ykcheungab
45 lines
1.3 KiB
Python
45 lines
1.3 KiB
Python
import numpy as np
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from PIL import Image, ImageDraw
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# Parameters
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R = 9.0 # mm
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H = 20.0 # mm
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fov_half = np.radians(75) # 75 degrees half-angle
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pixels_per_mm = 100
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# Texture dimensions
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width = int(np.pi * 2 * R * pixels_per_mm) # circumference
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height = int(H * pixels_per_mm)
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# Desired dot pattern in image space (normalized)
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delta_theta = np.radians(10) # 10° azimuth spacing
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delta_r = 0.1 # radial spacing in normalized units
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rho = 0.08 # normalized dot radius (from reference)
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# Generate dot centers in image space
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r_vals = np.arange(R/H, np.tan(fov_half), delta_r)
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theta_vals = np.arange(0, 2*np.pi, delta_theta)
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# Create empty texture (white background)
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img = Image.new('L', (width, height), color=255)
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draw = ImageDraw.Draw(img)
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for r_img in r_vals:
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z = R / r_img
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v = z / H
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# Ellipse axes in texture coordinates
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a_u = (rho * z) / (2 * np.pi * R)
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a_v = (rho * z**2) / (R * H)
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# Convert to pixels
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a_u_px = a_u * width
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a_v_px = a_v * height
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for theta in theta_vals:
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u = theta / (2 * np.pi)
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cx = u * width
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cy = v * height
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# Draw ellipse (bounding box)
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bbox = [cx - a_u_px, cy - a_v_px, cx + a_u_px, cy + a_v_px]
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draw.ellipse(bbox, fill=0) # black dot
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img.save('cylinder_marker_texture.png')
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