llama.cpp/tools/mtmd/mtmd-image.cpp

1167 lines
49 KiB
C++

#include "mtmd-image.h"
#include <algorithm>
#include <cmath>
#include <vector>
//
// base implementation
//
void mtmd_image_preprocessor::img_u8_to_f32(const clip_image_u8 & src, clip_image_f32 & dst, const float mean[3], const float std[3]) {
dst.nx = src.nx;
dst.ny = src.ny;
dst.buf.resize(src.buf.size());
// TODO @ngxson : seems like this could be done more efficiently on cgraph
for (size_t i = 0; i < src.buf.size(); ++i) {
int c = i % 3; // rgb
dst.buf[i] = (static_cast<float>(src.buf[i]) / 255.0f - mean[c]) / std[c];
}
}
void mtmd_image_preprocessor::img_u8_to_f32(const clip_image_u8 & src, clip_image_f32 & dst) {
dst.nx = src.nx;
dst.ny = src.ny;
dst.buf.resize(src.buf.size());
for (size_t i = 0; i < src.buf.size(); ++i) {
dst.buf[i] = static_cast<float>(src.buf[i]);
}
}
// set of tools to manipulate images
// in the future, we can have HW acceleration by allowing this struct to access 3rd party lib like imagick or opencv
struct img_tool {
static void resize(
const clip_image_u8 & src,
clip_image_u8 & dst,
const clip_image_size & target_resolution,
resize_algo algo,
bool add_padding = true, // TODO: define the behavior for add_padding = false
std::array<uint8_t, 3> pad_color = {0, 0, 0}) {
dst.nx = target_resolution.width;
dst.ny = target_resolution.height;
dst.buf.resize(3 * dst.nx * dst.ny);
if (dst.nx == src.nx && dst.ny == src.ny) {
// no resize needed, simple copy
dst.buf = src.buf;
return;
}
if (!add_padding) {
// direct resize
switch (algo) {
case RESIZE_ALGO_BILINEAR:
resize_bilinear(src, dst, target_resolution.width, target_resolution.height);
break;
case RESIZE_ALGO_BICUBIC:
resize_bicubic(src, dst, target_resolution.width, target_resolution.height);
break;
case RESIZE_ALGO_BICUBIC_PILLOW:
resize_bicubic_pillow(src, dst, target_resolution.width, target_resolution.height);
break;
default:
throw std::runtime_error("Unsupported resize algorithm");
}
} else {
// resize with padding
clip_image_u8 resized_image;
float scale_w = static_cast<float>(target_resolution.width) / src.nx;
float scale_h = static_cast<float>(target_resolution.height) / src.ny;
float scale = std::min(scale_w, scale_h);
int new_width = std::min(static_cast<int>(std::ceil(src.nx * scale)), target_resolution.width);
int new_height = std::min(static_cast<int>(std::ceil(src.ny * scale)), target_resolution.height);
switch (algo) {
case RESIZE_ALGO_BILINEAR:
resize_bilinear(src, resized_image, new_width, new_height);
break;
case RESIZE_ALGO_BICUBIC:
resize_bicubic(src, resized_image, new_width, new_height);
break;
case RESIZE_ALGO_BICUBIC_PILLOW:
resize_bicubic_pillow(src, resized_image, new_width, new_height);
break;
default:
throw std::runtime_error("Unsupported resize algorithm");
}
// fill dst with pad_color
fill(dst, pad_color);
int offset_x = (target_resolution.width - new_width) / 2;
int offset_y = (target_resolution.height - new_height) / 2;
composite(dst, resized_image, offset_x, offset_y);
}
}
static void crop(const clip_image_u8 & image, clip_image_u8 & dst, int x, int y, int w, int h) {
dst.nx = w;
dst.ny = h;
dst.buf.resize(3 * w * h);
for (int i = 0; i < h; ++i) {
for (int j = 0; j < w; ++j) {
int src_idx = 3 * ((y + i)*image.nx + (x + j));
int dst_idx = 3 * (i*w + j);
dst.buf[dst_idx] = image.buf[src_idx];
dst.buf[dst_idx + 1] = image.buf[src_idx + 1];
dst.buf[dst_idx + 2] = image.buf[src_idx + 2];
}
}
}
// calculate the size of the **resized** image, while preserving the aspect ratio
// the calculated size will be aligned to the nearest multiple of align_size
// if H or W size is larger than longest_edge, it will be resized to longest_edge
static clip_image_size calc_size_preserved_ratio(const clip_image_size & inp_size, const int align_size, const int longest_edge) {
GGML_ASSERT(align_size > 0);
if (inp_size.width <= 0 || inp_size.height <= 0 || longest_edge <= 0) {
return {0, 0};
}
float scale = std::min(static_cast<float>(longest_edge) / inp_size.width,
static_cast<float>(longest_edge) / inp_size.height);
float target_width_f = static_cast<float>(inp_size.width) * scale;
float target_height_f = static_cast<float>(inp_size.height) * scale;
auto ceil_by_factor = [f = align_size](float x) { return static_cast<int>(std::ceil(x / static_cast<float>(f))) * f; };
int aligned_width = ceil_by_factor(target_width_f);
int aligned_height = ceil_by_factor(target_height_f);
return {aligned_width, aligned_height};
}
// calculate the size of the **resized** image, while preserving the aspect ratio
// the calculated size will have min_pixels <= W*H <= max_pixels
// this is referred as "smart_resize" in transformers code
static clip_image_size calc_size_preserved_ratio(const clip_image_size & inp_size, const int align_size, const int min_pixels, const int max_pixels) {
GGML_ASSERT(align_size > 0);
const int width = inp_size.width;
const int height = inp_size.height;
auto round_by_factor = [f = align_size](float x) { return static_cast<int>(std::round(x / static_cast<float>(f))) * f; };
