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A Relative Rotation between Two Overlapping UAV's Images Edwin Tjahjadi, Martinus; Agust, Fransisca
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 5: EECSI 2018
Publisher : IAES Indonesia Section

In this paper, we study the influence of varying baseline components on the accuracy of a relative rotation between two overlapping aerial images taken form UAV flight. The case is relevant when mosaicking UAV's aerial images by registering each individual image. Geotagged images facilitated by a navigational grade GPS receiver on board inform the camera position when taking pictures. However, these low accuracies of geographical coordinates encoded in an EXIF format are unreliable to depict baseline vector components between subsequent overlapping images. This research investigates these influences on the stability of rotation elements when the vector components are entered into a standard coplanarity condition equation to determine the relative rotation of the stereo images. Assuming a nadir looking camera on board while the UAV platform is flying at a constant height, the resulted vector directions are utilized to constraint the coplanarity equation. A detailed analysis of each variation is given. Our experiments based on real datasets confirm that the relative rotation between two successive overlapping image is practically unaffected by the accuracy of positioning method. Furthermore, the coplanarity constraint is invariant with respect to a translation along the baseline of the aerial stereo images.

Precise Wide Baseline Stereo Image Matching for Compact Digital Cameras Tjahjadi, Martinus Edwin; Handoko, Fourry
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 4: EECSI 2017
Publisher : IAES Indonesia Section

NumerousÂ image Â matching Â methods Â for Â wide range Â of Â applications Â have Â been Â inventedÂ in Â the Â last Â decade. When high precision Â and reliability Â of the Â object spaceÂ point coordinates Â is Â highly Â demanding,Â a Â stereo Â image Â matching method which can produce conjugate point of images and a standard deviation of Â the Â matched pointÂ is Â examined. InÂ this approach, image gradients are used locally to seek a conjugate patch. Â The Â normalizedÂ cross Â correlation Â is Â first Â utilized Â to estimate an approximate location of the conjugate patch between two normalized images. Then the location of conjugate patch is further refined by using Gaussian-Newton least squares image matching. Both radiometric and geometric parameters of least squares models are used selectively in seeking the best possible accuracy.Â Iterative Â computation is Â conducted toÂ incrementally refine the geometric location of the conjugate point. After a matched patch has been found, a variant-covariant matrix of the parameter is analyzed to inform the precision of the conjugate points Â both Â on Â images Â and Â object Â space. Â This Â methodÂ can compute high precision object space points and some examples demonstrate the insight of the approach.

Single Frame Resection of Compact Digital Cameras for UAV Imagery Tjahjadi, Martinus Edwin; Handoko, Fourry
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 4: EECSI 2017
Publisher : IAES Indonesia Section

Recently, UAVs (Unmanned Aerial Vehicles) gaina wider acceptance from many disciplines. One major applicationis for monitoring and mapping. Flying beyond eye sightautonomously and collecting data over large areas are theirobvious advantages. To support a large scale urban city mapping,we have developed a UAV system which can carry a compactdigital camera as well as a navigational grade of a GlobalPositioning System (GPS) board mounted on the vehicle.Unfortunately, such a navigational system fails to providesufficient accuracy required to process images become a largescale map. Ubiquitous digital compact cameras, despite their lowcost benefits, are widely known to suffer instabilities in theirinternal lenses and electronics imaging system. Hence thesecameras are less suitable for mapping related purposes. However,this paper presents a photogrammetric technique to preciselydetermine intrinsic and extrinsic camera parameters ofphotographed images provided that sufficient numbers ofsurveyed control points are available. A rigorous Mathematicalmodel is derived to compute each image position with respect tothe imaging coordinate system as well as a location of theprincipal point of an image sensor and the focal length of thecamera. An iterative Gaussian-Newton least squares adjustmentmethod is utilized to compute those parameters. Finally, surveyeddata are processed and elaborated to justify the mathematicalmodels.

Novel Image Mosaicking of UAV’s Imagery using Collinearity Condition Martinus Edwin Tjahjadi; Fourry Handoko; Silvester Sari Sai
International Journal of Electrical and Computer Engineering (IJECE) Vol 7, No 3: June 2017
Publisher : Institute of Advanced Engineering and Science

This paper presents a preliminary result of ongoing research on unmanned aerial vehicle (UAV) for cooperative mapping to support a large-scale urban city mapping, in Malang, Indonesia. A small UAV can carry an embedded camera which can continuously take pictures of landscapes. A convenient way of monitoring landscape changes might be through accessing a sequence of images. However, since the camera’s field of view is always smaller than human eye’s field of view, the need to combine aerial pictures into a single mosaic is eminent. Through mosaics, a more complete view of the scene can be accessed and analyzed. A semi-automated generation of mosaics is investigated using a photogrammetric approach, namely a perspective projection which is based on collinearity condition. This paper reviews the general projection model based on collinearity condition and uses that to determine a common projective plane from images. The overlapped points for each RGB channel are interpolated onto that of orthographic plane to generate mosaics. An initial attempt shows a promising result.

