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pixel scale for frame widening

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Roz K
2025-09-17 20:59:34 +02:00
parent e6c417f0f6
commit 1385b3e6f3
2 changed files with 2 additions and 37 deletions
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36
gopro_8:7/compute_gopro_8:7.py
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@ -1,36 +0,0 @@
# RozK
# Computes fisheye removal parameters for GoPro 11+, 8:7 ratio, without hypersmooth,
# keeping the vertical FOV and widening the frame to preserve the diagonal FOV
# https://www.bobatkins.com/photography/technical/field_of_view.html
# https://community.gopro.com/s/article/HERO11-Black-Mini-Digital-Lenses-FOV-Information?language=fr
import math
frame_width = 8
frame_height = 7
input_ratio = frame_width / frame_height
input_vertical_fov = 108.0
input_diagonal_fov = 156.0
input_vertical_length = math.radians(input_vertical_fov * 0.5)
input_diagonal_length = math.radians(input_diagonal_fov * 0.5)
output_horizontal_length = math.sqrt((input_diagonal_length ** 2) / (input_vertical_length ** 2))
output_diagonal_length = math.hypot(output_horizontal_length, input_vertical_length)
output_diagonal_fov = math.degrees(math.atan(output_diagonal_length)) * 2.0
output_ratio = 1.0 / (output_horizontal_length / input_vertical_length)
print("Output FOV = %f" % output_diagonal_fov)
print("Output Ratio = %f" % output_ratio)
print("= Resolutions =====================")
def width_rounded_8(height):
width = int(round(height * input_ratio))
return ((width + 4) // 8) * 8
print("HD = %i x 720" % width_rounded_8(720))
print("Full HD = %i x 1080" % width_rounded_8(1080))
print("4K = %i x 2160" % width_rounded_8(2160))

3
gopro_8:7/unfish_gopro_8:7.glsl
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@ -21,6 +21,7 @@ uniform float pts;
const vec2 sensor_dimensions = vec2(5.949440, 5.205760); const vec2 sensor_dimensions = vec2(5.949440, 5.205760);
const float fisheye_focal_length = 2.92; const float fisheye_focal_length = 2.92;
const float rectilinear_focal_length = 2.102263; const float rectilinear_focal_length = 2.102263;
const vec2 pixel_scale = vec2(0.871558, 1.0);
const int subsampling = 4; const int subsampling = 4;
// constants // constants
@ -37,7 +38,7 @@ vec2 sensor_to_texture;
void initialize() { void initialize() {
texture_center = myResolution * 0.5; texture_center = myResolution * 0.5;
texture_to_sensor = (sensor_dimensions / myResolution); texture_to_sensor = (sensor_dimensions / myResolution) * pixel_scale;
sensor_to_texture = (myResolution / sensor_dimensions); sensor_to_texture = (myResolution / sensor_dimensions);
} }