auto ceil_by_factor = [f = align_size](float x) { return static_cast<int>(std::ceil(x / static_cast<float>(f))) * f; };
auto floor_by_factor = [f = align_size](float x) { return static_cast<int>(std::floor(x / static_cast<float>(f))) * f; };
// always align up first
int h_bar = std::max(align_size, round_by_factor(height));
int w_bar = std::max(align_size, round_by_factor(width));
if (h_bar * w_bar > max_pixels) {
const auto beta = std::sqrt(static_cast<float>(height * width) / max_pixels);
h_bar = std::max(align_size, floor_by_factor(height / beta));
w_bar = std::max(align_size, floor_by_factor(width / beta));
} else if (h_bar * w_bar < min_pixels) {
const auto beta = std::sqrt(static_cast<float>(min_pixels) / (height * width));
h_bar = ceil_by_factor(height * beta);
w_bar = ceil_by_factor(width * beta);
}
return {w_bar, h_bar};
}
// draw src image into dst image at offset (offset_x, offset_y)
static void composite(clip_image_u8 & dst, const clip_image_u8 & src, int offset_x, int offset_y) {
for (int y = 0; y < src.ny; ++y) {
for (int x = 0; x < src.nx; ++x) {
int dx = x + offset_x;
int dy = y + offset_y;
// skip pixels that would be out of bounds in the destination
if (dx < 0 || dy < 0 || dx >= dst.nx || dy >= dst.ny) {
continue;
}
size_t dst_idx = 3 * (static_cast<size_t>(dy) * dst.nx + static_cast<size_t>(dx));
size_t src_idx = 3 * (static_cast<size_t>(y) * src.nx + static_cast<size_t>(x));
dst.buf[dst_idx + 0] = src.buf[src_idx + 0];
dst.buf[dst_idx + 1] = src.buf[src_idx + 1];
dst.buf[dst_idx + 2] = src.buf[src_idx + 2];
}
}
}
// fill the image with a solid color
static void fill(clip_image_u8 & img, const std::array<uint8_t, 3> & color) {
for (size_t i = 0; i < img.buf.size(); i += 3) {
img.buf[i] = color[0];
img.buf[i + 1] = color[1];
img.buf[i + 2] = color[2];
}
}
private:
// Bilinear resize function
static void resize_bilinear(const clip_image_u8 & src, clip_image_u8 & dst, int target_width, int target_height) {
dst.nx = target_width;
dst.ny = target_height;
dst.buf.resize(3 * target_width * target_height);
float x_ratio = static_cast<float>(src.nx - 1) / target_width;
float y_ratio = static_cast<float>(src.ny - 1) / target_height;
for (int y = 0; y < target_height; y++) {
for (int x = 0; x < target_width; x++) {
float px = x_ratio * x;
float py = y_ratio * y;
int x_floor = static_cast<int>(px);
int y_floor = static_cast<int>(py);
float x_lerp = px - x_floor;
float y_lerp = py - y_floor;
for (int c = 0; c < 3; c++) {
float top = lerp(
static_cast<float>(src.buf[3 * (y_floor * src.nx + x_floor) + c]),
static_cast<float>(src.buf[3 * (y_floor * src.nx + (x_floor + 1)) + c]),
x_lerp
);
float bottom = lerp(
static_cast<float>(src.buf[3 * ((y_floor + 1) * src.nx + x_floor) + c]),
static_cast<float>(src.buf[3 * ((y_floor + 1) * src.nx + (x_floor + 1)) + c]),
x_lerp
);
dst.buf[3 * (y * target_width + x) + c] = static_cast<uint8_t>(lerp(top, bottom, y_lerp));
}
}
}
}
// Bicubic resize function
// part of image will be cropped if the aspect ratio is different
static bool resize_bicubic(const clip_image_u8 & img, clip_image_u8 & dst, int target_width, int target_height) {
const int nx = img.nx;
const int ny = img.ny;
dst.nx = target_width;
dst.ny = target_height;
dst.buf.resize(3 * target_width * target_height);
float Cc;
float C[5] = {};
float d0, d2, d3, a0, a1, a2, a3;
int i, j, k, jj;
int x, y;
float dx, dy;
float tx, ty;
tx = (float)nx / (float)target_width;
ty = (float)ny / (float)target_height;
// Bicubic interpolation; adapted from ViT.cpp, inspired from :
// -> https://github.com/yglukhov/bicubic-interpolation-image-processing/blob/master/libimage.c#L36
// -> https://en.wikipedia.org/wiki/Bicubic_interpolation
for (i = 0; i < target_height; i++) {
for (j = 0; j < target_width; j++) {
x = (int)(tx * j);
y = (int)(ty * i);
dx = tx * j - x;
dy = ty * i - y;
for (k = 0; k < 3; k++) {
for (jj = 0; jj <= 3; jj++) {
d0 = img.buf[(clip(y - 1 + jj, 0, ny - 1) * nx + clip(x - 1, 0, nx - 1)) * 3 + k] - img.buf[(clip(y - 1 + jj, 0, ny - 1) * nx + clip(x, 0, nx - 1)) * 3 + k];
d2 = img.buf[(clip(y - 1 + jj, 0, ny - 1) * nx + clip(x + 1, 0, nx - 1)) * 3 + k] - img.buf[(clip(y - 1 + jj, 0, ny - 1) * nx + clip(x, 0, nx - 1)) * 3 + k];
d3 = img.buf[(clip(y - 1 + jj, 0, ny - 1) * nx + clip(x + 2, 0, nx - 1)) * 3 + k] - img.buf[(clip(y - 1 + jj, 0, ny - 1) * nx + clip(x, 0, nx - 1)) * 3 + k];
a0 = img.buf[(clip(y - 1 + jj, 0, ny - 1) * nx + clip(x, 0, nx - 1)) * 3 + k];
a1 = -1.0 / 3 * d0 + d2 - 1.0 / 6 * d3;
a2 = 1.0 / 2 * d0 + 1.0 / 2 * d2;
a3 = -1.0 / 6 * d0 - 1.0 / 2 * d2 + 1.0 / 6 * d3;
C[jj] = a0 + a1 * dx + a2 * dx * dx + a3 * dx * dx * dx;
d0 = C[0] - C[1];
d2 = C[2] - C[1];
d3 = C[3] - C[1];
a0 = C[1];
a1 = -1.0 / 3 * d0 + d2 - 1.0 / 6 * d3;
a2 = 1.0 / 2 * d0 + 1.0 / 2 * d2;
a3 = -1.0 / 6 * d0 - 1.0 / 2 * d2 + 1.0 / 6 * d3;
Cc = a0 + a1 * dy + a2 * dy * dy + a3 * dy * dy * dy;
const uint8_t Cc2 = std::min(std::max(std::round(Cc), 0.0f), 255.0f);
dst.buf[(i * target_width + j) * 3 + k] = float(Cc2);
}
}
}
}
return true;
}
// Bicubic resize function using Pillow's ImagingResample algorithm