Pembuatan Model 3D Jalan Raya Bayat Untuk Keperluan Existing Menggunakan Metode Foto Udara (UAV) di Klaten Dwiki Altito Priambodo; Martinus Edwin Tjahjadi; Ketut Tomy Suhari
TERAS JURNAL Vol 12, No 1 (2022): Volume 12 Nomor 1, Maret 2022
Publisher : UNIVERSITAS MALIKUSSALEH

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29103/tj.v12i1.654

Abstrak Penggunaan teknologi pada geodesi serta geomatika, yaitu teknologi fotogrametri udara unmanned aerial vehicle (UAV) dapat berguna dalam mengetahui kondisi jalan raya terkini. Untuk mengetahui hal tersebut, dapat dilakukan pembuatan suatu model 3 dimensi jalan raya, sehingga mendapatkan informasi-informasi terkini dari jalan raya. Penggunaan teknologi tersebut digunakan agar memperoleh data yang digunakan dalam pembuatan model 3 dimensi. Pembuatan model tersebut dilakukan menggunakan metode level of detail (LoD)0-3 jalan raya dan dilakukan perhitungan uji validasi geometrik jalan raya, yaitu lebar jalan raya mencakup perhitungan nilai root mean square error (RMSE) serta standar deviasi. Penelitian ini memperoleh visualisasi model 3 dimensi jalan raya, kemampuan foto udara hanya mengidentifikasi objek jalan dalam pembuatan model 3 dimensi jalan raya, dan hasil uji validasi geometrik jalan raya dengan RMSE 0.0455141 meter (lapangan dengan foto), 0.155467038 meter (lapangan dengan model), serta standar deviasi 0.078829245 meter (lapangan dengan foto), 0.310609926 meter (lapangan dengan model). Visualisasi model 3 dimensi jalan raya dengan metode level of detail (LoD)0-3 telah dilaksanakan. Kemampuan foto udara hanya mengidentifikasi objek jalan pada pembuatan model 3 dimensi jalan raya. Hasil pemodelan 3 dimensi jalan raya dilakukan uji validasi untuk mengetahui kedekatannya dengan model sebenarnya. Kata kunci: jalan raya, 3 dimensi, level of detail, validasi, Abstract The use of technology in geodesy and geomatics, that’s aerial photogrammetry technology using an unmanned aerial vehicle (UAV) useful to realize the current roadway condition. To find out, making a roadway 3-dimensional model is done, so that’s the current of roadway information. That technology is used to obtain data in the manufacturing 3-dimensional model. The modeling was performed using the level of detail (LoD)0-3 method of the roadway and performed the calculation roadway geometrics validation test, that’s the width of roadway including the calculation of root mean square error (RMSE) and standard deviation. This study obtained a visualization of roadway 3-dimensional model, the ability of aerial photo to only identification of roadway object in the manufacture of a 3-dimensional model, and the results of the test with RMSE 0.0455141 meters (field with photos), 0.155467038 meters (field with model), and standard deviation 0.078829245 meters (field with photos), 0.310609926 meters (field with model). The visualization of roadway 3-dimensional model with the level of detail (LoD)0-3 method already implemented. The ability of aerial photos to only identification of roadway objects in the manufacture of roadway 3-dimensional model. The 3-dimensional models of the roadway model are validated to determine its proximity to the actual model. Keywords: roadway, 3-dimensional, level of detail, validation

Aplikasi Metode Object Based Image Analysis (OBIA) untuk Identifikasi Atap Bangunan Alifah Noraini; I Nyoman Sudiasa; Martinus Edwin Tjahjadi
Poltanesa Vol 22 No 1 (2021): Juni 2021
Publisher : P2M Politeknik Pertanian Negeri Samarinda

Salah satu permasalahan dalam proses pembuatan peta skala besar adalah belum terdapat metode ekstraksi objek secara otomatis, sehingga dijitasi secara manual masih dilakukan. Metode ekstraksi objek secara otomatis diharapkan dapat mempercepat pemetaan skala besar. Di Indonesia, pemetaan skala besar digunakan untuk penyusunan Rencana Detil Tata Ruang (RDTR) Kota/ Kabupaten. Objek detil yang terdapat dalam dokumen RDTR tersebut adalah bangunan. Tujuan dilakukan penelitian ini adalah identifikasi atap bangunan menggunakan metode klasifikasi berbasis objek. Data yang digunakan berupa citra foto udara. Dilakukan proses segmentasi menggunakan algoritma multiresolusi dengan parameter segmentasi skala, bentuk, dan kekompakan Setelah proses segmentasi, dilakukan proses klasifikasi menggunakan metode nearest neighbor. Hasil penelitian menunjukkan bahwa masih terdapat kesalahan dalam proses klasifikasi objek. Atap bangunan tidak teridentfikasi secara keseluruhan dalam kelas objek bangunan.

