!3〇25〇4 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種車距偵測的方法與裝置，尤指一種 方、仃車時，用以偵測本車與其他車輛距離的方法與裝置。 【先前技術】 由农〉飞車的普遍，使得路上車輛的密度越來越高，因 此追撞的事故亦層出不帛’為此，許多廉商針對汽車防追 撞研發了許多的設計’例如以超音波或紅外線測量前後車 的距'，或以影像操取裳置操取本車前後方車辅的影像， 經为析该影像後，卽可 土 、' > 传知本車刖後方車輛的距離，當太 車别後方車輛的距逵隹；两、^ 士 β、守，I1返即驅動一警示裝置尊告 .居士人。 巧 …取裝置偵測本車前後方車輛距離之作 4 纟針對该影像擷取裝置擷取到的影像資料進r 析，檢知出該影像資料之敕個…广像貝科進仃解 礙物個晝面中會料本車行驶之障 物应太/ 物與本車之距離，進而判斷該障礙 物與本車之距離是否小於—臨界設定值。 所一 然上述作法有幾個缺點： 1由方；—般係針對每個影像資料的整個 析’因此必須先進㈣礙物 -了解 物，以避免警示裝置莩動你也L刀駟礙物與非障礙 的一環。 乍，惟辨識障礙物往往是最耗時 2 ·由於車輛行駛的速戶一 會受到行車速度的快 又且接近障礙物的時間 又知专，因此若僅判斷障礙物與本車 3 1302504 離是否小於臨界設定值，將可能造成駕駛人反應不及 或警示裝置過度動作。 在車輛數量激增，且高速道路隨處可見的今曰，對於 車距判斷時間的要求只會越加嚴袼 视± 厭L因此如何提高影像處 的速度’進而縮短防撞裝置對於障礙物之判斷時間以及 楗南判斷之準確度，尚有待進一步之改進方案。 【發明内容】 為縮短行車距離偵測的處理速度’本發明之主要目的 在提供-種偵、測車距之方法，為達成此目的所採取之主要 ，術手段係令該方法應用於一汽車内的處理器，該汽車另 設有連接處理器之一影像擷取單元與一警示單元，其中該 處理器可擷取車速信號與煞車信號，而該方法 驟： 丨^ 程序啟動，係當車速信號換算得知的目前車速大於一 預設值時啟動； 擷取影像，係自該影像擷取單元取得影像資料； 定義目標區域’係執行一目標定義程序自該影像資料 中定義出一目標區域； 分析是否有障礙物，係判斷目標區域内是否有障礙 物； 若未有障礙物，則繼續擷取影像步驟； 若有障礙物，則推算該障礙物距離與接近時間，係計 算障礙物與本車之間的㈣以及根據車速信號預估本車接 近障礙物之所需時間； 4 1302504 'M kff與障礙物是否過於接近 所需時間是否小於一臨界值； ⑧右5亥接近障礙物所需時間大於該臨界值，則繼續擷 影像步驟； 、 止 以接近障礙物所需時間小於該臨界值，則發出警 告，係驅動該警示單元作動警告駕驶人； 口 判斷駕駛人是否踩煞車，係根據該煞車信號判斷駕駛 Ζ針對警不單元發出之警告做出反應而踩下煞車； 若是則結束，若否則繼續發出警告。 又關於本發明之另一主要目的在提供一種偵測車距之 ^ 係°又於一汽車上，而該車距偵測裝置包括·· I處11 ’可彳貞測車速信號與料信號，並内建有„ 車距偵測程序； 思, :像擷取單元，係擷取影像資料送入前述處理器； 警告4::，其:連接前述處理器，由處理器控制發出 域，貞:…分析該影像資料以定義-目標區 近本車戶”時…猶則勿，並判斷該障礙物接 元通知駕駛人。 右疋則驅動该警示單 行倩ΙΓ上述技術手段’本發明藉由先定義出目標區域再 析目」因此毋需對影像資料的整個晝面進行解析，僅八 析目標區域内是否有障礙物過於接近僅刀 可減少處理哭瞀士 如此不但 乂處理…的時間’以增加伯測的反應速度，且提 5 1302504 "'崔度令警示單元不致誤動作或過度動作。 [實施方式】 第一囷戶、本I明偵測車距之裝置的一較佳實施例，請參閱 圖了不，係裝設於一汽車上，該車距偵測裝置包括： y ϋ ^員取車速彳§號以及煞車信號之處理器 ㈣序（容後詳述）； ’ “象蝻取單元（1 2 )，係連接前述處理器（1丄）， 同應用而擷取汽車前方或後方之影像資料，於本 二：：乜’所述影像擷取“（12)係擷取汽車前方之 衫像育料以送入該處理器（1工）； 之 --替 yy. 單 — 广 70 ( 1 3 )，係連接前述處理器（1 1 ) = ”"）控制啟閉，所述警示單…2)可為 :蜂二广=或一車内顯示器，於本實施例[係採用 人。”、、。。，处理器（1 1 )控制發出警報音以警告駕駛 /亥車距偵測程序係分析影像擷取單元（1 2 )所 的影像資料，並定義出一目 ' 是否有障礙物存在，若有：二…亥目標區域中判斷 障礙物的本車接近该 - 、，1 匕界值，若是則驅動該馨示 …通知駕駿人，請進-步參閱第二圖所示，於本：；： 例中’鱗距_程序包括下列步驟： 汽& 程序啟動（300)，传去n & 口上 於-預設值時啟動；田車仏賴算得知的目前車速大 取得汽 榻取影像(301)，係自該影像擁取單元（11) 6 1302504 車前方之影像資料； 疋義目標區域（302)，係執行一目標定義程序，自該影 像資料中定義出一目標區域； ~ 分析是否有降礙物（303)，係偵測目標區域内是否有障 礙物； 右未有障礙物，則繼續擷取影像（3〇1)步驟； 右偵测到障礙物，則推算障礙物距離與接近時間〇 〇 〇 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 车 车 车 车 车 车Distance method and device. [Prior Art] The popularity of agricultural vehicles has made the density of vehicles on the road higher and higher, so the accidents of chasing are also unresolved. To this end, many low-cost businesses have developed many designs for vehicle anti-collision. For example, the distance between the front and rear vehicles is measured by ultrasonic or infrared rays, or the image of the front and rear of the vehicle is taken by the image manipulation. After analyzing the image, the soil can be smashed, '> The distance of the rear vehicle, when the distance of the vehicle behind the car is not the same; two, ^ 士 β, 守, I1 return to drive a warning device to honor. Qiao... Take the device to detect the distance between the front and rear of the vehicle. 