// Adapted from https://github.com/python-pillow/Pillow/blob/main/src/libImaging/Resample.c
//
// Key Difference with resize_bicubic:
// 1. Uses separable filtering: horizontal pass followed by vertical pass
// 2. Pre-computes normalized filter coefficients for each output pixel
// 3. Applies convolution using fixed-point integer arithmetic for performance
static bool resize_bicubic_pillow(const clip_image_u8 & img, clip_image_u8 & dst, int target_width, int target_height) {
// Fixed-point precision: 22 bits = 32 (int32_t) - 8 (uint8_t pixels) - 2 (headroom for accumulation)
// This allows encoding fractional weights as integers: weight * 2^22
const int PRECISION_BITS = 32 - 8 - 2;
// Bicubic filter function with a = -0.5 (Note that GGML/PyTorch takes a = -0.75)
// Returns filter weight for distance x from pixel center
// Support: [-2, 2], meaning the filter influences pixels within 2 units of distance
auto bicubic_filter = [](double x) -> double {
constexpr double a = -0.5;
if (x < 0.0) {
x = -x;
}
if (x < 1.0) {
return ((a + 2.0) * x - (a + 3.0)) * x * x + 1;
}
if (x < 2.0) {
return (((x - 5) * x + 8) * x - 4) * a;
}
return 0.0; // Zero outside [-2, 2]
};
// Filter support radius: bicubic extends 2 pixels in each direction
constexpr double filter_support = 2.0;
// Clipping function for 8-bit values
auto clip8 = [](int val) -> uint8_t {
if (val < 0) return 0;
if (val > 255) return 255;
return static_cast<uint8_t>(val);
};
// Precompute filter coefficients for ONE dimension (horizontal or vertical)
//
// Parameters:
// inSize - Number of pixels in input dimension (e.g., src_width or src_height)
// outSize - Number of pixels in output dimension (e.g., target_width or target_height)
// bounds - [OUTPUT] Array of size outSize*2 storing input pixel ranges:
// bounds[xx*2+0] = first input pixel index for output pixel xx (xmin)
// bounds[xx*2+1] = number of input pixels for output pixel xx (xcnt)
// weights - [OUTPUT] Array of size outSize*ksize storing fixed-point filter weights:
// kk[xx*ksize + x] = weight for input pixel x contributing to output pixel xx
//
// Returns: kernel size (ksize) - number of input pixels that contribute to each output pixel
auto precompute_weights = [&](int inSize, int outSize,
std::vector<int> & bounds, std::vector<int32_t> & weights) -> int {
double support, scale, filterscale;
double center, ww, ss;
int xx, x, ksize, xmin, xmax, xcnt;
// Calculate scaling factor: ratio of input range to output size
filterscale = scale = (double)inSize / outSize;
// For upsampling (scale < 1), keep filterscale = 1 to maintain filter sharpness
// For downsampling (scale > 1), widen filter to prevent aliasing
if (filterscale < 1.0) {
filterscale = 1.0;
}
// Determine filter support radius and kernel size
support = filter_support * filterscale; // Widen filter when downsampling
ksize = static_cast<int>(std::ceil(support)) * 2 + 1; // Total pixels in kernel
std::vector<double> pre_weights(outSize * ksize); // Temporary weights
bounds.resize(outSize * 2);
// For each output pixel, compute its filter coefficients
for (xx = 0; xx < outSize; xx++) {
// Calculate the center position in input space (pixel-center convention: +0.5)
center = (xx + 0.5) * scale;
ww = 0.0; // Sum of weights for normalization
ss = 1.0 / filterscale; // Scale factor for filter function
// Determine the range of input pixels that contribute to this output pixel
xmin = static_cast<int>(center - support + 0.5);
if (xmin < 0) {
xmin = 0;
}
xmax = static_cast<int>(center + support + 0.5);
if (xmax > inSize) {
xmax = inSize;
}
xcnt = xmax - xmin;
// Compute filter weights for each contributing input pixel
for (x = 0; x < xcnt; x++) {
// Distance from input pixel center to output pixel center in input space
double w = bicubic_filter((x + xmin - center + 0.5) * ss);
pre_weights[xx * ksize + x] = w;
ww += w; // Accumulate for normalization
}
// Normalize weights to sum to 1.0 (preserves brightness)
for (x = 0; x < xcnt; x++) {
if (ww != 0.0) {
pre_weights[xx * ksize + x] /= ww;
}
}
// Zero-pad remaining kernel positions
for (; x < ksize; x++) {
pre_weights[xx * ksize + x] = 0;
}
// Store input pixel range for this output pixel
bounds[xx * 2 + 0] = xmin;
bounds[xx * 2 + 1] = xcnt;
}
// Convert floating-point coefficients to fixed-point integers
// Formula: int32 = round(float * 2^PRECISION_BITS)
weights.resize(outSize * ksize);
for (int i = 0; i < outSize * ksize; i++) {
if (pre_weights[i] < 0) {
weights[i] = static_cast<int32_t>(-0.5 + pre_weights[i] * (1 << PRECISION_BITS));
} else {
weights[i] = static_cast<int32_t>(0.5 + pre_weights[i] * (1 << PRECISION_BITS));
}
}
return ksize;
};
// Horizontal resampling pass
// Resizes width from imIn.nx to imOut.nx, preserving height
auto resample_horizontal = [&](const clip_image_u8 & imIn, clip_image_u8 & imOut,
int ksize, const std::vector<int> & bounds, const std::vector<int32_t> & weights) {
imOut.ny = imIn.ny;
imOut.buf.resize(3 * imOut.nx * imOut.ny);
// Process each row independently
for (int yy = 0; yy < imOut.ny; yy++) {
// For each output pixel in this row
