# applyPolynomial(coefficientSegments:boundaries:destination:) Applies a set of piecewise polynomials to an 8-bit planar buffer and writes the result to a 32-bit planar buffer. ``` func applyPolynomial(coefficientSegments: [[Float]], boundaries: [Float], destination: vImage.PixelBuffer) ``` ## Parameters `coefficientSegments` An array that contains the polynomial coefficient array. Each polynomial must be of the same order. `boundaries` An array of boundary values, in increasing order, that separates adjacent ranges of pixel values. `boundaries` must contain `coefficientSegments.count + 1` elements. `destination` The destination pixel buffer. ## Discussion The following code shows an example of applying three polynomials to a [`vImage.Planar8`](/documentation/Accelerate/vImage/Planar8) buffer: ```swift let src = vImage.PixelBuffer( pixelValues: [32, 64, 128, 192, 255], size: vImage.Size(width: 5, height: 1)) let dest = vImage.PixelBuffer( size: src.size) src.applyPolynomial(coefficientSegments: [ [1, 1, 0], [0, 1, 0], [0, 0, 1] ], boundaries: [0, 1/3, 2/3, 1] as [Float], destination: dest) // Prints: // 1.0 ≅ 1 * (32 / 255)⁰ // 1.0 ≅ 1 * (64 / 255)⁰ // 0.5019608 ≅ 1 * (128 / 255)¹ // 0.56692046 ≅ 1 * (192 / 255)² // 1.0 ≅ 1 * (255 / 255)² print(dest.array) ``` ## See Also --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)