4 纟 影像 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟 纟In the object, the obstacle that the vehicle is driving should be too far from the distance between the object and the vehicle, and then determine whether the distance between the obstacle and the vehicle is less than the critical setting value. As mentioned above, there are several shortcomings in the above practice: 1 by the party; the general analysis of the entire analysis of each image data 'There must be advanced (four) obstruction - understanding, to avoid warning devices to shake you and L-shaped obstacles and A barrier to non-obstacles. Oh, but it is often the most time-consuming to identify obstacles. · Because the speed of the vehicle is fast, it is fast and close to the obstacles. So, if you only judge the obstacle and the car 3 1302504 Less than the critical set value may cause the driver to fail to respond or the warning device to move excessively. In the current increase in the number of vehicles, and the high-speed roads everywhere, the requirements for the judgment of the distance of the vehicle will only be more severely despised. How to improve the speed of the image at the end of the road, and thus shorten the judgment time of the anti-collision device for obstacles. As well as the accuracy of the judgment in Weinan, there is still room for further improvement. SUMMARY OF THE INVENTION In order to shorten the processing speed of driving distance detection, the main purpose of the present invention is to provide a method for detecting and measuring the distance of a vehicle, and the main method for achieving this purpose is to apply the method to a vehicle. The processor further has an image capturing unit and a warning unit connected to the processor, wherein the processor can capture the speed signal and the braking signal, and the method is: 丨^ The program starts, and the speed signal is When the current speed of the conversion is greater than a preset value, the image is captured from the image capturing unit; the target area is defined to execute a target definition program, and a target area is defined from the image data; Analyze whether there is an obstacle, determine whether there is an obstacle in the target area; if there is no obstacle, continue to capture the image step; if there is an obstacle, calculate the obstacle distance and proximity time, calculate the obstacle and the original (4) between the vehicles and the estimated time required for the vehicle to approach the obstacle based on the vehicle speed signal; 4 1302504 'M kff is too close to the obstacle Whether the time is less than a critical value; 8 When the time required to approach the obstacle is greater than the threshold, then the image step is continued; if the time required to approach the obstacle is less than the threshold, a warning is issued, and the warning is driven The unit activates to warn the driver; the mouth judges whether the driver is stepping on the brake, and judges that the driver 踩 responds to the warning issued by the police unit according to the brake signal, and then presses the brake; if yes, it ends, if otherwise, the warning continues. Still another object of the present invention is to provide a method for detecting a distance between a vehicle and a vehicle, and the distance detecting device includes an '11' to detect a vehicle speed signal and a material signal. And built-in „ distance detection program; think, like the capture unit, the image data is