for (int xx = 0; xx < imOut.nx; xx++) {
// Get the range of input pixels and filter coefficients
int xmin = bounds[xx * 2 + 0]; // First input pixel index
int xcnt = bounds[xx * 2 + 1]; // Number of input pixels
// Initialize accumulators for RGB channels with rounding bias (0.5 in fixed-point)
int32_t ss0 = 1 << (PRECISION_BITS - 1);
int32_t ss1 = 1 << (PRECISION_BITS - 1);
int32_t ss2 = 1 << (PRECISION_BITS - 1);
// Convolve: sum weighted input pixels
for (int x = 0; x < xcnt; x++) {
int src_idx = ((yy * imIn.nx) + (x + xmin)) * 3;
ss0 += static_cast<uint8_t>(imIn.buf[src_idx + 0]) * weights[xx * ksize + x]; // R channel
ss1 += static_cast<uint8_t>(imIn.buf[src_idx + 1]) * weights[xx * ksize + x]; // G channel
ss2 += static_cast<uint8_t>(imIn.buf[src_idx + 2]) * weights[xx * ksize + x]; // B channel
}
// Convert back from fixed-point (divide by 2^PRECISION_BITS) and clamp to [0,255]
int dst_idx = (yy * imOut.nx + xx) * 3;
imOut.buf[dst_idx + 0] = clip8(ss0 >> PRECISION_BITS);
imOut.buf[dst_idx + 1] = clip8(ss1 >> PRECISION_BITS);
imOut.buf[dst_idx + 2] = clip8(ss2 >> PRECISION_BITS);
}
}
};
// Vertical resampling pass
// Resizes height from imIn.ny to imOut.ny, preserving width
auto resample_vertical = [&](const clip_image_u8 & imIn, clip_image_u8 & imOut,
int ksize, const std::vector<int> & bounds, const std::vector<int32_t> & weight) {
imOut.nx = imIn.nx;
imOut.buf.resize(3 * imOut.nx * imOut.ny);
// For each output row
for (int yy = 0; yy < imOut.ny; yy++) {
// Get the range of input rows and filter coefficients
int ymin = bounds[yy * 2 + 0]; // First input row index
int ycnt = bounds[yy * 2 + 1]; // Number of input rows
// Process each column in this output row
for (int xx = 0; xx < imOut.nx; xx++) {
// Initialize accumulators for RGB channels with rounding bias
int32_t ss0 = 1 << (PRECISION_BITS - 1);
int32_t ss1 = 1 << (PRECISION_BITS - 1);
int32_t ss2 = 1 << (PRECISION_BITS - 1);
// Convolve: sum weighted input pixels vertically
for (int y = 0; y < ycnt; y++) {
int src_idx = ((y + ymin) * imIn.nx + xx) * 3;
ss0 += static_cast<uint8_t>(imIn.buf[src_idx + 0]) * weight[yy * ksize + y]; // R channel
ss1 += static_cast<uint8_t>(imIn.buf[src_idx + 1]) * weight[yy * ksize + y]; // G channel
ss2 += static_cast<uint8_t>(imIn.buf[src_idx + 2]) * weight[yy * ksize + y]; // B channel
}
// Convert back from fixed-point and clamp to [0,255]
int dst_idx = (yy * imOut.nx + xx) * 3;
imOut.buf[dst_idx + 0] = clip8(ss0 >> PRECISION_BITS);
imOut.buf[dst_idx + 1] = clip8(ss1 >> PRECISION_BITS);
imOut.buf[dst_idx + 2] = clip8(ss2 >> PRECISION_BITS);
}
}
};
// Main resampling logic using separable two-pass approach
const int src_width = img.nx;
const int src_height = img.ny;
dst.nx = target_width;
dst.ny = target_height;
bool need_horizontal = (target_width != src_width);
bool need_vertical = (target_height != src_height);
// Precompute filter coefficients for both dimensions
std::vector<int> bounds_horiz, bounds_vert;
std::vector<int32_t> weights_horiz, weights_vert;
int ksize_horiz = 0, ksize_vert = 0;
if (need_horizontal) {
ksize_horiz = precompute_weights(src_width, target_width, bounds_horiz, weights_horiz);
}
if (need_vertical) {
ksize_vert = precompute_weights(src_height, target_height, bounds_vert, weights_vert);
}
// Perform two-pass resampling
if (need_horizontal && need_vertical) {
// Both horizontal and vertical
clip_image_u8 temp;
temp.nx = target_width;
resample_horizontal(img, temp, ksize_horiz, bounds_horiz, weights_horiz);
resample_vertical(temp, dst, ksize_vert, bounds_vert, weights_vert);
} else if (need_horizontal) {
// Only horizontal
resample_horizontal(img, dst, ksize_horiz, bounds_horiz, weights_horiz);
} else if (need_vertical) {
// Only vertical
resample_vertical(img, dst, ksize_vert, bounds_vert, weights_vert);
} else {
// No resizing needed - direct copy
dst.buf = img.buf;
}
return true;
}
static inline int clip(int x, int lower, int upper) {
return std::max(lower, std::min(x, upper));
}
// Linear interpolation between two points
static inline float lerp(float s, float e, float t) {
return s + (e - s) * t;
}
};
//
// mtmd_image_preprocessor_llava_uhd
//
bool mtmd_image_preprocessor_llava_uhd::preprocess(const clip_image_u8 & img, clip_image_f32_batch & output) {
const clip_image_size original_size{img.nx, img.ny};
auto const inst = get_slice_instructions(original_size);
std::vector<clip_image_u8_ptr> imgs = slice_image(img, inst);
for (size_t i = 0; i < imgs.size(); ++i) {
// clip_image_save_to_bmp(*imgs[i], "slice_" + std::to_string(i) + ".bmp");
clip_image_f32_ptr res(clip_image_f32_init());
img_u8_to_f32(*imgs[i], *res, hparams.image_mean, hparams.image_std);
output.entries.push_back(std::move(res));
}
output.grid_x = inst.grid_size.width;
output.grid_y = inst.grid_size.height;
return true;
}
mtmd_image_preprocessor_llava_uhd::slice_instructions mtmd_image_preprocessor_llava_uhd::get_slice_instructions(const clip_image_size & original_size) {
mtmd_image_preprocessor_llava_uhd::slice_instructions res;
const int patch_size = hparams.patch_size;
