遙感原理與應(yīng)用ppt課件-文庫吧資料
2025-05-10 13:40本頁面
【正文】 而改善圖像質(zhì)量的圖像處理方法。 ?方法演示 Colour Composites ? A colour posite is a colour image produced through optical bination of multiband images by projection through filters. ? True Colour Composite: A colour imaging process whereby the colour of the image is the same as the colour of the object imaged. ? False Colour Composite: A colour imaging process which produces an image of a colour that does not correspond to the true colour of the scene (as seen by our eyes). 48 TM1 TM2 TM3 TM4 TM5 TM6 TM7 Landsat TM 5 subscene showing the region around the Alpinforschungszentrum Rudolfsh252。 ③ 處理過程 ④ 效果分析 單波段彩色變換（假彩色密度分割） 多波段色彩變換 ?概念： 利用計(jì)算機(jī)將同一地區(qū)不同波段的圖像存放在不同通道的存儲(chǔ)器中，并依照彩色合成原理，分別對(duì)各通道的圖像進(jìn)行單基色變換，在彩色屏幕上進(jìn)行疊置，從而構(gòu)成彩色合成圖像。這種方法又叫 密度分割。 38 Image Enhancement ? Enhancements are used to make it easier for visual interpretation and understanding of imagery. ? The advantage of digital imagery is that it allows us to manipulate the digital pixel values in an image ? There are three main types of image enhancement: – Contrast enhancement – Spatial feature enhancement – Multiimage enhancement 第三節(jié) 遙感數(shù)字圖像增強(qiáng) 一、彩色變換 ? 把數(shù)字圖像組合轉(zhuǎn)換成 彩色圖形 ，或者把各種增強(qiáng)或分類圖像組合疊加，以 彩色圖像 顯示出來。 ? 特征變化大的地區(qū)應(yīng)多選些。 幾何畸變校正 ④ 控制點(diǎn)的選取 (P111) ? 數(shù)目的確定 :最小數(shù)目； 6倍于最小數(shù)目。 ② 具體步驟 1）計(jì)算校正后每一點(diǎn)所對(duì)應(yīng)原圖中的位置； 2）計(jì)算每一點(diǎn)的亮度值。 ⑤ 地球自轉(zhuǎn)的影響： 產(chǎn)生影像偏離。 ③ 地球表面曲率的影響： 一是像點(diǎn)位置的移動(dòng)；二是像元對(duì)應(yīng)于地面寬度不等，距星下點(diǎn)愈遠(yuǎn)畸變愈大，對(duì)應(yīng)地面長(zhǎng)度越長(zhǎng)。 and, the curvature and rotation of the Earth. ? Geometric corrections are intended to pensate for these distortions so that the geometric representation of the imagery will be as close as possible to the real world. ? The geometric registration process involves identifying the image coordinates (. row, column) of several clearly discernible points, called ground control points (or GCPs), in the distorted image (A A1 to A4), and matching them to their true positions in ground coordinates (. latitude, longitude). ? The true ground coordinates are typically measured from a map (B B1 to B4), either in paper or digital format. 遙感影像變形的原因 ① 遙感平臺(tái)位置和運(yùn)動(dòng)狀態(tài)變化的影響： 航高、航速、俯仰、翻滾、偏航。 – the platform altitude, and velocity。 – the motion of the scanning sy
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