sent to the aforementioned processor; Warning 4::, it: connect the aforementioned processor, the processor controls the issue domain, 贞:...Analyzing the image data to define - the target area is close to the owner of the car... If you do not, and judge the obstacle to inform the driver. The right-hander drives the warning single-line method. The above-mentioned technical means "the invention first defines the target area and then analyzes the object". Therefore, it is not necessary to analyze the entire surface of the image data, and only analyze whether there are obstacles in the target area. Proximity to the knife only reduces the time it takes to deal with the crying gentleman so that it does not only deal with ... to increase the speed of the beta test, and mentions 5 1302504 " 'Cui Du Ling warning unit does not cause malfunction or excessive action. [Embodiment] A preferred embodiment of the apparatus for detecting the distance between the first tenant and the first one is shown in the figure. The distance detecting device comprises: y ϋ ^ The speed of the 取 彳 煞 煞 煞 煞 煞 煞 煞 煞 煞 煞 煞 煞 处理器 ( 彳 ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( The rear image data, in this two:: 乜 'The image capture " (12) is to pick up the car in front of the car like the feed to the processor (1 work); - for yy. Single - Wide 70 (1 3 ), connected to the aforementioned processor (1 1 ) = "") to control the opening and closing, the warning list ... 2) can be: bee two wide = or an in-vehicle display, in this embodiment Adopt people.",,. . The processor (1 1 ) controls the alarm sound to warn that the driving/heling distance detection program analyzes the image data of the image capturing unit (1 2 ) and defines a target 'whether an obstacle exists, if any: In the second target area, the vehicle that judges the obstacle is close to the -, and 1 threshold, and if so, the driver is informed... notify the driver, please refer to the second figure, in this::: In the example, the 'scale' program includes the following steps: the steam & program start (300), the n & mouth is activated at the preset value; the current speed of the car is calculated to obtain the image of the steamer ( 301), from the image capturing unit (11) 6 1302504 image data in front of the vehicle; the target area (302) is a target definition program, a target area is defined from the image data; There is a hindrance (303) to detect whether there is an obstacle in the target area; if there is no obstacle on the right, continue to capture the image (3〇1) step; if the obstacle is detected on the right, the obstacle distance is estimated Approaching time
(304) ’係計算障礙物與本車之距離以及根據車速信號預估 本車接近障礙物之時間11 ; 時間 判=與障礙物是否過於接近（3G5)，係分析接近障礙物 11疋否小於一臨界值丨2 ; ^ 大方、t2，則繼續掏取影像（30 1)步驟； J、衣t2，則發出警告（3〇6)，係驅動該警示單元 1 3 )作動以警告駕駛人有障礙物接近； 判斷是否駕駛人踩煞車（307)， 駕駛人是否針對警示單元（i 3) 踩煞車； 係根據該煞車信號判斷 發出之警告做出反應而 若是則結束（308)，若否則繼續發出警告⑽）。 由上述可知，本發明由於先定義一 域中偵測有|障礙物 V區或再於該區 …、J早石旋物，因此相勒j 面，本發明^ 此相Μ知描整個影像資料晝 但令本發明較 取制’如此一來，不 度，亦降低罄亍m 〃有較仏的運算反應速 另旧於+ 块動作或過度動作之機會。 声、、4目標定義程序·之一較 貝知例’係利用比對 7 1302504 車道線作為定義基礎，定義車道線内的區域為目標 ’因此該處理器（1 1)内建有一判斷比對用的”道後 寬度值，請進一步參閱第三與第四圖所示， 忒 序包括下列步驟： ^疋義程 掃描影像資料（400)，係掃描影像資料晝面的下半 僅掃描下半部之原因在於，一船光 ° ,0 _ 舨水千裝设之影像擷取單元 (2〇)搁取晝面時’地平線如同一橫向中心線般 切割成上下兩部分，因此車道線料中於 ^面 第四圖所示）； J卜牛。