const int slice_size = hparams.image_size;
const int original_width = original_size.width;
const int original_height = original_size.height;
const bool has_slices = original_size.width > slice_size || original_size.height > slice_size;
const bool has_pinpoints = !hparams.image_res_candidates.empty();
if (!has_slices) {
// skip slicing logic
res.overview_size = clip_image_size{slice_size, slice_size};
res.refined_size = clip_image_size{0, 0};
res.grid_size = clip_image_size{0, 0};
return res;
}
if (has_pinpoints) {
// has pinpoints, use them to calculate the grid size (e.g. llava-1.6)
auto refine_size = select_best_resolution(
original_size,
hparams.image_res_candidates);
res.overview_size = clip_image_size{slice_size, slice_size};
res.refined_size = refine_size;
res.grid_size = clip_image_size{0, 0};
LOG_DBG("%s: using pinpoints for slicing\n", __func__);
LOG_DBG("%s: original size: %d x %d, overview size: %d x %d, refined size: %d x %d\n",
__func__, original_width, original_height,
res.overview_size.width, res.overview_size.height,
res.refined_size.width, res.refined_size.height);
for (int y = 0; y < refine_size.height; y += slice_size) {
for (int x = 0; x < refine_size.width; x += slice_size) {
slice_coordinates slice;
slice.x = x;
slice.y = y;
slice.size.width = std::min(slice_size, refine_size.width - x);
slice.size.height = std::min(slice_size, refine_size.height - y);
res.slices.push_back(slice);
LOG_DBG("%s: slice %d: x=%d, y=%d, size=%dx%d\n",
__func__, (int)res.slices.size() - 1,
slice.x, slice.y, slice.size.width, slice.size.height);
}
}
res.grid_size.height = refine_size.height / slice_size;
res.grid_size.width = refine_size.width / slice_size;
LOG_DBG("%s: grid size: %d x %d\n", __func__, res.grid_size.width, res.grid_size.height);
return res;
}
// no pinpoints, dynamically calculate the grid size (e.g. minicpmv)
auto best_size = get_best_resize(original_size, slice_size, patch_size, !has_slices);
res.overview_size = best_size;
{
const int max_slice_nums = 9; // TODO: this is only used by minicpmv, maybe remove it
const float log_ratio = log((float)original_width / original_height);
const float ratio = (float)original_width * original_height / (slice_size * slice_size);
const int multiple = fmin(ceil(ratio), max_slice_nums);
auto best_grid = get_best_grid(max_slice_nums, multiple, log_ratio);
auto refine_size = get_refine_size(original_size, best_grid, slice_size, patch_size, true);
res.grid_size = best_grid;
res.refined_size = refine_size;
LOG_DBG("%s: original size: %d x %d, overview size: %d x %d, refined size: %d x %d, grid size: %d x %d\n",
__func__, original_width, original_height,
res.overview_size.width, res.overview_size.height,
res.refined_size.width, res.refined_size.height,
res.grid_size.width, res.grid_size.height);
int width = refine_size.width;
int height = refine_size.height;
int grid_x = int(width / best_grid.width);
int grid_y = int(height / best_grid.height);
for (int patches_y = 0, ic = 0;
patches_y < refine_size.height && ic < best_grid.height;
patches_y += grid_y, ic += 1) {
for (int patches_x = 0, jc = 0;
patches_x < refine_size.width && jc < best_grid.width;
patches_x += grid_x, jc += 1) {
slice_coordinates slice;
slice.x = patches_x;
slice.y = patches_y;
slice.size.width = grid_x;
slice.size.height = grid_y;
res.slices.push_back(slice);
LOG_DBG("%s: slice %d: x=%d, y=%d, size=%dx%d\n",
__func__, (int)res.slices.size() - 1,
slice.x, slice.y, slice.size.width, slice.size.height);
}
}
}
return res;
}
std::vector<clip_image_u8_ptr> mtmd_image_preprocessor_llava_uhd::slice_image(const clip_image_u8 & img, const mtmd_image_preprocessor_llava_uhd::slice_instructions & inst, bool overview_first) {
std::vector<clip_image_u8_ptr> output;
// resize to overview size
clip_image_u8_ptr resized_img(clip_image_u8_init());
img_tool::resize(img, *resized_img, inst.overview_size, hparams.image_resize_algo_ov,
hparams.image_pad_ov, hparams.image_pad_color_ov);
if (overview_first) {
output.push_back(std::move(resized_img));
}
if (inst.slices.empty()) {
// no slices, just return the resized image
if (!overview_first) {
output.push_back(std::move(resized_img));
}
return output;
}
// resize to refined size
clip_image_u8_ptr refined_img(clip_image_u8_init());
img_tool::resize(img, *refined_img, inst.refined_size, hparams.image_resize_algo_rf,
hparams.image_pad_rf, hparams.image_pad_color_rf);
// create slices
for (const auto & slice : inst.slices) {
int x = slice.x;
int y = slice.y;
int w = slice.size.width;
int h = slice.size.height;
clip_image_u8_ptr img_slice(clip_image_u8_init());
img_tool::crop(*refined_img, *img_slice, x, y, w, h);
output.push_back(std::move(img_slice));
}
if (!overview_first) {
output.push_back(std::move(resized_img));
}
return output;
}
clip_image_size mtmd_image_preprocessor_llava_uhd::get_best_resize(const clip_image_size & original_size, int scale_resolution, int patch_size, bool allow_upscale) {
int width = original_size.width;
int height = original_size.height;
if ((width * height > scale_resolution * scale_resolution) || allow_upscale) {
