Program Studi S-1 Teknik Informatika FMIPA Universitas Padjadjaran

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1 D10K-6C01 Pengolahan Citra PCD-06 Algoritma Pengolahan Citra 3 Geometry Process
Program Studi S-1 Teknik Informatika FMIPA Universitas Padjadjaran Semester Genap

2 GEOMETRIC PROCESS Geometric Processes modify the arrangement of pixels based on some geometric transformation Topik Bahasan Forward Mapping vs Reverse Mapping Transformasi Geometrik Dasar Skala Rotasi Translasi

3 ILUSTRASI DAN LINKS Simple Image Processing

4 Ilustrasi Klasik

5 Algorithms Pixel art scaling algorithms Efficiency
EPX/Scale2×/AdvMAME2× Scale3×/AdvMAME3× and ScaleFX Eagle 2×SaI Super 2×SaI and Super Eagle hqnx family xBR family RotSprite Kopf–Lischinski SuperRes EDIUpsizer FastEDIUpsizer eedi3 EEDI2 NEDI NNEDI NNEDI2 ChromaNEDI NNEDI3 SuperChromaRes Waifu2x

6 TRANSFORMASI GEOMETRIK

7 FORWARD MAPPING vs REVERSE MAPPING
Forward mapping adalah suatu teknik pemetaan piksel yang mentransformasikan piksel input ke piksel output melalui fungsi pemetaan x dan y Problem dalam FM: holes dan overlap Holes merupakan piksel yang tak terdefinisi, dimana piksel output tidak memiliki piksel koresponden pada citra input Overlap timbul pada saat sebuah piksel output memiliki rujukan pada lebih dari satu piksel input Bagiamana meng-eliminasi problem tersebut ? Dengan Reverse Mapping Teknik yang digunakan: Interpolasi Jenis Interpolasi: Nearest Neighbor, Bilinear, Higher Order, Cubic Convolution, B-Spline

8 ILUSTRASI

9 CONTOH HASIL FORWARD MAPPING

10 Istilah Resampling is the mathematical technique used to create a new version of the image with a different width and/or height in pixels. Increasing the size of an image is called upsampling; reducing its size is called downsampling.

11 INTERPOLASI Interpolasi (secara matematis) Ilustrasi
interpolation is a method of constructing new data points within the range of a discrete set of known data points. Metode untuk menentukan titik data baru menggunakan titik data yang diketahui sebelumnya Ilustrasi

12 INTERPOLASI CITRA Interpolasi Tanpa Interpolasi
Pengolahan Citra Dijital

13 Image Rotation

14 INTERPOLASI Mengapa diperlukan?
We want BIG images When we see a video clip on a PC, we like to see it in the full screen mode We want GOOD images If some block of an image gets damaged during the transmission, we want to repair it We want COOL images Manipulate images digitally can render fancy artistic effects as we often see in movies Metode: Nearest Neighbour, Bilinier, Bicubic Penggunaan Digital zooming (resolution enhancement) Image inpainting (error concealment) Geometric transformations (where your imagination can fly)

15 INTERPOLASI Resolution Enhancement Image Inpainting Image Warping

16 ANTI ALIASING Anti-aliasing is a process which attempts to minimize the appearance of aliased or jagged diagonal edges, termed "jaggies." These give text or images a rough digital appearance:

17 OPTICAL ZOOM vs DIGITAL ZOOM
Most of digital cameras can perform both an optical and a digital zoom. A camera performs an optical zoom by moving the zoom lens so that it increases the magnification of light before it even reaches the digital sensor. In contrast, a digital zoom degrades quality by simply interpolating the image — after it has been acquired at the sensor. 10x Digital Zoom 10x Optical Zoom

18 Types of Interpolation Algorithm
Common interpolation algorithms can be grouped into two categories: adaptive and non-adaptive. Adaptive methods change depending on what they are interpolating (sharp edges vs. smooth texture) proprietary algorithms in licensed software : Qimage, PhotoZoom Pro, Genuine Fractals and others. Non-adaptive methods treat all pixels equally. nearest neighbor, bilinear, bicubic, spline, sinc, lanczos and others

19 JENIS-JENIS INTERPOLASI
Pixel replication Bilinear Bicubic Edge-Directed Interpolation Polynomial Interpolation Lagrange Newton Natural Splines Bezier Splines, Cubic Splines

20 CONTOH INTERPOLASI Pixel Replication low-resolution image (100×100)
high-resolution image (400×400)

21 Bilinear Interpolation
CONTOH INTERPOLASI Bilinear Interpolation low-resolution image (100×100) high-resolution image (400×400)

22 CONTOH INTERPOLASI Bicubic Interpolation low-resolution
image (100×100) high-resolution image (400×400)

23 Edge-Directed Interpolation, (Li&Orchard’2000)
CONTOH INTERPOLASI low-resolution image (100×100) high-resolution image (400×400)

24 CONTOH LAIN

25 CONTOH LAIN

26 Pengolahan Citra Dijital
CONTOH LAIN Pengolahan Citra Dijital

27 TRANSLATION

28 PERHITUNGAN NUMERIS INTERPOLASI
Nearest Neighbor Translasi 1.7 piksel

29 PERHITUNGAN NUMERIS INTERPOLASI
Bilinear Translasi 0.5 piksel

30 PERHITUNGAN NUMERIS INTERPOLASI
Bicubic Translasi 0.5 piksel

31 Error Concealment/Penghilangan Noise
interpolated damaged

32 Image Mosaicing/Penggabungan Citra

33 Geometric Transformation

34 SCALING Memperbesar : enlarging, magnification, scaling up, zooming, upsampling, stretching, zoom-in Memperkecil : shrinking, scaling down, decimation, downsampling, minification, zoom-out hal yang perlu diperhatikan pada proses penskalaan: Resolusi citra tidak bisa ditingkatkan Jumlah piksel yang dimiliki tidak lebih daripada jumlah yang ada pada citra asli Selalu ada degradasi citra Dalam memperbesar, holes harus diisi dengan nilai piksel tertentu melalui interpolasi ataupun educated guest Dalam memperkecil, ada piksel-piksel yang dihilangkan melalui cara perataan (averaging)

35 TEKNIK SCALING Pembesaran Pengecilan Pixel replication
Median Representation Average Representation

36 MINIFIKASI

37 ILUSTRASI SCALE a=1/2

38 ILUSTRASI SHEAR

39 ROTASI TRANSLASI MIRRORING
Formula Jika angle kelipatan 90° maka rotasi dapat dilakukan lebih sederhana (tanpa operasi floating-point) dengan cara transposisi Translasi Proses move piksel, bukan copy piksel Mirroring Flip pada sumbu x atau sumbu y Horizontal mirroring ~ flip pada sumbu y Vertical mirroring ~ flip pada sumbu x

40 ROTASI

41 CONTOH ROTASI θ=3o

42 Ilustrasi Program