p (如 初步解析車道線_)，係自掃描影像資料之書面的下 半部中選取出灰階值變化劇烈之細長區域，此舉 於車道線多為長條形狀且灰階值較高的白色或黃色，； ，則多為灰階值較低的黑色，因此在車道線與道路緊鄰^ 處，畫面的灰階值必有較大的變化； 解析車道線（402)，係自上述灰階 選取灰階值較高之具細長特徵的邻…/'、之&域中 條部分即可能是車道線； 此灰階值較高的長 ^財道線（403)，係自上述灰階值較高且具細長 之段㈣覓度d與内建標準車道線寬度值進行比^ Λ 右上述比對結果近似，則 則记錄車道線（404)，係記錄哕 車道線於影像資料畫面上之座標位置； μ 義目‘區域(4〇5) ’係定義兩 以 區域為目標區域（2〇)(如第四圖所示）。之間的 此外’關於該預估接近障礙物時間U之一計算方式實 8 1302504 施例，請參閱第五圖所示，假設影像擷取單元（丄2)與 一正刚方車輛（3 〇 )後輪的水平距離係D，而影像擷取 單元（1 2 )與本車車頭之距離係d丨，影像擷取單元（1 2 )距地面之高度係Hc，影像擷取單元（丄2 )之焦距係 f〇，另本車速度係V，因此將影像擷取單元（丄2 )、前 方車輛（3 0 )之後輪以及影像擷取單元（丄2 )對應於 地面之位置三點㈣，可得一第一直角三角形"〇)， 其中該第-直角三角形（40)之底邊長度即I D，垂直 邊長度即是He，·當影像擷取單元（丄2 )擷取畫面後，等 同於该影像擷取單元（丄2 )後方距♦ fc處所產生一假想 影像平面（5 0 )⑲影，請配合參閱第五與第六圖，由於 假想衫像+ Φ ( 5 0 )才5:影之影像係與f際影像之方向恰 好相反，因此若以該假想影像影平面（5 〇 )之縱轴下緣 作為座標原點，則於第六圖中所示之晝面巾，該座標原點 係在畫面上方’其中該假想影像平面（5 〇 )《縱軸長度 係R個單位像素，自晝面平面底端至前方車輛後輪投影： 之長度係rhv個單位像素，因此將影像擷取單元（丄2 )、 影像平面中點以及前方車輛後輪之投影點三點相連，可得 -第二直角三角形（40，），且該第一與第二直角三角形 Έ, 4 5 )( 4 0 ’）係為相似三角形，因此可由公式 =求得影像擷取單元（1 2 )與前方車輛（3 〇 )後輪的水平距離D = &*/(:/ ^ ^ /Pr*(、m)，其中Pr係每個 單位像素的高度，此外，由於影像擷取單元（丄2)與本 車車頭之距耗cn，故由此可得知，本車車頭至前方車輛 1302504 可、軍管：後輪的水平距離係d2==D-dl，配合本車速度v則 、异出接近障礙物時間tl==d2/V。 例，接近障礙物時^之另—計算方式實施 像平 ：理Μ建有-換算表，該換算表内存有該影 次料，去、之縱軸上各單位像素與其實際距離之對照 地1接:偏到有卜礙物時，即可由影像平面上障礙物盘 7心標’自該換算表中取得對應 距 每隹，再將實際距離除以本車車姑 、丨不距 、、 个早早逑即疋接近障礙物時間tl。 上述可知，本發明除利用於目標區域内進行障礙物 偵測可以軔輛66 R士叫A、 Λ〕疋叮I早％I物 •物接近時間的㈣測’且更可利用該障礙 本車所需的時門二輕易簡單地估算出障礙物接近 發明：：1Τ 本發明之運算反應速度，且由於本 知明配合則車距離與本車 + 所需之e士 Μ # 早订車速度4异出障礙物接近本車 嚴瑾，X /日-Γ ^ 、接近本車之條件更為 L堇不但可“判斷之準確度， •動作或過度動作之機會。 更了減/吕不早兀誤 惟本發明雖已於前 垂 前述實施例中所提及之肉男“1所揭露’但並不僅限於 圍内所作之任何變化與修改 Η月之精神和乾 r卜所、十、，士 句屬於本夯明之保護範圍。 ^ 發明已具備顯著功效增進，並符入菸明 專利要件，爰依法提起申請。 I付合發明(304) 'The calculation of the distance between the obstacle and the vehicle and the time to estimate the vehicle approaching the obstacle according to the vehicle speed signal 11; Time judgment = whether the obstacle is too close (3G5), whether it is close to the obstacle 11 or less than A critical value 丨2; ^ generous, t2, continue to capture image (30 1) step; J, clothing t2, then issue a warning (3〇6), drive the warning unit 1 3) to warn the driver to have Obstacle approaching; determining whether the driver is stepping on the brake (307), whether the driver is slamming the vehicle for the warning unit (i 3); responding to the warning issued by the brake signal; and if so, ending (308), if otherwise continuing Issue a warning (10)). It can be seen from the above that the present invention firstly defines the entire image data by detecting the presence of an obstacle V region in the domain or the region ..., J early stone rotation, and therefore the j surface. However, the invention is more versatile, and the 罄亍m 〃 has a lower operational response speed than the + block action or excessive action. The sound, and 4 target definition programs are better than the other examples. The system uses the comparison of the 7 1302504 lane line as the basis for definition, and defines the area within the lane line as the target. Therefore, the processor (1 1) has a built-in judgment comparison. For the "post-track width value", please refer to the third and fourth figures. The sequence includes the following steps: ^ Scanning image data (400), scanning the image data in the lower half and scanning only the lower half The reason is that a ship light °, 0 _ 舨 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千 