float r = static_cast<float>(width) / height;
height = static_cast<int>(scale_resolution / std::sqrt(r));
width = static_cast<int>(height * r);
}
clip_image_size res;
res.width = ensure_divide(width, patch_size);
res.height = ensure_divide(height, patch_size);
return res;
}
clip_image_size mtmd_image_preprocessor_llava_uhd::resize_maintain_aspect_ratio(const clip_image_size & orig, const clip_image_size & target_max) {
float scale_width = static_cast<float>(target_max.width) / orig.width;
float scale_height = static_cast<float>(target_max.height) / orig.height;
float scale = std::min(scale_width, scale_height);
return clip_image_size{
static_cast<int>(orig.width * scale),
static_cast<int>(orig.height * scale),
};
}
clip_image_size mtmd_image_preprocessor_llava_uhd::select_best_resolution(const clip_image_size & original_size, const std::vector<clip_image_size> & possible_resolutions) {
clip_image_size best_fit;
int min_wasted_area = std::numeric_limits<int>::max();
int max_effective_resolution = 0;
for (const clip_image_size & candidate : possible_resolutions) {
auto target_size = resize_maintain_aspect_ratio(original_size, candidate);
int effective_resolution = std::min(
target_size.width * target_size.height,
original_size.width * original_size.height);
int wasted_area = (candidate.width * candidate.height) - effective_resolution;
if (effective_resolution > max_effective_resolution || (effective_resolution == max_effective_resolution && wasted_area < min_wasted_area)) {
max_effective_resolution = effective_resolution;
min_wasted_area = wasted_area;
best_fit = candidate;
}
LOG_DBG("%s: candidate: %d x %d, target: %d x %d, wasted: %d, effective: %d\n", __func__, candidate.width, candidate.height, target_size.width, target_size.height, wasted_area, effective_resolution);
}
return best_fit;
}
int mtmd_image_preprocessor_llava_uhd::ensure_divide(int length, int patch_size) {
return std::max(static_cast<int>(std::round(static_cast<float>(length) / patch_size) * patch_size), patch_size);
}
clip_image_size mtmd_image_preprocessor_llava_uhd::get_refine_size(const clip_image_size & original_size, const clip_image_size & grid, int scale_resolution, int patch_size, bool allow_upscale) {
int width = original_size.width;
int height = original_size.height;
int grid_x = grid.width;
int grid_y = grid.height;
int refine_width = ensure_divide(width, grid_x);
int refine_height = ensure_divide(height, grid_y);
clip_image_size grid_size;
grid_size.width = refine_width / grid_x;
grid_size.height = refine_height / grid_y;
auto best_grid_size = get_best_resize(grid_size, scale_resolution, patch_size, allow_upscale);
int best_grid_width = best_grid_size.width;
int best_grid_height = best_grid_size.height;
clip_image_size refine_size;
refine_size.width = best_grid_width * grid_x;
refine_size.height = best_grid_height * grid_y;
return refine_size;
}
clip_image_size mtmd_image_preprocessor_llava_uhd::get_best_grid(const int max_slice_nums, const int multiple, const float log_ratio) {
std::vector<int> candidate_split_grids_nums;
for (int i : {multiple - 1, multiple, multiple + 1}) {
if (i == 1 || i > max_slice_nums) {
continue;
}
candidate_split_grids_nums.push_back(i);
}
std::vector<clip_image_size> candidate_grids;
for (int split_grids_nums : candidate_split_grids_nums) {
int m = 1;
while (m <= split_grids_nums) {
if (split_grids_nums % m == 0) {
candidate_grids.push_back(clip_image_size{m, split_grids_nums / m});
}
++m;
}
}
clip_image_size best_grid{1, 1};
float min_error = std::numeric_limits<float>::infinity();
for (const auto& grid : candidate_grids) {
float error = std::abs(log_ratio - std::log(1.0 * grid.width / grid.height));
if (error < min_error) {
best_grid = grid;
min_error = error;
}
}
return best_grid;
}
//
// mtmd_image_preprocessor_fixed_size
//
bool mtmd_image_preprocessor_fixed_size::preprocess(const clip_image_u8 & img, clip_image_f32_batch & output) {
clip_image_u8 resized_image;
int sz = hparams.image_size;
img_tool::resize(img, resized_image, {sz, sz},
hparams.image_resize_algo,
hparams.image_resize_pad,
hparams.image_pad_color);
clip_image_f32_ptr img_f32(clip_image_f32_init());
img_u8_to_f32(resized_image, *img_f32, hparams.image_mean, hparams.image_std);
output.entries.push_back(std::move(img_f32));
return true;
}
//
// mtmd_image_preprocessor_dyn_size
//
bool mtmd_image_preprocessor_dyn_size::preprocess(const clip_image_u8 & img, clip_image_f32_batch & output) {
GGML_ASSERT(hparams.image_min_pixels > 0 && hparams.image_max_pixels > 0);
clip_image_u8 resized_image;
const clip_image_size original_size{img.nx, img.ny};
// the original pixtral model doesn't have n_merge
const int cur_merge = hparams.n_merge == 0 ? 1 : hparams.n_merge;
const clip_image_size target_size = img_tool::calc_size_preserved_ratio(
original_size,
hparams.patch_size * cur_merge,
hparams.image_min_pixels,
hparams.image_max_pixels);
img_tool::resize(img, resized_image, target_size,
hparams.image_resize_algo,
hparams.image_resize_pad,
hparams.image_pad_color);
clip_image_f32_ptr img_f32(clip_image_f32_init());
