A Novel Approach to Real-time Bilinear Interpolation

Gribbon, K.T.; Bailey, Donald G.

doi:10.1109/delta.2004.10055

Cited by 146 publications

(69 citation statements)

References 2 publications

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“…The integer part is used to determine the location of a 2 * 2 window for interpolation, whereas the offset is used as the weight of the interpolation. The interpolation can be operated according to (5) [15].…”

Section: Interpolationmentioning

confidence: 99%

An Improved Look-Up Table-Based FPGA Implementation of Image Warping for CMOS Image Sensors

Luo

Chong

2012

IEICE Trans. Inf. & Syst.

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SUMMARYImage warping is usually used to perform real-time geometric transformation of the images captured by the CMOS image sensor of video camera. Several existing look-up table (LUT)-based algorithms achieve real-time performance; however, the size of the LUT is still large, and it has to be stored in off-chip memory. To reduce latency and bandwidth due to the use of off-chip memory, this paper proposes an improved LUT (ILUT) scheme that compresses the LUT to the point that it can be stored in on-chip memory. First, a one-step transformation is adopted instead of using several on-line calculation stages. The memory size of the LUT is then reduced by utilizing the similarity of neighbor coordinates, as well as the symmetric characteristic of video camera images. Moreover, an elaborate pipeline hardware structure, cooperating with a novel 25-point interpolation algorithm, is proposed to accelerate the system and reduce further memory usage. The proposed system is implemented by a fieldprogrammable gate array (FPGA)-based platform. Two different examples show that the proposed ILUT achieves real-time performance with small memory usage and low system requirements.

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Section: Interpolationmentioning

confidence: 99%

An Improved Look-Up Table-Based FPGA Implementation of Image Warping for CMOS Image Sensors

Luo

Chong

2012

IEICE Trans. Inf. & Syst.

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“…Then, grid points are put into a parallax TIN, and the triangle ∆P ei P ej P ek where P egi lies is obtained. Bilinear interpolation is conducted on the parallaxes of the three vertices of the triangle [15] to obtain the initial parallax of P egi . Then 61 × 61 pixels are used as the matching window.…”

Section: Semi Patch Matching Algorithm Based On Epipolar Constraintsmentioning

confidence: 99%

UAV Low Altitude Photogrammetry for Power Line Inspection

Zhang

Yuan

Fang

et al. 2017

IJGI

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When the distance between an obstacle and a power line is less than the discharge distance, a discharge arc can be generated, resulting in the interruption of power supplies. Therefore, regular safety inspections are necessary to ensure the safe operation of power grids. Tall vegetation and buildings are the key factors threatening the safe operation of extra high voltage transmission lines within a power line corridor. Manual or laser intensity direction and ranging (LiDAR) based inspections are time consuming and expensive. To make safety inspections more efficient and flexible, a low-altitude unmanned aerial vehicle (UAV) remote-sensing platform, equipped with an optical digital camera, was used to inspect power line corridors. We propose a semi-patch matching algorithm based on epipolar constraints, using both the correlation coefficient (CC) and the shape of its curve to extract three dimensional (3D) point clouds for a power line corridor. We use a stereo image pair from inter-strip to improve power line measurement accuracy by transforming the power line direction to an approximately perpendicular to epipolar line. The distance between the power lines and the 3D point cloud is taken as a criterion for locating obstacles within the power line corridor automatically. Experimental results show that our proposed method is a reliable, cost effective, and applicable way for practical power line inspection and can locate obstacles within the power line corridor with accuracy better than ±0.5 m.

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“…First, linear interpolation is performed in one direction and then one more linear interpolation is performed in the perpendicular direction. For linear interpolation, a single interpolation kernel is: u(s) = 0 for |s| > 1 1 -|s| for |s| < 1 where s is the distance between the point to be interpolated and the grid point being considered [3] . …”

Section: A Bilinear Interpolationmentioning

confidence: 99%

A Novel Algorithm to Optimize Image Scaling in OpenCV: Emulation of Floating Point Arithmetic in Bilinear Interpolation

Subramanian¹

2012

IJCEE

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Abstract-Scaling is a complex algorithm wherein interpolation techniques are designed to achieve an optimum between factors such as efficiency and smoothness. One of these techniques is bilinear interpolation wherein the surrounding 2-by-2 source pixel values can be linearly weighed according to how close they are to the destination pixel. However, for applications in embedded systems with weak or no FPUs (floating point processors), the floating point values that arise after calculating weighted averages of the new pixel values have to be emulated. The algorithm presented to bypass floating point usage has been constructed based on the concept of resampling. It manipulates the pixels such that the fractional parts in the resulting floating numbers obtained are discrete in step, so that an optimal integer may be used to convert the floating point values to unsigned integers or signed integers by up-sampling. It has primarily been designed for scale factors, of integers which are multiples of 4 as well as the case of 2. This algorithm has been implemented in code in OpenCV and has been found to be faster and more efficient than the resize functions in OpenCV, and is therefore an alternative method to the scaling functions of the aforementioned library.

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A Novel Approach to Real-time Bilinear Interpolation

Abstract: Abstract

Cited by 146 publications

References 2 publications

An Improved Look-Up Table-Based FPGA Implementation of Image Warping for CMOS Image Sensors

An Improved Look-Up Table-Based FPGA Implementation of Image Warping for CMOS Image Sensors

UAV Low Altitude Photogrammetry for Power Line Inspection

A Novel Algorithm to Optimize Image Scaling in OpenCV: Emulation of Floating Point Arithmetic in Bilinear Interpolation

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