千^图四图)); J Bu Niu.p (such as the preliminary analysis of the lane line _), from the written lower part of the scanned image data, select the slender area where the gray scale value changes drastically, this is in the lane The line is mostly white or yellow with a long strip shape and a high gray scale value;;, mostly black with a lower gray scale value, so the gray scale value of the screen must be larger at the lane line and the road immediately adjacent to the road. Change; analyze lane line (402), select from the above gray scale The adjacent part of the .../', the & field in the higher-order gray-scale value may be the lane line; the long-duration line (403) with a higher gray-scale value is derived from the above gray-scale value. The high and slender section (4) The twist d is compared with the built-in standard lane line width value ^ Λ The right comparison result is similar, then the lane line (404) is recorded, and the lane line is recorded on the image data screen. Coordinate position; μ meaning 'area (4〇5)' defines two areas with the area as the target area (2〇) (as shown in the fourth figure). In addition to the 'the estimated time to approach the obstacle U A calculation method 8 1302504 example, please refer to the fifth figure, assuming that the horizontal distance D between the image capturing unit (丄2) and the rear wheel of a positive rigid square vehicle (3 ,), and the image capturing unit ( 1 2) The distance from the front of the car is d丨, the image capturing unit (1 2) is at a height Hc from the ground, the focal length of the image capturing unit (丄2) is f〇, and the speed of the vehicle is V, so The image capturing unit (丄2), the front vehicle (30) rear wheel, and the image capturing unit (丄2) correspond to the position of the ground. Point (4), a first right triangle "quote" is obtained, wherein the length of the base of the first right triangle (40) is ID, and the length of the vertical side is He, · when the image capturing unit (丄2) captures After the screen, it is equivalent to the imaginary image plane (5 0 ) 19 shadow generated by the image capturing unit (丄2) at the back of the ♦ fc. Please refer to the fifth and sixth figures, because the imaginary shirt image + Φ ( 5 0 ) 5: The image of the shadow is exactly opposite to the direction of the f-image. Therefore, if the lower edge of the vertical axis of the imaginary image plane (5 〇) is used as the coordinate origin, the face towel shown in the sixth figure The coordinate origin is at the top of the screen, where the imaginary image plane (5 〇) "the length of the vertical axis is R unit pixels, from the bottom of the plane of the plane to the rear of the rear wheel of the vehicle: the length is rhv unit pixels, Therefore, the image capturing unit (丄2), the midpoint of the image plane, and the projection point of the rear wheel of the front vehicle are connected at three points, and the second right triangle (40,) is obtained, and the first and second right triangles are 4 5 )( 4 0 ') is a similar triangle, so it can be obtained by the formula = The horizontal distance between the image capturing unit (1 2 ) and the rear wheel of the preceding vehicle (3 〇) is D = &*/(:/ ^ ^ /Pr*(,m), where Pr is the height of each