img_u8_to_f32(resized_image, *img_f32, hparams.image_mean, hparams.image_std);
output.entries.push_back(std::move(img_f32));
return true;
}
//
// mtmd_image_preprocessor_longest_edge
//
bool mtmd_image_preprocessor_longest_edge::preprocess(const clip_image_u8 & img, clip_image_f32_batch & output) {
GGML_ASSERT(hparams.image_longest_edge > 0);
clip_image_u8 resized_image;
const clip_image_size original_size{img.nx, img.ny};
// the original pixtral model doesn't have n_merge
const int cur_merge = hparams.n_merge == 0 ? 1 : hparams.n_merge;
const clip_image_size target_size = img_tool::calc_size_preserved_ratio(
original_size,
hparams.patch_size * cur_merge,
hparams.image_longest_edge);
img_tool::resize(img, resized_image, target_size,
hparams.image_resize_algo,
hparams.image_resize_pad,
hparams.image_pad_color);
clip_image_f32_ptr img_f32(clip_image_f32_init());
img_u8_to_f32(resized_image, *img_f32, hparams.image_mean, hparams.image_std);
output.entries.push_back(std::move(img_f32));
return true;
}
//
// mtmd_image_preprocessor_lfm2
//
mtmd_image_preprocessor_llava_uhd::slice_instructions mtmd_image_preprocessor_lfm2::get_slice_instructions(const clip_image_size & original_size) {
mtmd_image_preprocessor_llava_uhd::slice_instructions inst;
const int align_size = hparams.patch_size * hparams.n_merge;
inst.overview_size = img_tool::calc_size_preserved_ratio(
original_size, align_size,
hparams.image_min_pixels, hparams.image_max_pixels);
// tile if either dimension exceeds tile_size with tolerance
const bool needs_tiling = original_size.width > tile_size * max_pixels_tolerance || original_size.height > tile_size * max_pixels_tolerance;
if (!needs_tiling) {
inst.refined_size = clip_image_size{0, 0};
inst.grid_size = clip_image_size{0, 0};
return inst;
}
const clip_image_size grid = get_grid_layout(original_size.height, original_size.width);
inst.grid_size = grid;
inst.refined_size = clip_image_size{tile_size * grid.width, tile_size * grid.height};
LOG_DBG("%s: original size: %d x %d, overview size: %d x %d, refined size: %d x %d, grid size: %d x %d\n",
__func__,
original_size.width, original_size.height,
inst.overview_size.width, inst.overview_size.height,
inst.refined_size.width, inst.refined_size.height,
grid.width, grid.height);
for (int row = 0; row < grid.height; row++) {
for (int col = 0; col < grid.width; col++) {
mtmd_image_preprocessor_llava_uhd::slice_coordinates slice;
slice.x = col * tile_size;
slice.y = row * tile_size;
slice.size = clip_image_size{tile_size, tile_size};
inst.slices.push_back(slice);
LOG_DBG("%s: slice %d: x=%d, y=%d, size=%d x %d\n",
__func__, (int)inst.slices.size() - 1,
slice.x, slice.y, slice.size.width, slice.size.height);
}
}
return inst;
}
clip_image_size mtmd_image_preprocessor_lfm2::find_closest_aspect_ratio(
float aspect_ratio,
const std::vector<clip_image_size> & target_ratios,
int width, int height) {
float best_ratio_diff = std::numeric_limits<float>::max();
clip_image_size best_ratio = {1, 1};
const float area = static_cast<float>(width * height);
for (const auto & ratio : target_ratios) {
const float target_aspect_ratio = static_cast<float>(ratio.width) / ratio.height;
const float ratio_diff = std::abs(aspect_ratio - target_aspect_ratio);
if (ratio_diff < best_ratio_diff) {
best_ratio_diff = ratio_diff;
best_ratio = ratio;
} else if (ratio_diff == best_ratio_diff) {
const float target_area = static_cast<float>(tile_size * tile_size * ratio.width * ratio.height);
if (area > 0.5f * target_area) {
best_ratio = ratio;
}
}
}
return best_ratio;
}
std::vector<clip_image_size> mtmd_image_preprocessor_lfm2::get_target_ratios() {
std::vector<clip_image_size> ratios;
for (int n = min_tiles; n <= max_tiles; n++) {
for (int w = 1; w <= n; w++) {
for (int h = 1; h <= n; h++) {
if (w * h >= min_tiles && w * h <= max_tiles) {
bool found = false;
for (const auto & r : ratios) {
if (r.width == w && r.height == h) {
found = true;
break;
}
}
if (!found) {
ratios.push_back({w, h});
}
}
}
}
}
std::sort(ratios.begin(), ratios.end(), [](const clip_image_size & a, const clip_image_size & b) {
return a.width * a.height < b.width * b.height;
});
return ratios;
}
clip_image_size mtmd_image_preprocessor_lfm2::get_grid_layout(int height, int width) {
const float aspect_ratio = static_cast<float>(width) / height;
const auto ratios = get_target_ratios();
return find_closest_aspect_ratio(aspect_ratio, ratios, width, height);
}
//
// mtmd_image_preprocessor_idefics3
//
bool mtmd_image_preprocessor_idefics3::preprocess(const clip_image_u8 & img, clip_image_f32_batch & output) {
// The refined size has two steps:
// 1. Resize w/ aspect-ratio preserving such that the longer side is
// the preprocessor longest size
// 2. Resize w/out preserving aspect ratio such that both sides are
// multiples of image_size (always rounding up)
//
// CITE: https://github.com/huggingface/transformers/blob/main/src/transformers/models/idefics3/image_processing_idefics3.py#L737
const clip_image_size original_size{img.nx, img.ny};
const clip_image_size refined_size = img_tool::calc_size_preserved_ratio(