Fast and stable direct relative orientation of UAV-based stereo pair Martinus Edwin Tjahjadi; Fransisca Dwi Agustina
International Journal of Advances in Intelligent Informatics Vol 5, No 1 (2019): March 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26555/ijain.v5i1.327

Coplanarity-based relative orientation (RO) is one of the most crucial processes to obtain reliable 3D model and point clouds in Computer Vision and Photogrammetry community. Whilst a classical and rigorous procedure requires very close approximate values of five independent parameters, a direct method needs additional constraints to solve the parameters. This paper proposes a new approach that facilitates a very fast but stable and accurate solution from five point correspondences between two overlapping aerial images taken form unmanned aerial vehicle (UAV) flight. Furthermore, if 3D coordinates of perspective centers are available form geotagged images, rotational elements of the RO parameters can be quickly solved using three correspondences only. So it is very reliable for a provision of closed-form solutions for the rigorous methods. Our formulation regards Thompson’s parameterizations of Euler angles in composing a coplanarity condition. Nonlinear terms are subsequently added into a stereo parallax within a constant term under a linear least squares criteria. This strategy is considered new as compared with the known literatures since the proposed approach can find optimal solution. Results from real datasets confirm that our method produces a fast, stable and reliable linear solution by using at least five correspondences or even only three conjugate points of geotagged image pairs.

Precise Wide Baseline Stereo Image Matching for Compact Digital Cameras Martinus Edwin Tjahjadi; Fourry Handoko
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 4: EECSI 2017
Publisher : IAES Indonesia Section

Numerous image matching methods for wide range of applications have been invented in the last decade. When high precision and reliability of the object space point coordinates is highly demanding, a stereo image matching method which can produce conjugate point of images and a standard deviation of the matched point is examined. In this approach, image gradients are used locally to seek a conjugate patch. The normalized cross correlation is first utilized to estimate an approximate location of the conjugate patch between two normalized images. Then the location of conjugate patch is further refined by using Gaussian-Newton least squares image matching. Both radiometric and geometric parameters of least squares models are used selectively in seeking the best possible accuracy. Iterative computation is conducted to incrementally refine the geometric location of the conjugate point. After a matched patch has been found, a variant-covariant matrix of the parameter is analyzed to inform the precision of the conjugate points both on images and object space. This method can compute high precision object space points and some examples demonstrate the insight of the approach.

Single Frame Resection of Compact Digital Cameras for UAV Imagery Martinus Edwin Tjahjadi; Fourry Handoko
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 4: EECSI 2017
Publisher : IAES Indonesia Section

Recently, UAVs (Unmanned Aerial Vehicles) gaina wider acceptance from many disciplines. One major applicationis for monitoring and mapping. Flying beyond eye sightautonomously and collecting data over large areas are theirobvious advantages. To support a large scale urban city mapping,we have developed a UAV system which can carry a compactdigital camera as well as a navigational grade of a GlobalPositioning System (GPS) board mounted on the vehicle.Unfortunately, such a navigational system fails to providesufficient accuracy required to process images become a largescale map. Ubiquitous digital compact cameras, despite their lowcost benefits, are widely known to suffer instabilities in theirinternal lenses and electronics imaging system. Hence thesecameras are less suitable for mapping related purposes. However,this paper presents a photogrammetric technique to preciselydetermine intrinsic and extrinsic camera parameters ofphotographed images provided that sufficient numbers ofsurveyed control points are available. A rigorous Mathematicalmodel is derived to compute each image position with respect tothe imaging coordinate system as well as a location of theprincipal point of an image sensor and the focal length of thecamera. An iterative Gaussian-Newton least squares adjustmentmethod is utilized to compute those parameters. Finally, surveyeddata are processed and elaborated to justify the mathematicalmodels.

A Relative Rotation between Two Overlapping UAV's Images Martinus Edwin Tjahjadi; Fransisca Agust
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 5: EECSI 2018
Publisher : IAES Indonesia Section

In this paper, we study the influence of varying baseline components on the accuracy of a relative rotation between two overlapping aerial images taken form UAV flight. The case is relevant when mosaicking UAV's aerial images by registering each individual image. Geotagged images facilitated by a navigational grade GPS receiver on board inform the camera position when taking pictures. However, these low accuracies of geographical coordinates encoded in an EXIF format are unreliable to depict baseline vector components between subsequent overlapping images. This research investigates these influences on the stability of rotation elements when the vector components are entered into a standard coplanarity condition equation to determine the relative rotation of the stereo images. Assuming a nadir looking camera on board while the UAV platform is flying at a constant height, the resulted vector directions are utilized to constraint the coplanarity equation. A detailed analysis of each variation is given. Our experiments based on real datasets confirm that the relative rotation between two successive overlapping image is practically unaffected by the accuracy of positioning method. Furthermore, the coplanarity constraint is invariant with respect to a translation along the baseline of the aerial stereo images.

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