unit pixel, Since the distance between the image capturing unit (丄2) and the front of the vehicle is cn, it can be known that the front distance of the vehicle head to the front vehicle 1302504, the military tube: the horizontal distance of the rear wheel is d2==D-dl, In conjunction with the speed v of the vehicle, the time of the obstacle is close to the obstacle time tl==d2/V. For example, when approaching an obstacle, the other method is calculated. The calculation method is implemented: the conversion table has a conversion table, and the conversion table has the shadow material, and the unit pixels on the vertical axis are compared with the actual distance thereof. Connected: When there is a blockage, you can get the corresponding distance from the conversion table by the obstacle plate on the image plane. Then divide the actual distance by the car, the car, the distance, and Early in the morning, it is close to the obstacle time tl. As can be seen from the above, in addition to utilizing obstacle detection in the target area, the present invention can be used to detect the number of 66 Rs, A, Λ, 疋叮, I, and I. The required time gate 2 can easily and easily estimate the obstacle approaching the invention::1Τ The speed of the operation reaction of the present invention, and because of the knowledge of the vehicle, the distance between the vehicle and the required e-Μ# of the vehicle + is 4 different. Obstacles are close to the car, X / Γ - Γ ^, close to the conditions of the car is more than L "can not only judge the accuracy, / the opportunity of action or excessive action. More reduction / Lu not early fallacy However, the present invention has been disclosed in the foregoing description of the meat man "1" but is not limited to any changes made in the circumference and the spirit of the modification of the month and the tenth, the ten, the sentence It belongs to the scope of protection of this book. ^ The invention has achieved significant improvement in efficiency and is subject to the patent requirements of Yanming. I pay for invention
【圖式簡單說明J ::係本發明-較佳實施例之功能方塊圖。 弟二圖：係本發明中車距偵測程序之流程圖。 10 1302504 第三圖：係本發明中目標定義程序之一較佳實施例流 程圖。 第四圖：係本發明之影像擷取單元所擷取晝面之示意 圖。 第五圖：係本發明計算本車與前車距離之示意圖。 第六圖：係本發明之影像擷取單元所擷取晝面的座標 示意圖。 【主要元件符號說明】 (1 1 )處理器 （1 2 )影像擷取單元 (13)警示單元 （20)目標區域 (3 0 )前方車輛 (40)第一直角三角形 （40，）第二直角三角形 (5 0 )影像平面 11BRIEF DESCRIPTION OF THE DRAWINGS The following is a functional block diagram of a preferred embodiment of the present invention. The second figure is a flow chart of the distance detection procedure in the present invention. 10 1302504 Third drawing: A flow chart of a preferred embodiment of a target definition program in the present invention. Figure 4 is a schematic view of the image capture unit of the present invention. The fifth figure is a schematic diagram of calculating the distance between the vehicle and the preceding vehicle according to the present invention. Fig. 6 is a schematic diagram showing the coordinates of the face taken by the image capturing unit of the present invention. [Main component symbol description] (1 1 ) Processor (1 2 ) Image capturing unit (13) Warning unit (20) Target area (30) Front vehicle (40) First right triangle (40,) Second right angle Triangle (5 0 ) image plane 11