original_size, hparams.image_size, hparams.image_longest_edge);
// LOG_INF("%s: original size: %d x %d, refined size: %d x %d\n",
// __func__, original_size.width, original_size.height,
// refined_size.width, refined_size.height);
mtmd_image_preprocessor_llava_uhd::slice_instructions instructions;
instructions.overview_size = clip_image_size{hparams.image_size, hparams.image_size};
instructions.refined_size = refined_size;
instructions.grid_size = clip_image_size{
static_cast<int>(std::ceil(static_cast<float>(refined_size.width) / hparams.image_size)),
static_cast<int>(std::ceil(static_cast<float>(refined_size.height) / hparams.image_size)),
};
for (int y = 0; y < refined_size.height; y += hparams.image_size) {
for (int x = 0; x < refined_size.width; x += hparams.image_size) {
// LOG_INF("%s: adding slice at x=%d, y=%d\n", __func__, x, y);
instructions.slices.push_back(mtmd_image_preprocessor_llava_uhd::slice_coordinates{
/* x */x,
/* y */y,
/* size */clip_image_size{
std::min(hparams.image_size, refined_size.width - x),
std::min(hparams.image_size, refined_size.height - y)
}
});
}
}
auto imgs = slice_image(img, instructions);
// cast and normalize to f32
for (size_t i = 0; i < imgs.size(); ++i) {
// clip_image_save_to_bmp(*imgs[i], "slice_" + std::to_string(i) + ".bmp");
clip_image_f32_ptr res(clip_image_f32_init());
img_u8_to_f32(*imgs[i], *res, hparams.image_mean, hparams.image_std);
output.entries.push_back(std::move(res));
}
output.grid_x = instructions.grid_size.width;
output.grid_y = instructions.grid_size.height;
return true;
}
//
// mtmd_image_preprocessor_internvl
//
bool mtmd_image_preprocessor_internvl::preprocess(const clip_image_u8 & img, clip_image_f32_batch & output) {
GGML_ASSERT(!hparams.image_res_candidates.empty());
const clip_image_size original_size{img.nx, img.ny};
auto const inst = get_slice_instructions(original_size);
std::vector<clip_image_u8_ptr> imgs = slice_image(img, inst, false);
for (size_t i = 0; i < imgs.size(); ++i) {
clip_image_f32_ptr res(clip_image_f32_init());
img_u8_to_f32(*imgs[i], *res, hparams.image_mean, hparams.image_std);
output.entries.push_back(std::move(res));
}
return true;
}
//
// mtmd_image_preprocessor_deepseekocr
//
bool mtmd_image_preprocessor_deepseekocr::preprocess(const clip_image_u8 & img, clip_image_f32_batch & output) {
const std::vector native_resolutions = {
/*512 tiny , 640 small, */ 1024 /* base */, 1280 /* large */
};
// original image size
const clip_image_size original_size{img.nx, img.ny};
const int orig_w = original_size.width;
const int orig_h = original_size.height;
const int orig_area = orig_h * orig_w;
size_t mode_i = 0;
int min_diff = orig_area;
for (size_t i = 0; i < native_resolutions.size(); i++) {
int r = native_resolutions[i];
if (std::abs(orig_area - r * r) < min_diff) {
mode_i = i;
min_diff = std::abs(orig_area - r * r);
}
}
/* Native Resolution (Base/Large) */
const int image_size = native_resolutions[mode_i];
// scaled and padded image
clip_image_u8_ptr scaled_img(clip_image_u8_init());
img_tool::resize(img, *scaled_img, clip_image_size{image_size, image_size}, hparams.image_resize_algo);
clip_image_f32_ptr res(clip_image_f32_init());
img_u8_to_f32(*scaled_img, *res, hparams.image_mean, hparams.image_std);
output.entries.push_back(std::move(res));
output.grid_x = 1;
output.grid_y = 1;
return true;
}
//
// mtmd_image_preprocessor_youtuvl
//
bool mtmd_image_preprocessor_youtuvl::preprocess(const clip_image_u8 & img, clip_image_f32_batch & output) {
const int patch_size = hparams.patch_size; // typically 16
const int merge_size = hparams.n_merge; // typically 2
const int align_size = patch_size * merge_size; // 32
const int max_num_patches = hparams.image_max_pixels > 0 ?
hparams.image_max_pixels / (patch_size * patch_size) : 256;
// Linear search for optimal scale to fit within max_num_patches
float scale = 1.0f;
int target_height = img.ny;
int target_width = img.nx;
auto get_scaled_image_size = [align_size](float scale, int size) -> int {
float scaled_size = size * scale;
// Round up to nearest multiple of align_size
int aligned = static_cast<int>(std::ceil(scaled_size / align_size)) * align_size;
// Ensure at least one patch
return std::max(align_size, aligned);
};
// Linear search with 0.02 step size
while (scale > 0.0f) {
target_height = get_scaled_image_size(scale, img.ny);
target_width = get_scaled_image_size(scale, img.nx);
int num_patches_h = target_height / patch_size;
int num_patches_w = target_width / patch_size;
int num_patches = num_patches_h * num_patches_w;
if (num_patches > max_num_patches) {
scale -= 0.02f;
} else {
break;
}
}
clip_image_size new_size = {target_width, target_height};
// Resize the image
clip_image_u8 resized;
img_tool::resize(img, resized, new_size, hparams.image_resize_algo, hparams.image_resize_pad);
// Normalize to float32
clip_image_f32_ptr img_f32(clip_image_f32_init());
img_u8_to_f32(resized, *img_f32, hparams.image_mean, hparams.image_std);
// Add to results
output.entries.push_back(std::move(img_f32));
return true;
}