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fix: denoise cutout alpha masks

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134 2026-07-03 20:10:52 +08:00
parent 27b0098bf9
commit 2875b02d2a
1 changed files with 28 additions and 10 deletions
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38
app/api/canvas/local-edit/route.ts
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@ -111,7 +111,8 @@ const SCALE_ADJUST_STRUCTURE_LOCK_MIN_MASK_RATIO = 0.006;
const SCALE_ADJUST_STRUCTURE_LOCK_COMPONENT_MIN_RATIO = 0.00018;
const SCALE_ADJUST_RMBG_MIN_ALPHA_RATIO = 0.012;
const SCALE_ADJUST_RMBG_MAX_SOLID_ALPHA_RATIO = 0.92;
const SCALE_ADJUST_RMBG_ALPHA_CLEAN_THRESHOLD = 42;
const SCALE_ADJUST_RMBG_ALPHA_CLEAN_THRESHOLD = 96;
const SCALE_ADJUST_RMBG_ALPHA_MEDIAN_SIZE = 5;
const MIN_REGION_EDGE_PX = 24;
const SCALE_ADJUST_OPERATION = "scale-adjust";
type LocalEditOperation = "local-edit" | typeof SCALE_ADJUST_OPERATION;
@ -1709,23 +1710,38 @@ function getScaleAdjustAlphaBoundingBox(params: {
};
}
function cleanScaleAdjustAlphaChannel(params: {
async function cleanScaleAdjustAlphaChannel(params: {
height: number;
rawRgba: Buffer;
threshold?: number;
width: number;
}) {
const { rawRgba, threshold = SCALE_ADJUST_RMBG_ALPHA_CLEAN_THRESHOLD } = params;
const {
height,
rawRgba,
threshold = SCALE_ADJUST_RMBG_ALPHA_CLEAN_THRESHOLD,
width,
} = params;
const pixelCount = Math.floor(rawRgba.length / 4);
const initialAlpha = Buffer.alloc(pixelCount);
for (let index = 0; index < pixelCount; index += 1) {
const sourceAlpha = rawRgba[index * 4 + 3] || 0;
initialAlpha[index] = sourceAlpha >= threshold ? 255 : 0;
}
const alphaData = await sharp(initialAlpha, {
raw: { channels: 1, height, width },
})
.median(SCALE_ADJUST_RMBG_ALPHA_MEDIAN_SIZE)
.threshold(128)
.raw()
.toBuffer();
const cleanedRaw = Buffer.from(rawRgba);
const cleanedAlpha = Buffer.alloc(pixelCount);
const range = Math.max(1, 255 - threshold);
for (let index = 0; index < pixelCount; index += 1) {
const alphaIndex = index * 4 + 3;
const sourceAlpha = rawRgba[alphaIndex] || 0;
const nextAlpha =
sourceAlpha < threshold
? 0
: Math.max(0, Math.min(255, Math.round(((sourceAlpha - threshold) / range) * 255)));
const nextAlpha = alphaData[index] >= 128 ? 255 : 0;
cleanedRaw[alphaIndex] = nextAlpha;
cleanedAlpha[index] = nextAlpha;
}
@ -1807,8 +1823,10 @@ async function buildScaleAdjustRmbgStructureLockedComposite(params: {
.ensureAlpha()
.raw()
.toBuffer();
const { cleanedAlpha, cleanedRaw } = cleanScaleAdjustAlphaChannel({
const { cleanedAlpha, cleanedRaw } = await cleanScaleAdjustAlphaChannel({
height: cutoutHeight,
rawRgba: cutoutRaw,
width: cutoutWidth,
});
const cleanedCutout = await sharp(cleanedRaw, {
raw: { channels: 4, height: cutoutHeight, width: cutoutWidth },