unit calculates a logarithmic gray level value for each pixel of a vehicle shirt image. A horizontal gradient calculation unit then calculates a logarithmic gray level straight horizontal degree for each pixel, and then calculates a horizontal gradient two operation unit. The real value of the water thousand gradient is converted to a binary value. Finally, the binarized horizontal gradient densest area search unit searches for the entire vehicle image according to the preset license plate length and width values. The total binarized horizontal degrees of the two regions are the two most, and then the region is cut out as the license plate region. The location of the license plate area of the vehicle image as described in item i of the patent application range, where the logarithmic grayscale value calculation unit calculates its logarithmic grayscale value for each pixel in the vehicle image. The gray value of the pixel ranges from 0 to 255. In order to avoid the mathematical operation of logarithmic operation to 0, 'Bromo' is added in the logarithmic operation. First, the gray value of the pixel is added, and the range of gray values becomes steep. The method for extracting the license plate area of a vehicle image as described in Item 1 of the patent scope, wherein the logarithmic grayscale value of the pixel at the coordinate position (x, y) in the horizontal gradient operation unit is g, (x, y) , Then the logarithmic gray level value of the pixel is a horizontal degree island [g, (x + l, y)-g, (xl, y)] / 2. The license plate area of the vehicle image as described in the first scope of the patent application A cutting method, in which the binarization operation unit of the horizontal gradient Ping 悌 -10- Chinese National Standard (CNS) A4 Specification (21ϋ X 297 male (please read the precautions on the back before filling out this page) I Binding &quot; ------- Intellectual Property aR Staff Consumption泎 Print 3.20 4 · 544643 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Λ8 heart B8 J CS D8 _____________________________________________________________ PA ^ gnpop?, ^ Ρ ,, ίΐΐ-11 / -1? F. The real value is converted to a binary value of 0 or i '. The conversion method is to set the real number of horizontal children in all Mongolian to the largest one percent and the smallest one percent. Is 1, the binarized horizontal gradient of the remaining pixels is set to 0. 5 5_The method for extracting the license plate region of a vehicle image as described in item 1 of the scope of the patent application, wherein the binarized horizontal gradient is the densest area search unit for islands Coarse search and fine search are two steps. 6. The license plate region extraction method of the vehicle image as described in item 5 of the patent application scope, wherein the coarse search of the binarized horizontal gradient densest area search unit uses the license plate length and width. Straight two The range is used as the range window frame for calculating the gradient sum. The range window frame for calculating the gradient sum is moved in the entire vehicle image and the sum of all binarized horizontal gradients in each range is calculated. The range window frame for calculating the gradient sum is calculated. Move the length of a license plate horizontally or move the width of a license plate vertically each time. From 15 in each move, find the range where the sum of the two childish horizontal gradients is the largest. Coarse search results for the unit. 7. The method for extracting the license plate area of a vehicle image as described in item 5 of the scope of the patent application, wherein the two straightened horizontal gradient densest area search unit f 糸 20 is a rough search of the binarized horizontal gradient densest area search unit Perform a fine search on the range defined by the results: use the license plate length and width value island range as the range window to calculate the gradient sum, move the range window to calculate the gradient sum in the range defined by the coarse search result and calculate the Sum of all the di-slagging levels, calculate the range of the total change window -11-(Please read the precautions on the back before filling out this page) One pack t ti n 1 —- ____ τ ____ 1 1 I Dance paper ruler The country of use of the country of origin (CNS) A4 regulations CIO: &lt; 297 kf &gt; 544643 ^ Α8906Ω8 ΑΜ1-B8 CS D8, the patent application frame moves one pixel horizontally or one pixel vertically. From each move, find a range where the sum of the binarized horizontal gradients is the largest. This range is the detailed search result of the search unit of the binarized horizontal gradient's densest area. This range is also the license plate region. --- 1 (Please read the notes on the back before filling out this page} T »4 fff n is — n 1-¾ Intellectual Property of the Ministry of Economic Affairs 咼 Employee Consumption Cooperative Press. T -12-払 The paper has been t Chinese national standard KNS) Ai specification (21〇χ 297 Male f)